It was a first for veteran anglers at one of the Allegheny River's hottest spots. They were being asked to donate their fish to science. On a recent Saturday, a cadre of fishermen at the Highland Park Dam filled buckets with white bass and channel catfish so that Dan Volz, a public health expert, can tell them someday soon whether what they catch is loaded with heavy metals and estrogen-like compounds, or chemicals that mimic the effect of estrogen, a hormone produced by the body and needed for the development and growth of female sex organs. snip While there are...