Nat Scholz examines how pesticides that run off the land and mix in rivers and streams combine to have a greater than expected toxic effect. He examines the salmon nervous system, but these mixtures in the food supply for humans may also pose unexpected health risks for people.

According to Scholz, “We have a pretty good handle on how to assess the health effects of single chemicals in conventional toxicity trials. But the real world is usually more complex, and exposures to mixtures of chemicals can be more of the rule than the exception. One of the major scientific challenges of our generation is to develop new approaches to anticipate and head off any ill effects of interacting chemicals.”

Scholz and his colleagues found that salmon died when exposed to combinations of pesticides that were not deadly in the same amounts individually. The research points to the need for more study of how combinations of pesticides found on fruits and vegetables affect humans.