(NaturalNews) Pervasive, toxic forms of mercury are derived from more than just the pollution of unclean coal-fired power plants around the world. Traces of toxic mercury, often measured in waste water, can be exacerbated by chemical processes that take place in wastewater after it's released into the ground. Biogeochemist Carl Lamborg found in recent studies that mercury pollution is made more mobile and pervasive in the presence of specific microbial actions which take place exclusively in underground wastewater.
When waste in the water enters the ground, it interacts with the environment in chemical processes that break down waste into more pervasive forms of "un-sticky" mercury which accumulates in ponds, fish and, ultimately, humans.
A recent study from the Woods Hole Oceanographic Institution explains this action, showing how elevated levels of mercury can accumulate in the ocean, through silent processes that start in wastewater. Lamborg explains this conversion process.
Cape Cod wastewater "extracting" mercury into more pervasive forms that accumulate in the ocean
Throughout 2010, 2011 and 2012, Lamborg set out to measure mercury concentrations in long-standing survey wells in Cape Cod. Installed by the US Geological Survey and managed by the Massachusetts Military Reservation, these survey wells were the ideal study site, since wastewater was discharged into the ground of this Cape Cod site for nearly 70 years. The site consists of a 3-kilometer area where contaminants seep and interact freely, traveling about 200 meters every year through an aquifer that pours out into a coastal saltwater pond. The 3-km depression between the towns of Falmouth, Sandwich and Mashpee, Massachusetts, continues to show increasing mercury levels that also resurface later in ponds and the ocean.
After analyzing three years' worth of samples in a lab, Lamborg reported on the findings, "The amount of mercury flowing out of the watershed and into the ocean and these ponds is something like twice as much as it would be if wastewater was not being put into the ground."
Through further investigation, Lamborg keyed in on two spots along the plume that were considered anoxic. The anoxic sites contain sediment and groundwater void of all oxygen due to microbial action that had consumed all oxygen by breaking down carbon and nitrogen from the waste.
Lamborg studied the microbes responsible for this breakdown at an upstream site and found that they were using iron to break down the waste. In that process, the most common form of mercury is broken down into a less sticky form of elemental mercury. This kind of "less sticky" mercury readily breaks free from sediment and seeps into groundwater where it is transported downstream and further into the environment. He pointed out that excessive use of fertilizers may serve as an added catalyst that breaks down elements in wastewater into toxic forms of mercury.
Microbial actions in wastewater "mine out" toxic monomethylmercury
His investigation did not end there. After investigating downstream, another form of mercury was discovered in high concentrations -- monomethylmercury. This is the kind of mercury that accumulates in fish and is passed on into the bodies of unsuspecting humans, causing toxicity.
Lamborg commented, "This should make us all think twice about what we dump into the ground. Adding more nitrogen into the ground through wastewater, and even fertilizers for our agricultural fields and golf courses, offers a potential for mercury to accumulate and move through the aquifer to our ponds, lakes, and the ocean. That's something I don't think people are really thinking about."
Intrigued, Lamborg continued his investigation, focusing in on a chemical process that microbes undergo using organic carbon with nitrate to break down organic matter. This process, called denitrification, is contributing to higher levels of monomethylmercury, the toxic form found in seafood.
Basically, mercury that has been stored in the earth for several thousands of years is being pulled out by chemical processes occurring in wastewater. "What it looks like is, the mercury that was already there in the aquifer or sand is being mined out when the groundwater goes anoxic," said Lamborg. [emphasis added]
The finding was a scientific breakthrough. Lamborg reported, "This kind of thing where you see denitrification resulting in the methylation of mercury has never been observed before."
Lamborg is now pursuing research that highlights the specific triggers that cause these drastic changes in the various forms of mercury.