title: Macrobenthic community in the Douro estuary: relations with trace metals and natural sediment characteristics.
abstract: The relationship between macrobenthic community structure and natural characteristics of sediment and trace metal contamination were studied in the lower Douro estuary (Portugal, NW, Iberian Peninsula), using an innovative threefold approach (SQG, Sediment Quality Guidelines), metal normalization to Fe, and macrobenthic community structure. This study allowed detection of a clear signature of anthropogenic contamination, in terms of Zn, Cu, Pb, and Cr in the north bank of the estuary, which experiences high urban pressure. Using the SQG approach, metal concentrations above ERM (effects range-median) were observed only at one sampling station, but several stations had levels above ERL (effects range-low). The macrobenthic community had a low diversity, with only 19 species found in the entire estuarine area, dominated by opportunistic species. The granulometric distribution of the sediments (estimated from the combination of organic matter, Fe and Al) seemed to be the major structuring factor for the communities, establishing the natural macrobenthic distribution pattern. The metals (Zn, Cu, Pb, and Cr) seemed to act as a disturbing factor over the natural distribution, with deleterious consequences for the macrobenthic communities.
authors.affiliation: Laboratory of Hidrobiology, Institute of Biomedical Sciences, University of Porto, Largo Professor Abel Salazar, No. 2, 4099-003 Porto, Portugal. amucha@icbas.up.pt
authors.forename: Ana P
authors.initials: AP
authors.lastname: Mucha
authors.forename: M Teresa S D
authors.initials: MT
authors.lastname: Vasconcelos
authors.forename: Adriano A
authors.initials: AA
authors.lastname: Bordalo
mesh_terms: D000818:Animals; D002857:Chromium / Q000032:analysis; D003300:Copper / Q000032:analysis; D005618:Fresh Water; D019015:Geologic Sediments; D007448:Invertebrates / Q000502:physiology*; D007501:Iron / Q000032:analysis; D007854:Lead / Q000032:analysis; D008670:Metals / Q000032:analysis*; D011174:Portugal; D012623:Seawater; D014873:Water Pollutants / Q000032:analysis*; D014876:Water Pollution; D015032:Zinc / Q000032:analysis
chemical_list: D008670:Metals; D014873:Water Pollutants; D002857:Chromium; D007854:Lead; D003300:Copper; D007501:Iron; D015032:Zinc