Marriott et al. 2023 — PHEs in fish and aquaculture, Lake Victoria, Kenya
This study examined potentially harmful elements (PHEs) in wild and farmed Nile tilapia (Oreochromis niloticus) from Winam Gulf, Lake Victoria, Kenya, alongside water and sediment measurements, as part of a broader biogeochemical and food-security assessment of the lake system. Cadmium, chromium, and lead concentrations in fish tissue exceeded provisional maximum tolerable intake (PMTI) thresholds established by regulatory agencies, raising concerns about consumption safety for local populations dependent on the lake’s fishery.
Key numbers
Metals measured in fish tissue: As, Cd, Cr, Cu, Pb, Al, Ni, Zn by ICP-MS. Cd, Cr, and Pb in fish samples exceeded PMTI thresholds. Specific concentrations reported in the paper’s tables (wet weight basis, fish muscle/tissue). Water collected 2018-2019 from Winam Gulf sampling sites. Both wild-caught and aquaculture tilapia samples included, allowing comparison between production systems. Al, Ni, and tAs also reported but at lower concern levels relative to PMTI comparators.
Methods (brief)
ICP-MS analysis of fish tissue (muscle), water, and sediment. Sampling from Winam Gulf / Lake Victoria, Kenya, 2018-2019. Tilapia (Oreochromis niloticus) is the dominant commercial species. Comparison of measured concentrations against PMTI-based benchmarks for human health risk assessment. Wet weight basis reported for fish tissue.
Implications
Certification: Nile tilapia from sub-Saharan freshwater systems shows Cd, Cr, and Pb exceedances of PMTI thresholds; relevant context for geographic origin flags in supply-chain assessments. Courses: Documents aquaculture vs. wild-catch comparison in a heavily utilized East African lake system. App: Supports geographic risk flagging for tilapia originating from heavily impacted East African freshwater systems.