Dietary Exposure and Cancer Risk Assessment of Heavy Metals from Fish and Vegetables Consumed in Nguru Wetlands, Yobe State, Nigeria

Publication Details

Publication Date

10/09/2026

Volume / Issue

Vol 1, Issue 4 (2026)

Article No.

007

Journal

British Journal of Contemporary Research

DOI

https://doi.org/10.67693/BJCR-4L6JCHVT

Received

09 Aug 2026

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6

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0

Abstract

Wetland dependent communities may experience chronic dietary exposure to toxic metals through regular consumption of locally produced fish and vegetables. This study assessed arsenic (As), cadmium (Cd), chromium (Cr), and nickel (Ni) in selected fish and vegetables consumed around Nguru Wetlands, Yobe State, Nigeria, and evaluated estimated daily intake (EDI), cancer risk (CR), and total cancer risk (TCR). Tomato, lettuce, and sorrel tissues, together with catfish, tilapia, and ray-finned fish tissues, were collected and analyzed using microwave-assisted acid digestion followed by atomic absorption spectroscopy. In vegetables, the highest measured concentrations were 3.76 ± 0.96 mg/kg As in sorrel root, 9.41 ± 0.00 mg/kg Cd in tomato root, 8.30 ± 4.78 mg/kg Cr in sorrel root, and 3.78 ± 1.28 mg/kg Ni in sorrel root. In fish, the highest concentrations were 3.47 ± 0.89 mg/kg As in tilapia gills, 6.31 ± 1.79 mg/kg Cd in ray-finned fish intestine, 4.32 ± 2.39 mg/kg Cr in tilapia gills, and 3.19 ± 1.25 mg/kg Ni in catfish intestine. The reported EDI values were highest for As in tilapia at 0.000926 mg/kg/day, Cd in tomato at 0.001946 mg/kg/day, Cr in sorrel at 0.001374 mg/kg/day, and Ni in catfish at 0.000931 mg/kg/day. Total cancer-risk values ranged from 0.001830 in lettuce to 0.002909 in tilapia. These findings indicate that fish and vegetables from Nguru Wetlands may represent important dietary exposure pathways for multiple metals and support the need for continued monitoring, improved exposure assessment, and contamination-control measures. Interpretation of chromium-related risk should be made cautiously because total chromium measurements do not distinguish between Cr(III) and Cr(VI) (European Food Safety Authority [EFSA], 2020; International Agency for Research on Cancer [IARC], 2012).

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