Tag Archives: water

Compound droughts risk destabilizing the global food supply if we keep burning fossil fuels

Climate change could severely impact our food and water security in the future by increasing the probability of droughts co-occurring in food-producing areas around the world, a new study says.

Image via Pixabay.

Research led by scientists at the Washington State University (WSU) warns that the future may hold less bountiful tables, and fewer meals, for us all. According to the findings, the probability of droughts co-occurring will increase by 40% by the mid 21st century, and by 60% by the end of the century, relative to the late 20th century (before the year 2000). All in all, this amounts to an almost-ninefold increase in the exposure of agricultural lands and human populations to severe, co-occurring droughts relative to today.

While modern technology and distribution systems insulate us from the effects of drought to a much larger extent than any time previously in history, co-occurring (or ‘compound’) droughts, if they affect key food-producing areas, can severely impact the global food and water availability. If such an event were to come to pass, millions of people would encounter some difficulty in accessing food in the same quantities and varieties as before.

Table troubles

“There could be around 120 million people across the globe simultaneously exposed to severe compound droughts each year by the end of the century,” said lead author Jitendra Singh, a former postdoctoral researcher at the WSU School of the Environment now at ETH Zurich, Switzerland. “Many of the regions our analysis shows will be most affected are already vulnerable and so the potential for droughts to become disasters is high.”

This increased risk of compound droughts is mainly the result of climate change, which itself is the product of greenhouse gas emissions associated with decades of reliance on fossil fuels. The other element factoring in is a projected 22% increase in the frequency of El Niño and La Niña events — the two opposite phases of the El Niño Southern Oscillation (ENSO) — caused by warmer average temperatures.

Roughly 75% of compound droughts in the future will occur during these irregular but recurring periods of variation in the world’s oceans, the team explains. The shifting phases of the ENSO have historically played a part in some of the greatest periods of environmental upheaval globally, as they influence precipitation patterns across a huge stretch of the planet. Compound droughts occurring across Asia, Brazil, and Africa during 1876-1878 were generated by these shifts. They led to massive crop failures and famines which killed in excess of 50 million people.

“While technology and other circumstances today are a lot different than they were in the late 19th century, crop failures in multiple breadbasket regions still have the potential to affect global food availability,” said study coauthor Deepti Singh, an assistant professor in the WSU School of the Environment. “This could in turn increase volatility in global food prices, affecting food access and exacerbating food insecurity, particularly in regions that are already vulnerable to environmental shocks such as droughts.”

The team focused their analysis on the ten areas of the world that receive most of their rainfall between June and September, have monthly summer precipitation showing great variability, and fall under the influence of ENSO variations — factors that leave them exposed to co-occurring droughts. Several of these are important agricultural areas on a global level, they add, and they also include countries that are already experiencing food and water insecurity.

Of the investigated areas, North and South America were among the most likely to experience compound droughts in the future. Certain regions of Asia are also at risk, however, large stretches of agricultural land here are projected to become wetter instead of drier, heavily mitigating the risk of crop failure and subsequent famine.

Still, that leaves us in quite a dire situation. The United States today is a major exporter of grains, including maize, for multiple countries around the world. In the event of a severe drought, reduced production here would impact food security around the world, with increases in the price of grains and a significant decrease in food security — grains are staple foods and lack of such foods heavily impacts the most vulnerable groups throughout communities.

“The potential for a food security crisis increases even if these droughts aren’t affecting major food producing regions but rather many regions that are already vulnerable to food insecurity,” said coauthor Weston Anderson, an assistant research scientist at the Earth System Science Interdisciplinary Center at the University of Maryland.

“Simultaneous droughts in food insecure regions could in turn amplify stresses on international agencies responsible for disaster relief by requiring the provision of humanitarian aid to a greater number of people simultaneously.”

Still, for what it’s worth, these estimates are assuming that the world maintains a high rate of fossil fuel usage. If carbon emissions continue to fall, the risk and intensity of co-occurring droughts would be greatly mitigated, the team explains. Knowing that nearly 75% of compound droughts occur alongside ENSO events also gives us the chance to predict where such droughts may occur and prepare for them in advance.

“This means that co-occurring droughts during ENSO events will likely affect the same geographical regions they do today albeit with greater severity,” said Deepti Singh. “Being able to predict where these droughts will occur and their potential impacts can help society develop plans and efforts to minimize economic losses and reduce human suffering from such climate-driven disasters.”

The paper “Enhanced risk of concurrent regional droughts with increased ENSO variability and warming” has been published in the journal Nature Climate Change.

We could blast microplastics out of water using loudspeakers, although the tech is still young

Sound can help us deal with the growing issue of microplastics plaguing the world’s oceans, according to new research.

Image via Pixabay.

Microplastics are building up in all layers of the environment, from soils to waterways, even in the atmosphere. Such particles are produced directly by cosmetics, clothing, or industrial processes, or indirectly through the breakdown of larger pieces of plastic.

They’re becoming a genuine environmental concern risking the health of both humans and wildlife. Considerable effort has been put into developing efficient ways of disposing of microplastics, with varying success. Now, new research from the Institut Teknologi Sepuluh Nopember in Surabaya, Indonesia offers an unusual solution to the problem — filtering them out of the water using sound.

Speakers to the rescue

The approach involves using speakers to generate “bulk acoustic waves” (sound waves that propagate throughout the volume of a substance) in order to force microplastic particles in water to separate from the liquid. This allows for the quick and easy removal of the particles through mechanical means, offering a clean and quick method to scrub waters of microplastics.

During lab testing of their technique, the researchers used two speakers to generate acoustic waves through a sample of water laden with microplastic particles that was circulated through a tube. The force of these waves (sounds propagate through physical motions of a material’s particles) created pressure inside the tube, forcing the plastic microparticles to move towards the center of the tube. This tube eventually split into three channels, with the middle one removing the plastic while the other two carried the cleaner water away.

During the testing, the team’s device scrubbed around 150 liters of polluted water an hour. They tested three types of microplastic particles in pure water and seawater. The effectiveness of the rig depended mostly on the type of water that was flowing through it but also varied with the type of plastic it contained. However, the lowest efficiency ratings of the device were slightly above 56% in pure water and 58% in seawater across all types of microplastics used in the trial.

The team explains that this was only a proof-of-concept run. They’re confident that with further tweaking to the frequency of acoustic waves they generate, of the distance between the speakers and the tube, and the water flow through the tube, higher efficiencies can be attained. How much plastic can be removed throughout a cycle of the device directly depends on how much pressure can be generated in the water using the sound waves, and all those elements would affect this parameter.

One potential issue with the technology that may severely limit its applicability in the wild is that many marine species are highly sensitive to sounds in the audible range of frequency — the same range over which the team blasts their speakers. The authors are hard at work finding potential solutions to this problem. In case this can’t be addressed, the technology still holds promise in scrubbing water before it is dumped in waterways. While this won’t help clean the plastic already floating around the oceans, it can at least limit the influx of new microplastics.

“We believe further development is necessary to improve the cleaning rate, the efficiency, and particularly the safety of marine life,” said Dhany Arifianto, Chair of Vibration and Acoustics at Institut Teknologi Sepuluh Nopember Surabaya, lead researcher on the project.

The findings will be presented at the 181st Meeting of the Acoustical Society of America in Seattle, Washington on Dec. 1st.

This hydrogel tablet can purify a liter of water in just one hour

Researchers from the University of Texas at Austin have come up with a new way to rapidly purify contaminated water. They’ve devised a simple hydrogel tablet that can disinfect a liter of river water and make it drinkable in just one hour. The new approach could be significant for the millions of people across the world that lack access to clean drinking water. 

Municipal water disinfection using chemicals, such as chlorine (Cl2), chloramines (NH2Cl, NHCl2), chlorine dioxide (ClO2), ozone (O3), is currently used worldwide due to its efficacy and low cost. However, this process can lead to the formation of potentially toxic byproducts, which can be detrimental to human health if proper filtering isn’t in place — this may not be the case in some low-income regions or countries. Alternatively, thermal-based water treatments can also remove most contaminants by repeated boiling, but this requires a lot of energy and centralized infrastructures for wide-scale distribution of clean water.

Looking for other alternatives, a group of scientists have developed anti-bacterial hydrogels. These generate hydrogen peroxide that neutralizes bacteria with an almost 100% efficiency rate by reacting with activated carbon particles that disrupt the metabolism of bacteria. It doesn’t need any energy and doesn’t create toxic byproducts. 

“Our multifunctional hydrogel can make a big difference in mitigating global water scarcity because it is easy to use, highly efficient and potentially scalable up to mass production,” Guihua Yu, an associate professor at the University of Texas at Austin and co-author of the new study, said in a statement.

The hydrogel tablet. Credit: The University of Texas at Austin.

The hydrogels are cheap, the researchers argue, and they can be adapted for a wide range of applications. The synthesis process is very simple and and the tablets can be manufactured using existing technology. That’s why scaling up their use wouldn’t be difficult and the range of microorganisms that they could neutralize is tweakable.

Credit: The University of Texas at Austin.

The researchers are optimistic that the hydrogels can also improve the process of solar distillation — using sunlight to separate water from contaminants via vaporization. The hydrogels could prevent the distillation systems from running into malfunction problems because of the accumulation of bacteria on equipment. 

