Tag Archives: toxicity

Parking sign wheelchair.

Excessive use of dental fixture cream leaves UK man without use of his legs

A 62-year-old UK man has lost feeling in both his legs from prolonged heavy use of zinc-containing dental fixture.

Parking sign wheelchair.

Image credits Paul Brennan.

The 62-year-old man first visited a neurology clinic complaining of a tingling sensation and numbness in his hands, and pain and weakness in his legs. This made it difficult for him to move, and the tap-tap-tap of his cane would follow him into the doctor’s office. Six months later, his symptoms had become so severe that he had to use a wheelchair to move about, and had became largely housebound.

This, a recently published paper reports, is the latest among a handful of reported cases in which denture cream use has led to neurological issues.

Too much zinc

MRI scans performed at the clinic showed several abnormalities in the patient’s spinal chord — the man had slight degeneration of six vertebrae in his neck, and he’d also lost more than a dozen pounds. Follow-up tests revealed the cause: copper deficiency myelopathy, a brain syndrome caused by a lack of copper. This element plays an important role in maintaining nerve cells, the health of the immune system, and supports the production of red blood cells. But the man’s affliction was a little strange to say the least, since it’s pretty hard to develop a copper deficiency. Our bodies only need trace amounts of it, way less than your average diet provides.

The man’s blood also contained unusually high levels of zinc, which pointed his doctors at the Queen Elizabeth University Hospital, led by Dr. Liam Carroll, on-track as to the cause of his ailment: zinc toxicity caused by dental adhesive cream use. Now, zinc is a pretty common thing to find in denture adhesive creams. In fact, it’s actually pretty useful for your body. Zinc is a building block of DNA and supports your immune system in killing off bad guys — but too much of it starts messing with the body’s ability to metabolize copper.

According to the U.S. Food and Drug Administration (FDA), if these products are used as per their instructions they won’t lead to a toxic build-up of the element. The man, however, reported that he’d been using two to four tubes of dental fixture every week for 15 years because his ill-fitting dentures kept falling off. Which is far above the 11-milligram daily dose recommended for adult men.

The man was instructed to immediately stop using the cream and was prescribed copper supplements to help treat his condition. The symptoms didn’t progress any further. He reported a gradual reduction in tingling and numbness but remains mostly wheelchair-bound. The doctors say he may have irreversible nerve damage due to the delayed diagnosis.

The paper “Zinc containing dental fixative causing copper deficiency myelopathy” has been published in the journal BMJ Case Reports.

Basic fracking life cycle scheme. Image: Wikipedia Commons

One third of fracking chemicals are of unknown toxicity

Pump jacks dot oil fields between the California towns of Taft and Maricopa. The very deep petroleum would be hard to reach. Methods such as fracking would bring environmental concerns and no guarantees. Photo: Los Angeles Times

Pump jacks dot oil fields between the California towns of Taft and Maricopa. The very deep petroleum would be hard to reach. Methods such as fracking would bring environmental concerns and no guarantees. Photo: Los Angeles Times

A while ago I wrote about the disheartening status quo of energy today: frack now, ask questions later. In the article, I argue that there’s a disproportion between the amount of hydraulic fracturing (9 out of 10 wells in the US are fracking wells) and the number of research articles that discuss the bio impact of the practice in the long term. A new study presented by William Stringfellow of the Lawrence Berkeley National Laboratory at 248th National Meeting of the American Chemical Society seems to echo these notes. Stringfellow warns that one third of the fracking chemicals he found (remember there are many chemicals that makeup fracking fluid that are undisclosed and are kept this way under government protection – yes, trade secrets) are of unknown toxicity. In other words, oil and gas companies are dumping chemicals in the ground and they have no idea what might happen.

Toxicity unknown for a third of fracking chemicals

Hydraulic fracturing or fracking as it’s commonly referred to involves releasing shale gas trapped beneath rocks. The rocks are broken using a high-pressure liquid mix of water, sand and other chemicals, which can include carcinogens and radioactive substances. Water makes up most of the liquid, with 85% of the mass, followed by sand which acts to keep the fracture open. The most dangerous compounds are so called biocides which are included in the mix to kill bacteria that more often than not form and congregate on the pipe walls, clogging the well.

Basic fracking life cycle scheme. Image: Wikipedia Commons

Basic fracking life cycle scheme. Image: Wikipedia Commons

Like gourmet chefs, each company has its own recipe for the mix and like to keep it secret, as if once it’s known it stops being magic! States like Texas and Wyoming, however, mandate companies to publicly disclose the make-up of their fracking fluids. But not all of them – companies make us of loopholes and keep some compounds secret by claiming they’re trade secrets.

“The industrial side was saying, ‘We’re just using food additives, basically making ice cream here,'” Stringfellow says. “On the other side, there’s talk about the injection of thousands of toxic chemicals. As scientists, we looked at the debate and asked, ‘What’s the real story?'”

Stringfellow decided to investigate and chose to focus on 81 fracking chemicals commonly used in the U.S he found listed in government databases. Again, he looked at those chemicals that are actually disclosed. Most of these were found to be harmless, either non-toxic or of very low-toxicity; like any pharmacologist will tell you, it’s the dosage that makes a poison.  However, one-third of them have hardly any public information about their toxicity or their physical and chemical properties, and eight are downright toxic to mammals.

The EPA has yet to discover any evidence that suggests fracking contaminates groundwater, despite independent studies that say otherwise. Nevertheless, experts agree that fracking fluids are most dangerous when their outside, not inside the ground. After a fracking well is done and spent, the contaminated wastewater is most commonly dispensed into depleted oil wells. Although this is the safest method, it’s been found also to cause micro earthquakes. Another alternative is to recycle the waster, which involves  removing chemicals and rock fragments from fracking wastewater and reusing it to frack more wells.

Next, Stringfellow  and his team plan on assessing  the risk and concentration of the chemicals when mixed into fracturing fluid. While alone some chemicals in a certain concentration might be deemed toxic, when mixed and injected these compounds might break down.

“There’s a national need to get a complete picture of the chemicals that are used everyday,” Stringfellow says. “It should be a priority to try to close that data gap.”