沉水植物苦草(Vallisneria natans)对多环芳烃污染沉积物的修复作用

Remedial function of submersed macrophyte Vallisneria natans to PAHs-contaminated sediments

沉水植物是浅水湖泊生态系统的关键种群,对水环境质量及水生生态系统结构有重要影响.以东太湖大水港和湖湾区2个典型的具有不同污染程度的沉水植物苦草(Vallisneria natans)生长区域为研究对象,考察苦草对多环芳烃(PAHs)的修复效果.结果表明,经过34 d植物修复试验,重度污染的东太湖大水港沉积物中PAHs的去除率为62%,沉积物中PAHs降解速率为0.024 d-1;而中度污染的东太湖湖湾区沉积物的PAHs去除率为42%,其降解速率为0.015 d^(-1).种植苦草的沉积物中PAHs的降解速率是未种植苦草的降解速率的2~3倍.苦草对沉积物中高分子量PAHs的修复效果尤为显著.因此,苦草可以有效地用于PAHs污染沉积物的修复,尤其是在重污染和高分子量PAHs污染沉积物中,苦草的修复作用更加明显.

Submersed macrophytes are an important functional and structural element of shallow aquatic ecosystems. Remedial function of submersed macrophyte（ Vallisneria natans） to PAHs in freshwater sediments was investigated in different pollution levels in east Lake Taihu. Over a 34-day plant remediation experiment,the removal rate and the first-order rate constants of PAHs degradation in the heavily contaminated sediments of Dashui harbour from east Lake Taihu was 62% and 0.024 d^（-1）,respectively.However,42% PAHs removal and 0.015 d-1 of PAHs degradation rate was also observed in the moderately contaminated sediments of east Lake Taihu bay. The degradation rate of PAHs in the planted sediments was 2-3 times higher than those in the unplanted sediments. The removal of high molecular weight（ HMW） PAHs in sediments with planting V. natans was significantly observed.Thus,V. natans can be effectively used for the remediation of PAHs contaminated sediments,especially in heavily polluted and HMW-PAHs contaminated sediments.