Spatio-temporal monitoring of potentially toxic elements in Lagos harbour water and its health risk implications

Abstract

AbstractContinuous discharge of industrial and domestic inputs from various processes into the Lagos lagoon has significantly affected the quality of the aquatic environment, as a result of potentially toxic elements (PTEs) being released into the harbour during anthropogenic activities. This study involved monitoring the concentration and distribution of heavy metals in Lagos harbour during the dry and wet seasons. The PTEs can pose a serious ecological threat to the marine environment as well as human beings when the level of priority metals like cadmium, lead, and chromium is beyond World Health Organization (WHO) limits of 0.003, 0.05, and 0.1 mg/L, respectively. The shipping activities within the harbour play a significant role in the generation of these toxic metals. The diverse nature of these metals coexisting with their oxidation states in aquatic environments and their bioaccumulation influences the toxicity of PTEs towards the living organism. The quantification of these metals with highly selective and accurate instrumentation is imperative. Ion-selective exchangers and other functionalized composite nanomaterial are critical for harbour water remediation because of the high risk that could be associated with prolonged exposure to these toxic elements especially when the carcinogenic risk value is greater than 1 × 10−6 mg/kg/day.