The challenging access to clean water

Clean water has long been an international goal. Millions of deaths are reported annually in developing nation as a result of diseases caused by the consumption of unsafe water that contains pathogenic microorganisms. The global population growth and the ongoing pandemic have heightened the challenge of safe water access.

Whether it’s for domestic use, food production, drinking or recreation, clean water is very important for public health. Better access and management of water resources can boost countries’ economic growth and reduce poverty. The UN General Assembly explicitly recognized the universal human right to water and sanitation back in 2010.

Contaminated water is linked to the transmission of diseases such as polio, cholera, diarrhea, hepatitis A and dysentery. Over two billion people use a drinking water source that has been contaminated with feces, while about 785 million people don’t have a basic drinking-water service, including 144 million that rely on surface water.

Water supply systems could face further problems in the medium-term because of climate change, population growth, demographic changes, and urbanization. According to the World Health Organization (WHO), half of the world’s population will be living in areas with a high level of water-stress. This will make the reutilization of wastewater an important strategy. 

The study was published in the journal Advanced Materials.

Scientists turn water into shiny metal

With enough pressure, you can turn anything into metal, and water is no exception. However, scientists Czech Academy of Sciences in Prague managed to turn liquid water into a bronze-like metallic state without having to apply ungodly amounts of pressure, which makes the achievement all the more impressive.

Electrons from alkali metals diffused into a thin water layer, giving it metallic properties and a characteristic golden hue. Credit: Philip Mason.

If squeezed together tightly enough, atoms and molecules can become so compacted in their lattice that they begin to share their outer electrons, allowing them to travel and basically conduct electricity as they would in a copper wire. Case in point, in 2020, French scientists turned the simplest gas in the universe, hydrogen, into a metal and fulfilled a prediction made in 1935 by Nobel Prize laureates Eugene Wigner and Hillard Bell Huntington. Metal hydrogen is, in fact, a superconductor, meaning it conducts electricity with zero electrical resistance.

To do so, the French researchers subjected hydrogen to a staggering 425 gigapascals of pressure — more than four million times the pressure on Earth’s surface, and even higher than that in the planet’s inner core. Therefore, it’s impossible to find metallic hydrogen on Earth, although it may very well be found in Jupiter and Saturn, which are mostly composed of hydrogen gas and have stronger internal pressures than the Earth. Likewise, Neptune and Uranus are believed to host water in a metallic state thanks to their huge pressure.

With the same approach, water would require 15 million bars of pressure to turn it into a metal, more than three times the requirement for metallic hydrogen. That’s simply out of our current technology’s reach. However, there may be another way to turn water metallic without having to squeeze it with the pressure of a gas giant’s core, thought Pavel Jungwirth, a physical chemist at the Czech Academy of Sciences in Prague.

Jungwirth and fellow chemist Phil Mason wondered if water could be coxed to behave like a metal if it borrowed electrons from alkali metals, which are highly reactive elements in the 1st group of the periodic table. They got this idea after previously, Jungwirth and colleagues found that under similar conditions, ammonia can turn shiny.

But despite their willingness to go along with this experiment, the researchers faced a predicament. You see, alkali metals are so reactive in the presence of water that they tend to react explosively.

The solution was to design an experimental setup that dramatically slowed down the reaction so that a potentially catastrophic explosion was averted.

Ironically, the key to mitigating the explosive behavior of the water-alki metal reaction was the adsorbtion of water at very low pressure, about 7,000 smaller than that found at sea level. This setup ensured that the diffusion of the electrons from the alkali metal was faster than the reaction between the water and the metals.

Credit: Philip Mason.

The researchers filled a syringe with an alkali metal solution composed of sodium and potassium, which was placed in a vacuum chamber. The syringe was triggered remotely to expel droplets of the mixture which were exposed to tiny amounts of water vapor.

The water condensed into each droplet of alkali metal, forming a layer over them just one-tenth of a micrometer thick. Electrons from the mixture diffused into the water, along with positive metallic ions, giving the water layer a shiny, bronze-like glow. The entire thing only lasted for a mere couple of seconds, but for all intents of purposes, the scientists had just turned water into metal at room temperature, a fact confirmed by synchrotron experiments.

“We show that a metallic water solution can be prepared by massive doping with electrons upon reacting water with alkali metals. Although analogous metallic solutions of liquid ammonia with high concentrations of solvated electrons have long been known and characterized, the explosive interaction between alkali metals and water has so far only permitted the preparation of aqueous solutions with low, submetallic electron concentrations,” the authors wrote in the journal Nature.

Researchers develop cheap, simple, on-demand water disinfection process

Clean, disinfected water is essential for a good life, but millions of people around the world lack access to it. Researchers at the Cardiff University plan to change this state of affairs with an on-site disinfection approach that is massively more efficient than our current disinfection approaches. The method relies only on atmospheric hydrogen, oxygen, and a gold-palladium catalyst.

The new method aims to provide clean, safe water for consumption and hygiene in areas without access to such resources or reliable disinfection methods. All in all, it could help improve life for billions of people who are struggling with lack of water or water insecurity.

On-demand cleaning

“The significantly enhanced [anti-viral and anti-bacterial] activities achieved when reacting hydrogen and oxygen using our catalyst, rather than using commercial hydrogen peroxide or chlorination, shows the potential for revolutionizing water disinfection technologies around the world,” says Professor Graham Hutchings, Regius Professor of Chemistry at the Cardiff Catalysis Institute, co-author of the paper.

The gold-palladium catalyst allows for hydrogen and oxygen atoms in the air to merge into hydrogen peroxide. This is a common chemical produced in huge quantities around the world which also sees heavy use as a disinfectant. Over four million tons of the compound are produced globally each year.

Typically, hydrogen peroxide is produced at one site and used (for various purposes, including water disinfection) at another. This means it requires storage and transport before use, so hydrogen peroxide is often mixed with other chemicals that stabilize it and keep it fresh until it’s used. While these do perform their intended role, they also cut down its efficiency as a disinfectant (since it’s now, essentially, diluted).

One alternative to this approach is to use chlorine as a disinfectant — add enough of it to water and it’ll kill most pathogens swimming their way around in there, just like hydrogen peroxide does. However, chlorine can react with naturally occurring chemicals in the water creating compounds that can be toxic to humans.

The novel approach however works around these issues by producing the disinfecting agent — hydrogen peroxide — at the point where it is used. The team first tested the efficiency of commercially-available hydrogen peroxide and chlorine in disinfecting water, and then compared this to the efficiency of their catalytic method. All of them were compared based on their ability to destroy Escherichia coli, a common bacteria species, under identical conditions. After this quantitative step, a qualitative step followed, where the team investigated exactly how each method killed the germs.

First off, their method proved to be the most effective, being 10,000,000 times more potent at killing the bacteria per unit of volume than hydrogen peroxide, and over 100,000,000 times more effective than chlorine per unit of volume. It also killed the bacteria faster than either of the two other methods.

Its secret seems to be that the reaction which creates the hydrogen peroxide also produces reactive oxygen species (ROS), highly-reactive compounds that bind to other chemicals, degrading them in the process. Bacteria are also made of chemicals — hence, they’re also being degraded. This process is the same one that makes us grow ‘old’ with age.

Interestingly enough, the team found that these ROSs are what’s killing the bacteria and other pathogens, not the hydrogen peroxide itself.

The team notes that an estimated 785 million people around the world lack access to water, and around 2.7 billion experience water scarcity for at least one month every year. Inadequate sanitation, which is also powered by lack of clean water, affects a further 2.4 billion people worldwide and can lead to a host of water-borne illnesses.

This on-site disinfection method could help all of those people finally have reliable access to clean water for drinking, washing, and any other need they might have. Hopefully, the team’s work will quickly find its way into practice.

“We now have a proven one-step process where, besides the catalyst, inputs of contaminated water and electricity are the only requirements to attain disinfection.”Crucially, this process presents the opportunity to rapidly disinfect water over timescales in which conventional methods are ineffective, whilst also preventing the formation of hazardous compounds and biofilms, which can help bacteria and viruses to thrive.”

The paper “A residue-free approach to water disinfection using catalytic in situ generation of reactive oxygen species” has been published in the journal Nature Catalysis.

The Greenland Ice Sheet is leaking mercury — likely natural, but still dangerous

As climate change keeps making our planet hotter and our glaciers melty, scientists report on an unforeseen issue: glacial meltwater from the Greenland Ice Sheet contains high levels of mercury, a toxic heavy metal. According to the report, these levels are comparable to those in rivers where factories dump their waste, creating a major threat to the seafood industry and people who enjoy its products.

Image via Pixabay.

It’s never a dull day with environmental woes. A study that began as an effort to analyze the quality of meltwater from the Greenland ice sheet, and how nutrients therein might support coastal wildlife, ended up uncovering very high levels of mercury in the runoff. The finding raises new questions about how global warming will impact wildlife in the region, one of the foremost exporters of seafood worldwide.

