Bioaccumulation of trace elements in the Mekong river floodplain, Laos: implications for human health

Abstract

To investigate trace element bioaccumulation in floodplain regions and its impact on human health, samples of groundwater, soil, and food crops were taken from two floodplain locations (Champasak (CH) and Attapeu (AT)) along the Mekong River in the Lao People's Democratic Republic (Lao PDR). Inductively coupled plasma–mass spectrometry (ICP–MS) analyzed trace element concentrations in groundwater and food crops, while soil samples were examined using ICP–optical emission spectrometry (ICP–OES). The concentrations of arsenic (As), iron (Fe), and manganese (Mn) in groundwater surpassed WHO guidelines by 13.3%, 5%, and 56.6%, respectively, in CH (n = 60) and by 23.9%, 1.1%, and 38%, respectively, in AT (n = 92). In soil, 67%, 33.3%, and 11.1% of samples from CH (n = 9) and 22.6%, 9.6%, and 3.2% from AT (n = 31) exceeded permissible levels for As, copper (Cu), and chromium (Cr). Geographical variations contributed to discrepancies in environmental quality between the two areas, as demonstrated by pollution index evaluations. The study region is at high ecological risk, with both children and adults potentially exposed to non-carcinogenic and carcinogenic risks via the food chain, especially through ingestion. These findings are crucial for informing policy and enhancing risk management strategies in the floodplain regions. © The Author(s), under exclusive licence to Springer Nature Switzerland AG 2025.