Impact Of Black Cardon On The Sorption And Bioavailability Of Chlorantraniliprole In Soils

Chlorantraniliprole (CAP), is a new pesticide belonging to the anthranilic and phthalic diamide class which sharing a special mode of action on the insect ryanodine receptor. Recent, the research of CAP mainly focuses on the field efficacy test and residue analysis method, there is not reported in the study of CAP on environmental behavior in China. Black cardon, as a super absorbent of contaminants, plays an important role in the sorption/desorption of pesticides in soil environment. However, the effects of black cardon on bioavailability of CAP in soils have not been reported. In this paper, the sorption/desorption, degradation behaviors and bioavailability of CAP in five typical Chinese soils with and without amended black cardon were studied, which can supply the scientific evidence of the environmental and ecological safety evaluation.The main conclusions of experiments were as follows:1. An analytical method to determine chlorantraniliprole residues in water, Soil, Brassica chinensis, Earthworm by liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed and validated. The acetonitrile was added into the brassica chinensis samples to extract chlorantraniliprole residues.Then the mixture was homogenized with high speed and added with some anhydrous magnesium sulfate and sodium chloride. After shaking thoroughly and centrifugation, the upper layer was transferred and diluted for direct analysis. LC-MS/MS with electriospray ionization in positive ion scan mode was used to determine chlorantranilip. The fortification recoveries of chlorantraniliprole in soil including five kinds of soil were91.7%-99.79%at fortification levels ranging from0.1mg/kg to20mg/kg. The limit of detection was0.003mg/kg and the LOQ was0.01mg/kg for chlorantraniliprole. The method has the ad vantage of simplicity, repeatability and sensitivity.2. To investigate the effects of black cardon amendment on the sorption and desorption of CAP in5different agricultural soils, the sorption and desorption behavior of chlorantraniliprole on four kinds of sorbents (Five typical agricultural soils collected around China, Two kinds of Black cardon made in Lab, Soil amended with Black cardon, Soil amended with Black cardon aging two months) were investigated by means of batch equilibrium technology and decant refilled technology, respectively. The results showed that sorption of chlorantraniliprole on the five soils followed an increasing order of Black soil> Yellow soil> Purplish soil> Red soil>Fluvo aquice soil. The Freundlich sorption coefficients were from1.06-4.45L/Kg. Physical sorption is the main mechanism of chlorantraniliprole sorption on the tested soils. Soil organic matters and cation exchange capacity are the most important factors that affect the sorption behavior of chlorantraniliprole in soils. The apparent sorption-desorption hysteresis was found in all the tested soils from the results of desorption experiment.3. The Freundlich sorption coefficients of BC850and BC450were79036L/Kg and1974L/Kg, respectively, indicating that the sorption capacity of two kinds of black cardon was much more than soils. Due to the greater surface area, high microporosity of BC850, the apparent sorption-desorption hysteresis was more obvious.4. Black cardon application in soils could enhance the sorption of CAP, but the magnitudes were varied among soils and black cardon with different properties. We found the sorption of CAP on soil amended with BC850was much higher than the soil amended with BC450. Amendment of0.5%(by weight) black cardon in the black soil, which have high content of organic matter (4.59%), resulted in an increase of sorption coefficient (Kd) by2.17%; while for the fluvo-aquic soil with organic matter content of1.16%, amendment of black cardon at the same level led to an increase of139.13%. The sorption capacity of black cardon was partially suppressed when black cardon was mixed with soils. The calculated KF.biochar of BC450after mixed in the black soil, yellow soil, red soil, purplish soil, and fluvo-aquic soil were decreased by96.94%,90.6%,91.31%,68.26%, and34.59%, and KF,blochar of BC850after mixed in the black soil, yellow soil, red soil, purplish soil, and fluvo-aquic soil were decreased by62.81%、47.65%、40.30%、49.85%and358.38%,respectively, compared to that of the original biochar. The sorption of CAP on soil amended with aging black cardon was enhanced a little. Yet the surface of black cardon was filled with soil organic matter or soil particles, the sorption capacity of black cardon was partially suppressed more when biochar was aged in soils.5. To investigate the effects of black cardon amendment on the dissipation of CAP in5different agricultural soils, the dissipation behaviors of CAP in soils with and without biochar amendment were measured by dissipation kinetic experiment. The result show that The half-lives of CAP in black soil, yellow soil, red soil, purplish soil, and fluvo-aquic soil were115.52,133.30,154.03,144.41and169.06d, respectively. Soil organic matters and silt clay are the most important factors that affect the dissipation behavior of chlorantraniliprole in soils. In soils amended with biochar, the corresponding half-lives of CAP were extended by20.39,35.76,38.51,79.19, and119.75d, respectively. Similar to the effects of biochar on CAP sorption, in soil with higher content of organic matter, the retardation of CAP dissipation by amending biochar was smaller than that in soil with lower content of organic matter.6. To investigate the effect of Black Cardon on the bioavailability of CAP for earthworms in soils, we measured the bioaccumulation experiment of CAP in five soils in the presence and absence of BC450and BC850. The result show that the passive dermal diffusion is the major uptake route of CAP accumulated in earthworm, and the addition of Black cardon to the soil suppressed the release of CAP into the soil solutions, resulted in the decrease the bioavailability of CAP in earthworm. Bioaccumulation of CAP for earthworms in the soils amended with BC450was higher than that in the soils amended with BC850. The bioconcentration factor (BCF) for earthworm on CAP in soil absence of black cardon was higher than that in soil presence of black carbon, indicating that the bioaccumulation of CAP was decreased with the presence of black cardon in soil. BCF in low concentration soil was greater than that in high concentration soil, which is relevant to the enrichment ability of CAP for earthworm.