Mermaids, mercury

“There are surprisingly high levels of mercury in the glacier meltwaters we sampled in southwest Greenland,” said Jon Hawkings, a postdoctoral researcher at Florida State University and the German Research Centre for Geosciences. “And that’s leading us to look now at a whole host of other questions such as how that mercury could potentially get into the food chain.”

Together with glaciologist Jemma Wadham, a professor at the University of Bristol’s Cabot Institute for the Environment, Hawkings initially set out to sample water from three different rivers and two fjords next to the Greenland Ice Sheet. Their aim was to understand how nutrients from glacial meltwater can help to support coastal ecosystems.

Although they also measured for mercury, they didn’t expect to find any meaningful concentrations. Which made the levels of this metal they found in the water all the more surprising.

The baseline for mercury content in rivers is considered to be about 1 to 10 ng / L-1. That’s roughly equivalent to a sand grain of mercury in an Olympic pool of water — so, very low. However, the duo found that mercury levels in the water they sampled were in excess of 150 ng / L-1. Mercury levels in the sediment (called “glacial flour” when it’s produced by glaciers) were over 2000 ng / L-1, which is simply immense.

So far, it remains unclear whether mercury levels drop farther away from this ice sheet, as meltwater gets progressively more diluted. It’s also not yet clear whether the metal is making its way into the marine food web, which would likely make it concentrate further (as animals eat plants and each other).

Although the findings are local, the issue could have global ramifications, as they echo findings in other arctic environments. Greenland is an important producer of seafood, with the export of cold-water shrimp, halibut, and cod being its primary industry. If mercury here does end up in the local food web, it could unknowingly be exported to and consumed by people all over the world.

“We didn’t expect there would be anywhere near that amount of mercury in the glacial water there,” said Associate Professor of Earth, Ocean, and Atmospheric Science Rob Spencer, co-author of the paper. “Naturally, we have hypotheses as to what is leading to these high mercury concentrations, but these findings have raised a whole host of questions that we don’t have the answers to yet.”

“For decades, scientists perceived glaciers as frozen blocks of water that had limited relevance to the Earth’s geochemical and biological processes. But we’ve shown over the past several years that line of thinking isn’t true. This study continues to highlight that these ice sheets are rich with elements of relevance to life.”

Roughly 10% of our planet’s dry land is covered in ice, and the results here raise the worrying possibility that they may be seeping mercury into the waters around them. The issue is compounded by the fact that global warming is making these glaciers melt faster, while we still have an imperfect understanding of how the melting process influences the local geochemistry around them.

So far, the team explains that this mercury is most likely coming from a natural source, not from something like fossil fuel use or industrial activity. While this is very relevant for policy-makers, the fact remains that natural mercury is just as toxic as man-made mercury. If it is sourced from natural processes, however, managing its levels in the wild will be much more difficult to do .

“All the efforts to manage mercury thus far have come from the idea that the increasing concentrations we have been seeing across the Earth system come primarily from direct anthropogenic activity, like industry,” Hawkings said. “But mercury coming from climatically sensitive environments like glaciers could be a source that is much more difficult to manage.”

The paper “Large subglacial source of mercury from the southwestern margin of the Greenland Ice Sheet” has been published in the journal Nature Geoscience.

Iran’s groundwater resources are rapidly depleting, and everyone should pay attention

People have been relying on groundwater resources for all their drinking and washing needs since time immemorial. But some seem to be depleting fast when faced with today’s levels of demand, a new paper reports, explaining more than three-quarters of Iran’s groundwater resources are being overexploited.

Image credits Igor Schubin.

Over 75% of Iran’s land is faced with “extreme groundwater overdraft”, the paper reports. This describes the state where the natural refill rate of an area’s groundwater deposits is lower than the rate people are emptying them at. The paper was published by an international team of researchers led by members from the Concordia University, Canada.

Drying out

“The continuation of unsustainable groundwater management in Iran can lead to potentially irreversible impacts on land and the environment, threatening the country’s water, food, and socioeconomic security,” says Samaneh Ashraf, a former Horizon postdoctoral researcher now at the Université de Montréal, and co-author of the paper.

Mismanagement of these resources seems to be the biggest issue at play, the team explains. This exacerbates the obvious difficulties that a semi-arid country would have in securing water resources. Aquifers are further hampered by inefficient agricultural practices, which further drain them needlessly.

Without urgent action, the team notes, multiple, nationwide crises can arise when groundwater levels drop too low.

Iran has around 500 groundwater basins and sub-basins, and between 2002 and 2015, an estimated total of 74 km3 of water (73 billion liters) has been drained from them. This helped increase overall soil salinity across Iran and promotes land sinking (land subsidence). The Salt Lake Basin, where the country’s capital of Tehran is located is one of the most at-risk regions for land sinking.

This is quite worrying as the region, home to 15 million people, is already quite seismically active, and at risk of being hit by earthquakes.

Public data from the Iranian Ministry of Energy was used for the study.

“We wanted to quantify how much of Iran’s groundwater was depleted,” explains co-author Ali Nazemi, an assistant professor in the Department of Building, Civil, and Environmental Engineering at Concordia University. “Then we diagnosed why it was depleted. Was it driven by climate forces, by a lack of natural recharge, or because of unsustainable withdrawal?”

Agricultural use of water was the leading cause of aquifer depletion, they explain, with Iran’s west, southwest, and northeast regions being the most affected. These are agricultural areas where strategic crops like wheat and barley are grown. Consequentially, groundwater resources are most heavily depleted in these areas.

The number of registered wells for agricultural use has doubled in the last 15 years, they explain — from roughly 460,000 in 2002 to roughly 794,000 in 2015. Overall anthropogenic withdrawals of groundwater decreased in 25 of the country’s 30 basins over the same period, which suggests consumption is being concentrated in a few, overexploited aquifers.

Ground salinity levels are also rising across the country, too, as evidenced by soil electrical conductivity readings.

The national and local governments are not able to deal with this growing issue for a variety of reasons — including international sanctions, local corruption, and low trust among the population. However, the authors explain that both short- and long-term solutions are dearly needed in order to avoid these issues ballooning into huge crises.

“In the short term, the unregistered wells need to be shut down,” Nazemi says. “But longer term, Iran clearly needs an agricultural revolution. This requires a number of elements, including improving irrigation practices and adopting crop patterns that fit the country’s environment.”

Other countries would be wise to pay attention to what’s currently happening in Iran, Nazemi adds, and learn from their mistakes.

“Iran’s example clearly shows that we need to be careful how we manage our water because one bad decision can have a huge domino effect. And if the problem is ignored, it will easily get out of control,” he says. “It also illustrates the importance of environmental justice and stewardship. These are even more important when addressing the problem of climate change.”

The paper “Samaneh Ashraf et al, Anthropogenic drought dominates groundwater depletion in Iran” has been published in the journal Scientific Reports.

What’s the difference between hard and soft water

Drop coming out of a faucet coated with calcium from the hard water. Credit: Wikimedia Commons.

Not all water is the same. Most people aren’t aware of the differences but hard water refers to water high in dissolved minerals, such as calcium and magnesium. Soft water, on the other hand, is either rainwater or treated water whose only ion is sodium.

Most groundwater is naturally hard to some extent since it picks up minerals as it percolates through the soil. These include chalk, lime, as well as calcium, and magnesium. If you’d be drinking water from a natural well system, the odds are it will contain hefty amounts of minerals.

Where do you draw the line between hard and soft water?

The answer to the question ‘what exactly is hard water?’ is a matter of mineral concentration, measured in milligrams per liter or grains per gallon.

Each country may have a different standard for what constitutes hard water, but in the United States, the American National Standards defines soft water as containing less than 17.1 mg/L. Although there are different standards in different parts of the world, generally speaking, the following levels be used to assess water hardness:

  • 0-60 mg/L: soft
  • 61-120 mg/L: moderately hard
  • 121-180 mg/L: hard
  • more than 180 mg/L: very hard

The most common dissolved minerals are calcium and magnesium, both alkaline earth metals found in the 2nd group of the periodic table. These elements have a 2+ charge so they lose two electrons to form cations, such as Ca2+ and Mg2+, which easily dissolve in water.

Effects on Hard waterSoft water
AppliancesLeaves deposits of limescale
Stains water fixture
Can leave clothes discolored
Can contain high levels of corrosive salts
Cleans dishes with less water and detergent
Drinking Has potential health benefits due to presence of calcium and magnesium
Generally tastes better
Can deprive you of vital minerals
Has high levels of sodium
SkinMy harm hair
May trigger eczema
Strips skin of surface oils
Lathers soap well
Rinses shampoo from hair easier and quicker
Hard water vs soft water.

Which one is better?

Close-up of a shower head with hard water buildup. Credit: Flickr, Ivan Radic.

It’s not a case where one is better than the other — it all depends on the application. Hard water contains essential minerals that the body needs for the growth and function of bones and muscles, as well as for regulating blood pressure and enzyme action. What’s more, hard water is not only healthier but also tastier, whereas soft water tastes salty. Research supported by the World Health Organization found soft water is unhealthy. So hard water is typically a better option for drinking (although in very high quantities, it’s still not recommended).

In all other instances, hard water is not desirable. Just take a look at your sink, washing machine, and teakettle. If you notice mineral deposits and stubborn white spots that can only be removed with extra scrubbing, hard water is the culprit.

