Sentinels of Health Threats from Human Consumption

“Is my fish safe to eat?”

Anglers fish in rivers and streams that may appear to be pristine, but in fact, can contain trace amounts of contaminants that make the water impure and the fish unsafe to eat. USGS scientists are studying how contaminants in water and sediments, such as mercury and DDT, accumulate and concentrate in fish tissues. The presence of these substances can create a potential health risk to people who eat the fish.

Swallows also serve as sentinels for toxic substances in the food web. Insect-feeding swallows can warn of soil and water impurities such as PCBs and arsenic that may sit below the surface of our soils, lakes, and harbors. USGS scientists use swallows as sentinels to assess heavy metals, dioxins, PCB, and other soil contaminants.

In Pakistan, USGS scientists are investigating how a drug for sick cattle turned out to be highly toxic to white-backed vultures. These wild raptors are sentinels for a problematic new drug that unexpectedly threatened public health when the vulture populations declined precipitously. Feral dog populations increased to replace the vultures, and communities lost their traditional means of disposing of cattle carcasses in a country where people do not eat cows.

Links to USGS Sentinel Research Projects

• USGS Mercury Activities
• USGS scientists use swallows as sentinels to assess heavy metals, dioxins, PCB, and organochlorines in sediments.
• Pharmaceutical residues in cow carcasses in Pakistan cause vulture deaths/declines.

More Information

• Human Health and the Great Lakes, fish consumption
• Orca Study on Contaminants in Puget Sound Salmon: Washington Dept. of Fish and Wildlife

Accessibility FOIA Privacy Policies and Notices

U.S. Department of the Interior | U.S. Geological Survey
URL: http://health.usgs.gov/sentinels/human_consumption.html
Page Contact Information: Herb Buxton
Page Last Modified: 15-Jun-2006@08:37