Natural rates of sediment containment of PAH, PCB and metal inventories in Sydney Harbour, Nova Scotia

• Published in: The Science of the total environment Vol. 407; no. 17; pp. 4858 - 4869
• Main Authors: Smith, J.N., Lee, K., Gobeil, C., Macdonald, R.W.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 15-08-2009; [Amsterdam; New York]: Elsevier Science; Elsevier
• Subjects: Applied sciences; Contaminant; Contaminants; Earth sciences; Earth, ocean, space; Engineering and environment geology. Geothermics; Exact sciences and technology; Geochronology; Geologic Sediments - chemistry; Harbors; Harbours; Iron and steel plants; Mathematical models; Metals - analysis; Nova Scotia; PAH; PCB; Pollution; Pollution sources. Measurement results; Pollution, environment geology; Polychlorinated Biphenyls - analysis; Polycyclic Compounds - analysis; Sediment; Sediments; Soil and sediments pollution; Water Pollutants, Chemical - analysis; Canada; Nova Scotia; North America; America; Canada, Nova Scotia; Canada, Nova Scotia, Cape Breton I., Sydney Harbour; Australia, New South Wales, Sydney; ANW, Canada, Nova Scotia, Cape Breton I., Sydney Harbour; Geochronology; Pb; Sediment; PAH; PCB; Contaminant; Harbor; Historical aspects; Estuaries; Persistent organic pollutant; Pollution; Chlorocarbon; Lead; Aromatic compound; Organic compounds; Anthropogenic factor; Hydrocarbon; Polychlorobiphenyls; Polycyclic aromatic compound; Sediments; Organic chlorine compounds; Heavy metal; Trace element; Trend analysis; Pollution source
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2009.05.029

Analyses of metal and organic contaminants were carried out on 41 sediment cores, dated using
210Pb and
137Cs, from the heavily industrialized region of Sydney Harbour, N.S. to evaluate the history of contamination and to predict the rates of natural containment of the harbour by sediment burial. Geochronologies for metals (eg. Pb, As) and polycyclic aromatic hydrocarbons (PAHs) are correlated with the development of the steel and coke industries in the Sydney region while polychlorinated biphenyl (PCB) geochronologies reflect the disposal of electrical equipment used in the steel mill/coking operations. Pb was derived mainly from atmospheric emissions and its concentration has declined exponentially with time in harbour sediments since the closure of the steel mill/coke ovens in the 1980s with a time constant of about 15 years. This represents the time scale for the circulation of this particle-associated contaminant in transient catchment basins prior to permanent deposition in the sediments. PAH and PCB sediment concentrations have also declined exponentially with time since the 1980s, but with a smaller time constant of 10 years owing to the fact that they enter the harbour directly with steel mill and coke oven effluent rather than through atmospheric pathways. Since the time dependence for the burial of metal and organic inventories can be modeled by first order processes, future contaminant levels can be predicted for surface sediments in Sydney Harbour. Mean sediment concentrations of metal and organic contaminants in the upper 5 cm throughout most of the harbour are predicted to decline to levels below the
effects range-medium (above which organisms are very likely to be negatively affected by the presence of a contaminant) by 2030.