Chemicals

Dioxin in Lake

Challenge:

A large, popular recreational lake near a paper plant in Alabama suddenly sprouted signs posted by the Alabama State Department of the Environment warning that the lake was contaminated and any fish caught there were toxic to humans. The lake was closed to all recreational activity. Fisherman were frightened, homeowners were worried about the value of their property and citizens who used the lake for recreation didn't know whether it was safe to boat, swim or water-ski. Resort owners were calling state agencies, angry about cancellations.

Solution:

Regular testing of the fish in the lake had revealed dioxin present at 3 ppt (parts per trillion); one fish exceeded a federal guideline (at 8 ppt). We performed a review of the available toxicological literature, including that considered by the federal government's Agency for Toxic Substances and Disease Registry (ATSDR), the Environmental Protection Agency (EPA) and the World Health Organization's International Agency for Research on Cancer (IARC). None of the literature revealed any risk to human health from dioxin at such levels. The Alabama EPA used a thousand fold measure of safety in its decision to post warning signs, far below any known toxicologically harmful levels. We communicated our findings to various stakeholders and to the local medical society, whose members then became a part of the communication solution. The signs were removed.

Reflection:

Understanding stakeholders' concerns, finding local allies, like the physicians we collaborated with in this case, and equipping them with relevant medical and scientific information was an effective approach in assuaging this distressed community.

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