Assessing urban stormwater toxicity: methodology evolution from point observations to longitudinal profiling

• Published in: Water science and technology Vol. 57; no. 9; pp. 1375 - 1381
• Main Authors: Grapentine, L, Rochfort, Q, Marsalek, J
• Format: Journal Article
• Language: English
• Published: England IWA Publishing 01.01.2008
• Subjects: acute toxicity; Amphipoda; Animals; Aquatic crustaceans; Aquatic habitats; Aquatic insects; aquatic invertebrates; Aromatic compounds; Aromatic hydrocarbons; Benthic fauna; benthic organisms; Canada; Chironomidae; Chironomidae - drug effects; Chironomidae - growth & development; chronic toxicity; Contamination; Cores; Detention basins; Ecotoxicology; Environmental Monitoring - methods; Geography; Geologic Sediments - chemistry; Habitats; Invertebrates; Invertebrates - drug effects; Invertebrates - growth & development; Laboratory tests; longitudinal studies; Macroinvertebrates; Metal concentrations; metals; Metals - analysis; Metals - toxicity; methodology; Molecular weight; mortality; Oligochaeta; Polycyclic aromatic hydrocarbons; Polycyclic Aromatic Hydrocarbons - analysis; Polycyclic Aromatic Hydrocarbons - toxicity; Ponds; population density; Road salt; Runoff; salinity; salts; Sediment; sediment contamination; Sediments; Soil contamination; species diversity; Storm runoff; Stormwater; Stormwater management; Toxicity; toxicity testing; Trace metals; Upstream; urban areas; urban runoff; vegetation; wastewater treatment; Water column; Water management; Water Movements; Water Pollutants - analysis; Water Pollutants - toxicity; water pollution; Zoobenthos; Ontario; Canada, Ontario, Toronto
• ISSN: 0273-1223; 1996-9732
• DOI: 10.2166/wst.2008.261

The quality of aquatic habitat in a stormwater management facility located in Toronto, Ontario, was assessed by examining ecotoxicological responses of benthic invertebrates exposed to sediment and water from this system. Besides residential stormwater, the facility receives highway runoff contaminated with trace metals, polycyclic aromatic hydrocarbons (PAHs), and road salt. The combined flow passes through two extended detention ponds (in series) and a vegetated outlet channel. Toxicity of surficial sediment collected from 14 longitudinally arrayed locations was assessed based on 10 acute and chronic endpoints from laboratory tests with four benthic organisms. Greatest overall toxicity was observed in sediment from sites in the upstream pond, where mortality to amphipods and mayflies reached up to 100%. Downstream pond sediment was less toxic on average than the upstream pond sediment, but not the outlet channel sediment where untreated stormwater discharges provided additional sources of contamination. Macroinvertebrate communities in sediment cores were depauperate and dominated by oligochaetes and chironomids, with minimum densities and diversity at the deeper central pond sites. While sediment toxicity was associated with high concentrations of trace metals and high-molecular weight PAHs, benthic community impoverishment appeared related to high water column salinity.