Interesting study on bees...scientists have been looking at potential impacts of coal ash applications to soil for quite awhile. You can download the study free at PLoS One. Here's an excerpt from an article about the study:
Heavy metals and toxic soil contaminates that build up in plants may be killing bees and reducing their ability to pollinate crops and produce honey.
New research by entomologists at the University of California suggests selenium - a trace mineral used as a superconductor in the electronics industry - can kill bees foraging for pollen from plants in heavily polluted areas, such as disposal sites for fly-ash from coal-fired power stations.