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The eggs of bluefish caught off South Carolina contain 4.11 ppm of DDT residues. According to Dr. Lionel A. Walford, director of the U.S. Bureau of Sport Fisheries laboratory at Sandy Hook, N.J., where most of the research on Atlantic coast bluefish has been done, these South Carolina bluefish were probably migrating north from Florida when caught. Baby bluefish spawned in Carolina offshore waters in the spring eventually grow up to supply an important sport fishery as far north as southern New England. Striped bass from the Rappahannock River have 2.03 ppm of DDT residues in the eggs. Striped bass from this river and others tributary to Chesapeake Bay, the single most important striper spawning ground on the Atlantic coast, migrate from Virginia to Massachusetts. The majority offish tested also had traces of BHC, another chlorinated hydrocarbon, in the flesh and eggs. The effect of BHC on fish reproduction is unknown, and the Food and Drug Administration has set no maximum on BHC in fish. As Taylor Quinn of the FDA remarked as this article was being prepared, "It's unusual, to say the least, to find BHC in fish."
WARF Institute also tested all egg and flesh samples for residues of PCBs, the abbreviated name given to the poly-chlorinated biphenyls, a synthetic chemical compound used by various industries. PCBs are heat resistant and are widely used in the electrical industry as insulating fluids for transformers and capacitors. They are also used in plastics and adhesives.
PCBs have been made in the U.S. since 1929, but they were not identified as such in fish and birds until a few years ago. Chemically similar to DDT, they baffled investigators who reported finding "unknown but chlorine-containing compounds." In 1966 Dr. Soren Jensen, a Swedish scientist, was able to separate the compounds from DDT and identify them as PCBs in a sea eagle and in the bodies of more than 200 fish taken from different parts of Sweden. Dr. Jensen then analyzed eagle feathers in a museum collection. Some of the feathers were collected as far back as 1880, but Dr. Jensen first found PCB residues in feathers collected in 1944. After Dr. Jensen published a paper on his findings, Dr. Robert Risebrough of the Institute of Marine Resources at the University of California at Berkeley found PCBs in a number of Californian, Mexican and Arctic sea birds. He noted that the highest levels of PCBs in birds were from those closest to industrialized areas. In a later investigation he also found PCBs in samples of mother's milk from women in San Francisco and Los Angeles. In a paper in Environment early this year he called for the establishment of tolerance limits of the compound in human food. Thus far, the FDA has set no standard.
Another scientist, Robert Huggett of the Virginia Institute of Marine Science, says the toxicity of PCBs to marine animals seems to be about the same as that of DDT. At present, the Virginia Institute of Marine Science is conducting studies to determine the levels of PCBs in estuarine sediments, oysters, fish and crabs in the Chesapeake. The institute is also trying to locate the origins of the PCBs. At the Bureau of Commercial Fisheries lab in Gulf Breeze, Dr. Thomas Duke and associates have found that only 1.0 part per billion of PCBs in water will adversely affect the growth of oysters.
The precise significance of the WARF findings of PCB residues in the eggs and flesh of the fish submitted by SI has yet to be determined. However, PCBs are present in the flesh and eggs of all samples. The WARF findings, it should be noted, are estimates based on one peak on a gas chromatogram, but scientists who have reviewed the data for SI and who have experience in the field say the estimates are valid. The highest PCB residues in flesh are in the Hudson River striped bass, 4.01 ppm. The California striped bass had the highest PCB residues in eggs, 17.0 ppm. Other egg residues of possible significance were Hudson stripers, 11.4 ppm; South Carolina bluefish, 2.81; and Rappahannock stripers, 2.31.
In assessing the WARF findings for SI, Dr. Robert Smolker, an ecologist at the State University of New York at Stony Brook, said, "I'm horrified by some of the data. I am quite surprised to find such residues in fish from the ocean, but I certainly don't think people should panic." What, then, should the public do or demand? There are a number of steps that can be taken.
For one, the study is merely a first effort, and nationwide monitoring programs of more samples are needed to determine the presence and levels of contaminants in wildlife. Moreover, considerable research needs to be done on the ecological side effects of new pesticides coming on the market. This research is very expensive. It now costs as much as $10 million to clear a new pesticide for federal registration. As of this year, however, the Department of the Interior has a ceiling of $3 million in appropriations for all pesticide research, and of that less than $700,000 is allotted to the Bureau of Sport Fisheries and Wildlife for fish research. Several scientists have proposed that the additional needed money come not from Government funds but be raised instead by imposing a small excise tax, based on volume sold, on pesticide manufacturers. No scientist queried doubted the need for pesticides; the only question was which pesticides will not damage the environment. At present, problems remain considerable and seemingly insoluble. There has been a great deal of talk about phasing out DDT, but DDT continues to be used on a substantial basis, and the same is true of other persistent chlorinated hydrocarbons. For instance, there has been a rapid increase in the use of two chlorinated hydrocarbons, chlordane and toxaphene, as substitutes for DDT, and both these compounds, which can be discerned in animals only after very involved laboratory testing, are starting to turn up in all sorts of places.
Not long ago Drs. Richard Schoettger and David Stalling of the U.S. Bureau of Sport Fisheries and Wildlife pesticide laboratory in Columbia, Mo. began a study of still another chlorinated hydrocarbon, endrin, in fish. They planned to feed the fish food containing endrin residues of 0.1 to 0.5 ppm. They ordered their test fish, channel catfish brood stock from national hatcheries and, as a routine check, they analyzed some of these fish for endrin. To their dismay, they discovered that the catfish already contained 0.5 to 0.88 ppm of endrin, more than was to be given them in the test food. This should not be surprising. Schoettger has yet to find a commercial dry fish food for sale in the U.S. that is not contaminated by chlorinated hydrocarbons.
Besides establishing a constant monitoring program of contaminants in fish and wildlife, efforts should be made to determine harmful levels to various species. Although worrisome, DDT residues in eggs are meaningless until we know that 5.0 ppm of DDT residues in conjunction with 8.0 ppm of PCBs, or whatever the figures may be, kill off a certain percentage of the hatch, be it none, a third or 90%. Then, of course, we need to know what levels may be harmful to humans.
Writing in Pesticides, Dr. Robert van den Bosch of the University of California at Berkeley points out that the public good requires that salesmen for pesticide manufacturers be brought under control. "The salesman is the key to the system, for he serves as the diagnostician, therapist and pill dispenser," van den Bosch says, "and what is particularly disturbing is that he need not demonstrate technical competence to perform in this multiple capacity. In other words, the man who analyzes pest problems, recommends the chemicals to be used and effects their sale is neither required by law to demonstrate (by examination) his professional qualifications (as do medical doctors, dentists, lawyers, veterinarians, barbers, beauticians, realtors, etc.) nor is he licensed. Yet this person deals with extremely complex ecological problems and utilizes some of the most deadly and ecologically disruptive chemicals devised by science."