Research heightens concerns about chemical effects on salmon

Nat Scholz of the National Marine Fisheries Service in Seattle continues to make startling discoveries about what may be killing our Pacific Northwest salmon.

In findings under review for publication, Scholz has found that common organophosphate pesticides can inhibit neurologicial enzymes that can be key to behavior, such as finding food. See this item in today’s Science Now, a publication of the American Association for the Advancement of Science.

The article quotes Scholz:

The biggest surprise was the strength of the synergistic punch from the pesticides diazinon and malathion, which killed all the salmon exposed to them. Even at the lowest concentration, fish were extremely sick, Scholz says. “It was eye-opening,” Scholz says. “We’re seeing relatively dramatic departures” from what happens with each pesticide by itself.

Scholz says the findings, which are in review for publication, mean that the U.S. Environmental Protection Agency may be underestimating the hazard pesticides pose to salmon. Given the hundreds of millions of dollars being spent to help salmon populations recover, it’s crucial to have a good handle on the biggest threats, he adds.

Scholz has been involved in critical research regarding the toxic effects of copper on the ability of salmon to home in on their natal streams. See National Marine Fisheries Service or a two-part series I wrote about stormwater in 2006. Part 1 and Part 2.

We’ll be hearing more about these issues when they come out in publication and as the EPA is further challenged to address low-level toxics.

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