摘要:
重金属与农药共同暴露产生的联合毒性作用可以对实际环境产生潜在的风险。为了研究重金属与农药混合物在不同浓度比毒性相互作用(协同、拮抗与加和)及其定量评估相互作用大小,根据单个物质无观测浓度(NOEC)、5%效应浓度(EC5)、10%效应浓度(EC10)和50%效应浓度(EC50),设计3组混合物体系(即农药-农药、重金属-重金属和农药-重金属)分别按NOEC、EC5、EC10和EC50浓度比的12条混合物射线,测试单个化合物及混合物对以费氏弧菌的发光抑制急性毒性,利用浓度加和(CA)、独立作用(IA)、模型偏差比(MDR)及其观测值置信区间定性和定量评估12条混合物射线的毒性相互作用。结果表明,农药-农药二元混合物体系和农药-重金属六元混合物体系均产生明显的协同作用,其中农药-农药混合物体系中,混合物射线EE-NOEC在50%效应下协同作用大小达到30.6(MDRCA和MDRIA数值);混合物射线EE5、EE10的协同作用大小接近于混合物射线EE-NOEC,混合物射线EE50的效应大于15%时CA和IA计算的MDR值均在置信区间上限的上方,即混合物发生协同作用;农药-重金属混合物体系的4条混合物射线EE-NOEC、EE5、EE10和EE50在所有测试浓度水平的MDR值均在置信区间上限的上方,呈现出明显的协同作用;在50%效应下,混合物射线EE-NOEC、EE5、EE10和EE50的MDRCA和MDRIA值分别为4.05和4.91、6.12和7.98、3.70和4.60、2.62和2.59。重金属-重金属四元混合物体系除了EC50浓度比混合物表现出拮抗作用,其余混合物在所有测试浓度范围的MDR值均在置信区间范围内,均为加和作用。因此,混合物的毒性相互作用大小随着组分浓度比变化而发生变化。
Abstract:
Heavy metals and pesticides co-exposure may exert potential risk in the real environment. In order to investigate the toxicity interaction (synergism, additive, and antagonism) among heavy metals and pesticides at different concentration ratios and evaluate the toxicity interaction quantitatively, three mixture systems (pesticide-pesticide, heavy metal-heavy metal, and pesticide-heavy metal) with a total of 12 mixture rays were designed at the equivalent-effect concentrations of no observed effect concentration (NOEC), 5% effect concentration (EC5), 10% effect concentration (EC10) and 50% effect concentration (EC50) of individual compound. Acute toxicities of singe chemicals and mixtures to Vibrio fischeri were tested. The toxicity interaction of mixture was qualitatively and quantitatively evaluated by concentration addition (CA), independent action (IA), model deviation rate (MDR), and 95% observed confidence interval (OCI). The results demonstrated that the mixture systems of pesticide-pesticide and pesticide-heavy metal mixtures exerted significant synergetic effects. In the pesticide-pesticide mixture system, the extent of interaction for mixture ray EE-NOEC was up to 30.6 at 50% effect concentration (MDR value for CA and IA). The extents of the synergetic effects presented in the mixture rays EE5 and EE10 were nearly the same as the mixture ray EE-NOEC. The mixture ray EE50 performed synergetic effect at the effect concentration above 15% as the MDR values of CA and IA located above the upper limit of the confidence interval. In the pesticide-heavy metal mixture system, four mixture rays EE-NOEC, EE5, EE10 and EE50 presented obviously synergetic effects at the whole tested concentrations as the MDR values located above the upper limit of the confidence interval. The MDRCA and MDRIA values for four mixture rays EE-NOEC, EE5, EE10 and EE50 were 4.05 and 4.91, 6.12 and 7.98, 3.70 and 4.60, and 2.62 and 2.59, respectively. For the quaternary mixture system of the heavy metal-heavy metal, the mixture rays presented additive effects at all tested concentrations that the MDR values ranged between the lower and upper 95% OCI except for the mixture ray mixed at the EC50 presented antagonism. Thus, the synergetic degree for the mixtures changed with the different individual concentrations.