Tolerance and remedial function of rooted submersed macrophyte Vallisneria spiralis to phenanthrene in freshwater sediments

Abstract

Tolerance and remedial function of submersed macrophyte Vallisneria spiralis to phenanthrene in freshwater sediments were investigated by manipulating initial phenanthrene concentrations in sediments from 8 to 80mgkg−1 dry sediment. The biomass growth of V. spiralis on phenanthrene-spiked sediments was not adversely affected until initial phenanthrene concentrations in sediments increased to 80mgkg−1 dry sediment. V. spiralis might evolve adaptive mechanisms to toxic contaminants in sediment, and then could change the growth patterns in order to decrease the toxicity on its growth. The removal efficiencies of phenanthrene from the planted sediments were 18% higher than those from the sediments without plant even under an initial phenanthrene concentration of 80mgkg−1 dry sediments. The enhanced removal of phenanthrene in sediments by the plant might be achieved mainly by the synergism between plant roots and microbes in the rhizosphere.