Hard water makes your appliances work hard thereby raising energy bills, causing wear and tear on these appliances, and reducing the lifespan of your plumbing. According to a recent Water Quality Research Foundation study, appliances using soft water have a 30-50% longer life and use 27% less energy. This is why it’s worth investing in the best water softener system — they can be expensive but you actually save money over time by prolonging the lifespan of your washing machine and other appliances.

These undesirable effects are due to the properties of hard water. For instance, when water with a high content of dissolved minerals is heated, it often leaves a coating on pots or containers. That’s because the solution forms calcium carbonate (CaCO3) precipitate.

This precipitate is harmless to human health, but not to that of your appliance. Over time, the build-up constricts the space where water is able to flow, forcing you to replace your dishwasher or plumbing.

To make matters worse, hard water also interferes with cleaning. For instance, the Ca2+ and Mg2+ ions interfere with the surfactant qualities of soap, which means you need to use more laundry or cleaning agents to finish the job properly.

Clothes laundered with hard water can get discolored by a mineral film and can turn stiff and scratchy. Due to the micro-abrasives in hard water, clothes may also fade more quickly and wear out faster.

Hard water can ruin your skin

Besides appliances and plumbing, hard water can also take a toll on skin and hair. When shampoo and soap come in contact with calcium and magnesium ions, the chemical reaction leaves a residue on your skin. Over time, this skin residue can clog up pores, which, in turn, can lead to acne and exacerbate skin conditions like eczema and dermatitis.

Hard water can also affect the skin on your scalp, making it dry and itchy. This is especially true for those with sensitive skin, such as those with psoriasis and eczema. For those with really sensitive skin, even laundering clothes in hard water can irritate the skin.

If you travel somewhere else for a week and notice a significant improvement in your skin, there’s a high chance that your water back home is to blame. In this case, fitting a good mineral filter for your faucet and showerhead is desirable.

How to tell if your water supply is hard or soft

  • Water hardness test kits. You can directly test your water quality using a number of affordable options, from services that test for hundreds of substances, to simple dip-in, instant read strips.
  • Warning signs. If you see white scaling on your faucets, if glasses come out of the dishwasher covered in cloudy film, or if you have trouble rinsing off soap and suffer chronic dry skin, you may have hard water.
  • The soap test. This DIY test works wonders. Fill a glass halfway with water and add soap. Cover the top and give it ashake. If the glass has hard water, the water will be cloudy with minimal suds. If it’s soft, the water will be mostly clear, bu the top will be filled with bubbles.

In the end, hard water can lead to expensive repairs and can dramatically shorten appliance life. Hard water is great for drinking, whereas soft water is the better agent for other household uses.

Mars’ water didn’t escape; it’s trapped in the red crust

New research from Caltech and JPL suggests that Mars never lost its water — it just drank it up, so to speak.

Digital rendering of Mars. Image credits Kevin Gill via Wikimedia.

Billions of years ago, our red neighbor had an atmosphere and maintained liquid water on its surface. We know this because Mars’ surface is littered with ancient river- and lake beds. The prevailing wisdom today is that once the planet lost its geological activity and thus, its magnetic field, it lost, in turn, its atmosphere and surface water, which were blown away by solar winds.

But new research says that at least the water might still be there. According to the findings, anywhere between 30% to 99% of its original water is trapped in minerals within the Martian crust.

Better red than dry

“Atmospheric escape doesn’t fully explain the data that we have for how much water actually once existed on Mars,” says Caltech PhD candidate Eva Scheller, lead author of the paper.

According to the team, around four billion years ago Mars had enough liquid water to cover its entire surface in an ocean between 100 to 1,500 meters deep. That, they explain, would be roughly equivalent to half the entire volume of the Atlantic Ocean. However, around three billion years ago, Mars looked as it does today — dry as bone. The planet’s low gravitational pull was believed to have allowed this water to escape to space over time under the action of solar winds.

For the study, the team looked at how much water Mars has in all of its forms, as well as the chemical composition of its current atmosphere and crust. They used data beamed back by virtually every Mars rover and orbiter and that we gleaned from meteorites. A particular point of interest for them was to analyze the ratio of deuterium to hydrogen (D/H) isotopes in this water.

The vast majority of water molecules have ‘vanilla’ hydrogen in their molecules — hydrogen atoms with one proton in their nucleus. Around 0.02% of all naturally-occurring water molecules in the Universe, however, include deuterium atoms — “heavy” hydrogen, which has one proton and one neutron at its core — instead.

The value of the D/H ratio in Mars’ atmosphere over time. Image credits L. J. Hallis via Researchgate.

Regular hydrogen is also known as protium and, because of its lower atomic weight, should have an easier time escaping a planet’s gravity into space. But this also means that such a process would increase the D/H ratio in Mars’ current atmosphere (i.e. increase the presence of deuterium above the 0.02% mark), which is something we can check. What the paper argues, however, is that this escape process can’t explain where all the water that’s missing has gone, and the D/H ratio, by itself. Instead, the team proposes that another mechanism worked at the same time: the trapping of water in minerals inside the planet’s crust. Together, the team explains, they could produce the conditions we see today on Mars.

The interaction between water and silicate rocks generates minerals such as clay through a process called (chemical) weathering. These minerals often contain water in their structure. While chemical weathering takes place on both Earth and Mars all the time, Earth is tectonically active, meaning weathered minerals eventually find their way back into the mantle where they’re recycled, which brings the water back out through volcanic eruptions. Since Mars isn’t tectonically active, the water trapped in its crust is no longer being cycled back out.

“Atmospheric escape clearly had a role in water loss, but findings from the last decade of Mars missions have pointed to the fact that there was this huge reservoir of ancient hydrated minerals whose formation certainly decreased water availability over time,” says Ehlmann.

“All of this water was sequestered fairly early on, and then never cycled back out,” adds Scheller.

The team previously used a similar approach to understand how habitability on Mars evolved over time by tracking carbon dioxide, currently the main ingredient of its atmosphere. In the future, they plan to continue examining the processes through which Mars’ water disappeared in their lab, and later expand their research to nitrogen and sulfur-rich minerals. Samples to-be-recovered by the Perseverance rover will help confirm or deny their current hypothesis.

The paper “Long-term drying of Mars by sequestration of ocean-scale volumes of water in the crust” has been published in the journal Science.

One of the largest ecosystems on Earth lives beneath the seafloor and eats radiation byproducts

Researchers at the University of Rhode Island’s (URI) Graduate School of Oceanography report that a whole ecosystem of microbes below the sea dines not on sunlight, but on chemicals produced by the natural irradiation of water molecules.

Image credits Ely Penner.

Whole bacterial communities living beneath the sea floor rely on a very curious food source: hydrogen released by irradiated water. This process takes place due to water molecules being exposed to natural radiation, and feeds microbes living just a few meters below the bottom of the open ocean. Far from being a niche feeding strategy, however, the team notes that this radiation-fueled feeding supports one of our planet’s largest ecosystems by volume.

Cooking with radiation

“This work provides an important new perspective on the availability of resources that subsurface microbial communities can use to sustain themselves. This is fundamental to understand life on Earth and to constrain the habitability of other planetary bodies, such as Mars,” said Justine Sauvage, the study’s lead author and a postdoctoral fellow at the University of Gothenburg who conducted the research as a doctoral student at URI.

The process through which ionizing radiation (as opposed to say, visible light) splits the water molecule is known as radiolysis. It’s quite natural and takes place wherever there is water and enough radiation. The authors explain that the seafloor is a particular hotbed of radiolysis, most likely due to minerals in marine sediment acting as catalysts for the process.

Much like radiation in the form of sunlight helps feed plants, and through them most other life on Earth, ionizing radiation also helps feed a lot of mouths. Radiolysis produces elemental hydrogen and oxygen-compounds (oxidants), which serve as food for microbial communities living in the sediment. A few feet below the bottom of the ocean, the team adds, it becomes the primary source of food and energy for these bacteria according to Steven D’Hondt, URI professor of oceanography and a co-author of the study.

“The marine sediment actually amplifies the production of these usable chemicals,” he said. “If you have the same amount of irradiation in pure water and in wet sediment, you get a lot more hydrogen from wet sediment. The sediment makes the production of hydrogen much more effective.”

Exactly why this process seems to be more intense in wet sediment, we don’t yet know. It’s likely the case that some minerals in these deposits can act as semiconductors, “making the process more efficient,” according to D’Hondt.

The discovery was made after a series of experiments carried out at the Rhode Island Nuclear Science Center. The team worked with samples of wet sediment collected from various points in the Pacific and Atlantic Oceans by the Integrated Ocean Drilling Program and other U.S. research vessels. Sauvage put some in vials and then blasted these with radiation. In the end, she compared how much hydrogen was produced in vials with wet sediment to controls (irradiated vials of seawater and distilled water). The presence of sediment increased hydrogen production by as much as 30-fold, the paper explains.

“This study is a unique combination of sophisticated laboratory experiments integrated into a global biological context,” said co-author Arthur Spivack, URI professor of oceanography.

