title: Nematode species at risk--a metric to assess pollution in soft sediments of freshwaters.
abstract: Soft sediments are often highly polluted as many of the toxic chemicals introduced into surface waters bind to settling particles. The resulting accumulation of pollutants in the sediments poses a risk for benthic communities. However, pollution induced changes in benthic communities have been difficult to determine when using macro-invertebrates as bioindicators, as these organisms are often absent in soft sediment. The present study therefore examined the ability of meiofaunal organisms, specifically, nematodes, to assess the ecological status of soft sediments. Over a 9-year period, nematode communities present in sediments collected from large rivers and lake Constance in Germany were studied. These sediments showed a large range of physico-chemical properties and anthropogenic contamination. After the degree of metal and organic contamination was translated into ecotoxicologically more relevant toxic units (TUs), multivariate methods were used to classify nematode taxa in species at risk (NemaSPEAR) or not at risk (NemaSPE(not)AR). This approach clearly distinguished the influence of sediment texture from that of the toxic potential of the samples and thus allowed classification of the nematode species according to their sensitivity to or tolerance of toxic stress. Two indices, expressing the proportion of species at risk within a sample (NemaSPEAR[%](metal), NemaSPEAR[%](organic)), were calculated from independent data sets obtained in field and experimental studies and showed good correlations with the toxic potential (field data) or chemical concentrations (microcosm data). NemaSPEAR[%] indices for metal and organic pollution were therefore judged to be suitable for assessing the impact of chemical contamination of freshwater soft sediments.
authors.affiliation: Federal Institute of Hydrology (BfG), Mainzer Tor 1, Koblenz, Germany. hoess@ecossa.de
authors.forename: S
authors.initials: S
authors.lastname: Höss
authors.forename: E
authors.initials: E
authors.lastname: Claus
authors.forename: P C
authors.initials: PC
authors.lastname: Von der Ohe
authors.forename: M
authors.initials: M
authors.lastname: Brinke
authors.forename: H
authors.initials: H
authors.lastname: Güde
authors.forename: P
authors.initials: P
authors.lastname: Heininger
authors.forename: W
authors.initials: W
authors.lastname: Traunspurger
mesh_terms: D000818:Animals; D044822:Biodiversity; D004784:Environmental Monitoring / Q000379:methods*; D052918:Environmental Restoration and Remediation; D005618:Fresh Water / Q000737:chemistry*; D019015:Geologic Sediments / Q000737:chemistry*; D007220:Industrial Waste / Q000032:analysis; D008670:Metals / Q000032:analysis / Q000633:toxicity; D009348:Nematoda / Q000187:drug effects*; D009930:Organic Chemicals / Q000032:analysis / Q000633:toxicity; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000633:toxicity*; D014876:Water Pollution / Q000706:statistics & numerical data
chemical_list: D007220:Industrial Waste; D008670:Metals; D009930:Organic Chemicals; D014874:Water Pollutants, Chemical