Technician at the BCF Ann Arbor Biological Laboratory determines concentration of pesticides in samples of river and lake water. More study is needed to identify toxic substances that may be dangerous or lethal to aquatic life and humans when contaminated food is eaten.

Image ID: fish7938, NOAA's Historic Fisheries Collection
Location: Michigan, Ann Arbor
Photo Date: 1969 circa
Credit: NOAA Central Library Historical Fisheries Collection; P. 350 of "Our Changing Fisheries" 1970 Centenary NMFS centenary volume

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