MULTIVARIATE STATISTICAL EXAMINATION OF SPATIAL AND TEMPORAL PATTERNS OF HEAVY-METAL CONTAMINATION IN NEW-BEDFORD HARBOR MARINE-SEDIMENTS

Thirteen sediment cores were examined for 10 metals and organic carbon along a pollution gradient from highly contaminated sediments in New Bedford Harbor to cleaner sediments in Buzzards Bay. Multiple regression of metal content against organic carbon, aluminum, and iron was significant for all metals. However, partial correlation coefficients indicated that organic carbon explained most of the variance for Cr, Ni, Cu, Zn, Cd, and Pb. Conversely, most of the explained variance in Mn was related to iron, while the explained variance in Co was equally distributed between the three factors. The pattern recognition technique principal components analysis (PCA) was also applied to the data and revealed two distinct gradients in the types of metals present in the sediments. The first gradient was between uncontaminated sediments of Buzzards Bay and lesser contaminated sediments from the outer portion of New Bedford Harbor. A second gradient revealed temporal and spatial differences in the types of metals present in the contaminated harbor sediments.