Document QXj687xeQ8O9rngKQMO5bkBN6

r i3 V"> r- ** r: j 1 Vi TH H '<5 J ^ '.14 v '-.y r;a \\ ,.i . i :j j J Editor's Note: This is a speech given at a Symposium on Pesticides and Environmental Health in March at Montgomery. By JAMES E. KEELER ` . Research Biologist Came and Fish Division ` HE TERM, "chlorinated hydrocarbons," T first became widely used in wildlife circles in Alabama during the Fire Ant Eradication Program of 1957-58. Prior to that time, limited use of powerful pesti cides had not attracted the attention of - the majority of conservationists simply because few dead wildlife specimens were found that could be directly at tributed to pesticide poisoning. As man leaves the destructive 1960's, he carries a tremendous load of chlorin ated hydrocarbons with him. His suitcase . is packed with such TNT as DDT, aldrin, dieldrin, endrin, and heptachlor. A small space was still available so this v/as packed with organic phosphates. With such a deadly arsenal of pesti cides facing every living thing in the world, one can only speculate as to what the 1970's will bring. Man awakens slowly, and even then he hesitates to ad mit his mistakes. How do you tell that to the eagles, the pelicans and the pere grine falcons which are rapidly being decimated from our environment? Pesticide Levels Since 1962, much v/ork has been ac complished on the effects of pesticides on wildlife, both in the field and in laboratories. Even with more sophisti cated techniques, it still remains difficult to ascertain just how much DDT or other chlorinated hydrocarbons it takes to kill O quail, a deer, or a robin. A multitude of laboratory tests have been conducted on certain species of birds and mam mals where controlled amounts of a cer tain pesticide have been fed to each animal only to have about six of the 10 die, two others exhibit traumatic symp toms and perhaps two others to exhibit no symptoms at all. Due to the differ ences in the physiology of the individual animal, minimum lethal dosages of pes ticides are very difficult to determine. Of great concern to wildlife biologists ore the animals that survive high dosages of pesticides. Studies have shown dras tic changes in reproduction and also pronounced behavioral changes in cer tain birds and mammals carrying large doses of chlorinated hydrocarbons. An example of how pesticide levels can increase in animals at the top c' the food chain would be the study con ducted at Clear Lake, Calif. DDD was applied- to Clear Lake to a level of .02 ppm (20 parts per billion) of water for nuisance midge control. Thirteen months later, analyses showed the residue levels were 10 ppm in plankton, 903 ppm in the fat of plankton-eating fish, 2690 ppm. in the fat of carnivorous fish, end 213 ppm in the fat of fish-eating birds, most of which had died. This represents a 100,000 fold increase in fish-eoting birds over levels in the lake water. Other Examples Cited Other examples of pestcides in wild life ore as follows: 1. Dieldrin in big game mammals cf South Dakota exceeds the zero toler ance for dieldrin in meats set by the U. S. Government. 2. Brain tissues of dead robins on arecs sprayed with DDT for Dutch elm dis ease have contained as much cs 2-0 ppm of DDT residues. 3. A 10-acre area in Autauga County, was treated with heptachlor at the rate of two pounds of undiluted tech nical grade chemical per cere as a part of the Fire Ant Eradication Pro gram. Seven days efier application, three quail, six rabbits, three opos sums, one raccoon, one barred owl, 10 cardinals, 20 sparrows, two blue jays, one mockingbird and ore white ' footed mouse were found dead or dying. In Wilcox County, a total c: 180 animals of 24 species were found dead or dying during a seven week period after application. Important To Hunters, Fishermen Pesticide residues in game species are .important to hunters and fishermen. A national survey conducted in 1950 showed that two of every five persons in the United States went hunting or fishing, or both, and spent $3.9 billion annually. The average consumption cf ggme per individual in the U. S. is 2.7 pounds per year. Earthworms, which constitute the ma'n food of many birds such os woodcocks and robins, show a resistance to all ex cept very heavy doses of pesticides. Earthv/orms from 67 fields of 14 crop types in eight states concentrated or ' A LA BA MA COXSFRIVITIOS STLCOPCB4059452 ganochlorines to ae average of nine times the concentration of llie surroundr^frfQ^soil. I Recently, polychlorinated biphcrvyls have been discovered in wildlife sam^ I pics. These PCB's are industrial pollu tants and, like insecticides, are widely distributed in wildlife from Great Brit ain, Sweden, and North-America. PCB's have interferred with the determination