47 



The six metals were also highly correlated to each other in terms of 

 their distribution and concentration (Table 5). The only exceptions to 

 this generalization are the correlations of nickel with cadmium and lead 

 with chromium. 



Comparison of trace metal levels in Casco Bay sediments with levels 

 found in other recent New England investigations will help to put these 

 results into perspective. Five studies utilizing comparable methodology 

 are available for comparison. Lyons et at. (in press) examined trace 

 metal levels in five northern New England estuaries. They concluded 

 from sediment profiles that three of them, Machias Bay, Cape Rosier and 

 the Seabrook River estuary show little increase in trace metal 



Table 5. Correlation matrix for Casco Bay trace metal samples 



X grain 

 Org. C Cd Cr Cu Pb Ni Zn size 



Organic Carbon 1 .000 



Cadmium 0.762 1.000 



Chromium 0.822 0.461 1.000 



Copper 0.578 0.705 0.635 1.000 



Lead 0.476 0.775 0.287 0.802 1.000 



Nickel 0.675 0.319 0.826 0.466 0.175 1.000 



Zinc 0.853 0.786 0.766 0.775 0.724 0.625 1.000 



Mean Grain Size 0.774 0.495 0.761 0.528 0.470 0.813 0.775 1.000 



n = 32 except for lead and organic carbon where n = 31. 

 Significant at 99% confidence interval if r > 0.449 for n = 32 and 

 r > 0.456 for n = 31. 



