农药类化合物对大型溞的毒性作用模式:与基线毒性化合物比较研究
作者简介:
闫俐辰(1993-),女,硕士研究生,研究方向为环境化学,E-mail:yanlc691@nenu.edu.cn
- 东北师范大学环境学院, 长春 130117
摘要: 农药在控制有害生物的同时,对水生生态系统产生较大的毒性效应。本文通过实验获得了25种基线化合物对大型溞的急性毒性数据,并与57种农药类化合物对大型溞的急性毒性数据进行比较研究,同时根据体外浓度LC50、生物富集因子BCF和体内临界浓度CBR的关系,计算了这些化合物在大型溞体内的临界浓度,研究了农药类化合物对大型溞的毒性作用机理。结果表明,基线化合物在大型溞体内的临界浓度log1/CBR值在一个很窄的范围波动,而农药类化合物在大型溞体内的临界浓度log1/CBR值范围广且较高。这说明多数农药类化合物对大型溞为反应性毒性作用模式。其中,除草剂对大型溞的毒性显著低于杀菌剂和杀虫剂对大型溞的毒性。这可能是因为除草剂主要通过干扰植物光合作用、植物激素或植物分子合成发挥毒性效应,从而导致其对大型溞的生理系统难以发生反应性毒性效应。而杀虫剂和杀菌剂主要通过干扰生物神经系统、生殖系统、呼吸作用或大分子合成发挥毒性效应,因此易与大型溞生理系统发生生物化学反应,从而具有较高的毒性效应。本文分别建立了除草剂、杀菌剂和杀虫剂对大型溞的急性毒性QSAR模型。除草剂对大型溞的急性毒性机理较简单,其毒性与化合物疏水性程度和离子化程度有关;而杀菌剂对大型溞的急性毒性主要与化合物的标准生成热和极性表面积有关;杀虫剂对大型溞的急性毒性作用机理较复杂,它们对大型溞的毒性效应与其和生物分子之间的氢键和范德华力有关。
The Modes of Action of Agricultural Chemicals to Daphnia magna: A Comparative Study with Baseline Compounds
- School of Environment, Northeast Normal University, Changchun 130117, China
- Received Date:
2017-09-28
Fund Project:
Abstract: Agricultural chemicals serve as effective control of weeds and pests. However, most of them were of great toxic effects to aquatic organisms. In the present study, the acute toxicity data of 25 baseline compounds to Daphnia magna were obtained by experiment, and 57 agricultural chemicals to Daphnia magna were obtained from literatures. The critical body residue (CBR) of these chemicals were calculated based on the relationship between external effect concentration (LC50), bioconcentration factor (BCF) and CBR. The toxic modes of action of these agricultural chemicals to Daphnia magna were investigated through a comparative study with baseline compounds. The results showed that the log1/CBR values of baseline compounds were close to a constant, the log1/CBR values of agricultural chemicals were however varying within a wide range. This suggests that most of agricultural chemicals were of reactive modes of action to Daphnia magna. Among these agricultural chemicals, the herbicides were much lower toxic to Daphnia magna than fungicides and insecticides. The herbicides act through disrupting photosynthesis, phytohormone and biosynthesis in plants. This may lead to lower toxicity of the herbicides to Daphnia magna. However, the fungicides and insecticides act through disrupting nervous or reproductive systems, respiration or biosynthesis. This may lead to great reactivity between chemicals and biomolecules, thus leading to higher toxicity to Daphnia magna. Additionally, we developed QSAR models of chemical toxicities and molecular descriptors for the herbicides, fungicides and insecticides, respectively. The toxic modes of action of the herbicides were simple, and their toxicity were related to the hydrophobicity and ionization of the compounds. The toxic modes of action of the fungicides mainly depended on the heat of formation and polar surface area. The toxic modes of action of the insecticides were however more complicated. The toxic effects of these insecticides may be related to the hydrogen-bond and vander waals interaction between and chemicals and biomolecules in Daphnia magna.