of other compounds and have caused a' l re-evaluation of the original findings, \ especially the readings on DDT and its, \jjetabolites. Pesfi2Tde~Efife"cts On Reproduction laboratory tests show that DDT and dieldrin can pass from mother to off spring through the placenta in mice, dogs, rabbits and man. They are also found in the eggs of birds. In birds, DDE appears to be the en vironmental pollutant most responsible for thin eggshells. DDT residues cause hormone induction in eagles and other birds which upset calcium metabolism ond produce egg shells too thin to pro tect embryos. More specifically, DDE causes inhibition of the enzyme, carbonic onhydase, which is responsible for egg shell thickness. The story of the brown pelican is a good example of what is happening to birds at the top of the food chain. On March 20, 1969, an expedition was sent to Anacapa Island, off California, to study pelican nesting success. Some 298 nests were counted. Intact eggs were present in only 12 nests. Nine contained a single egg and three contained two eggs. Fifty-one nests contained a single broken egg. These eggs had shells that were spongy in texture and a slight pres sure produced a change in their shape. Portions of the shell were flaking, ex posing the membrane. The remaining 235 nests contained no eggs. Some broken eggs were collected for analysis. One egg analyzed contained 68 ppm of DDE. Second Colony Visited On April 18, 1969, a second nesting colony was visited on a different part of the island and 339 nests were found. Nineteen contained intact eggs. Of the 320 nests without entire eggs, one of three had a collapsed, dehydrated egg. The reproduction at both nesting sites was a complete failure. Farther south, in the Gulf of California, reproduction in 1969 v/as reduced by one-third. On the Atlantic Coast, the thickness of brown pelican eggshells has been reduced by os much as 18 percent. Since 1947, eggshells have become thinner in all of the meat-eating birds. Eggshells have decreased from 19 to 26 percent in ihe U. S. peregrine falcqn April. 1970 i&imisra BROWN PELICAN MARCH 20,1969 j________ APRIL 18,1969 51 235 o 19 107 223 nests. Eggshells of bald eagles have de creased 18 percent; golden eagles, nine percent; ospreys, 25 percent; ond spar row hawks from 16 to 25 percent. Serious At Top In the eastern half of the United States where pesticides have been more widely used, the situation has become very se rious for birds at the top of the food chain. The peregrine folcon has ceased to breed in this area. The nesting suc cess of bald eagles in the Chesapeake Bay region has decreased from 97 per cent in 1936 to between nine gnd 23 percent during the past five years. ' Studies conducted in white pelican and cormorant nesting colonies show a marked change in the behavior of these birds around their nests. Birds carrying high concentratons of DDT residues not only lay thinner eggs but exhibit a more careless attitude around their nests. This behavior, when combined with the lay ing of eggs with thinner shells causes many broken eggs. Since the appearance of the white man in what is now continental United States, four birds ond eight mammals hove become extinct ond many others are becoming rare ond endangered. The major cause of extinction of these birds ond mammals hos been attributed to habitat destruction. All became ex tinct before the introduction of chlorin ated hydrocarbons. It appears that an other very destructive agent other than loss of habitat can now be added to man's inadvertent attempt to destroy life. This new agent is chlorinated hydrocar bons. How do you tell that to the eagles? Reference Sources 1. MacMullan, Ralph A., 1968. The Case Against Hard Pesticides, Reprinted from Michigan Conservation. Jan.- Feb. 1968. 2. Anonymous, 1966. Fish, Wildlife and Pesticides, USDI. 3. Stickei, Lucille F., 1968. Orgonochlor- ine Pesticides in the Environment. USDI. Special Scientific Report -- Wildlife No. 119. October 1968. 4. Davey, Stuart P., 1963. Effects of Chemiccls on Earthworms: A Re view of the Literature. USDI Spe cial Scientific Report -- Wildlife No. 74. September 1963. 5. Anderson, Daniel W., Joseph J. Hick ey, RobertVARisebroyghi_Dongld f. Hughes ond Robert E. Christen sen, 1969, Significance of Chlor inatecTHydrocarbon Residues to Breeding Pelicans and Cormorants ' The Canadian Field-Naturalist, Vol 83, No. 2, pp. 91-112, April-June 1969. --- -------------- 6. Porter, Richard D., and Stanley N Wiemeyer, 1969. Dieldrin and DDT: Effects on Sparrow Hawk Eggshells and Reproduction. Sci ence, Vol. 165, pp. 199-200. July 11, 1969. 7. May 5, 1969. Conservation Founda tion Newsletter. 8. Brown Pelican Newsletter, National Audubon Society July .1969. DSW 201388 STLCOPCB4059453