Songbirds and bats suffer some of the same types of neurological disorders from mercury as humans and especially children, says the study “Hidden Risk” by the Biodiversity Research Institute. New US federal standards limiting pollution from power plants are meant to safeguard human health, but they should have an important side benefit to also protect a broad array of wildlife that has been harmed by mercury emissions.
Songbirds with blood mercury levels of just 0.7 parts per million (ppm) generally showed a 10 per cent reduction in the rate at which eggs successfully hatched. As mercury increases, reproduction decreases. At mercury levels of greater than 1.7 ppm, the ability of eggs to hatch is reduced by more than 30 per cent. Overall, birds at contaminated sites were found to be three times as likely to abandon their nests or exhibit abnormal incubation or feeding behaviour.
Mercury, which occurs naturally in the earth, is released into the air when coal is burned in power plants. The gaseous mercury can drift hundreds of miles before settling back to earth, sometimes along with rain. The organic form, methylmercury, is a neurotoxin that can enter the food chain. Small insects, worms and snails that feed on forest litter absorb the mercury. They in turn are eaten by birds and other small animals, and so on through the food chain.
Source: The New York Times, 23 January 2012