Heavy metals research in Nigeria: a review of studies and prioritization of research needs

Abstract

Nigeria is experiencing continuous economic and industrial transformations, typical of many developing nations. In addition to its well-established oil industry, which is infamous for exuding various kinds of pollutants, there is increased mining operations, indiscriminate disposal and burning of wastes, illegal oil re nery, and terroristic insurgency, all poised to increase the levels of heavy metal contaminants in the Nigerian environment. A recent revelation indicates that about 2 million people in Southwestern Nigeria alone could potentially be poisoned by lead (Pb) and mercury (Hg), emanating from illegal mining operations. This further underscores the importance of investigations of toxic trace metal levels in the country. The current review of 136 research articles was conducted to provide an understanding of the scope of heavy metals research in Nigeria and to prioritise needed research. The review recognised that the scope of heavy metals studies has been wide, covering matrices such as cosmetics, human blood, hair, medicines, foods, beverages, water, air, soil and crude-oil. However, important toxic metals, especially mercury (Hg), arsenic (As) and antimony (Sb) are largely under-investigated. Also, there is a need for more studies to be conducted in the Northern part of the country. Furthermore, studies need to focus on marine environments rather than the freshwater ecosystems alone. Techniques such as the inductively coupled plasma -optical emission spectrometry (ICP-OES) and particle -induced X-ray emission (PIXE) analyses are herein recommended to bridge the data gap, and to overcome limitations in trace metals analyses in the Nigerian total environment.

Environmental impacts of covid-19 pandemic: Release of microplastics, organic contaminants and trace metals from face masks under ambient environmental conditions

“…These results imply that the Fe content of the soil is very high, thereby obscuring any contributions resulting from release of Fe from the dumped face masks. The observation of high Fe levels in the current study is in agreement with previous studies which had investigated heavy metals concentrations in soil in Nigeria, and had reported higher Fe levels compared to all other metals ( Aiyesanmi et al, 2020 ; Duru et al, 2022 ; Idowu, 2022 ).…”

“…This result suggests that a considerable amount of Cu may have ended up in the environment as a result of the huge number of medical face masks used and disposed of during the covid-19 pandemic. Cu has the ability to change between Cu(I) and Cu (II) oxidation states in living systems, causing the generation of hydroxyl and superoxide radicals which are toxic to living tissues ( Stern, 2010 ; Idowu, 2022 ). Although a cofactor for many enzymes, high concentration of Cu destroys bacterial and fungal species in the environment, via lethal interaction of the cupric (Cu 2+ ) state with essential proteins, nucleic acids and metabolites ( Trevors and Cotter, 1990 ).…”

Bioavailability of Metals in the Biosphere

“…Once metals have passed through these stages and accumulated in plants, they become available to the local population and herbivores immediately or through the food pyramid. The entry of food pyramid elements is often limited by the movement from the soil to the plant root (Hussain et al, 2021;Vasile et al, 2021;Chen et al, 2022). This crucial step stands heavily influenced by the elements levels in earth orifice mixture that, in turn, are measured by several confined ground properties, including acidity index, water content, humidity, redox potential, and other criteria.…”

Heavy Metal Toxicity and Remediation in Human and Agricultural Systems: An Updated Review

“…Many environmental pollutants, such as toxic metals, are the primary resources of HMs, contaminating water during discharges of industrial and agricultural wastes like pesticides, coal and oil combustion, plastics, and phosphate fertilizers (Munir et al, 2021;Idowu, 2022;Mawari et al, 2022;Mukhi et al, 2022;Borah and Deka, 2023;Xu et al, 2023). The fish accumulated toxic metals from the water via direct water uptake or absorption via the gills, skin, and gut (Marzouk et al, 2016).…”