229 



Butler, Philip A. 1973. 



Organochlorine residues in estuarine mollusks , 1965-1972 - National 

 pesticide monitoring program. Pt. I. General summary and conclusions. 

 In Residues in Fish, Wildlife, and Estuaries. Pestic. Monitor. J. 6(4): 

 238-246. 



Meroenaria meroenaria was not regarded as a satisfactory species to monitor 

 accumulation and retention of organochloride compounds because under similar 

 laboratory conditions, hard clams accumulated residues half as large as 

 American oyster and flushed these compounds much more quickly. Hard clam 

 was examined in Del. and N.Y. Residues were low as compared with carnivores 

 such as fish-eating birds. Metabolites of DDT were the only residues 

 detected in many analyses of filter-feeding mollusks. In most areas a 

 pronounced decline in number of samples containing high residues of DDT 

 was noted over the period, but in N.Y. more samples had residues in excess 

 of 10 ppb in 1971 than earlier. Organochloride residues are flushed rapidly 

 from molluscan tissues when water supply is not contaminated. - J.L.M. 



Pt. II. Residue data - Individual states. Sect. C: Delaware: 263-267. 



Samples were examined from 9 stations each month from Oct 1966 to Aug 1969. 

 At stations 1-2, in upper Delaware Bay, only Modiolus demissus was examined; 

 at stations 3-5, from Bowers Beach to Broadkill River, only Crassostrea 

 virginiaa; at stations 6 to 8 , Cape Henlopen and Rehoboth Bay, only Meroenaria 

 meroenaria; and at station 9, in Indian River Bay, only M. demissus . Residues 

 in oysters and clams showed no upward or downward trend in 3 yrs . In ribbed 

 mussels residues declined markedly in the final year at the 3 stations. The 

 relative inefficiency of hard clam in storing organochloride residues made 

 it appear that Rehoboth Bay was free from this type of pollution, which it 

 probably was not. Residues of DDE, TDE , DDT, and Dieldrin are reported for 

 each month. - J.L.M. 



Pt. II. Sect. J: New York: 303-315. 



M. meroenaria was collected at 4 different sites to monitor organochloride 

 pollution from March 1966 to June 1972. Other bivalves were sampled at 

 other sites. In Conscience Bay, Long Island, when hard clam was substituted 

 for blue mussel, DDT pollution apparently disappeared, but this was a 

 consequence of the inefficiency of hard clam in storing such residues. PCBs 

 were present in some samples in 1972, but were not identified or measured. 

 Details of analyses are given by month for DDE, TDE, DDT, and Dieldrin. - J.L.M. 



230 



Byrne, C. J., and J. A. Calder. 1977. 



Effect of the water-soluble fractions of crude, refined and waste oils on 

 the embryonic and larval stages of the quahog clam, Meroenaria sp. Mar. 

 Biol. 40(3): 225-231. 



Embryonic and larval stages of hybrids of M. meroenaria and M. oampechiensis 

 were exposed to water-soluble fractions of 6 oils to note effects on survival 

 and growth. Kuwait crude oil was least toxic on initial exposure to 2nd 

 cleavage stage eggs and 2-day-old straight-hinge larvae. Median lethal 

 concentration (LC5Q) values in excess of 10 ppm were reached only after 

 continuous exposure to water-soluble fraction (WSF) for up to 6 days. 

 However, at 10 days, Kuwait was slightly more toxic than Southern Louisiana 

 crude oil. At that stage both oils had LC50 near 2 ppm. Florida Jay crude 

 oil was much more toxic, having an LC50 value less than 1 ppm at 4 8 hr 

 and less than 0.2 ppm at 10 days. Refined oils. No. 2 fuel oil, and Bunker 

 "C" , had LC50 values of 0.10 ppm or less at all exposure times. Surviving 

 larvae often grew more slowly than controls. - modified authors' abstract 

 - J.L.M. 



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