Table 3. ANOVA table of multiple regression analysis of organic carbon 

 on mean grain size, bottom depth and their interaction. 



31 



Source 



Degrees of Type IV F 



Freedom Sum of Squares Value 



PR>F 



Mean Grain Size 1 



Depth 1 



Grain Size-Depth 1 



Error 50 



451.0196 



8.5920 



2.9443 



2079.9867 



10.84 0.0018 

 0.21 0.6515 

 0.07 0.7917 



Total Kjeldahl nitrogen values are also presented in Table 2. 

 Values range from 0.038 to 1.294 mg/g. To date no attempt has been made 

 to interpret these results. They are included for completeness. 



Trace Metals 



Subsamples from 32 stations were analyzed by atomic absorption 

 spectrometry for the metals cadmium, chromium, copper, lead, nickel and 

 zinc. Results, as ppm dry weight, are presented in Table 4. 



Cadmium is present in the sediments of Casco Bay in concentrations 

 ranging from 0.20 to 0.90 ppm with a mean value of 0.50 ppm. Highest 

 cadmium values occur in the Portland vicinity and at station 53, the 

 former domestic dumpsite for Peaks Island residents (Fig. 13). Lowest 

 cadmium levels are found at the offshore stations while the remaining 

 stations deviate little from the mean. 



Chromium levels average 34.5 ppm and range from 5.85 to 55.0 ppm 

 (Table 4). The approaches to Portland Harbor exhibit the lowest 



