Document O17aJBNywN8EYr0k6b7BDaO3L

C-- '/*R'i3GE, JV'O. CAIWER D. G,5D0 JUN 4 875 ----Growing More Complex- It' good to kno# two major blrdi of prey, oaglei and oapreya, are staging a itrong comeback lit the Cheaapeake Bay area. Aerial surveys confirm more than a dosen pairs of eagles this year have produced offspring in the Blackwater River area. Ospreys are reported nesting in good numbers in Dorchester County. . ' DDT is usually blamed for the failure of breeding birds to reproduce in the 1150s and 1900s. The nationwide ban on the pesticide is credited with the good showing made this spring by Dor chester's bald eagles. Yet the Chesapeeke populations were never as badly threatened as were birds in other parts of the country and biologists successfully moved osprey eggs from . i the Chesapeake to Long Island Sound - and eagle eggs from Marylend to Maine where reproduction had fallen almost to sero. . Yet all the blame can't be put on DDT alone. Ornithologist Jan Reese of St. Michaels, a man who is more knowledgeable about bay ospreys than anyone else in Maryland noted thet the Mg birds do better in the Choptank than In Eastern Bay. Waterfront development, heavier water travel and other factors may be responsible for the Eastern Bay situation, Reese told the Dorchester Bird Club recently. Ris statement that the polychlorinated, biphenyls XPJvSJu. materials used widely by Industry far ,, their insulating and solvent properties, may be a significant threat to wildlife is borne out in a recent article In Oceanus, a publication of the Woods Hole Oceanographic Institution. Researchers have found a number of significant things. "DDT is not as persistent ss once believed and is confined fairly close to the point of its introduction." The food chain magnification concept, popularised by Rachel Carson, which said chlorinated hydrocarbons are concentrated in the higher organisms, works for air breathing animals but not water breathing animals. And the ocean sediments close to shore show the ability to absorb heavy quantities of DDT and PCB In areas where the chemical and marine life con centrations are greatest These preliminary findings suggest that the question of environmental pollution is extremely complex. While there is hope in the discovery that the .oceans of water and air seem to possess self-healing qualities, the ban on DDT did not end the pollution problem. PCB and other chemicals not yet identified may well be time bombs. Analysis of the Choptank and other waters by the state this year is scheduled to be carried out this year. Until that is done, we cannot know how much of a burden our local waterways are carrying. The findings could have a bearing on men as well as oysters, ospreys and rockfish. HONS 031222