---

Mercury Toxicity in the Food Chain

Poster presented May 1999, at the South Florida Restoration Science Forum

 

Locations in the United States which have
the highest concentration of mercury in freshwater fish*

The Florida Department of Health issues advisories on consumption of fish in some areas because of mercury (the most frequent) and other contaminants. The advisories are online at: http://www.state.fl.us/fwc/fishing/health.html [note: new URL is http://myfwc.com/Fishing/health.html]. A map of the advisory areas can be seen at: http://www.state.fl.us/fwc/fishing/Fishes/images/mercmap.gif.
[note: new map URL is http://www.floridaconservation.org//fishing/images/mercmap.gif ]

The U.S. Environmental Protection Agency also maintains a web site of fish and wildlife advisories at: http://fish.rti.org.

The advisories indicate that fish with Mercury levels of less than 0.5 ppm are safe for unlimited consumption while fish with Mercury levels exceeding 1.5 ppm are unsafe and should not be eaten, especially by children and women of child bearing age. The advisories and map show that along most of Florida's coast, certain species of marine fish should only be eaten in moderation. In the central Everglades, the advisories and map show that many freshwater fish should not be eaten due to very high levels of Mercury.

The U.S. Environmental Protection Agency has a national database with results from the Mercury analyses done by all the states. For comparative purposes, we did a review to identify the locations with the highest concentrations of Mercury* in freshwater fish.

The locations with the highest concentrations of Mercury in freshwater fish* are (see graph above):

• Florida (L-67A Canal in the Everglades): 4.36 - 3.2 ppm
• New Jersey (Atlantic City): 4.11 - 3.45 ppm
• New Jersey (Manasquan River): 3.87 - 2.49 ppm
• North Carolina (Columbus County): 3.6 - 2.9 ppm

* The results for the 7,000 Large-mouth Bass fillets in the database were used for this purpose. (There are various species of fish and sampling tissues in the database. Large-mouth Bass fillets were chosen as being the most common throughout all the states and the most likely to be eaten by humans.) The ranges shown in parts per million (ppm). For further information, please see "Mercury Study Report to Congress" (December 1997), U.S. Environmental Protection Agency: http://www.epa.gov/ttn/oarpg/t3/reports/volume1.pdf (95 pages).

Mercury Update: Impact on Fish Advisories (EPA fact sheet, 8 pages, pdf ) http://www.epa.gov/ost/fishadvice/mercupd.pdf

Heath Risks from consuming contaminated noncommercially caught fish and wildlife: http://www.epa.gov/ost/fish/

Mercury in Fish: Guidelines for Consumers: http://foodsafety.ifas.ufl.edu/il/il104.htm

South Florida Mercury Science Program (Florida Dept. of Environmental Protection)

Websites that convey the toxicity of mercury:

In 1996, a laboratory researcher was fatally poisoned by a one time, momentary exposure to a very tiny drop of dimethylmercury onto a latex glove covered hand. (Note: dimethylmercury is far more toxic than methyl mercury that exists in the environment, but the mercury poisoning effects are the same.)

Dartmouth researcher poisoned by material she was studying (Associated Press, 3/28/97)

Dartmouth College scientist whose specialty was the dangers of heavy metals died of mercury poisoning this week (Associated Press, 6/11/97)

Final report regarding the diemthyl mercury fatality at Dartmouth

Mercury and Mercury Compounds Hazards

Back to the Mercury homepage