Table 6. Annual geometric mean concentrations of chemicals in mollusks for sites sampled in at 

 least six years from 1986 to 1993. Concentration units: Ug g"^-dry for elements and ng g'*-dry for 

 organic compounds with XBT in terms of ng of Sn g'^-dry. Last column is the Spearman rank 

 correlation coefficient of concentration versus year with an asterisk (*) denoting statistical sig- 

 nificance at the 95% level of confidence. 



Chemical 1986 1987 1988 1989 1990 1991 1992 1993 Js 



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