Study of microplastics in a catchment under market gardening pressure

Microplastics Workshop, ATHENES, GRECE, 13-/06/2022 - 17/06/2022Microplastics are present in all environmental matrices (water, soil, biological matrices, aerosols), in the various links of the food chain, and even in human blood according to a recent study (Leslie et al., 2022). It is therefore becoming urgent to elucidate their source and transfer in the land-to-sea continuum in order to put in place regulations on their uses. In this context, it is essential to increase the number of studies on the sources and transfer routes from the anthropogenic environment to the natural environment. In the space of 40 years, market gardening has increased its surface area by an average of 50 ha/year in France and the average surface area per farm has increased from 3 to 20 ha (Prefecture of Loire Atlantique region, 2017). Fruit and vegetable growing practices have also evolved over time with the gradual arrival of plastic (small tunnels, greenhouses and large plastic shelters). Market gardening therefore appears to be a potential source of microplastic emissions into continental soils and waters. A sampling campaign was carried out in a catchment area with a high density of infrastructures dedicated to fruit and vegetable growing. Five sediment samples were taken from the main stream channel draining this catchment area, which then streams into the Loire, a river flowing into the Atlantic Ocean, also qualified of the last wild river in Europe. The quantities and types of plastic were analysed via µFTIR (Fourier Transform Infrared Spectroscopy) and comparisons were made with the polymers composing the plastic tarps used for market gardening in this area