Debbie Burniston

Dechloranes 602, 603, 604, Dechlorane Plus, and Chlordene Plus, a newly detected analogue, in tributary sediments of the Laurentian Great Lakes.

A chlorinated compound (Chlordene Plus, CP), structurally related to Dechloranes (Dec) 602, 603, 604, and Dechlorane Plus (DP), was identified, and concentrations and spatial trends of Dec 602, 603, 604, CP, and DP in tributary sediments of the Laurentian Great Lakes are reported. The dechloranes were widely detected with their concentrations varying considerably across the Great Lakes basin. Spatial trends of Dec 602, 604, and DP in Canadian tributary sediments were similar to that of BDE 209, which suggested these flame retardant chemicals in tributaries were associated with industrial and urban areas. The highest concentrations of Dec 602, 604, and DP observed in tributaries of the Niagara River confirmed that past or ongoing manufacturing of these compounds at plants along the river were important sources to Lake Ontario. Dec 603 was detected in technical products of aldrin and dieldrin, and its spatial trend was consistent with historic pesticide usage. Similarly, CP was detected in technical products of chlordene and chlordane, and it was found in higher concentrations in sediments near urban areas, possibly related to past chlordane use in home termite control.

Fate, distribution, and contrasting temporal trends of perfluoroalkyl substances (PFASs) in Lake Ontario, Canada

Lake Ontario water and sediment collected from tributary, nearshore, and open lake sites were analyzed for perfluoroalkyl substances (PFASs), namely perfluoroalkyl carboxylic acids (PFCAs, F(CF(2))(n)CO(2)(-); n=6-11,13) and perfluoroalkane sulfonic acids (PFSAs, F(CF(2))(n)SO(3)(-); n=6,8,10). Survey results of surface sediment and water indicated that shorter chained PFASs were predominant in and near urban/industrial area watersheds, while longer chained PFASs were predominant in fine-grained sediment from major depositional basins. Niagara River suspended solids (1981-2006) demonstrated temporal trends that may have been influenced by recent changes in North American production and use of PFASs. Perfluorooctane sulfonate (PFOS) reached a peak concentration in 2001 of 1.1 ng/g, followed by a decrease from 2001 to 2006 (half-life=9 years). Perfluorooctanoic acid (PFOA) increased from 2001 to 2006 (doubling time= 2 years) reaching a peak concentration of 0.80 ng/g. In contrast, three sediment cores from western, central, and eastern Lake Ontario showed increasing temporal trends to surface sediment for all PFASs. PFOA and PFOS concentrations increased from 1988 to 2004 (doubling time= ~ 4 years) in the western Lake Ontario core. The observed variations in temporal trends from different environmental compartments may be a result of the physico-chemical properties of PFASs, ongoing emissions, and the environmental transformation and degradation of PFAS precursor compounds.

Occurrence and sources of polychlorinated dibenzo-p-dioxins, dibenzofurans and dioxin-like polychlorinated biphenyls in surficial sediments of Lakes Superior and Huron.

Concentrations and congener profile patterns of 2378-substituted PCDD/Fs and DLPCBs in offshore, nearshore and tributary sediments of Lakes Superior and Huron are reported, and spatial trends and source contributions assessed. PCDD/F concentrations ranged from 5 to 18,000 pg/g dw (Lake Superior) and 3 to 6100 pg/g dw (Lake Huron); DLPCBs ranged from 9 to 11,000 pg/g dw (Lake Superior) and 9 to 27,000 pg/g dw (Lake Huron). Our analysis indicated atmospheric deposition is a primary source to depositional areas of both lakes; however, greater PCDD/F and DLPCB concentrations were observed at several nearshore and tributary sites, and were attributed to corresponding land use in the watershed. Statistical analysis and pattern comparison suggested that industrial inputs mainly associated with wood treatment plants, pulp and paper mills, mining operations, and chlorine-based chemical manufacturing also contributed to contamination by PCDD/Fs and DLPCBs in certain nearshore and offshore areas of Lakes Superior and Huron.

Spatial distributions and temporal trends in polybrominated diphenyl ethers in Detroit River suspended sediments

Suspended sediments from the Detroit River were collected using sediment traps at sites ranging from western Lake Erie to southern Lake St. Clair to assess spatial distributions and temporal trends of polybrominated diphenyl ethers (PBDEs). The distribution of PBDEs in suspended sediments in the Detroit River appeared influenced by shoreline-based contemporary urban and industrial activities, which stood in contrast to PCBs that were associated with areas of historic industrial activity. Temporal trend data indicate that total PBDE concentrations decreased in the period after 2000 in response to cessation of production of the penta- and octa BDE formulations. Concentrations of total PBDEs ranged from roughly 7 ng g(-1) (4 ng g(-1) BDE 209) in southern Lake St. Clair to several hundred ng g(-1) (60-180 ng g(-1) BDE 209) in the lower reaches of the Detroit River. The widespread occurrence of PBDEs in Detroit River suspended sediments suggests that large urban areas can act as diffuse sources of these chemicals that are used in modern industrial applications and consumer products.

Trends in Hamilton Harbour suspended sediment quality

Suspended sediment quality in Hamilton Harbour has been assessed as part of a long-term monitoring study (1987–2012). Sampling locations reflected a range of shoreline activities and sources of chemical contamination to the harbour. Temporal data showed a trend toward decreasing levels of contamination by polycyclic aromatic hydrocarbons and polychlorinated biphenyls over the period from the late 1980s to the early 1990s, with a subsequent leveling off over the next two decades. The highest concentrations of both contaminants were detected in areas impacted by industrial activities along the southern shoreline and Windermere Arm, and deep-water areas of the harbour where fine-grained sediments ultimately accumulate. Areas of the harbor discharging residential or rural parts of the watershed exhibited generally lower levels of contamination. In addition to the relatively higher contaminant levels, areas along the southern shoreline and Windermere Arm characterized by historical industrial activities and associated contaminated sediments exhibited chemical profiles indicating an impact on suspended sediment and bottom sediment quality throughout the harbour. Continued monitoring after scheduled remedial activities should provide an assessment of the overall efficacy of management actions to improve sediment quality in Hamilton Harbour.

Trends in sediment quality in Hamilton Harbour, Lake Ontario

Bottom sediment quality in Hamilton Harbour was assessed as part of a long-term research and monitoring program over a period of three decades in order to support remedial activities. Sampling locations reflected a range of shoreline activities and sources of chemical contamination to the harbour. An assessment of temporal trends in metals, polycyclic aromatic hydrocarbons and polychlorinated biphenyls indicate that concentrations of all three classes of contaminants have decreased in sediments in most areas of the harbour since the period 1990–2000; however, the Windermere Arm area impacted by historical industrial activities along the southeastern shoreline area of the harbour was an exception, as trends in some metals and polychlorinated biphenyls showed overall increases. Assessment of spatial distributions of contaminants and the associated polycyclic aromatic hydrocarbon and polychlorinated biphenyl profiles showed that Randle Reef and Windermere Arm continue to be significant contributors to harbour-wide contamination by polycyclic aromatic hydrocarbons and polychlorinated biphenyls, respectively. Continuation of the program after remedial activities should provide an assessment of the overall efficacy of management actions to improve environmental quality in Hamilton Harbour.