Research advance of environmental fate of herbicide atrazine and model fitting in farmland ecosystem
农田生态系统中除草剂阿特拉津的环境行为及其模型研究进展

Among the postemergent herbicides,atrazine(2-chloro-4-ethylamino-6-isopropylamino-1,3,5-s-triazine) is the most commonly applied worldwide to control broadleaf and grassy weeds on both agricultural and non-agricultural land.It is,unfortunately,also very widely detected in surface water,subsurface water,and groundwater in the countries where it has been used.Due to long-term and chronic exposure to groundwater supplies,the presence of atrazine in groundwater underlying agricultural regions causes the potential animal reproductive and human health problems.This paper introduces advances in the domestic and international use of atrazine.It also provides a key review concerning atrazine's absorptive mechanism and influential factors(such as pH,soil organic matter,temperature,agricultural management practice,etc.),its chemical and biological degradation,its eco-toxicological assessment,and its closeness of fit with the CXTFIT mathematical model.The primary objectives for introducing progress in atrazine research are two fold.First,an evaluation of the potential for atrazine to contaminate groundwater requires an understanding of transport mechanisms that occur in the field,and second an understanding of the behavior of atrazine is required for the evaluation of environmental and health risks. Analytical solutions to the classical convection-dispersion equation(CDE),or alternative equations,have been widely used as models of chemical transport in the soil-water system.Although such models are limited to steady-state water flow conditions in homogeneous soils,they are especially useful for interpreting laboratory experiments.In fact,valuable information has been gained through their use.Transport regulation also governs the environmental behavior of atrazine in a farmland ecosystem.Physical and chemical nonequilibrium conditions can accelerate contaminant transport and have important consequences on the fate of atrazine.Under steady-state and saturated or unsaturated flow rate conditions,miscible displacement experiments and equilibrium adsorption batch experiments in a soil column indoors can be conducted to acquire breakthrough curves(BTCs) that reflect the characteristics of atriazine transport and to depict the partitioning coefficient of atrazine adsorption to a soil.Also application of a mathematical model to atrazine transport in the farmland ecosystems' soils can be used to fit nonequilibrium BTCs in order to acquire atrazine's quantitative cognition of the transport mechanism.Then parameters that the mathematical model simulates can be applied to predict the concentration variability and determine the amount of atrazine leached at different depths of the farmland ecosystems' soils.This should be key to future research work.