Evaluation of Ceratophyllum demersum as the accumulative bioindicator for trace metals

摘要

Ceratophyllum demersum,an ubiquitous submerged aquatic plant, was tested as a passive bioindicator of trace metal pollution. The content and bioaccumulation ability of the wide range of trace metals (Ba, Cd, Co, Cr, Cu, Fe, Li, Mn, Mo, Ni, Pb, Rb, Ti, V and Zn) in this species growing in areas with different type and intensity of anthropogenic activity was analyzed and a synthetic pollution index was calculated to assess the level and spatial distribution of trace metal contamination. The results of Bioaccumulation Factor exceeding index of 103for Ba, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Rb and Zn showed considerably high trace metal uptake ability ofC. demersumand makes it a good metal accumulator. Moreover, multivariate statistics of trace metal content inC. demersumand the Nemerow Pollution Index allowed to indicate the type of land use in the surrounding of reservoirs: recreational; urban and agricultural; or urban with direct impact of industrial pollution. Plants growing in areas with agriculture, intensive housing and vehicle traffic contained significantly more Ba, Cd, Co, Cr, Cu, Fe, Li, Mn, Ni, Pb, Rb, Ti, V and Zn than plants from recreational areas, while the industrial areas distinguished from other urban areas by particularly high content of Li and Ti. The differences in level of pollution between study sites were highlighted by the Nemerow Pollution Index, which was proved to indicate silimar gradient of pollution for water and plants. Therefore, we concluded that the NPI could be a recommended tool helping to analyse ecological condition of the environment andC. demersummay be utilized as a relevant biomonitor of trace metal pollution in areas with diversified and multifactor man-made influence.