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BLUBBER TESTING
By Sean Henahan, Access Excellence
SANTA CRUZ- Marine biologists have developed a new technique for measuring toxins in marine mammals that can provide a wealth of information on environmental pollution. Scientists have been lacking a simple and cost effective way of measuring environmental toxins in the tissues of live marine mammals. Until recently, the only source of this kind of data was in the form of dead whales or seals washed up on the beach. The new method allows marine biologists to extract information of contaminants from very small samples of seal blood and blubber. First, the animals receive an injection of a sedative and are restrained. The technique then involves using a 6 mm biopsy needle to extract 0.1 gm of blubber from a 1 cm incision near the seal's hip. Blood is drawn from the extradural vein of the seals, which have been immobilized before the specimen collection. The new method yields a high level of accuracy, well within guidelines established by Environmental Protection Agency. "This new method is good for several reasons. It uses small samples, it's cheap and it saves lots of time," notes Dr. Walter Jarman, a post-doctoral researcher at the Institute of Marine Science, University of California at Santa Cruz. As part of a study of severe skin disease observed in elephant seals, the researchers obtained specimens from 20 elephant seals at the Ano Nuevo Reserve, an island populated by a variety of marine mammals (and no humans). They were then able to determine accurately the levels of pesticide and PCB residues in each animal. Marine mammals have been used for many years as a kind of index of marine pollution. These mammals are vulnerable to pollution as toxic substances accumulate in their tissues over the years. Previous studies have shown that organochlorine compounds of the type being measured in the current study can cause reproductive problems in both seals and whales. These pollutants have also been shown to produce vitamin A and thyroid deficiency as well as reduced testosterone levels in whales. The new screening method gives researchers a much improved way to measure toxin levels in marine animals. In addition to aiding in the study of these animals, the data gained from the testing also provides critical clues to local pollution levels and can serve a warning of new contaminants in a given region. The new method is so effective that scientists at the Center for Disease Control in Atlanta plan to use it to measure dioxins in human blood. The study appeared in Chemosphere, Vol.23, No.14, 1795-1804. Transmitted: 95-02-28 18:30:57 EST
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