23 



SAL and QUI are reported to have "high" concentrations of many metals (Cr, Cu, 

 Hg, Pb); CAGH has "high" concentrations of Pb only; and DBCI is a sandy site without any 

 reported "high" concentrations of any metal or organic contaminant (NOAA 1991). In 

 general, CAGH and DBCI have lower concentrations of all metals than SAL and QUI (Table 

 4-2). 



The maximum measured concentration of Ni, Pb, and Zn in MBDS samples was 

 higher than both QUI and SAL. However, the statistical ranges of all metals concentrations 

 from MBDS samples were intermediate between the two highest metals sites (SAL and QUI), 

 and the two lowest metals sites (CAGH and DBCI). One exception was the maximum Pb 

 value, which was greater than that measured at QUI (Table 4-2). 



Relative to national values, the mean values of MBDS metals concentrations were less 

 than the national mean for all metals except Cu, Hg, and Pb (Table 4-2). All of the Cu and 

 Hg concentrations measured at MBDS were less than the value classified as "high" by 

 NS&T, but the statistical maximum value of Pb measured at MBDS was higher than this 

 "high" value. In general, Ni values are lower in the entire Massachusetts Bay region, 

 including the MBDS, relative to national concentrations. 



Table 4-2 



MBDS Trace Metal Data Relative to Regional Massachusetts Bay 



Location 







Petals (ppm) 









Cr 



Cu 



Hg 



Ni 



Pb 



Zn 



Cape Ann - Gap Head 











Duxbury Bay 



19 



5 







7 



11 



20 



Quincy Bay 



224 



134 



1.38 



30 



96 



192 



Salem Harbor 



1586 



71 



0.91 



30 



141 



185 



MBDS Maximum 



139 



74 



0.47 



35 



155 



221 



MBDS Minimum 



19 



19 



0.05 



14 



29 



66 



MBDS Mean 



70 



43 



0.22 



21 



71 



126 



Statistical Range* 



42-97 



29-58 



0.1-0.3 



15-27 



40-101 



91-161 



NS&T National Mean 



110 



35 



0.17 



34 



43 



140 



NS&T National "High" 



230 



84 



0.49 



69 



89 



270 



"Kange is calculated a: 



, the mean +/- 



one standard deviation 









NS&T = National Status and Trends (NOAA 1991). 



Pesticides and PAHs. All organic data for both MBDS and the NS&T sites were 

 normalized to TOC. Natural variations in sedimentary parameters can influence the 

 concentration of trace metal and organic constituents measured in the laboratory. For 

 example, an increase in the fine-grained fraction and in TOC are both positively correlated 



Chemical Analyses of Sediment Sampling at the Massachusetts Bay Disposal Site, June 1989 



