Effects of corn straw on dissipation of polycyclic aromatic hydrocarbons and potential application of backpropagation artificial neural network prediction model for PAHs bioremediation

Abstract

In order to provide a viable option for remediation of PAHs-contaminated soils, a greenhouse experiment was conducted to assess the effect of corn straw amendment (1%, 2%, 4% or 6%, w/w) on dissipation of aged polycyclic aromatic hydrocarbons (PAHs) in contaminated soils. Backpropagation artificial neural network (BP-ANN) was applied to model the relationships between soil properties and PAHs concentration in soils. The removal rate of PAHs, enzyme activity (catalase and dehydrogenase), dissolved organic carbon (DOC) and microbial biomass carbon (MBC) in soils were investigated to evaluate the dissipation of PAHs under different ratio of corn straw amendment. The present study showed that corn straw amendment apparently accelerated the dissipation of PAHs after incubation of 112 days, especially under 4% and 6% treatments. Compared with non-amended soil, corn straw amendment significantly (p < 0.05) increased the removal rate of low molecular weight (LMW) PAHs and significantly (p < 0.05) enhanced the dissipation of high molecular weight (HMW) PAHs only under 6% treatment. Moreover, corn straw amendment increased activities of catalase and dehydrogenase, concentrations of DOC and MBC in soils, which are beneficial to the degradation of PAHs in soils. The performance of the BP-ANN model was assessed through the root mean square error (RMSE) and determination coefficient (R2). The results indicated that BP-ANN model could provide satisfactory prediction of PAHs concentration in soils during incubation period at R2 and RMSE values of 0.948, 187.4 μg kg−1, respectively. The results indicated that high amendment of corn straw was a potential option for remediation of PAHs-contaminated soils and that the BP-ANN model could successfully provide prompt prediction of PAHs concentration in soils.