Study on the Prevalence and Characteristics of Microplastics in the Agricultural Soil of Rice Bowl of Puducherry – Bahour, India

Abstract

Microplastics (MPs) are an emerging pollutant that has been extensively detected in all the compartments of the environment. However, little study has been done on MP pollution in terrestrial environments. In this study, we investigated the MPs abundance in the agricultural soil of Bahour, Puducherry, during pre and post-irrigation periods. A total of 995 MPs were found in pre-irrigation samples ranging from 53 to 90 particles/kg of soil with a mean (± SE) of 66.33 ± 2.61 particles/kg. In the post-irrigation samples, 899 MPs ranged from 53 to 72 particles/kg of soil, with a mean (± SE) of 59.93 ± 1.76 particles/kg were detected. The average abundance of MPs found was 63.13 ± 2.19 particles/kg of soil. MPs size ranges from 50 µm to 4.5 mm were detected using microscopic identification. The main morphotypes of MPs observed were fiber, fragments, film, foams, and pellets. Fibers were the most abundant polymer, with 63.67%, and foams were the least abundant polymer, with 0.89%. FTIR data showed the probable presence of Nylon as a major polymer type along with Polystyrene, High-Density Polyethylene, Low-Density Polyethylene, and Polypropylene. MPs in this agricultural soil may result from the degradation of macroplastics due to UV radiations, mechanical weathering, contamination through wastewater irrigation, atmospheric deposition, and contaminated composts. This is the first report on the prevalence and characteristics of microplastics in the agricultural soil of Puducherry’s ‘rice bowl.’ The results of this study will motivate further research to enhance our understanding of the sources, impacts, and accumulation of MPs in agricultural soil and to identify effective management practices and mitigation strategies.