Cu. Higher levels of Pb appeared after four weeks of exposure. The relatively 

 quick response time established in the case of Ni and Cu represents an obvious 

 advantage to the use of M. edulis as a biological monitor. For these metals, 

 M. edulis quickly reflects a situation which effects the long-lived indigenous 

 species, M. mercenaria. 



These results encourage further study. Our three specific goals listed in the 

 Introduction have been answered in the affirmative: 



1. Introduced M. edulis from polluted areas reflect elevated levels of metals, 

 as did sediments and M. mercenaria reported in previous work. 



2. M. edulis displays a relatively short response time in accumulating 

 elevated metal levels — three weeks in the case of Ni and Cu, and four 

 weeks in the case of Pb. 



3. M. edulis, the introduced biological monitor, took up three of the four 

 metals previously demonstrated to have been accumulated and retained 

 by the resident species, M. mercenaria. 



The results reported here are based on data collected when the annual 

 temperature cycle was declining toward winter levels. Tliis fact may account 

 for the leveling-off of Ni and Cu observed between weeks three and four at 

 Station 2. 



Further studies along the transect in Narragansett Bay, and in other 

 comparable areas, including a complete annual temperature cycle, are being 

 carried out to supplement the knowledge gained in this study on the use of 

 M. edulis as an introduced biological indicator of man's impact on the 

 environment. 



REFERENCES 



I.Phelps, D.K., G. Telek, and R. L. Lapan, Jr. 1975. Assessment of Heavy 

 Metal Distribution Within the Food Web. In Marine Pollution and Waste 

 Disposal. Pearson and Frangiapane, editors. Pergamon Press, pp. 341 348. 



2. Myers, A. C, and D.K. Phelps. 1978. Criteria of Benthic Health: a Tran- 

 sect Study of Narragansett Bay, Rhode Island. Final Report. Contract 

 No. P.O. 53203, U RI Division of Marine Resources, Graduate School of 

 Oceanography, Kingston, R.I. 



3. Farrington, J.W. and J.G. Quinn. 1973. Petroleum Hydrocarbons in 

 Narragansett Bay. I. Survey of Hydrocarbons in Sediments and Clams. Est. 

 and Coastal Mar. Sci. 1:71-79. 



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