33 



1980). All of the samples taken in the upper 1 meter of the cores had PCB concentrations 

 less than the maximum value (0.81 ppm) measured in MQR surface sediments following final 

 disposal (SAIC 1990a). Also, PCBs (Arochlor 1254 only) were measured in Black Rock 

 Harbor samples prior to dredging and disposal at MQR, and ranged from 0.11 to 9.17 ppm. 

 The anomalously high value of 31 ppm was an indication of the inhomogeneity and 

 patchiness of the source materials present in the MQR mound. 



All but three of the pesticide compounds were undetected in all samples. Four 

 samples had detected values of lindane (19-63 ppb, 19 ppb at the surface), two samples had 

 detections of 4,4'-DDD (DDD; 19-20 ppb), and 7 samples had detections of 4,4'-DDT 

 (DDT; 13-43 ppb). These are relatively low concentrations of pesticides as compared to 

 recent measurements from other CLIS cores. For example, samples from CS-2, which also 

 received sediments from Black Rock Harbor, contained up to 929 ppb DDD, and 150 ppb 

 DDT. Original measurements of total DDT in Black Rock Harbor sediments were all below 

 detection. 



3.3.2 Metal Results 



The range of metals concentrations was generally small (Table 3-3). One sample had 

 the highest value of all metals except Sb, As, and Se (MQR-6D), but was only higher by 

 approximately a factor of 2-3 over the lowest detected values. For example, Cu ranged from 

 80 to 610 ppm, with no obvious down-core pattern (Figure 3-6). Several samples were 

 below detection in Se and Tl, and only four samples contained detectable amounts of Ag. 

 Chromium and Hg were below detection in one sample, Cd was below detection in 2 

 samples, and Be was below detection in 5 samples. 



Normalizing the trace metal data to the percentage fine grain size reduced the 

 variation between cores and showed a distinct pattern of increasing metals concentrations 

 with depth (Figure 3-7). This increase in normalized metals concentrations is a direct 

 function of the increase in the sand fraction (Figure 3-4). Metals previously have been 

 analyzed for MQR source sediments, at the MQR mound, and also at other cores at CLIS. 

 These results were compared in detail with the MQR core sample results below (Section 

 4.2). 



3.3.3 PAH Results 



Although several PAH compounds were below detection limits in the core samples, 

 no individual PAH compound was below detection in every sample. In addition, no sample 

 was below detection in every PAH compound (Table 3-4). PAHs were relatively high in 

 many samples. Two samples stood out as having the highest PAH compound concentrations 

 (MQR3-F and MQR5-E); for example, phenanthrene had a concentration of 212 ppm and 

 322 ppm, respectively (Figure 3-8). This trend was similar for all low and high 



Sediment Core Chemistry Data Summary from the MQR Mound, August and December 1991 