The implications of these findings are applicable both to Earth and other planets. For starters, it gives us a better understanding of where life can thrive and how — even without sunlight and in the presence of radiation. This not only helps us better understand the depths of the oceans, but also gives clues as to where alien life could be found hiding. For example, many of the minerals found on Earth are also present on Mars, so there’s a very high chance that radiolysis could occur on the red planet in areas where liquid water is present. If it takes place at the same rates it does on Earth’s seafloor, it “could potentially sustain life at the same levels that it’s sustained in marine sediment.”

With the Perseverance rover having just landed on Mars on a mission to retrieve samples of rocks and to keep an eye out for potentially-habitable environments, we may not have to wait long before we can check.

At the same time, the authors explain that their findings also have value for the nuclear industry, most notably in the storage of nuclear waste and the management of nuclear accidents.

“If you store nuclear waste in sediment or rock, it may generate hydrogen and oxidants faster than in pure water. That natural catalysis may make those storage systems more corrosive than is generally realized,” D’Hondt says.

Going forward, the team plans to examine how the process takes place in other environments, both on Earth and beyond, with oceanic crust, continental crust, and subsurface Mars being of particular interest to them. In addition to this, they also want to delve deeper into how the subsurface communities that rely on radiolysis for food live, interact, and evolve.

The paper “The contribution of water radiolysis to marine sedimentary life” has been published in the journal Nature Communications.

Why is the ocean blue?

Credit: Pixabay.

Although this might seem like a trivial inquiry, it is in fact a rather wonderful question because answering it involves the physics of light, which kickstarted a golden age of science in the early 20th century. For instance, it was thanks to research into the properties of light, which also includes giving things their color, that Einstein developed his theories of special and general relativity.

As alluded to, the short answer to why the ocean is blue has to do with the way water absorbs and reflects wavelengths of light.

Why is anything colored?

In order to understand why the ocean is colored blue, it helps to understand why things, in general, have color, and it all has to do with some fundamental physics.

You’ve probably heard that light is made of tiny particles known as photons. White light is composed of photons that have many different wavelengths, and together comprise all the colors of the rainbow. The photons with the shortest wavelengths appear blue in the visible spectrum, while those with the longest wavelengths are red.

The only pure type of light is the one immediately shone by the sun. Afterward, the light will inevitably become altered as it interacts with various matter. Depending on what light interacts with, some photons will be absorbed, while others will bounce back. This latter action is known as ‘scattering’.

The way our eyes work is that we only see things when light bounces off of them and hits our retinas. We can’t see absorbed photons, and this has important consequences for color. For instance, leaves are green because red and blue wavelengths are absorbed by chlorophyll, while green photons bounce back towards our eyes. In the fall, leaves appear bright yellow and red because deciduous plants stop producing chlorophyll for the winter.

Likewise, experiments have shown that when light passes through pure water, red photons are absorbed, as well as short-wavelength light such as violet and ultraviolet. If that’s so, why is a glass of water, well, colorless? First of all, it’s not exactly colorless, since even a glass of water has a slight blue tint.

The ocean being distinctly colored blue can be explained by the fact that the quantity of red light absorbed depends on how much water the light has to pass through. The effect becomes more apparent when dealing with quantities of water at least as big as a swimming pool. Oceans absorb a phenomenal amount of red light, making the entire planet look like a marvelous blue marble even from millions of miles away.

This only works up to a point, though. Hardly any light penetrates deeper than 200 meters (650 feet), and absolutely no light exists at depths greater than 1,000 meters (3,280). This means that the vast majority of the ocean is actually in total darkness.

Not always blue

Shallow waters can sometimes look green due to sediments and tiny plants and marine life.

It’s important to realize that oceans aren’t made of pure water. There are many impurities such as salts or small fragments of tissue from marine creatures. For this reason, the light that bounces off the ocean also has a greenish tint.

What about the sky? It is true that the ocean acts as a mirror, reflecting some of the light from the sky, which is blue. However, its role in coloring the ocean blue isn’t critical. An indoor swimming pool’s water will appear blue even at night under artificial lighting.

The reason why some moving bodies of water, such as rivers and even stationary bodies of water such as ponds, appear to be muddy brown rather than blue is due to the presence of sediments that have been stirred up.

Shallow water is also more likely to appear in other colors, such as lighter shades of blue or even green as a result of light bouncing off floating sediments and life forms such as algae and phytoplankton. In fact, even ocean regions with high concentrations of phytoplankton will appear blue-green to green, since phytoplankton is rich in the green pigment chlorophyll.

Because the ocean’s color is so greatly influenced by the presence of phytoplankton, researchers often analyze satellite images of the ocean to gauge the health of marine ecosystems. Although small, when they band together phytoplankton have a huge impact on the biosphere. They’re not only at the very bottom of the food web, but also provide almost half of the oxygen we breathe by converting CO2 pulled from the atmosphere through photosynthesis. 

In Poznan, Poland, eight clams get to decide if people in the city get water or not

Clean drinking water, like democracy, is one of those things you tend to take for granted until it runs out or becomes polluted. But just like democracy, securing it takes a lot of work and constant oversight.

In Poznań, a city in the western stretches of Poland, this work takes place in a round building with round windows in the middle of the Warta River. This building, the Dębiec Water Treatment Plant, harbors one of the most interesting and wacky takes on the issue of water quality management.

Here, artificial and biological monitoring systems ensure that the water pumped throughout the city’s pipes is safe to drink. The artificial systems take precise measurements of chemical contamination in the water, which is definitely handy. However, as Aquanet.pl explains, it is the plant’s biological systems (or ‘bioindicators’) that allow for a more reliable estimation of the water’s overall toxicity, as they account for a broad range of factors “simultaneously”.

Image credits Julia Pełka / GRUBA KAŚKA via Reddit.

These biological systems are comprised of eight mussels with sensors hot-glued to their shells. They work together with a network of computers and have been given control over the city’s water supply. If the waters are clean, these mussels stay open and happy. But when water quality drops too low, they close off and shut the water supply of millions of people with them.

Enter the mussel

According to a presentation from AquaNES, a project of the European Union that aims to integrate nature-based elements into water management systems, Poznań’s main source of water is the Warta River. The only issue here is that the Warta passes through some of the country’s densest population centers, and some of its oldest industrial areas (where heavy industry has been present since the later parts of the 19th century). This creates an avenue through which pollution can wind up into the city’s drinking water. One particular point of worry is heavy metals such as chromium seeping through the ground and into the river.

Which naturally raises a question — how can Poznań ensure that the drinking water running through its pipes isn’t dangerously contaminated?

“Using an organism as an indicator (bioindicator) cannot be accidental. It requires extensive field research that aims to accurately characterize natural occurrence conditions,” writes Aquanet.

“The best indicator organisms are those that have specific life requirements, i.e. they have a narrow ecological (occurrence) scale. This means that a number of different factors will limit their vital functions or even eliminate them from the environment.”

In essence, these “indicator organisms” allow engineers at the plant to know if the water is safe for human use or consumption, even if they don’t produce hard data on its quality. Organisms such as mussels are good indicators of water quality because they have a low tolerance for pollutants, and they show an obvious response to improper water quality: they clamp shut.

Shellfish service

Mussels require clean, well-oxygenated water with low levels of physical or chemical impurities to thrive. They’re less and less common in Polish lakes (and in virtually all coastal waters across the globe) because of pollution, which shows just how sensitive they are to changes in water quality. In Poland’s case, a former communist country, most of the damage is caused by pollutants seeping up from contaminated aquifers (groundwater) into lakes or rivers.

This sensitivity to pollutants made them ideal for monitoring Poznań’s water supply. When waters are nice and clean, mussels open up completely in order to feed — which they do by filtering water and eating any organic matter they find. When water quality drops, they very quickly close their shells, inlet siphon (their ‘mouth’), and slow down their metabolism.

The use of mussels as part of an automated water supply system was tested at the Department of Water Protection at the University of A. Mickiewicz in Poznań and found to be a very reliable indicator of water quality.

Whenever a mussel clamps down, it closes a circuit via a spring that was simply hot-glued to its shell, which alerts a computer that it may be time to turn off the water supply. The computer’s job is to monitor parameters obtained through artificial sensors and produce an alarm if anything seems amiss. This step is meant to account for any possible change in the individual behavior or mussels, of which there are 8; one presumes they may sometimes grow tired and close off for a nap.

If four of the mussels close at the same time, however, the system shuts down automatically. It’s engineering at its best.

Mussels are typically viewed as a nuisance that clogs and damages water supply systems. But the clam-powered system has been running at the Dębiec Water Treatment Plant since September 1994 and might change that view.

Gruba Kaśka (Fat Kathy)

This is one of those stories that you hear and just can’t believe its real. I first ran into it as a meme on Reddit and was convinced it’s just a funny story someone made up for laughs until I started digging around a bit.

But I’m definitely glad I did. The simplicity and creative thought that underpin this system is what I enjoy about it the most. I find it particularly exciting to see engineers cooperating with wildlife in such an important task: to protect public health and the quality of tap water.

Julia Pełka, the director of Gruba Kaska, a documentary film that follows the story of such mussels in Poland’s capital is the one who brought this story out of the plant and into the Internet. Her interest in the topic began when she was little, as Warsaw’s water pumping facility was clearly visible from a bridge she needed to pass over when going to visit her grandparents.

