Effects Of Dissolved Organic Matter On Behavior Of Chloratoluron In Environment

Chlorotoluron is a kind of root adsorption herbicide with a high activity and low toxicity. It is widely employed in binary mixtures or pre- or postemergence selective control of weeds in cereal crops.Dissolved organic matter is divided into two groups, hydrophilic and hydrophobic, The hydrophilic components can be further divided into hydrophilic acids and hydrophilic neutral compounds, the hydrophobic components can be further divided into hydrophobic acids and hydrophobic neutral compounds Dissolved organic matter with amphoteric properties can enhance the solubility of hydrophilic compounds in water and decrease their volatilization. The hydrophobic components of dissolved organic matter have a strong affinity for hydrophobic chemicals in the environment and was an impact on transport of them.Two types of dissolved organic matter from both non-treated sludge and heat-expanded sludge were employed to investigate the effect on the chlorotoluron solubility in water and its partition coefficient in 1-octanol and water. Results indicates that both DOMs showed a positive effect on the chlorotoluron solubility in water, and DOM from non-treated sludge had a greater effect on chlorotoluron solubility in water than DOM from heat-expanded sludge. However, no effect of DOMs on Kow was observed.Bath equilibrium techniques were used to examine the effect of DOM from non-treated sludge and heat-expanded sludge on chlorotoluron sorption-desorption by the two types of soil in China. Application of DOM from non-treated sludge and heat-expanded sludge led to a general decrease in sorption to the soil and increase in desorption from the soil. Compared with that from heat-expanded sludge, application of DOM extracted from non-treated sludge resulted in more decreases in sorption. However, this case was opposite for the desorption. The effect of DOM sorption-desorption depended on the type of soils. In the presence of the same source of DOM, the more inhibited sorption to yellow-fluvio aquic soil than red soil was observed. Compared with that from red soil, application of DOM led to the increased desorption of chlorotoluron from yellow-fluvio aquic soil.The dosage-toxicity effect of chorotoluron on inhibition of germination rates, bud androot elongation of two wheat cultivars was studied in this paper by indoor training. Two types of dissolved organic matter from both non-treated sludge and heat-expanded sludge were employed Results indicates that inhibition of germination rates , bud and root elongation of two wheat cultivars treated with chorotoluron was observed, NM-9 showed a higher sensitivity to chlorotoluron than YM-158, Both types of DOMs had no effect on the germination, but did had a positive effect on bud and root elongation, chlorotoluron in the presence of DOMs had an increased toxicity to wheat seedlings as compared with chlorotoluron applied alone. DOM from non-treated sludge had a greater effect on chlorotoluron toxicity to wheat than DOM from heat-expanded sludge. In the presence of the same source of DOM, a stronger chlorotoluron toxicity to YM-158 than to NM-9 was observed.