Figure 8. Detected malathion concentrations in the Hood River basin, Oregon, compared to USEPA and Oregon water-quality standards and toxicity and sublethal endpoints for salmonids and their prey. Acute, 24-hour exposure; chronic, 96-hour exposure; LC₅₀, 50 percent lethal concentration; NOEC, no observed effect concentration; EC_50, 50 percent effective concentration; LOEC, lowest observed effect concentration; *, values are for fathead minnow (Pimephales promelas), a less sensitive species, and are expected to be lower for salmonids.

First posted June 17, 2011