Publication Summary

In the fall of 2006, fish from the Similkameen River and Palmer Lake were analyzed for several forms of arsenic.

Inorganic arsenic was not detected. Less than half of the samples had detections of total arsenic and organic arsenic. Total arsenic was found to be slightly higher than Washington State and national average concentrations for total arsenic in freshwater fish.

The Washington State Department of Health reviewed the results of the study and concluded that there is no risk to human health based on the consumption of inorganic arsenic in fish from the lower Similkameen River and Palmer Lake.

In the fall of 2006, the Department of Ecology analyzed fish from the Similkameen River and Palmer Lake for total arsenic, inorganic arsenic, monomethylarsonic acid (MMA), and dimethylarsinic acid (DMA). This study was conducted to determine the potential of human health risk from consuming fish from the river. It was conducted as follow-up monitoring recommended by the 2005 Lower Similkameen River Arsenic Total Maximum Daily Load assessment and associated detailed implementation plan.

There were no detections of inorganic arsenic in fish tissue; inorganic arsenic is considered the most toxic form of arsenic to humans. Less than half of the samples had detections of total arsenic, MMA, and DMA. The detected arsenic results were highly variable, with detections occurring at all of the sampling locations.

Total arsenic was found mostly in suckers, and DMA was detected only in suckers and rainbow trout. MMA was found in lesser amounts in kokanee, rainbow trout, and mountain whitefish. Total arsenic was found to be slightly higher than Washington State and national average concentrations for total arsenic in freshwater fish.

The Washington State Department of Health reviewed the results of the study and concluded that there is no risk to human health based on the consumption of inorganic arsenic in fish from the lower Similkameen River and Palmer Lake.

Link to EIM data for User Study ID BERA0004