The study of bioavailability of adsorbed atrazine

• 1、College of Environmental Science and Engineering, Ministry of Education Key Laboratory of Environmental pollution process and benchmark, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, Tianjin 300457

Abstract：Atrazine is one of the most widely used herbicides, which is persistent in the environment. Therefore, its environmental behaviors and ecological risks should not be neglected. In this study, the sorption and desorption behavior of atrazine were investigated in soil. The desorption results were predicted by using a Dual-Equilibrium Desorption (DED) model. Meanwhile，atrazine degrading bacteria AD2 was inoculated into the soil-water system to further study the bioavailability of adsorbed atrazine. A mathematical model was applied to describe the relationship between desorption and biodegradation. The results showed that the atrazine sorption agreed well with the conventional linear sorption model, while the desorption were found to exhibit significant hysteresis, which could be well predicted by the DED model. When atrazine's concentration is low, desorption become the rate-limit step and biodegradation rate can be well fitted by the desorption-based biodegradation model. When the pollutant concentration is high, the bacteria can use the adsorbed pollutants directly. Therefore, more atrazine became bioavailable than that predicted from desorption rate.

Keywords： environmental sciense atrazine soil sorption-desorption microbial bioavailability