Environmental wellness was on the agenda this month as delegates from over 140 countries gathered in Geneva to finalise the first international treaty to reduce emissions of mercury. Four years in the works, the aims to protect human wellbeing from this very serious neurotoxin, but those involved in the treaty process have pointed out that the harm that mercury inflicts on wildlife was barely considered during the long deliberations.
According to David Evers, chief scientist at the Biodiversity Research Institute (BRI), who serves on a scientific committee informing the process, mercury may not kill many animals outright, but it does put a deep dent in the reproduction process. ‘It is a bit of a silent threat,’ he says. ‘You have to kind of add up what was lost through studies and demographic models.’ All kinds of animals have demonstrated harmful levels of mercury, from fish and birds in the Florida Everglades to polar bears roaming far from any sources of pollution. Biologists have tracked mercury’s footprints in unexpected habitats and species, illuminating the subtle effects of chronic exposure and showing that ever-lower levels cause harm.
We release mercury into water bodies or the atmosphere through coal burning, gold mining, and other human activities. A BRI report released just before the Geneva negotiations showed that there are 14 countries in which mercury levels regularly exceed US Environmental Protection Agency (EPA) standards. True, in Europe and North America mercury emissions are on the decline, but treaty coordinator United Nations Environment Programme assert that they are rising quickly in the developing world. With the new treaty, the production, import, and export of certain mercury-containing products will be banned, meaning that governments will need to create plans to reduce mercury in small gold mining operations, and puts some controls on industrial facilities.
However, some environmental groups have asserted that the requirements of the treaty are too weak. Evers notes, ‘In the end the treaty will reduce mercury that’s being released into the environment. And I think the question will be, as we move along, “Is it enough?” — especially for areas that are sensitive to mercury input. And then “Is it enough for wildlife conservation purposes?” which really wasn’t addressed all that well.’ One country that’s going further to prevent and reduce mercury emissions is the US, which has already implemented a ban on the export of elemental mercury. Moreover, the EPA is finalising new limits on coal plant emissions.
Still, is this enough to safeguard animals from mercury exposure? While much of the research is concentrated on how fish have been affected by mercury, Bill Hopkins, a Virginia Tech physiological ecologist, and other have recently uncovered mercury in reptiles, amphibians, insects, spiders, terrestrial songbirds, and a wider variety of mammals than expected. ‘All these different groups can be exposed to mercury and pass it on to their babies,’ he says. Even low doses can cause problems that aren’t always obvious, says Gary Heinz, a recently retired federal wildlife biologist who studied it over four decades. He argues, ‘Methylmercury is one of most toxic environmental pollutants we’ve ever come upon.’
Still, Evers points out that, weaknesses aside, the new treaty represents a ‘great step forward.’ The good news is that once local sources are controlled, there could be a quick drop in the mercury in nearby wildlife. However, the fact remains that mercury from coal burning can travel great distances — for instance, from China to North America — before settling. Therefore, Evers concludes that the future of wildlife and mercury exposure is cloudy, to say the least. ‘The more we look [for mercury exposure in wildlife] the more we find, and the more we find the lower that toxicity level is going. Right now at a global level, mercury is just being released more and more in the system. Those trend lines are going in the wrong directions.’