Microplastics contamination in Isinuka springs and CO 2 -seeping freshwater systems in South Africa: a baseline study

Abstract

Microplastic (MP) pollution is increasingly being reported in freshwater ecosystems, yet culturally significant and geochemically unique systems remain poorly studied. This study provides baseline evidence of MP contamination in South Africa’s sacred freshwater systems, specifically Isinuka springs and CO2-seeping freshwater systems along the Bongwana Fault. Surface water samples were collected from nine sites, including Isinuka springs (four sites; n = 4) and CO2-seeping freshwater systems (five sites; n = 5). Microplastics were found at all sites, with abundances ranging from 5 to 48 particles I−1 (average ≈ 20.4 particles I−1). Transparent MP particles were the most common colour (38.6%), fibres/filaments were the dominant shape (69.6%), particles ≥ 20 µm accounted for the highest proportion by size (51.1%), and polypropylene (PP) was the most frequently identified polymer (38%). A variety of MP patterns were observed, with the highest number of MP particles found at the most intensively used sacred site (Isinuka spring; Site 1). These findings highlight that sacred freshwater systems, often regarded as pristine due to their cultural and traditional significance, are vulnerable to MP contamination, with potential ecological, cultural and public health implications for communities that rely on these waters for drinking, healing and spiritual practices. This study provides essential baseline data and underscores the need for wider MP monitoring in South African sacred freshwater systems, including sediments and biota, while also emphasising the importance of combining scientific approaches with cultural management and community awareness to protect these sacred waters from MP pollution.