Analysis of the Degradation Characteristics of Chlorpyrifos in an Electrochemically Constructed Wetland Coupled System under Different Pesticide Exposure Conditions and Microbial Community Analysis

Abstract

This study investigates the degradation characteristics of chlorpyrifos under individual exposure and compound exposure to multiple pesticides in both traditional constructed wetlands and electrochemically constructed wetland coupled systems, while also analyzing the microbial communities within the systems using high-throughput sequencing technology. The results show that the electric field can enhance the degradation performance of the system. The degradation effect of the coupled electrochemically constructed wetland coupled system is better than that of the traditional constructed wetland, while the compound exposure to multiple pesticides inhibits the degradation efficiency. Under the influence of pesticides, the diversity of microbial communities decreases towards the end of the system operation, and the electrochemically constructed wetland coupled system exhibits lower diversity compared to the traditional constructed wetland. Proteobacteria is the dominant phylum under compound exposure to multiple pesticides, while Firmicutes, Fusobacteria, Verrucomicrobia, Aeromonas, and Methylophilus are the dominant electrochemically active phyla and genera in the electrochemically constructed wetland coupled system. The impact of pesticides and the electric field results in a decrease in amino acid metabolism and carbohydrate metabolism functions, while membrane transport functions increase. The compound exposure to multiple pesticides has a more significant impact on the microbial community structure and functionality than the electric field. The results also lay a theoretical foundation for the expansion of pesticide degradation technology and constructed wetland treatment technology to new fields, which is of great significance in realizing the “zero direct discharge” of agricultural production wastewater, solving the problem of agricultural non-point source pollution and ensuring the availability of agricultural production.