Giusti L, Taylor A
Centre for Research in Environmental Sciences, Faculty of Applied Sciences, UWE, Bristol, Coldharbour Lane, Bristol, BS16 1QY, UK.
Environ Monit Assess. 2007 Nov;134(1-3):211-31. doi: 10.1007/s10661-007-9611-8. Epub 2007 Feb 10.
Stream-bed sediment samples were collected in 2001 and 2004 along the Fratta-Gorzone River (Italy) to assess the level of heavy metal contamination. The river stretch most affected by discharges of tannery effluent showed total and pseudo-total Cr levels (up to 2,860 mg/kg) that greatly exceed national and international chemical sediment quality standards. The most contaminated section of the river bed is located downstream of the main industrial discharge. However, a large fraction of the Cr present in the sediment appears to be of lithogenic origin. At most sites, more than 50% of Cr is not soluble in aqua-regia and thus unlikely to be very mobile or easily bio-available. A negligible risk to the benthic community can be inferred for Pb, Zn, Cd, Cu and Ni. This work highlights the limitation of using existing chemical sediment quality standards alone for risk assessment. The collection and analysis of suspended solids, the determination of river discharge and of dissolved Cr at 10 field stations allowed to estimate the particulate and dissolved Cr load and to locate the river stretch that was the likely source of contaminated sediment. The pumping of dilution water from the Adige River into the Fratta-Gorzone River did not produce the expected contaminant dilution effect due to re-suspension of contaminated solid particles and the release of Cr in solution.
2001年和2004年，沿着弗拉塔 - 戈尔佐内河（意大利）采集了河床沉积物样本，以评估重金属污染水平。受制革厂废水排放影响最严重的河段，总铬和准总铬含量（高达2860毫克/千克）大大超过了国家和国际化学沉积物质量标准。河床受污染最严重的部分位于主要工业排放口的下游。然而，沉积物中存在的大部分铬似乎源自岩石成因。在大多数地点，超过50%的铬不溶于王水，因此不太可能具有很高的流动性或易于生物利用。可以推断，铅、锌、镉铜和镍对底栖生物群落的风险可忽略不计。这项工作突出了仅使用现有化学沉积物质量标准进行风险评估存在的局限性。通过在10个野外站点采集和分析悬浮固体、测定河流流量和溶解铬，得以估算颗粒态和溶解态铬的负荷，并确定了可能是受污染沉积物来源的河段。由于受污染固体颗粒的再悬浮和溶液中铬的释放，从阿迪杰河向弗拉塔 - 戈尔佐内河抽取稀释水并未产生预期的污染物稀释效果。
