Vandecasteele Bart, De Vos Bruno, Tack Filip M G
Institute for Forestry and Game Management, Ministry of the Flemish Community, Geraardsbergen, Belgium.
Sci Total Environ. 2002 May 6;290(1-3):1-14. doi: 10.1016/s0048-9697(01)00966-4.
For several decades, periodical dredging of river sediments has been necessary to allow for shipping traffic on the river Scheldt. Sediments were disposed along the shores in the alluvial plain without concern for the potential presence of contaminants. The aim of this study was to survey the alluvial plains of the Upper Scheldt river in Belgium for the presence of old dredged sediment landfills, and to appraise the heavy metal contamination at these sites. Up to 82% of the areas that were affected by dredged sediment disposal was found to be polluted by at least one of the metals Cd, Cr, Zn or Pb. Concentrations of Cd, Cr and Zn were, in 10% of the cases, higher than 26, 1900 and 2800 mg/kg, respectively. Cu and Ni concentrations were of no environmental concern on any site. Trends in metal concentrations as a function of location and time were explored and discussed. The highest average concentrations of Cd, Cr, Cu, Pb and Zn were found in the most downstream quarter of the Upper Scheldt. Contents of Pb and Cu were significantly lower for sediments disposed after 1965, but no indication for improvement of the sediment quality with time was observed for Cd, Cr and Zn. The pollution levels encountered warrant for caution as most of the soils affected by historical dredged sediment disposal are currently in use for agriculture, nature development or forestry.
几十年来，定期疏浚河流沉积物对于斯海尔德河上的航运至关重要。沉积物被倾倒在冲积平原的沿岸，而未考虑其中可能存在的污染物。本研究的目的是调查比利时斯海尔德河上游冲积平原上旧疏浚沉积物填埋场的情况，并评估这些场地的重金属污染。发现受疏浚沉积物处置影响的区域中，高达82%受到至少一种金属镉、铬、锌或铅的污染。在10%的情况下，镉、铬和锌的浓度分别高于26、1900和2800毫克/千克。铜和镍的浓度在任何场地都未引起环境问题。探讨并讨论了金属浓度随位置和时间的变化趋势。在斯海尔德河上游最下游的区域，镉、铬、铜、铅和锌的平均浓度最高。1965年之后处置的沉积物中铅和铜的含量显著降低，但未观察到镉、铬和锌的沉积物质量随时间改善的迹象。鉴于大多数受历史疏浚沉积物处置影响的土壤目前用于农业、自然开发或林业，所遇到的污染水平值得谨慎对待。
