Effect of Different Soil Treatments on Dissipation of Chlorantraniliprole and Dehydrogenase Activity Using Experimental Modeling Design

The fate of pesticides in soils has received increasing attention in recent decades because of concerns about the potential impacts on surface and groundwater quality and agricultural products (Gavrilescu 2005;Khan 2016;Kookana 2010).Among the many processes that rule the vital fate of pesticides in the environment, the degradation process plays an essential role (Khan and Manchur 2017).In order to assess the degradability or dissipation of pesticides in different soils, it is imperative that we understand their kinetics of degradation mechanisms in soils.Currently, many pesticides are widely used in agriculture; however, there is a lack of information on important environmental parameters such as half-life values (the time for 50% of initial residues to be dissipated) for a number of pesticides under various climatic and soil conditions in different Egyptian soils (Bajeer et al. 2016;El-Sebae 1989;Mansour 2004).Chlorantraniliprole (CAP), a new anthranilic diamide insecticide, is developed worldwide by E.I.Du Pont de Nemours and Company, Inc. with high biological activity for foliar applications at rates of 10 to 60 g chlorantraniliprole/ha in many crops against all Lepidoptera and some Coleoptera, Diptera and Isoptera species, such as codling moth, apple fruit moth and free leaf living larvae (Bassi et al. 2007;Cameron et al. 2015).However, the field dissipation rates of this insecticide are broadly variable, depending on the type of soil and other factors affecting the degradation process.In all conditions, an efficient degradation occurred owing to direct light absorption and microbial degradation processes involving either clays or natural organic matter (OM) contents (Mountacer et al. 2014).The residue of a novel insecticide, CAP was extracted from soil with acetonitrile by QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) method or solid phase extraction cartridge (Dong et al. 2011;Zhang et al. 2012).An effective analytical method for the residue analysis of CAP recently have been reported by high performance liquid chromatography (HPLC) (Xu et al. 2010).Average CAP recovery from soil at different levels (5 or 10, 40, and 100 μg/kg) ranged from 74.9 to 97.5%, with intra-day relative standard deviation (RSD) values of 1.9-11.3%and inter-day RSD values of 4.7-10.4%.The t 0.5 of CAP changed from 12.6 to 23.1 days in soil (Dong et al. 2011).