Microplastics in municipal water: analysing variations in contamination in a Lowveld city, South Africa

There are some concerns regarding the presence of microplastics in drinking water, and thus, the potential effects of this on human health. This study assessed water quality and the occurrence and distribution of microplastics in municipal drinking water across different locations within Nelspruit, South Africa. Furthermore, variations in microplastic types and plastic polymers were analysed, along with household tap aerator cleaning frequency and water consumption patterns. Microplastics were classified by colour and type, and their polymer composition was verified using a Fourier Transform Infrared Spectrometer (FTIR). Study findings showed no significant association between water quality and aerator maintenance and water quality and municipal water consumption patterns amongst locations. However, a weak negative correlation was observed between fibre microplastics and household faucet aerator cleaning frequency, suggesting that less frequent cleaning may contribute to higher microplastic fibre accumulation in municipal treated water. Diversity indices revealed low variability in microplastic distribution, indicating relatively uniform contamination levels across the study area. Fragments and/or fibres were the most dominant microplastics identified among the different localities. Low–density polyethylene (LDPE), high–density polyethylene (HDPE), and ethylene propylene diene terpolymer (EPDM), were the most commonly detected polymers and were evenly distributed. The occurrence of microplastics in drinking water could, in part, be attributed to the poor water treatment methods, employed by the contracted water services provider, in capturing and removing microscopic particles. Additionally, less frequent aerator cleaning may also contribute towards increased microplastic accumulation in municipal treated water, subsequently exacerbating microplastic contamination in drinking water systems. These findings indicate the need for further evaluation of the water treatment processes and the importance of routine faucet aerator maintenance to minimise household microplastic exposure. In addition, the findings provide an important baseline information on microplastic presence in drinking water of African systems.