The findings are consistent with increased emissions of mercury from coal-burning power plants in Asia and decreased emissions in North America, according to Peter Weiss-Penzias, an environmental toxicologist at UC Santa Cruz. Weiss-Penzias is first author of a paper on the findings published in the journal Science of the Total Environment.
Mercury is a toxic element released into the environment through a variety of human activities, including the burning of coal, as well as by natural processes. Rainfall washes mercury out of the atmosphere and into soils and surface waters. Bacteria convert elemental mercury into a more toxic form, methyl mercury, which becomes increasingly concentrated in organisms higher up the food chain. Mercury concentrations in some predatory fish are high enough to raise health concerns.
Comment: Mercury pollution released into the environment becomes a serious threat when it settles into oceans and waterways, where it is converted to methyl mercury. This transition is particularly significant for humans, who absorb methyl mercury easily and are especially vulnerable to its effects. Instead of dissolving or breaking down, mercury accumulates at ever-increasing levels. In adults, mercury poisoning can adversely affect fertility and blood pressure regulation and can cause memory loss, tremors, vision loss and numbness of the fingers and toes. A growing body of evidence suggests that exposure to mercury may also lead to heart disease.