Evaluation of arsenic pollution in field-contaminated soil at the soil’s actual pH  

作　　者：Tiancong Gao Haixia Tian Huimin Niu Mallavarapu Megharaj Wenxiang He 

机构地区：[1]College of Natural Resources and Environment,Northwest A&F University,Key Laboratory of Plant Nutrition and Agro-environment in Northwest China,Ministry of Agriculture,Yangling,Shaanxi 712100,China [2]Global Centre for Environmental Remediation,College of Engineering,Science and Environment,University of Newcastle,Callaghan,NSW 2308,Australia

出　　处：《Journal of Environmental Sciences》2024年第10期137-147,共11页环境科学学报（英文版）

基　　金：This work was supported by the National Natural Science Foundation of China(Nos.42377023,42007303,and 41571245);the National key research and development Program of the Ministry of Science and Technology(No.2019YFC1804101);Shaanxi Basic Research Program of Natural Science General Project(General)(No.2022JM-145).

摘　　要：The pollution and ecological risks posed by arsenic(As)entering the soil are the major environmental challenges faced by human beings.Soil phosphatase can serve as a useful indicator for assessing As contamination under specific soil pH conditions.However,the study of phosphatase kinetics in long-term field As-contaminated soil remains unclear,presenting a significant obstacle to the monitoring and evaluation of As pollution and toxicity.The purpose of this study was to determine phosphatase activity and explore enzyme kinetics in soils subjected to long-term field As contamination.Results revealed that the soil phosphatase activity varied among the tested soil samples,depending on the concentrations of As.The relationship between total As,As fractions and phosphatase activity was found to be significant through negative exponential function fitting.Kinetic parameters,including maximum reaction velocity(Vmax),Michaelis constant(Km)and catalytic efficiency(V_(max)/K_(m)),ranged from 3.14×10^(−2)–53.88×10^(−2) mmol/(L·hr),0.61–7.92 mmol/L,and 0.46×10^(−2)–11.20×10^(−2) hr^(−1),respectively.Vmax and Vmax/Km of phosphatase decreased with increasing As pollution,while Km was less affected.Interestingly,Vmax/Km showed a significant negative correlationwith all As fractions and total As.The ecological doses(ED10)for the complete inhibition and partial inhibition models ranged from0.22–70.33 mg/kg and 0.001–55.27 mg/kg,respectively,indicating that V_(max)/K_(m) can be used as an index for assessing As pollution in field-contaminated soil.This study demonstrated that the phosphatase kinetics parameters in the soil’s pH system were better indicators than the optimal pH for evaluating the field ecotoxicity of As.

关 键 词：Arsenic pollution Ecological risk Soil phosphatase Enzyme kinetics Catalytic efficiency(V_(max)/K_(m)) 

分 类 号：X53[环境科学与工程—环境工程] S15[农业科学—土壤学]