Monitoring of Pesticide Residues in Lebanese Vegetables and Agricultural Soils and Their Impact on Soil Microbiological Properties

The practice of pesticide application in agriculture done in Lebanon deviate from standard agricultural disciplines, raising awareness of their contamination of soil and vegetables as well as their repercussions on microbial communities. To this end, soil and vegetable samples from different pesticide-treated sites were quantified for chlorpyrifos (C) and methomyl (M) residues using Gas Chromatography-Mass Spectrometry. Moreover, clear soil specimens were treated with different concentrations of C, M, and CM assortment to assess their repercussion on the microbial population. High pesticide concentrations were recovered ranging between 31.13 and 53.74 mg/kg in eight agricultural fields, which abate gradually with time. After 20 days of pesticide implementation, their residues were above the maximum residual levels for lettuce, cabbage, tomato, and corn. Soil altered with pesticides showed fluctuation in its microbial community by suppressing some groups while favouring the propagation of tolerant species. Our data indicate the need for the requirement of strict laws to minimise pesticide usage and reduce their impact on soil quality, human health, and non-target organisms.