“I read an article about this building called ‘Gruba Kaśka’ which is a water pump and can be accessed through an underground 300-meter tunnel,” Julia Pełka told me. “Inside, 8 clams control the purity of our water.”

“No computer can replace these super-sensitive mussels.”

As an adult, she ran into a story detailing how clams help keep the water supply clean, and thus a documentary film was born. Julia’s documentary follows a clam-based control system similar to the one from Poznan in the city of Warsaw.

“These unassuming creatures take care of the safety of millions of people in Warsaw. I saw a certain metaphor in this, but at the same time a very good subject from a cinematic perspective,” , told me in an email.

She adds that the clams are “paid back after three months of work by releasing them to a place from which they will never be caught again”. While I definitely enjoy the thought of clams earning a comfortable retirement spot, this is done because they eventually become resistant to contamination in the water.

One thing that struck me in my back and forth with Julia (apart from the obvious coolness of the story) is the depth of themes that can be derived from a simple water safety system.

“By making this film I wanted to show man’s dependence on nature. I thought it was brilliant that humans are using mussels to create a warning system against danger. They use the clams’ senses to protect themselves from the dangers of modern civilization.”

“You could say that people use them as protection from themselves.”

Alongside malacologist Piotr Domek, who specializes in finding and selecting appropriate mussels for the Warsaw plant, Julia wanted to offer thanks to the Polish Waterworks, who allowed her to film “inside such a strictly guarded facility”. The documentary premiered late last month as part of the World Showcase Shorts Program 3.

It’s Erin Brockovich all over again: rusty iron pipes are exposing us to cancer-causing chemical

Erin Brockovich made this cancer-causing chemical famous across the world, but a new study showed we might still be exposed to chromium through rusted iron pipes. As they interact with residual disinfectants in drinking water distribution systems, the pipes can leak the chemical in drinking water, putting consumers at risk.

The rusted interior of this water pipe contains chromium that reacts with residual water disinfectants to form carcinogenic hexavalent chromium. Image credit: Water Chemistry and Technology Lab/UCR

In the Oscar-winning movie Erin Brockovich, Julia Roberts plays an activist leading a lawsuit against Pacific Gas & Electric (PG&E) for contaminating water with it. The movie is based on a true story, ended on a Hollywood high note with a $333 million settlement from PG&E — the largest settlement ever paid in a direct-action lawsuit in US history.

But all is not fixed in regards to chromium.

While the substance itself is thought to have a neutral effect on health, certain chemical reactions can change its atoms into a hexavalent form that can create cancer-causing genetic mutations in the cells. Exposure to it can cause lung cancer, liver damage, reproductive problems, and other types of developmental harm.

Even with adequate drinking water treatment prior to the entry point of the distribution systems, the chromium level at the consumers’ tap water may increase resulting from reactions taking place in the distribution systems. This is what researchers from UC Riverside wanted to check in their new study, and the conclusions look concerning.

Haizhou Liu, a professor at the Marlan and Rosemary Bourns College of Engineering, and two doctorate students at the university had the hypothesis that some of the chromium found in drinking water might come from chemical reactions between water disinfectants and the chromium in cast iron corrosion scales.

They obtained segments of two pipes that had been in service for about five and 70 years respectively and induced corrosion on portions. They scraped off the rust, ground it to a powder, measured the amount and type of chromium present. Then, they placed the samples in a form of chlorine used in drinking water plants.

The researchers found that the harmless zerovalent chromium detected in the rusted iron pipes quickly transformed into the toxic form. They followed up their findings with modeling experiments, which showed diverse possibilities for how much hexavalent chromium could come out of the tap under real-world conditions.

“These new findings change our traditional wisdom on hexavalent chromium control in drinking water and shine light on the importance of managing the drinking water distribution infrastructure to control toxic substances in tap water,” Liu said in a statement regarding the study.

The researchers warned that recycled and desalinated water, which tend to have higher levels of chromium, will become more important in the future due to the world’s looming water crisis. That’s why they argue that we need to understand and prevent chromium contaminant, suggesting the use of better pipes.

About 200 million Americans across all 50 states are exposed to unsafe levels of hexavalent chromium, according to a report released by the nonprofit research and advocacy organization Environmental Working Group (EWG). They reviewed EPA’s data on chromium contamination.

The highest concentration of chromium was found in the drinking water of Phoenix, Arizona. A total of 80 water samples were taken across the city and 79 showed average concentrations of 7.853 ppb. Scientists have recommended a 0.02 ppb level, but industry pressure led to the adoption in 2014 of a legal safe limit of 10 ppb.

The study was published in the journal Environmental Science and Technology.

Water could be a natural byproduct of rocky planets forming — so it could be almost everywhere

Water might be a byproduct of the formation of all rocky planets, a new study proposes.

The Curiosity rover on Mars. Image credits NASA / JPL-CALTECH.

From all we know of life today, water seems to be a key ingredient. Life on our planet spawned and lived its early years in water. So our efforts to find extraterrestrial life focused heavily on identifying planets with liquid water. However, a new study suggests that water may be much more bountiful in the universe than we’d expect. In fact, it may be a byproduct of the formation of any rocky planet.

Everywhere

“There are two hypotheses about the emergence of water. One is that it arrives on planets by accident, when asteroids containing water collide with the planet in question,” says Professor Martin Bizzarro from the Centre for Star and Planet Formation at the Faculty of Health and Medical Sciences, University of Copenhagen.

“The other hypothesis is that water emerges in connection with the formation of the planet. Our study suggests that this hypothesis is correct, and if that is true, it is extremely exciting, because it means that the presence of water is a byproduct of the planet formation process”.

Together with Assistant Professor Zhengbin Deng, Bizzarro performed an analysis of a black meteorite known as “Black Beauty”. This meteorite is 4.45 billion years old and found its way to Earth from the original crust of Mars. As such, it contains unique insight into the ancient history of the solar system. They explain that the findings showcase that water may be much more common in the universe than we’ve assumed up to now.

The duo found that Mars harbored water for the first 90 million years of its existence. This would be long before the planets in the inner Solar System (like Earth and Mars) were bombarded by water-rich asteroids, as per our previous hypothesis. In other words, it couldn’t have been asteroids seeding water onto planets (or, at least onto Mars).

Black Beauty was first discovered in the Moroccan desert, and soon found its way to the market — for around USD 10,000 dollars per gram. The team gathered the funds to buy some 50 grams of the meteorite back in 2017 and started working on it in the lab. They crushed and dissolved some 15 grams of the meteorite and processed them with a new technique they developed.

“We have developed a new technique that tells us that Mars in its infancy suffered one or more severe asteroid impacts. The impact, Black Beauty reveals, created kinetic energy that released a lot of oxygen. And the only mechanism that could likely have caused the release of such large amounts of oxygen is the presence of water,” Zhengbin Deng says.

“It suggests that water emerged with the formation of Mars. And it tells us that water may be naturally occurring on planets and does not require an external source like water-rich asteroids,” Bizzaro adds.

The dry river and lake beds visible on Mars today are undeniable proof that the planet once harbored liquid water. However, its surface is quite cold — so the authors wanted to understand how this could be. Their analysis suggests that asteroid impacts likely released a lot of greenhouse gases into its atmosphere. Their warming effect on the planet’s climate led to the conditions that allow for liquid water to exist on its surface.

Going forward, the team plans to examine microscopic water-bearing minerals in the asteroid, which have remained unchanged since they first formed.

The paper “Early oxidation of the martian crust triggered by impacts” has been published in the journal Science Advances.

The story of the three tons of water in your jeans

Your jeans have a massive water footprint, and that often comes from water-scarce areas. According to a new study, growing cotton and producing denim is putting a lot of water stress on these areas.

Credit Quinn Dombrowski. Flickr

Jeans have long been under the radar due to their large consumption of water. The UN estimates that it takes 3,781 liters of water to make a pair of jeans, from the production of the cotton to the delivery of the final product to the store. That means the emissions of 33.4 kilograms of carbon equivalent — making jeans have one of the larger footprints in the fashion industry. But when we consider the fashion industry as a whole, things get even uglier.

Every year, fashion uses 93 billion cubic meters of water — enough to meet the consumption needs of five million people. Around 20% of wastewater worldwide comes from fabric dyeing and treatment, according to the UN. This is where jeans come in.

The global blue jeans brand Guess Inc commissioned Robert Vos, a researcher at USC Donsife in California, to carry out a study looking at water use in its supply chain. Vos mapped out the water use and identified the hot spots in the production line, finding that most of the water use from producing the raw materials for the denim.

The study showed that the facilities involved in denim manufacturing are largely located in hot-spots, areas with large consumption of water despite not that much are actually available. This includes areas of Pakistan, Mexico, China and India and also parts of California.

“By including geographic context in the life cycle analysis of Guess jeans, we created a research outcome with specific, actionable data for our business, and for measurable environmental impact. My hope is that as life cycle analysis studies become more widespread, said Jaclyn Allen, head of sustainability at Guess.

The study also identified some low-hanging fruits — “priority facilities” in which improving water use would be relatively straightforward and simple. Nevertheless, changing the denim production cycle as a whole won’t be easy. The global supply chains are so complex that it’s difficult for a company to carry out big and immediate changes. Change is possible, but it starts with company accountability.

