GH018-02
Assessment of the possible human health hazard associated with exposure to naturally occurring potentially toxic elements in groundwater on the flanks of Meru volcano, Arusha, Tanzania
Tuesday, 15 December 2020: 20:35
Virtual
Ines Tomasek1,2, Hassina Mouri3, Joanna Wragg4, George Bennett5,6, Julian Ijumulana7, Prosun Bhattacharya7, Karen Fontijn8, Mary John Kisaka6,9, Ceven Shemsanga6, Kristine Walraevens5, Philippe Claeys10, Marc Elskens10, Yue Gao10, Martine Leermakers10 and Matthieu Kervyn11, (1)Vrije Universiteit Brussel, Department of Chemistry (AMGC), Ixelles, Belgium, (2)Vrije Universiteit Brussel, Department of Geography (FARD), Ixelles, Belgium, (3)University of Johannesburg, Department of Geology, Auckland Park, South Africa, (4)British Geological Survey Keyworth, Environmental Science Centre, Nottinghamshire, United Kingdom, (5)Ghent University, Laboratory for Applied Geology and Hydrogeology, Ghent, Belgium, (6)University of Dodoma, Department of Geology, Dodoma, Tanzania, (7)KTH Royal Institute of Technology, Department of Sustainable Development, Environmental Science and Technology, Stockholm, Sweden, (8)Université Libre de Bruxelles, Department of Geosciences, Environment and Society, Brussels, Belgium, (9)Vrije Universiteit Brussel, Department of Geography (FARD), Brussels, Belgium, (10)Vrije Universiteit Brussel, Department of Chemistry (AMGC), Brussels, Belgium, (11)Vrije Universiteit Brussel, Brussels, Belgium
Abstract:
The population resident in areas around the East African Rift System (EARS) is facing serious problems associated with the availability and quality of drinking water. Groundwater wells, boreholes and springs are the main sources of drinking water in these areas. These sources are, however, characterised by elevated fluoride concentration (> 1.5 mg/L), resulting from the interactions with the surrounding volcanic rocks. The high fluoride levels found in the groundwater are often associated with the presence of other naturally occurring potentially toxic elements (PTEs), such as As, Mo, U and V, which are known to cause adverse effects on human health. The occurrence of such PTEs in the groundwater on the populated flanks of Mt. Meru, an active volcano situated in the EARS, has not been previously reported.
The objective of this study is to determine the concentrations and distribution of PTEs in groundwater on the flanks of Mt. Meru to assess the potential health hazards that extend beyond the known fluoride issues in the study area. A large set of PTEs (Al, As, Ba, Cd, Cr, Cu, Fe, Mn, Mo, Ni, Se, Sr, Pb, U, V, W and Zn), physicochemical parameters and major elements were analysed in 48 groundwater samples sourced from wells, springs and tap water systems. To estimate the potential health risk associated with consumption of water with elevated concentrations of PTEs, chronic daily intake (CDI) and hazard quotient (HQ) were calculated. Preliminary results show that some of the water samples from the NE and SW flanks exceed the WHO tolerance limit for drinking water for some elements such as U (> 30 µg/L) and Mo (> 70 µg/L) as well as Na (> 200 mg/L) and K (> 50 mg/L). Estimated HQs indicate that such concentrations of Mo and U are not safe for consumption. Therefore, the continued drinking of water from these sources may result in serious health issues. Furthermore, the results show that some samples are characterised by total dissolved solids (TDS) values exceeding the permissible limits of WHO making the groundwater in the study area unsafe for drinking. The results presented in this paper are a part of a larger study on the groundwater quality in the Mt. Meru area and will serve to inform and direct exploitation of safe drinking water.
