Estimating Bioavailability of Acetochlor to Wheat Using in Situ Pore Water and Passive Sampling

The intensive use of acetochlor in China leads to its extensive existence in soil which may show contamination on the crop and commodities. Therefore, it is vital to assess the bioavailability and phytotoxicity of acetochlor to crops. In this study, four measurements involved in in situ pore water extraction ( C IPW ), passive sampling extraction ( C free ), ex situ pore water extraction ( C EPW ), and organic solvent extraction ( C soil ) were conducted to assess the bioavailability and phytotoxicity of acetochlor to wheat plant in five soils. The results showed that the acetochlor concentrations in five tested soils analyzed by C IPW method or C free method have a significant correlation with the acetochlor concentrations in wheat, and were also correlated with the IC 50 values of acetochlor in wheat foliage and root. These indicated that the C IPW and C free methods were effective to evaluate acetochlor toxicity to wheat and the acetochlor concentrations in wheat. The effects of soil physical and chemical properties including pH, organic matter content (OMC), total nitrogen, and cation exchange capacity (CEC) on the acetochlor toxicity to wheat were analyzed, and it can be found that soil OMC is the dominant factor affecting the toxicity of acetochlor in soil-wheat system