“By the time you get a piece of apparel there might have been dozens of companies in several countries involved in its production,” Vos said in a press release. “If the supply chain is that complex, it is very hard for a company to regulate the way the land and water are being used deep in its supply chain.”

Nevertheless, the company has already implemented a set of actions thanks to the research carried out by Vos. This includes a larger use of recycled and organic cotton and the development of zero-cotton denim styles, which use renewable, wood-based and sustainably sourced materials.

Several steps in the chain of denim production are located in “hot spots” — water-scarce areas where a lot of water is used to manufacture textiles. Credit: Robert Vos

The researcher said there should be better government control regarding labeling and standards, but in its absence, there is a group of NGOs that inform consumers over the ecological footprint of clothing brands, such as the Better Cotton Initiative and the Forest Stewardship Council.

Consumers have to take a different approach, individually and culturally, to shopping and fashion, said Vos. Nevertheless, the large presence of cheap clothing is masking the real costs of many items, not only on ecological terms but also on labor ones, with many reports of the close-to-slavery working conditions in the fashion sector.

“In no way are people paying the real costs of these goods,” Vos said. “We’re not paying the cost of the water damage involved in making our jeans in Pakistan or India. If a brand uses synthetic material and it’s contributing to climate change, that cost is not built in.”

The study was published in the journal Case Studies in the Environment.

Between 30% to 50% of the world’s water supply is stolen every year

As much as 30% to 50% of the world’s water supply is stolen annually, with the agricultural sector largely to blame, according to a new study. The findings highlight the lack of information behind water theft and the relevance of the issue amid a global competition for water.

Credit Flickr State of Israel

While there’s no agreed-on definition of water theft, it essentially involves taking water in violation of regulations. It can be anything from installing unauthorized connections to water distribution systems or tampering with meters, to tapping boreholes without licenses, all with the objective of not paying for water.

There’s a lack of accurate data around water theft, partly because those that steal the resource are often poor, vulnerable, and at-risk in developing countries, although there are also cases in the developed world. With that in mind, a group of researchers developed a novel framework and model, which they applied to three case studies.

The framework and model created by the researchers are aimed at helping water managers to test the impact of changes in detection, prosecution, and conviction systems, as well as accurately measuring the effectiveness of current penalties (which may not provide an effective deterrent).

“As the scarcity of our most precious resource increases due to climate change and other challenges, so too do the drivers for water theft,” said Loch in a press release. “If users are motivated to steal water because it is scarce, and they need it to keep a crop alive, then the opportunity cost of that water may far exceed the penalty, and theft will occur.”

Adam Lock from the University of Adelaide and his team looked at cotton farms in Australia, marijuana cropping in the US, and strawberry fields in Spain. They found that water theft increases when governments fail to support detection and prosecution, when there is uncertainty regarding water availability in the future, and when social attitudes regarding water theft are permissive. They suggest that stronger disincentives might be needed to dissuade users from stealing water.

One example of water theft came to light in Australia in 2017, for example, when a government program found cases of cotton irrigators taking water against embargoes. The program also found a lack of metering in parts of the country and inadequate rules regarding the use of water, making such embargoes difficult to apply.

The government implemented new water-sharing rules, appointed a new regulator, and allocated more resources to the enforcement of water laws. This had led to a large number of prosecutions. Nevertheless, progress has been slow in installing meters in some parts of the country, the researchers argue.

“A significant percentage of extractions across Australia are not metered or otherwise properly measured,” the special counsel at the Environmental Defenders Office, Dr. Emma Carmody, who participated in the study, told The Guardian.

“This is a critical issue as it makes it very difficult to assess the extent of non-compliance with water laws, which has a knock-on effect on the environment.”

The researchers said there are many cases of water theft that could be studied using the (free) framework and model that they created, encouraging institutions to use these tools. Recovering some of the “lost” water would be useful for the world’s water supply, they argue.

The study was published in the journal Nature Sustainability.

A limited resource

The United Nations sets the minimum water requirement per person at 50 liters per day. This is based on the idea that a person drinks about two liters per day, using the rest for cooking, washing, and sanitation. While people in water-stressed countries can’t meet that level, the average use in the US is between 400 to 600 liters per person a day.

Agriculture gobbles up around 70% of the water that is consumed globally. While it’s an economically relevant sector and can take people out of poverty, it can also massively deplete water resources. For example, it takes 140 liters of water to make a cup of coffee, with most of the water used on growing the coffee plant.

The way water is distributed around the world doesn’t match local supply and demand. China has 40 times more people than Canada but has much less water, for example. Thirteen Arab countries are among the world’s 19 most water-scarce nations. Even water-rich countries such as Brazil have had water scarcity problems in the past.

There’s intense competition for water resources around the world, likely to intensify due to population growth, urbanization, overuse of water, environmental degradation, and climate change. Groundwater is argued to become the main supply in the future, as surface water gets depleted or becomes polluted. Nevertheless, tapping groundwater also faces a wide array of challenges on its own.

Dwarf planet Ceres is an ocean world with liquid water beneath the surface

Astronomers have called Ceres many things: the largest object in the asteroid belt; a dwarf planet; a cold, barren rock. But ‘ocean world’ is not something they would have even considered — until very recently.

This animation shows dwarf planet Ceres as seen by NASA’s Dawn. The map overlaid at right gives scientists hints about Ceres’ internal structure from gravity measurements. Image credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

Ceres lies within the asteroid belt between Mars and Jupiter. First considered to be a planet in the 19th century, it is now known to be an asteroid, and classed as a dwarf planet, like Pluto.

Now, a flurry of studies forces us to rethink Ceres once again, as astronomers report evidence indicative of a salty ocean beneath its surface.

“We can now say that Ceres is a sort of ocean world, as are some of Saturn’s and Jupiter’s moons,” Maria Cristina De Sanctis, from Rome’s Istituto Nazionale di Astrofisica and one of the study authors, told AFP.

De Sanctis and colleagues analyzed images sent from NASA’s robotic Dawn spacecraft, which entered orbit around Ceres in 2015. As Dawn approached Ceres, it offered an unprecedented glimpse into the planetoid, showing impact craters and signs of cryovolcanic activity (volcanism that erupts frozen water, ammonia, or methane, instead of molten rock). Now, researchers also analyzed infrared images, which showed the presence of a rock called hydrohalite.

A fracture system inside the rim of the Occator Crater, where the new studies found evidence of water. Image credits: NASA.

As the name implies (hydro=water, halite=rock salt), hydrohalite is a mineral that forms in salty waters and has until now only been observed on Earth. The deposit seems to have built up during the last two million years, which is extremely recent in geologic history, suggesting that the processes behind it are still very much active. In other words, it seems that brine is still ascending from the planet’s interior, a “smoking gun” for liquid water.

“That material is unstable on Ceres’ surface, and hence must have been emplaced very recently,” said co-authors Julie Castillo-Rogez, from the California Institute of Technology’s Jet Propulsion Laboratory.

Another published paper found evidence of cryovolcanism that started around 9 million years ago and lasted for several million years, also indicative of a deep brine source. Gravity data and thermal modeling also imply an extensive deep brine reservoir beneath the Ceresian surface.

A crater on Ceres in enhanced color. Image credits: NASA.

In a separate paper, researchers used remote sensing to analyze the crust of Ceres, finding evidence of density and rheological variations, which are also consistent with a liquid ocean under the surface. Whether or not this is still an active ocean or just a remnant of one is unclear.

This finding could have massive implication for the field of astrobiology. Not only does Ceres (a seemingly dull object in the asteroid belt) feature liquid water beneath its surface, shielded from radiation — but it also features salt.

According to De Sanctis, the ingredients of life seem to be lining up nicely on Ceres.

“The material found on Ceres is extremely important in terms of astrobiology,” she said.

“We know that these minerals are all essential for the emergence of life.”

Journal References:

  • C. A. Raymond et al. Impact-driven mobilization of deep crustal brines on dwarf planet Ceres, Nature Astronomy (2020). DOI: 10.1038/s41550-020-1168-2
  • A. Nathues et al. Recent cryovolcanic activity at Occator crater on Ceres, Nature Astronomy (2020). DOI: 10.1038/s41550-020-1146-8
  • R. S. Park et al. Evidence of non-uniform crust of Ceres from Dawn’s high-resolution gravity data, Nature Astronomy (2020). DOI: 10.1038/s41550-020-1019-1
  • M. C. De Sanctis et al. Fresh emplacement of hydrated sodium chloride on Ceres from ascending salty fluids, Nature Astronomy (2020). DOI: 10.1038/s41550-020-1138-8
  • B. E. Schmidt et al. Post-impact cryo-hydrologic formation of small mounds and hills in Ceres’s Occator crater, Nature Geoscience (2020). DOI: 10.1038/s41561-020-0581-6

Microwaving water really isn’t the same as heating it

Every time you make a cup of tea (or whatever hot beverage you may prefer), your cup becomes the stage of an interesting physics experiment. Even heating the liquid creates a pretty interesting mechanism. If you place a water-filled recipient on a stove, the bottom part starts to heat up. As it does, it becomes less dense, which makes it move to the top, and a cooler section of the liquid sinks to the source, where it heats up, moves up, and so on.

