224 



Butler, Philip A. 1966. 



Pesticides in the marine environment. In Pesticides in the Environment 

 and their Effects on Wildlife. J. Appl . Ecol. 3 (Suppl.): 253-259. 



After exposure for 7 days to 1.0 ug DDT/liter in flowing seawater 

 Mercenaries mercenaries had accumulated 6 ppm DDT. This was considerably 

 less than residues in one species of mussel and 4 oyster species treated 

 similarly. After 15 days flushing hard clams retained residues of 0.5 

 ppm; the other species had higher residues. Rates of uptake and retention 

 were unpredictable and did not appear to be related directly to water- 

 pumping activity. On the east coast of the United States American oyster 

 is the best assay organism for DDT effects. If oysters are not present 

 Mercenaria or some other species may be substituted. - J.L.M. 



225 



Butler, Philip A. 1966. 



Fixation of DDT in estuaries. Trans. 31st N. Am. Wildl. Nat. Res. Conf.: 

 184. 



226 



Butler, Philip A. 1966. 



The problem of pesticides in estuaries. Trans. Am. Fish. Soc . 95(4) (suppl.) , 

 Spec. Pub. 3: 110-115. 



227 



Butler, Philip A. 1969. 



Monitoring pesticide pollution. BioScience 19(10) : 889-891. 



Mercenaria mercenaria was least efficient in storing pesticide residues of 

 all mollusks evaluated. - J.L.M. 



228 



Butler, P. A. 1971. 



Influence of pesticides on marine ecosystems. Proc. Royal Soc. London B177: 

 321-329. 



Mercenaria mercenaria accumulated various amounts of tissue residue after 

 5-day exposure to aldrin, DDT, dieldrin, endrin , heptachlor, lindane, and 

 methoxychlor. Mya arenaria accumulated substantially greater amounts of 

 all pesticides. After flushing for 7 and 15 days residues were reduced, 

 but the amount of reduction varied between compounds. Residues of some 

 compounds were reduced more effectively by Mya than by Mercenaria. For 

 meaningful assay it is obvious that capabilities of the assay animal must 

 be known. In general, however, accumulation in Mercenaria was slower and 

 flushing was also slower than by soft clam. One lesson learned from the 

 National Estuarine Monitoring Program in the U.S. was the importance of a 

 continuing series of samples collected at regular intervals, and adequate 

 control of sampling. At the monitoring station in Conscience Bay, N.Y. , 

 where mussels were the assay animal, residues of DDT remained fairly 

 constant at 0.5 to 1.0 ppm in 1967 and the first half of 1968, then 

 unaccountably dropped to zero and remained there. It was found that 

 technicians doing the sampling had switched to hard clam, which is in- 

 effective in storing polychlorinated hydrocarbon pesticides. A 5-year 

 study of pesticide residues in estuarine mollusks in the U.S. demonstrated 

 that residues were not high enough to be a human health hazard. Laboratory 

 experiments suggested that chronic pollution with low levels of pesticides 

 may have more widespread and permanent effects on estuarine biota than 

 episodic events, the effects of which usually are local. - J.L.M. 



61 



