Hamers T, Smit M G, Murk A J, Koeman J H
Toxicology Group, Wageningen University, The Netherlands.
Chemosphere. 2001 Nov;45(4-5):609-24. doi: 10.1016/s0045-6535(01)00017-0.
A newly developed method for measuring the integrated esterase inhibiting potency of rainwater samples was applied in practice, and the results are compared to the toxic potency calculated from concentrations of 31 organophosphate (OP) and carbamate pesticides, out of a total of 66 chemically analyzed pesticides. In addition, the general toxic potency of the rainwater samples was evaluated in a microtiter luminescence assay with Vibrio fischeri bacteria. Rainwater samples were collected over four consecutive 14-day periods in both open and wet-only samplers. The esterase inhibiting potency of the open rainwater samples (expressed as ng dichlorvos-equivalents/l) corresponded well with the chemical analyses of the rainwater samples collected by both types of samplers (r = 0.83-0.86). By far, the highest esterase inhibiting potency was found in a sample collected in an area with intense horticultural activities in June, and was attributed to high concentrations of dichlorvos, mevinphos, pirimiphos-methyl and methiocarb. The esterase inhibiting potency of this sample was equivalent to a dichlorvos concentration of 1380 ng/l in the rainwater, which is almost 2000 times higher than the maximum permissible concentration (MPC) of dichlorvos set for surface water in Netherlands. Maximum individual concentrations of dichlorvos and pirimiphos-methyl even exceeded the EC50 for Daphnia, suggesting that pesticides in rainwater pose a risk for aquatic organisms. Not all responses of the luminescence-assay for general toxicity could be explained by the analyzed pesticide concentrations. The bio-assays enable a direct assessment the toxic potency of all individual compounds present in the complex mixture of rainwater pollutants, even if they are unknown or present at concentrations below the detection limit. Therefore, they are valuable tools for prescreening and hazard characterization purposes.
一种新开发的测量雨水样品综合酯酶抑制效力的方法得到了实际应用，并将结果与根据66种化学分析农药中的31种有机磷酸酯（OP）和氨基甲酸酯类农药浓度计算出的毒力进行了比较。此外，通过费氏弧菌微滴定发光测定法评估了雨水样品的一般毒力。在开放采样器和仅湿式采样器中连续四个14天周期收集雨水样品。开放雨水样品的酯酶抑制效力（以ng敌敌畏当量/升表示）与两种采样器收集的雨水样品的化学分析结果吻合良好（r = 0.83 - 0.86）。到目前为止，在6月园艺活动频繁地区采集的一个样品中发现了最高的酯酶抑制效力，这归因于高浓度的敌敌畏、灭多威、甲基嘧啶磷和甲硫威。该样品的酯酶抑制效力相当于雨水中敌敌畏浓度为1380 ng/l，几乎比荷兰地表水设定的敌敌畏最大允许浓度（MPC）高2000倍。敌敌畏和甲基嘧啶磷的最大个体浓度甚至超过了大型溞的半数有效浓度（EC50），这表明雨水中农药对水生生物构成风险。发光法对一般毒性的所有反应并非都能通过分析的农药浓度来解释。生物测定法能够直接评估雨水污染物复杂混合物中所有单个化合物的毒力，即使它们未知或浓度低于检测限。因此，它们是用于预筛选和危害特征描述目的的有价值工具。