This process, called convection, ensures that there’s a uniform temperature throughout the water. But with microwave, it’s different.

Convection in a stove-heated recipient. Image credits: Bruce Blaus.

In a microwave, convection doesn’t take place because the heating comes from everywhere at the same time. Because the recipient itself also heats up, the hottest parts of the water rise to the surface and stay there, making the first sips much hotter than the ones at the bottom.

This helps to explain why, at least anecdotally, hot beverages just aren’t the same when you microwave or heat them with a conventional stove.

A team of researchers from the University of Electronic Science & Technology of China studied this common problem and found a way to trigger convection in microwave-heated cups as well.

The key, researchers say, is guiding the microwaves away from the surface of the liquid. They fitted a regular cup with custom-made silver plating that acts as a guide for the waves, reducing the field at the top and effectively blocking heating at the top, which creates a similar heating process to traditional approaches and results in a uniform temperature for the water.

“The experimental results show that when the modified glass cup with 7 cm metal coating is used to heat water in a microwave oven, the temperature difference between the upper and lower parts of the water is reduced from 7.8 °C to 0.5 °C.”

Naturally, placing metal plating inside a microwave oven seems like a bad idea and it almost always is — unless you really know what you’re doing. The team was able to design the metal plating in a way that’s both efficient and safe.

“After carefully designing the metal structure at the appropriate size, the metal edge, which is prone to ignition, is located at weak field strength, where it can completely avoid ignition, so it is still safe,” said Baoqing Zeng, one of the authors of the paper.

Zeng and colleagues are now working on ways to make the process scalable and cost-effective for brewing. They hope to commercialize their results soon — in which case, microwave tea could become a non-laughable option.

The team is also considering ways to do the same thing in heating solids, but the process is much more complex. For now, we’ll have to heat our leftovers the good old fashioned way.

Journal References: Multiphysics analysis for unusual heat convection in microwave heating liquid,” AIP Advances (2020). aip.scitation.org/doi/full/10.1063/5.0013295

How long can humans survive without food or water?

Credit: Flickr.

Despite what was some new age gurus might claim, humans aren’t light beings that can subsist on air and sunshine alone. Like all creatures, we require food and water to survive.

Typically, humans can go without food for about three weeks before the effects of starvation on the body kill a person. But since the adult body is made of 60% water, typically a person would only last three to four days without a drop of water.

These are average values, however. There are outliers who have managed to survive for longer without food or drink. How long a person can last without access to calories and liquids depends on many factors, such as environmental conditions and a person’s underlying health.

For instance, lacking access to water in the desert under the broiling sun will kill a person much faster than in the middle of the forest where it’s much cooler.

To make things easier, use this ‘rule of three’ to get an idea how long the human body can last without basics: 3 minutes without oxygen, three days without water, and three weeks without food.

How long can someone live without water?

Fluid intake has the most immediate effect on survival. While the body has fat and muscle that it can burn for energy in case food is nowhere to be found, water stockpiles are far less plentiful.

Our bodies mostly consist of water, but we lose a lot of it each day when we sweat, urinate, or even exhale. This is why water needs to be constantly replenished.

How much water a person needs on a daily basis depends on physical activity, age, body temperature (having a fever requires more water), the environment, and air humidity.

Water loss through respiration and sweating can be anywhere between 0.3 and 1 liter per 24 hours under typical conditions. However, under extreme conditions like trekking through the desert, an adult can lose as much as 1.5 liters of sweat per hour.

An adult will also lose around 1.5 liters of water through urine. If you add everything up, that’s around 2.5 liters of water lost per day. What flows in must flow out, so each adult should seek to intake at least that much water from their food and drink in order to maintain fluid balance.

Don’t worry though. You don’t have to keep your eyes on the pitcher all day, constantly measuring to make sure you’re not getting dehydrated. Each person’s water requirements vary, but the body already does a fantastic job of signaling its needs. If you don’t feel thirsty, that’s good enough.

But what happens if this delicate balance is suddenly thrown off? Within a few days without fluid intake, the kidneys lose much of their function and can collapse. Depending on how much water they lose due to physical activity, temperature, and humidity, a person can survive anywhere between 3 to 7 days without water, extreme cases notwithstanding.

An 18-year-old Austrian by the name of Andreas Mihavecz is believed to have survived the longest without water after police accidentally left him in a holding cell for 18 days in 1979. He allegedly licked condensation trails off the wall, but that doesn’t make this record any less impressive.

However, keep in mind that any dehydration that causes a loss of more than 10% of your body weight is classed as a medical emergency.

One of the most dangerous things about water loss is that it can cause blood volume to drop. With less blood circulating through the body, blood pressure can fall to levels that can be fatal.

How long can humans go without food?

The number of days a person can survive without one morsel of food has an even broader range than those suffering from water deprivation. Mahatma Gandhi, who is world-famous for his extremely long fasts, once went 21 days without food.

However, the longest a person has ever survived without food is 74 days. The record was set by Terence MacSwine, an Irish political prisoner, who went on hunger strike in protest, which eventually led to his untimely death in 1920. Generally, people who have voluntarily stopped eating during hunger strikes without ceasing their protest have died after 45 to 61 days, according to a 1997 study published in BMJ.

Hunger strike protestors are actually the most reliable evidence available that we have for how long people can go without food. Starvation experiments in controlled settings are impossible to perform, since it would be highly unethical to ask or force a person to stop eating for prolonged periods just to examine the outcome. Unfortunately, this also means that it is extremely difficult to estimate how long the average person can survive while forgoing food.

What we know for sure is that humans can survive without food for longer than without water. The body relies on calories and nutrients in food to provide cells with the energy they need to fuel vital biological processes.

When the body is deprived of food, it turns to stockpiles. First, the body turns to glycogen in the liver and muscles, converting it into sugar and amino acids.

When it runs out of glycogen, the body starts burning fat stores for energy. This is one of the reasons why fasting is excellent for weight loss. It’s not too fun when the body has to turn to proteins for energy, though. It causes significant muscle loss, including muscle tissue from the heart.

During starvation, the pulse and blood pressure drop because the heart doesn’t have enough energy to pump blood around the body as it normally would. If food isn’t ingested soon at this point, heart failure can become inevitable.

Starvation obviously interferes with the gastrointestinal system, leading to bloating, stomach pain, vomiting, nausea, and even bacterial infections.

Deprived of energy, the central nervous system is also affected. The brain consumes a fifth of a person’s energy, but with little energy to fuel its processes, starving people will have problems concentrating or sleeping.

Bottom line: it’s not clear how long the average person can go without food or water, but humans can typically survive for weeks while starving thanks to their energy stockpiles in their glycogen, fat, and muscles. 

Indian lake turns pink almost overnight

The water of Lonar Crater Lake in India is typically deep-green, but it has recently turned pink — almost overnight — and nobody knows why.

Image credits Maharashtra Tourism / Twitter.

I think it goes without saying that large bodies of water don’t typically just change color, but Lonar Lake did. The Indian landmark was a tourist attraction before, but it has now become a hotbed of visitors eager to see its bright pink waters.

Exactly what caused this change, or why it happened so fast, is as of yet unknown. 

Crater lake

The color change was captured best by two NASA images taken on May 25 and June 10 with the Operational Land Imager (OLI) on Landsat 8. The waters changed color over the span of a few days, according to NASA.

“India’s Lonar Crater began causing confusion soon after it was identified in 1823 by a British officer named C.J.E. Alexander,” NASA says of the crater.

“Lonar Crater sits inside the Deccan Plateau—a massive plain of volcanic basalt rock leftover from eruptions some 65 million years ago. Its location in this basalt field suggested to some geologists that it was a volcanic crater. Today, however, Lonar Crater is understood to result from a meteorite impact that occurred between 35,000 and 50,000 years ago.”

Lonar Lake is located in India’s west-central state of Maharashtra, and it isn’t the only pink lake we know of. Lake Hillier in Australia is permanently pink, with the color likely produced by Halobacteriaceae, pink-colored microorganisms that inhabit its salty waters, and a species of single-cell algae called Dunaliella salina. When stressed, D. salina releases carotenoids (a class of molecules that give plants such as carrots their color), including an orange-red colored one.

But Lake Hillier doesn’t change its color — it’s always pink. One possible explanation of the shift in Lonar Lake could be a rise in salinity due to a long period of warm, dry weather promoting evaporation, as is the case with Lake Urmia in Iran (whose color changes seasonally). In other words, it could be going to a very dramatic and pink algal bloom. A chemically-induced change hasn’t been ruled out yet, however.

Lonar Lake is quite visually striking and remote, and as such is dotted with small temples along its rim. Due to its salinity and alkaline nature, the late doesn’t house much wildlife. It was the discovery of maskelynite (a type of natural glass produced during asteroid impacts) revealed its true origin.

The lake has always been unique, and this change in color only adds to its quirkiness. Exactly what caused this change is still unknown — as is whether the colors will switch back or not. But researchers will undoubtedly try to find out what’s going on here, and will keep the lake under observation while drawing samples to analyze.