I think a lot of the disparity in the study between fresh & salt water populations is due to such a large portion of the salt water remains being decomposed or degraded beyond a point where cause of death could be determined.

That said, the freshwater results clearly indicate that lead contamination is an issue. If we REASONABLY curtail the use of lead in favor of less toxic/non toxic options I don't think we will see any improvement in the lead related mortality for quite some time due to the existing material already in the water, but we should be able to avoid any increased mortality due to lead and over time allow the causes of mortality to shift back to more natural ones.

A total lead ban is far from reasonable.