镉砷在线蚓中的毒物-毒效动力学过程及定量模拟  

Toxicokinetic-toxicodynamic processes of cadmium and arsenic in Enchytraeus crypticus

作　　者：李敏 龚冰 黄雪莹 肖雪 何尔凯[1] 仇荣亮[3,4] LI Min;GONG Bing;HUANG Xue-ying;XIAO Xue;HE Er-kai;QIU Rong-liang(School of Environmental Science and Engineering,Sun Yat-sen University,Guangzhou 510006,China;School of Environmental Science and Engineering,Shanghai Jiao Tong University,Shanghai 200240,China;Guangdong Provincial Key Laboratory for Environmental Pollution Control and Remediation Technology,Sun Yat-sen University,Guangzhou 510006,China;Guangdong Laboratory for Lingnan Modern Agriculture,South China Agricultural University,Guangzhou 510642,China)

机构地区：[1]中山大学环境科学与工程学院,广州510006 [2]上海交通大学环境科学与工程学院,上海200240 [3]广东省环境污染控制与修复技术重点实验室,中山大学,广州510006 [4]岭南现代农业科学与技术广东省实验室,华南农业大学,广州510642

出　　处：《农业环境科学学报》2020年第7期1451-1459,共9页Journal of Agro-Environment Science

基　　金：国家自然科学基金面上项目(41977115);广州市科技计划项目(201904010116);高校基本科研业务费青年教师培育项目(19lgpyl50)。

摘　　要：为探讨土壤污染物重金属镉(Cd)和类金属砷(As)在陆生生物体内的动态累积及毒性效应过程的差异性和规律性,以线蚓(Enchytraeus crypticus)为研究对象,以Cd和As为目标金属,采用室内试验和模型拟合手段定量描述两者的毒物动力学和毒效动力学过程。结果表明:线蚓体内Cd、As的累积量随着暴露浓度及时间的增加而不断上升并逐渐趋于平衡,Cd、As在暴露期间最大的累积量分别为459.6、32.91 mg·kg^-1;拟合得到的Cd总吸收速率常数Ku(1.761 mg·kg^-1·d^-1)显著大于As(0.102 mg·kg^-1·d^-1),Cd总排出速率常数Ke(0.015 d^-1)小于As(0.287 d^-1);Cd、As对线蚓的毒性作用随着暴露时间的增加而增强,基于体外暴露浓度计算的半数致死浓度(LC50)随时间的增加而降低,并在暴露约7 d后达到平衡,其最终半数致死浓度(LC50∞)分别为0.314、1.253 mmol·L^-1;进一步基于体内浓度计算其体内半数致死浓度(LC50inter),发现As的LC50inter值基本不受暴露时间的影响,而Cd的LC50inter值随着暴露时间的增加而上升,基于不同暴露时间下体内浓度和毒性数据整体拟合得到总的LC50interCd(468.8 mg·kg^-1·d^-1)显著大于LC50interAs(26.65 mg·kg^-1·d^-1)。整体上,Cd和As在线蚓体内的累积和毒性均受到时间的影响;Cd的累积能力显著强于As,基于体外暴露浓度时毒性强度Cd大于As,而体内累积的As则呈现更强的毒性效应;As的体内浓度和其动态毒性效应有很好的相关性(R2=0.75),而Cd的体内浓度不能很好地预测其毒性(R2=0.57),说明其体内浓度不能完全代表产生毒性的生物有效浓度。The dynamic accumulation and toxicity processes of a heavy metal(Cd)and metalloid(As)in terrestrial organisms were explored. In this study, laboratory experiments and a modeling approach were both applied to quantitatively describe the toxicokinetic and toxicodynamic processes of Cd and As in the soil organism Enchytraeus crypticus. The results showed that the accumulation of Cd and As in E.crypticus increased with increasing exposure concentration and time, and equilibrium was reached after a certain exposure period. The maximum body concentrations of Cd and As during the exposure period were 459.60 mg·kg^-1 and 32.91 mg·kg^-1, respectively. The estimated overall uptake rate constant(Ku)of Cd(1.761 mg·kg^-1·d^-1)was greater than that of As(0.102 mg·kg^-1·d^-1), while the elimination rate constant(Ke)of Cd(0.015 d^-1)was smaller than that of As(0.287 d^-1). Based on the external exposure concentrations, the median lethal concentration(LC50)for Cd and As decreased over time and reached equilibrium after 7 d of exposure, and the ultimate LC50(LC50∞)of Cd(0.314 mmol·L^-1)was smaller than that of As(1.253 mmol·L^-1). When based on the body concentrations, the LC50 inter was calculated, with an almost constant LC50 inter of As, while the LC50 inter of Cd increased over time. The overall LC50 inter Cd(468.80 mg·kg^-1·d^-1)was significantly higher than LC50 interAs(26.65 mg·kg^-1·d^-1). Overall, the accumulation and toxicity of Cd and As were both time-dependent. The accumulation capacity of Cd in E. crypticus was greater than that of As. The toxicity of Cd was higher than that of As when based on the external concentration, while the accumulated As in the organism showed a stronger toxic effect. There was a good correlation between the dynamic toxicity and the body concentration of As(R2= 0.75), but not for Cd(R2= 0.57), thereby suggesting that the accumulated Cd inside the organism cannot well represent the bioavailable fraction that causes toxicity. This study emphasizes the importance of considering th

关 键 词：镉 砷 毒物动力学 毒效动力学 剂量-效应关系 

分 类 号：X171.5[环境科学与工程—环境科学]