UW News

September 23, 2021

Video: Arsenic makes these south Puget Sound fish unsafe to eat

Researchers at the University of Washington and UW Tacoma have been studying arsenic levels in the mud, water and in creatures from lakes in the south Puget Sound area. Eating contaminated fish or snails from these lakes could lead to health risks because of the high arsenic levels found in those organisms.

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Pollution from regional smelter emissions is likely the source of high concentrations of arsenic found at the bottom of lakes in King and Pierce counties. Arsenic is a chemical linked to increased cancer risk. 

The researchers found that creatures that live in shallow lakes (such as Bonney, Steel and Killarney) were more likely to have higher levels of arsenic compared to creatures living in deeper lakes (such as Angle Lake) even though Angle Lake and Lake Killarney have similar levels of arsenic on the bottom. The team detected levels associated with increased cancer risk for the following activities: 

  • Eating snails from any of the studied lakes for one meal a month
  • Eating crayfish from Steel Lake and Lake Killarney for one meal a month
  • Eating sunfish from Lake Killarney for two meals a month

The team is currently working with the Department of Health and Department of Ecology on actions to protect human health. The researchers are also beginning to work on an affordable and effective way to clean up the lakes. 

A big mouth bass being held over a tank.

Big mouth bass caught in Lake Killarney.Kiyomi Taguchi / University of Wsahington

Read more about this research here. 


For more information, contact Jim Gawel at jimgawel@uw.edu and Rebecca Neumann at rbneum@uw.edu.