Tag Archives: Deepwater Horizon

Sponge based on common mattress foam could clean up oil spills

Fireboat response crews battle the blazing remnants of the offshore oil rig Deepwater Horizon in 2010. Credit: Wikimedia Commons/ US Coast Guard.

In 2010, mankind experienced one of the worst environmental disasters in history. The Deepwater Horizon oil spill off the Gulf of Mexico led to the discharge of 4.9 million barrels of oil, causing irreparable damage to the local ecosystem that is still felt to this day. There are, however, thousands of smaller spills that occur every year, but since they’re not that important you never hear about them in the news.

With this huge environmental challenge in mind, researchers at Imperial College London and the University of Toronto have developed a cheap sponge that can soak up oil relatively fast. The best thing about this sponge is that it can also work on wastewater from fracking (up to over 100 billion barrels a of such water are produced each year). At the moment, the toxic fracking byproduct is either injected deep underground or stored in huge tanks.

The team of chemical engineers led by Pavani Cherukupally sought to find a solution by turning to polyurethane foam, a common material used in everyday household items like mattresses. Although polyurethane foam has good oil absorption properties, it only works well under certain conditions of acidity, which can strengthen or weaken the affinity between oil droplets and the sponge.

“It’s all about strategically selecting the characteristics of the pores and their surfaces. Commercial sponges already have tiny pores to capture tiny droplets. Polyurethane sponges are made from petrochemicals, so they have already had chemical groups which make them good at capturing droplets,” said Cherukupally.

“The problem was that we had fewer chemical groups than what was needed to capture all the droplets.”

The researchers developed a coating that alters the foam’s texture, chemistry, and charge, thus making it more suitable for a broad range of situations. When viewed under a microscope, the coating contains hair-like particles of nanocrystalline silicon that act like fishing rods for the oil droplets.

“The critical surface energy concept comes from the world of biofouling research—trying to prevent microorganisms and creatures like barnacles from attaching to surfaces like ship hulls,” Dr. Cherukupally said in a statement.

“Normally, you want to keep critical surface energy in a certain range to prevent attachment, but in our case, we manipulated it to get droplets to cling on tight.”

When tested under four different scenarios of acidity, the coated foam soaked up between 95% and 99% of the oil and did so in no more than three hours.

The material can be washed with a solvent that extracts the oil, crucially allowing the foam to be reused.

Hopefully, this technology will soon become commercially available because, right now, our options are extremely limited and not very effective. For instance, British Petroleum used controversial chemicals called dispersants to clean up the Deepwater Horizon spill by breaking up the oil into smaller drops. The small size of the droplets allows microbes to digest the oil more easily while also emulsifying the oil in the process, harming the ocean ecosystems.

“Current strategies for oil spill cleanup are focused on the floating oil slick, but they miss the microdroplets that form in the water,” said Amy Bilton, a professor at the University of Toronto and co-author of the new study.

“Though our sponge was designed for industrial wastewater, adapting it for freshwater or marine conditions could help reduce environmental contamination from future spills.”

In the future, the researchers would like to use sponges to treat contamination from the gas, mining, and textile industries.

The findings appeared in the journal Nature Sustainability.

The Deepwater Horizon oil spill was 8 years ago. The ocean is still struggling to recover

Eight years ago, mankind created one of the biggest environmental disasters in history. The Deepwater Horizon oil spill led to the discharge of 4.9 million barrels (210 million US gal; 780,000 m3) of oil, and nature still hasn’t recovered, a new study has found.

Oil from the Deepwater Horizon oil spill approaching the coast of Mobile, Alabama, on May 6, 2010.

The spill area hosts 8,332 species, all of which are threatened by the hydrocarbon leaks. A 2014 study of the effects of the oil spill on bluefin tuna found that toxins from oil spills can cause irregular heartbeats leading to cardiac arrest. A further study also found that the toxins could severely damage the internal organs of predators and even humans in the area — directly contradicting BP, the oil company responsible for the spill.

To make matters even worse, the oil dispersant Corexit, previously only used as a surface application, was released underwater in unprecedented amounts. The goal was to make oil more easily biodegradable, but the plan backfired as the oil and dispersant mixture permeated the food chain through zooplankton — from which it proceeded to spread across the entire ecosystem. Chemicals from the spill were found in migratory birds as far away as Minnesota, with a devastating effect on marine wildlife. A 2016 study reported that 88% of 360 baby or stillborn dolphins within the spill area “had abnormal or underdeveloped lungs”, compared to 15% in other areas.

Birds were also severely affected, both directly and indirectly. Here, an oiled brown pelican near Grand Isle, Louisiana. Image credits: Governor Bobby Jindal.

No matter where and how you look, the scale of the disaster is shocking. Alas, it gets even worse: new study found that the basic building blocks of life in the ocean have been altered, indicating that the ocean still hasn’t recovered from the oil spill.

“At the sites closest to the spill, biodiversity was flattened,” study lead author and University of Southern Mississippi microbial ecologist Leila Hamdan told The Guardian. “There were fewer types of microbes. This is a cold, dark environment and anything you put down there will be longer lasting than oil on a beach in Florida. It’s premature to imagine that all the effects of the spill are over and remediated,” she said.

Researchers took sediment samples from shipwrecks scattered up to 150 km (93 miles) from the spill site to study how and if micro-biodiversity has recovered. Shipwrecks are biodiversity hotspots, so it’s a good place to see how life recovered. Researchers wrote:

“More than 2,000 historic shipwrecks spanning 500 years of history, rest on the Gulf of Mexico seafloor. Shipwrecks serve as artificial reefs and hotspots of biodiversity by providing hard substrate, something rare in deep ocean regions. The Deepwater Horizon (DWH) spill discharged crude oil into the deep Gulf. Because of physical, biological, and chemical interactions, DWH oil was deposited on the seafloor, where historic shipwrecks are present. This study examined sediment microbiomes at seven historic shipwrecks.”

Results weren’t encouraging. Microbes are still struggling to recover, and since they are affected, the entire food chain that’s built upon them is also affected. There’s a good chance we have still yet to see all the far-reaching consequences of this event.

“We rely heavily on the ocean and we could be looking at potential effects to the food supply down the road,” she said. “Deep sea microbes regulate carbon in the atmosphere and recycle nutrients. I’m concerned there will be larger consequences from this sort of event.”

The timing of the study is also very fitting — it comes just as a new measure by the Trump administration opens up 90% of U.S. coasts to offshore oil drilling, dismantling ocean conservation measures put in place by former president Barack Obama in the wake of the Deepwater Horizon calamity. This means that this type of disaster will become much more likely in the future, much to the chagrin of scientists and conservationists.

Journal Reference: Leila J. Hamdan, Jennifer L. Salerno, Allen Reed, Samantha B. Joye & Melanie Damour. “The impact of the Deepwater Horizon blowout on historic shipwreck-associated sediment microbiomes in the northern Gulf of Mexico,” Scientific Reports.