21 



Table 4-1 



Historical MBDS Reference Station Metal Data 



Reference 

 Station 



Sample Date 



Cr 



Zn 



Pb 



Ni 



Cu 



(ppm) 



18-17 



June 85 



70 



95 



41 



33 



18 



18-17 



January 86 



64 



110 



97 



12 



24 



18-17 



October 87 



50 



95 



47 



33 



22 



18-17 



June 89 



83 



135 



62 



26 



37 



FG-23 



October 87 



40 



95 



40 



33 



19 



FG-23 



June 89 



64 



97 



38 



21 



21 



Mean MBDS* 



June 89 



70 



127 



72 



21 



44 



*Data include all stations sampled in June 1989 except for reference stations. 



Pesticides were present (DDE) at both reference areas, including the maximum 

 measured concentration of 10.5 ppb at 18-17. The two replicate samples from 18-17 

 contained less than 3 ppb of the same compound, indicating that the elevated concentration of 

 DDE measured in the composite sample from 18-17 was not distributed across the entire 

 reference area. As will be discussed in Section 4.2.2, pesticides are fairly common in 

 Massachusetts Bay sediments in concentrations similar to those measured at most of the 

 MBDS stations (NOAA 1991). 



PAHs and pesticides generally have been undetected in previous surveys. Pesticide 

 detection limits were higher in the past, so the trace detections of DDE may have been 

 missed. The HMW PAH fluoranthene was detected prior to the June 1989 survey (510 ppb 

 at Station 14-9; SAIC 1990). 



Although all but one PCB replicate sample from MBDS were below detection, PCBs 

 have been detected in sediments at MBDS prior to the June 1989 survey. In September 

 1985, replicate samples were taken at Stations 18-17 and 9-8. Average concentrations of 

 PCBs were 75 and 1240 ppb, respectively. Sampling was duplicated at Stations 18-17 and 9- 

 8 in January of 1986 with lower results (48 and 329 ppb, respectively; all from SAIC 1987). 

 The 1985 sampling was repeated in 1986 with similar, although slightly lower, results, which 

 increases the validity of the historical data. The 1989 PCBs data were accompanied by 



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



