[Forms Distribution and Ecotoxicity of Three Forms of Sulfonamides in Root-Soil Interface of Maize]

Forms distribution and ecotoxicity of sulfonamides in root-soil interface of maize were studied by chemical analysis and luminescent bacteria toxicity assay. The results indicated that the water soluble residues were the main form in rhizosperic soils, and the organic solvent extractable residues were the main form in far-rhizosperic soils. The three forms of sulfonamides showed relatively lower toxicity to luminescent bacteria with the relative inhibition rates less than 30%. The toxicity of water soluble residues was lower than that of the organic solvent extractable residues, and the bound residues showed the lowest toxicity to luminescent bacteria. The contents and relative inhibition rates of water soluble residues in rhizosperic soils were higher than those in far-rhizosperic soils, while the contents and relative inhibition rates of organic solvent extractable and bound residues in rhizosperic soils were lower than those in far-rhizosperic soils.