Microplastic (MP) pollution in agricultural settings is an emerging field of study, with interest focusing on potential resource contamination of soil and water due to the use of plastic materials in farming practices. The Mississippi Delta, a highly agricultural region, is prone to both natural and intentional flooding, potentially exacerbating this issue. This exploratory study investigated MP (>30 µm) concentrations, sizes, and polymer compositions in floodwater, irrigation water, and surface runoff from soybean fields across two counties in the Mississippi Delta using micro-Fourier transform infrared spectroscopy (µ-FTIR). Mean ± SE concentrations (MPs/L) were 72 ± 66 in floodwater (n = 18), 169 ± 121 in source (irrigation pond) water (n = 4), and 30 ± 37 in runoff (n = 3) in Sunflower County, MS. In Coahoma County, MS, mean ± SE runoff concentration was 88 ± 76 MPs/L (n = 24). Mean concentrations were elevated as compared to other MP studies in agricultural environments. The most common polymers present were polyethylene terephthalate (PET), polyethylene (PE), polyethylene-ethyl vinyl acetate (PE/EVA), and thermoplastic elastomers (TPEs), which are commonly used in the manufacturing of agricultural materials. MPs from the smallest size fraction measured (30–100 µm) were the most common in all floodwater samples, ranging from 75.5–91% abundance. Using Attenuated Total Reflectance (ATR)-FTIR, larger plastic litter was identified as mostly PE and PET, which is consistent with polymer distributions in floodwater samples. Overall, MPs were prevalent in both floodwater and runoff, with relatively consistent concentrations and polymer compositions across samples. However, further research is needed to fully elucidate their fate and potential impacts on agricultural systems.
Heinen et al. (Wed,) studied this question.