title: Isolating the impact of sediment toxicity in urban streams.
abstract: Several factors can contribute to the ecological degradation of stream catchments following urbanization, but it is often difficult to separate their relative importance. We isolated the impact of polluted sediment on the condition of an urban stream in Melbourne, Australia, using two complementary approaches. Using a rapid bioassessment approach, indices of stream condition were calculated based on macroinvertebrate field surveys. Urban stream reaches supported impoverished macroinvertebrate communities, and contained potentially toxic concentrations of heavy metals and hydrocarbons. Using a field microcosm approach, a bioassay was carried out to assess sediment pollution effects on native macroinvertebrates. Sediment from urban sites substantially altered the microcosm macroinvertebrate community, most likely due to elevated heavy metal and hydrocarbon concentrations. Macroinvertebrate surveys combined with a bioassay approach based on field microcosms can help isolate the effect of stream pollutants in degraded ecosystems.
authors.affiliation: Centre for Environmental Stress and Adaptation Research (CESAR), The University of Melbourne, Bio21 Institute, 30 Flemington Road, Parkville, VIC 3010, Australia. s.marshall@zoology.unimelb.edu.au
authors.forename: Stephen
authors.initials: S
authors.lastname: Marshall
authors.forename: Vincent
authors.initials: V
authors.lastname: Pettigrove
authors.forename: Melissa
authors.initials: M
authors.lastname: Carew
authors.forename: Ary
authors.initials: A
authors.lastname: Hoffmann
mesh_terms: D000818:Animals; D001681:Biological Assay; D004784:Environmental Monitoring / Q000379:methods*; D019015:Geologic Sediments / Q000032:analysis*; D006838:Hydrocarbons / Q000633:toxicity; D007448:Invertebrates / Q000737:chemistry / Q000187:drug effects; D019216:Metals, Heavy / Q000633:toxicity; D045483:Rivers / Q000737:chemistry*; D014504:Urban Health; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D006838:Hydrocarbons; D019216:Metals, Heavy; D014874:Water Pollutants, Chemical