Implication of heavy metal(loid)s contamination for human health and preliminary application of water treatment in floodplain area along Mekong River, Lao PDR

Groundwater is widely used for domestic purposes, especially as a reliable source of drinking water in rural areas of the Lao People's Democratic Republic (Lao PDR). This preliminary study aims to examine heavy metal(loid)s contamination leading to human health risks while also focusing on a method that can improve drinking water quality in floodplain areas along the Mekong River in Lao PDR. Groundwater and surface water samples were collected during the monsoon season in 2022 in Attapeu and Champasak provinces. Heavy metal(loid)s concentrations and human health risks were investigated using inductively coupled plasma mass spectrometry (ICP-MS) and the USEPA method, respectively. A nanofiltration membrane technique was introduced to optimize the quality of groundwater. Results showed that groundwater quality was significantly poor (p < 0.05), particularly in Attapeu province, with high levels of electrical conductivity, total dissolved solids, and manganese, exceeding WHO standards of 400 µS cm−1, 300 mg L−1, and 80 µg L−1, respectively. With the groundwater ingestion pathway, children were found to be more vulnerable to non-carcinogenic risk than adults (Hazard Quotient, Hazard Index >1), but adults had a higher carcinogenic risk (Incremental Lifetime Cancer Risk >1E-04). The removal of fecal bacteria and heavy metal(loid)s was achieved using the nanofiltration membrane, demonstrating its potential as a practical point-of-use technology to provide cleaner water sources and enhance the health status of Lao residents.