It's no surprise that a chemical as potent as methylmercury harms wildlife when it enters an ecosystem in high concentration. In the case of wetland birds, researchers have found, it can even change sexual orientation, causing males to pair off with other males.
"We knew mercury could depress their testosterone (male sex hormone) levels," explained Dr Peter Frederick from the University of Florida, who led the study. "But we didn't expect this." [BBC News]
