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TRACE METAL AVAILABILITY TO PERIPHYTON COLONIZED BELOW NEAR-COASTAL WASTEWATER DISCHARGES IN THE GULF OF MEXICO
Citation:
Lewis, M A., D. A. Weber, AND J C. Moore. TRACE METAL AVAILABILITY TO PERIPHYTON COLONIZED BELOW NEAR-COASTAL WASTEWATER DISCHARGES IN THE GULF OF MEXICO. DIMENSIONS OF POLLUTION 1:86-103, (2002).
Description:
The significance of the many wastewater discharges in the Gulf of Mexico region as sources of trace metal contamination to indigenous biota in nearby coastal areas is relatively unknown. The primary objective of this baseline survey was to provide some insight on this issue by determining the concentrations of eight trace metals in periphyton colonized at 10 stations above and 34 stations below eight municipal, industrial and forest product wastewater outfalls. Trace metal residues and bioconcentration factors for periphyton colonized below each of the eight outfalls were typically greater than those for periphyton colonized in the corresponding unimpacted areas. The average increase in the total metal residues for periphyton colonized below all outfalls was 81 (? 1 standard deviation = 112)% which was significant (P<0.05). Mean percentage increases for the specific metals below the eight outfalls ranged from 53 to 478. These increases were more significant for chromium (P<0.05), zinc (P<0.07) and mercury (P<0.10). The increases in metal residues had no observable effect on ash free dry weight and chlorophyll a content based on the analysis of periphyton colonized on substrates adjacent to those used in residue analyses. Mean percentage increases in the bioconcentration factors for the eight metals were from 8 to 299 but only that for chromium was significant (P<0.05).