Endangered Great Lakes

For 20 years, U.S. and Canadian industries have dumped millions of pounds of toxic mercury into the Great Lakes watershed. Now the result has caused alarm in both countries. On the heavily fished Lake Saint Clair, recent tests of pike and pickerel showed mercury levels as high as seven parts per million--14 times the maximum level deemed safe in fish for human consumption.

Last month local officials in the U.S. and Canada totally banned fishing on Lake Saint Clair and partly banned it on Lake Erie. Last week Interior Secretary Walter J. Hickel ordered a federal investigation of all lethal substances discharged into the Great Lakes' U.S. waters. In Ludington, Mich., for instance, five electroplating companies were recently found dumping cyanide into Lake Michigan, source of drinking water for millions of people. As for mercury, Hickel will stop all lakeside discharges if Governors of the affected states ask him to do so.

Clear Threat. The sudden interest in mercury is based on a flurry of mercury-poisoning cases--including more than 100 deaths--in Japan, Iraq, Guatemala, Pakistan and New Mexico. The toxicity of mercury is well documented; Lewis Carroll's portrait of the Mad Hatter in Alice's Adventures in Wonderland was inspired by the fact that 19th century hat makers used mercury (to shrink fibers for felt) that damaged hatters' brains and literally drove them mad.

U.S. industry alone consumes 5,300,000 lbs. of mercury a year. Most of this is used by paper companies to prevent the formation of slime, and by chemical plants as an electrode in the production of chlorine. Much of the mercury lost in these processes is believed to be picked up by microorganisms in lakes and rivers and passed up the food chain to larger fish. By the time it reaches predators like the pickerel and perch, its potency has been multiplied as much as 4,000 times. Since these fish are prized by fishermen, the suspected ultimate poison (methyl mercury) is a clear threat to human health.

Everybody Wrong. Ontario officials have given eleven paper and chemical plants on Lakes Erie and Saint Clair until May 1 to clean up. Michigan officials have been less charitable. They closed Wyandotte Chemicals Corporation's mercury-dumping operation on the Detroit River last week, and will allow it to open only after the company has installed a temporary recycling system. A group of angry Ohio commercial fishermen last week filed a $100 million damage suit against both Wyandotte and a Dow Chemical plant at Sarnia, Ont. The Canadian government has agreed to pay fishermen $500,000 compensation for the new antifishing rules.

These steps are only a beginning. Neither the U.S. nor Canada has a system for monitoring mercury spillage; neither has set up standards for the safe amount of mercury in foodstuffs. Worse, many pollution experts are still quite unclear about the subtleties of water-borne mercury. As one Canadian official recently remarked: "Everybody thought that since mercury was 13 1/2 times heavier than water, it would sink right to the bottom." Everybody was wrong.

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