Historical Trace Metal Accumulation in the Sediments of an Urbanized Region of the Lake Champlain Watershed, Burlington, Vermont   总被引：3，自引：0，他引：3  

Ellen L. Mecray  John W. King  Peter G. Appleby  Allen S. Hunt 《Water, air, and soil pollution》2001,125(1):201-230

This study documents the history ofpollution inputs in the Burlington region of LakeChamplain, Vermont using measurements of anthropogenicmetals (Cu, Zn, Cr, Pb, Cd, and Ag) in four age-datedsediment cores. Sediments record a history ofcontamination in a region and can be used to assessthe changing threat to biota over time and to evaluatethe effectiveness of discharge regulations onanthropogenic inputs.Grain size, magnetic susceptibility, radiometricdating and pollen stratigraphy were combined withtrace metal data to provide an assessment of thehistory of contamination over the last 350 yr inthe Burlington region of Lake Champlain. Magneticsusceptibility was initially used to identify land-usehistory for each site because it is a proxy indicatorof soil erosion. Historical trends in metal inputs inthe Burlington region from the seventeenth through thetwentieth centuries are reflected in downcorevariations in metal concentrations and accumulationrates. Metal concentrations increase above backgroundvalues in the early to mid nineteenth century. Themetal input rate to the sediments increases around1920 and maximum concentrations and accumulation ratesare observed in the late 1960s. Decreases inconcentration and accumulation rate between 1970 andthe present are observed for most metals. Theobserved trends are primarily a function of variationsin anthropogenic inputs and not variations in sedimentgrain size. Grain size data were used to removetexture variations from the metal profiles and resultsshow trends in the anthropogenic metal signals remain. Radiometric dating and pollen stratigraphy providewell-constrained dates for the sediments therebyallowing the metal profiles to be interpreted in termsof land-use history.  相似文献   

Sediment Quality in Burlington Harbor,Lake Champlain,U.S.A.     

Lacey  E. M.  King  J. W.  Quinn  J. G.  Mecray  E. L.  Appleby  P. G.  Hunt  A. S. 《Water, air, and soil pollution》2001,126(1-2):97-120

Surface samples and cores were collected in 1993 fromthe Burlington Harbor region of Lake Champlain. Sediment samples were analyzed for trace metals(cadmium, copper, lead, nickel, silver and zinc),simultaneously extracted metal/acid volatile sulfide(SEM-AVS), grain size, nutrients (carbon and nitrogen)and organic contaminants (polycyclic aromatichydrocarbons (PAHs) and polychlorinated biphenyls(PCBs)). The concentrations of cadmium, copper,silver and zinc from the partial sediment digestion ofthe surface samples correlated well with each other(r ²>0.60) indicating that either a commonprocess, or group of processes determined the sedimentconcentrations of these metals. In an analysis of thespatial distribution of the trace metals and PAHs,high surficial concentrations were present in thesouthern portion of the Harbor. The trace metal trendwas strengthened when the concentrations werenormalized by grain size. A sewage treatment plantoutfall discharge was present in the southeasternportion of the Harbor at the time of this study and isthe major source of trace metal and PAH contamination. Evaluation of sediment cores provides a proxy recordof historical trace metal and organic inputs. Thepeak accumulation rate for copper, cadmium, lead, andzinc was in the late 1960s and the peak silveraccumulation rate was later. The greatestaccumulation of trace metals occurred in the late1960s after discharges from the STP began. Subsequentdeclines in trace metal concentrations may beattributed to increased water and air regulations. The potential toxicity of trace metals and organiccontaminants was predicted by comparing contaminantconcentrations to benchmark concentrations andpotential trace metal bioavailability was predictedwith SEM-AVS results. Surface sample results indicate lead,silver, ΣPAHs and ΣPCBs are potentially toxicand/or bioavailable. These predictions were supportedby studies of biota in the Burlington Harborwatershed. There is a clear trend of decreasing PAHand trace metal contaminant concentrations withdistance from the STP outfall.  相似文献