Applying isotopic techniques to assess the impact of plastic debris in tropical agroforestry systems

Besides the negative impact of industrial/domestic plastic debris in marine habitats, plastic materials also show a great concern in agroforest ecosystems (FAO, 2021). Soil erosion processes and the consequent loss of water quality from unsustainable agricultural activities significantly increase the microplastic contamination in soil, freshwater catchments and associated coastal-marine ecosystems. Common agricultural practices such as discarding plastic mulch, water pipes and plastic greenhouse covers have raised concerns due to their impact on the environment. In addition, microplastics are used for coating seeds and fertilizer pills (in controlled-release fertilizers), as well as for plant protection. Currently, agricultural lands are becoming the most plastic-contaminated places outside of landfills and urban spaces. The lack of sustainable land conservation practices allows microplastic-contaminated soils to be removed from watersheds, carried to rivers, and deposited in water reservoirs, lakes, lagoons, and coastal and oceanic habitats.