Have the bioavailabilities of trace metals to a suite of biomonitors changed over three decades in SW England estuaries historically affected by mining?

• Published in: The Science of the total environment Vol. 409; no. 8; pp. 1589 - 1602
• Main Authors: Rainbow, P.S., Kriefman, S., Smith, B.D., Luoma, S.N.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 15.03.2011; [Amsterdam; New York]: Elsevier Science; Elsevier
• Subjects: Animal, plant and microbial ecology; Animals; Applied ecology; Arsenic - chemistry; Ascophyllum nodosum; Bioavailability; Biological and medical sciences; Biomonitoring; Biomonitors; Bivalvia - metabolism; Contamination; Deposits; Ecotoxicology, biological effects of pollution; England; Environmental Monitoring; Estuaries; Feeders; Fucus vesiculosus; Fundamental and applied biological sciences. Psychology; Geologic Sediments - chemistry; Marine and brackish environment; Metals - analysis; Metals - metabolism; Mining; Nereis diversicolor; Polychaeta - metabolism; Scrobicularia plana; Seawater - chemistry; Seaweed - chemistry; Seaweed - metabolism; Sediment; Sediments; Silver; Trace metals; Water; Water Pollutants, Chemical - analysis; Water Pollutants, Chemical - metabolism; England; United Kingdom; Great Britain; Europe; ANE, British Isles, England; Water; Biomonitoring; Sediment; Bioavailability; Trace metals; Brackish water environment; Pollutant behavior; Estuaries; Metal; Sediments; Time variation; Mining; Trace element; Water pollution
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2011.01.012

Many estuaries of southwest England were heavily contaminated with toxic metals associated with the mining of copper and other metals, particularly between 1850 and 1900. The question remains whether the passage of time has brought remediation to these estuaries. In 2003 and 2006 we revisited sites in 5 metal-contaminated estuaries sampled in the 1970s and 1980s — Restronguet Creek, Gannel, West Looe, East Looe and Tavy. We evaluate changes in metal contamination in sediments and in metal bioavailabilities in sediments and water to local organisms employed as biomonitors. We find that the decline in contamination in these estuaries is complex. Differences in bioavailable contamination in the water column were detectable, as were significant detectable changes in at least some estuaries in bioavailable metal contamination originating from sediments. However, in the 100years since mining activities declined, bioavailable contamination has not declined to the regional baseline in any estuary affected by the mine wastes. The greatest decline in contamination occurred in the one instance (East Looe) where a previous industrial source of (Ag) contamination was considered. We used the macroalgae Fucus vesiculosus and Ascophyllum nodosum as biomonitors of dissolved metal bioavailabilities and the deposit feeders Nereis diversicolor and Scrobicularia plana as biomonitors of bioavailable metal in sediments. We found no systematic decrease in the atypically high Ag, Cu, Pb and Zn concentrations in the estuarine sediments over a 26year period. Accumulated metal (Ag, As, Cu, Pb, and Zn) concentrations in the deposit feeders are similarly still atypically high in at least one estuary for each metal, and there is no consistent evidence for general decreases in sediment metal bioavailabilities over time. We conclude that the legacy of mining in sheltered estuaries of southwest England is the ongoing presence of sediments rich in metals bioavailable to deposit feeders, while dissolved metal bioavailabilities from this historical source alone are no longer atypically high. ► SW England estuaries are contaminated with toxic metals from historical mining. ► High metal concentrations remain in the sediments. ► High metal concentrations still in biomonitors of sediment contamination. ► Mining legacy is sediments rich in metals bioavailable to deposit feeders. ► Bioavailabilities of dissolved metals from historical mining are no longer high.