Microplastics in Groundwater of Two Rural Communities in Mexico

Groundwater is used for drinking, agricultural production, and industrial use by almost two billion people worldwide, especially in rural areas. Microplastic (MP) pollution is found in every environment, even in areas considered virgin, remote, and inhospitable; however, studies on groundwater microplastic pollution are scarce, which is why the present study evaluated the amount and types of microplastics in ten rural wells where drinking water is extracted for human consumption of two small communities in Mexico. Groundwater was sampled for ten consecutive months. Air deposition of microplastics was considered, and in each well, two samples were taken, one of surface water (first 5 cm of depth) and another of water without contact with air. There were no differences between the communities in the average number of microplastics in deepwater and air deposition (0.41 and 0.25MP/L, respectively). MP measured 2,100 to 4,400 μm in length. 100% of the MP found were fragments. Regarding color abundance, black > white > blue > green > gray coincided in both communities. The polymers identified were nylon, HDPE, PP, PS, PVC, and PET. Seasonally (dry and rainy), there were no differences in the abundance of MP by air deposition; however, the deep water presented a statistically highest abundance in the dry season (0.41 MP/L), which indicates that rainwater dilutes this type of pollution (0.25 MP/L). Like many communities worldwide, Ixtacuixtla and Xocoyucan do not adequately manage their urban solid waste and wastewater, generating plastic pollution in the region's groundwater, which represents a risk to human health.