A SAMPLING of landlocked salmon from Maine's Sebago Lake, a famous and productive body of water for anglers, has shown that the fish contain amounts of D.D.T., the toxic insecticide, exceeding the safe limit set oy the Government for human food.
Of the sample of 22 fish, half of the 4 and 5yearold salmon were found to exceed the limit and onequarter were found to have ingested twice the safe maximum of poison that humans are cautioned not to exceed.
The Federal Food and Drug Administration has said that the limit for human food is seven parts of D.D.T. a million. The Maine fish had died from as little as one part D.D.T. a million, according to Ronald T. Speers, Fish and Game Commissioner, and Stuart DeRoche and Richard Anderson, state fishery biologists.
The study was begun in 1962 in an effort to find out why Sebago salmon were low in numbers and growing more slowly than had been the case in previous years.
Analysis by a laboratory specializing in such work showed nearly three times as much D.D.T. in the latest sample as there was in the sample taken in 1962.Continue reading the main story
The fish in the recent test were taken during the 1963 spawning run and included fish of both sexes. Salmon in good, or fat, condition as well as poor, or thin, fish were tested.
In the 1962 sample, whole salmon showed D.D.T. concentration of 1.16 parts a million and a similar fish in 1963 carried 3.22 parts a million. These figures would be conservative since the fish had been stripped of their eggs in which D.D.T. concentrates heavily. A test of salmon eggs from Lake Sebago fish disclosed a concentration of 7.5 parts a million.
The largest salmon were found to contain the most poison, which is taken in through various ways but accumulates in the fatty layers throughout the meat. Thus it cannot be removed by cleaning. D.D.T. is taken in by fish through water and from insects killed by D.D.T. sprayed on the land.
The report said that the poisonous residues averaged 1.3 parts a million for 3yearold salmon, 7.9 parts a million for 4yearold fish and 8.8 parts a million for 5yearold salmon analyzed in the latest sample.
The report also cited a chemical substance called D.D.E. that was found in the salmon. It was said that as a fish or animal used up its supply of fat in periods when food was scarce or unavailable, its body chemistry changed D.D.T. to D.D.E. In the fish tested, up to 42 parts a million of D.D.E. was found and “indicated that the salmon had actually taken more D.D.T. than was found when they were tested.”
The Fish and Game Department said it hoped that an understanding of the tests would lead the public to stop spraying D.D.T. around fishing waters.
Last year the New York State Conservation Department found that the D.D.T. it was spraying to kill insects was reducing lake trout population.
Since 1960 millions of catfish, mullet, weakfish and other species have died in the Mississippi River each year. After exhausting other areas of investigation, public health officials began examining the fish and the mud and the water they live in.
They have now discerned “minute” traces of toxic insecticides in the fish but have found no “immediate health problems.”Continue reading the main story