Environmental dynamics of heavy metals in recipient waters of produced water effluents: Bioaccumulation patterns in fish and ecological risks
1 African Centre of Excellence in Public Health and Toxicological Research, University of Port Harcourt, Choba, Rivers State, Nigeria.
2 Department of Environmental Health Science, School of Health Technology, Federal University of Technology Owerri.
3 Department of Chemical Sciences, Lead City University, Ibadan.
4 Department of Biological Sciences, Lead City University Ibadan.
5 Department of Biological Sciences, Lead City University, Ibadan, Nigeria.
6 Department of Biochemistry, Adekunle Ajasin University, Akungba Akoko.
7 Soil Science and Technology, School of Agric. And Agric. Technology, Federal University of Technology, Owerri.
Open Access Research Journal of Science and Technology, 2026, 16(02), 194-203
Article DOI: 10.53022/oarjst.2026.16.2.0046
Publication history:
Received on 03 March 2026; revised on 11 April 2026; accepted on 14 April 2026
Abstract:
Environmental discharge of water produced, the highest amount of waste that is generated during petroleum extraction, is a significant source of heavy-metal pollution in water bodies of the Niger Delta. Recent empirical evidence (2020-2025) on the environmental dynamics of produced-water recipient systems, bioaccumulation dynamics of trace metals in fish and the related ecological and human-health risk underwent the synthesis in this review. Sixty-three peer-reviewed and regulatory studies in the water, sediment, and the biotic matrices were next analyzed inception to PRISMA 2020 systematic review principles. The findings indicate that, cadmium (Cd), lead (Pb), chromium (Cr), and nickel (Ni) are found in amounts that are above national (NESREA, DPR) and international (WHO) standards in the various sites especially around the oil-production and gas-flaring areas. Metal burdens were always maximum in sediments compared to water, which proved their long-term sinks and secondary sources of contamination. Bioaccumulations in benthic and demersal fish species tended to be above FAO/WHO allowable levels, and hazard indices (HI > 1) and incremental lifetime cancer-risks (ILCR > 10-3) were above levels of hinting at chronic toxicity in the local biological. Most of the sites in the Niger Delta fall under categories of moderate-to-considerable risks as per ecological indices (Igeo, CF, PERI). These results show that the discharge of produced-water is one of the biggest sources of the enrichment and bioaccumulation of heavy-metals in the aquatic food chains of the region. The paper concludes with the idea that the successful management of pollution issues demanded the combination of pollution control methods, incorporation of zero-discharge technology, and the improvement of the communication with people as well as their health. The enforcing the environmental policies can be developed stronger as well as the scientific investigations on the metal speciation and transfer, trophic mobility as well as the search on the links with climate, is necessary to preserve the system on ecosystem health and livelihood in the Niger Delta.
Keywords:
Produced water; Heavy metals; Niger Delta; Bioaccumulation; Ecological risk; Fish contamination; Human health
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