基于四尾栅藻响应的有机磷农药生态风险评估

以系统评价有机磷农药在水域生态系统风险为目标,采用批次培养的方法研究了草甘膦和毒死蜱两种有机磷农药在高浓度下的毒性效应、低浓度下的刺激效应及微量条件下的无机磷替代效应.结果表明,草甘膦和毒死蜱对四尾栅藻(Scenedesmus quadricanda)的96h EC50值的分别为12.98,2.02μmol/L.低浓度草甘膦(0.014~1.35μmol/L)条件下细胞密度和最大光能转化效率表现出了显著的刺激作用,最大促进效应分别为13%和6.0%;草甘膦(0.40~0.67μmol/L)表现出显著的无机磷替代效应,而毒死蜱处理组未观察到刺激作用和替代效应.有机磷农药对微藻种群变化的作用方式以低浓度下的刺激作用为主,同时可以引发无机磷不足时某些可利用有机磷种类微藻的种群增长.

Ecological risks assessment of organophosphorus pesticides based on response of Scenedesmus quadricanda

Ecological risks assessment of organophosphorus pesticides, glyphosate-isopropylammonium(Glyphosate IPA) and chlorpyrifos, were conducted based on the chlorophyll a fluorescence of S. quadricanda in batch cultures. The dosage response was hypothesized as toxic effect under high concentrations and stimulating effect at low concentrations, besides, utilization of OPPs as sole phosphorus source were tested. The results showed median inhibitory effect concentrations of glyphosate IPA and chlorpyrifos at 96h were 12.98 μmol/L and 2.02 μmol/L respectively. The cell density and the maximum photochemical efficiency (Fv/Fm) were promoted significantly at low concentrations of glyphosate IPA (0.014~1.35 μmol/L), moreover, glyphosate IPA could be used as sole phosphorus source to sustain growth of S. quadricanda at the range of 0.40~0.67 μmol/L notably. However, such effects were not detected in chlorpyrifos treatments. In conclusion, ecological risks of OPPs were dominated by significant stimulating effect in yield, meanwhile, dynamic variation of algae community could be induced by organophosphorus pesticides at the deficiency of inorganic phosphorus.