Concentration and risk assessment of toxic metals in indoor dust in selected schools in Southeast, Nigeria

Environmental effects from petroleum product transportation spillage in Nigeria: a critical review

Nigeria has struggled to meet sustainable development goals (SDGs) on environmental sustainability, transportation, and petroleum product distribution for decades, endangering human and ecological health. Petroleum product spills contaminate soil, water, and air, harming humans, aquatic life, and biodiversity. The oil and gas industry contributes to environmental sustainability and scientific and technological advancement through its supply chain activities in the transport and logistics sectors. This paper reviewed the effects of petroleum product transportation at three accident hotspots on Nigeria highway, where traffic and accident records are alarming due to the road axis connecting the southern and northern regions of the country. The preliminary data was statistically analysed to optimise the review process and reduce risk factors through ongoing data monitoring. Studies on Nigeria's petroleum product transportation spills and environmental impacts between the years 2013 and 2023 were critically analysed to generate updated information. The searches include Scopus, PubMed, and Google Scholar. Five hundred and forty peer-reviewed studies were analysed, and recommendations were established through the conclusions. The findings show that petroleum product transport causes heavy metal deposition in the environment as heavy metals damage aquatic life and build up in the food chain, posing a health risk to humans. The study revealed that petroleum product spills have far-reaching environmental repercussions and, therefore, recommended that petroleum product spills must be mitigated immediately. Furthermore, the study revealed that better spill response and stricter legislation are needed to reduce spills, while remediation is necessary to lessen the effects of spills on environmental and human health.

Biosorption of potassium ion using bean seeds and its energy saving application

Ca and Mg have been implicated in causing hardness in beans resulting in relatively long cooking time. This study used potassium to replace the cations and determined the adsorption of potassium solution to bean seeds. Then, plantain peel, a natural source of potassium, was used to cook beans and its impact on the cooking time of beans was investigated. The adsorption experiments were performed using batch technique, while metal compositions of the bean seeds and plantain peel were determined by spectroscopy. Optimum removal conditions of potassium ion biosorption using bean seeds were observed at pH 10.2, 2 g bean seed dosage, 180 min agitation time, with 75 ppm as initial metal concentration. The kinetic model correlate with pseudo-second order reaction and the Langmuir adsorption model best fitted the adsorption. After cooking the beans with plantain peel, the concentration of Mg reduced in the bean seeds by about 48%, while the concentration of Ca reduced by about 22%, but the concentration of K increased by over 200% in the cooked bean seeds. Beans treated with plantain peel cooked earlier than the control experiment. This may be affected by pH, adsorbent dosage, metal concentration and contact time.

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

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 are increased mining operations, indiscriminate disposal and burning of wastes, illegal oil refinery 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 South-western 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 148 research articles was conducted to provide an understanding of the scope of heavy metals research in Nigeria and to prioritize needed research. The review recognized 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.

Bioavailability and health risk assessment of potentially toxic elements in salty water environment of Okposi, Southeastern Nigeria

Abstract

This study is to determine some physicochemical parameters and potentially toxic elements (PTE) in water samples collected from a borehole, a stream and a lake in Okposi, Nigeria, for their quality status and the human health risk of exposure to the waters. The physico-chemical properties: pH, electrical conductivity (EC), salinity, nitrate and sulphate, were determined by standard methods, while the level of PTE contamination was analysed by Flame Atomic Absorption Spectroscopy (FAAS). The results show that the levels of physicochemical parameters in the water samples are within the World Health Organisation (WHO) permissible limit. The PTE concentrations (mg/L) in the samples are in the ranges of 0.12–0.35 (Cr); 0.06–0.19 (Cu); 0.24–2.45 (Fe); 0.0–0.06 (Mn); 0.00–0.75 (Pb); and 0.0–02 (Zn). The levels of Cr and Pb in all the samples, except Pb in the downstream water, are above the WHO permissible limits, indicating that the waters are contaminated and unsafe for drinking. PTE form complexes with anions in water at high EC and salinity which reduces availability of toxic metals to organisms. Therefore, toxicity of PTE in the samples is in decreasing order: Upstream > Downstream > Lake water > borehole water. Calculations of hazard quotients shows possible adverse effects on adults and children on dermal contact with the waters due to Cr. Children might get cancer due to Pb on ingestion of water from the studied borehole, the Lake and the Upstream waters. Statistical analysis suggests that the geology of the area influenced PTE contamination of the water bodies.

Article highlights

Source identification and health risk assessments of heavy metals in indoor dusts of Ilorin, North central Nigeria

BACKGROUND AND PURPOSE

Exposure to heavy metals (HMs) in indoor dusts is a serious public concern that is linked to a myriad of deleterious health outcomes. The objectives of this study are to estimate the contamination levels of HMs in indoor dusts of different residential areas in Ilorin, Nigeria; identify HMs sources in different residential areas; and evaluate human health risks of HMs in selected residential areas.

METHODS

Indoor dust sampling was conducted in ten randomly selected from low, medium and high population density residential areas of Ilorin, Nigeria. Ten HMs concentration levels, their health risk implication and the associated potential ecological risks were evaluated.

RESULTS

The mean concentration levels measured for Fe, Pb, Zn, As, Co, Cr, Cu, Cd, Mn and Ni were 38.99, 5.74, 3.99, 0.08, 2.82, 2.13, 0.47, 0.60, 6.45 and 1.09 mg/kg, respectively. Positive Matrix Factorization (PMF) model was applied to ascertain sources of HMs in sampled indoor dust. Percentage contribution from oil-based cooking (29.82%) and transportation (29.77%) represented the highest source to HM concentrations among the six factors identified. The results of the various pollution indices employed showed that Pb, Zn, As, Co, Cr, Cu, Mn and Ni contributed moderately to HMs concentration levels in the sampled dusts. Cd had highest potential ecological risk factor E r i of between 160 and 320. The average values of Enrichment Factors (EFs) obtained aside from Fe used as the reference metal, ranged between 8.46 (As) and 2521.61(Cd). Health risk assessment results revealed that children are the most susceptible to the risks associated with HMs bound indoor dust than the adults. The percentage risk contributions of Hazard Quotient via ingestion route (HQ_ing) in Hazard Index (HI) for non-cancer risk of indoor HMs were 93.17% and 69.87% in children and adults, respectively. Likewise, the percentage cancer risks contribution through ingestion pathway (CR_ing) were higher than cancer risks through inhalation and dermal pathways (CR_inh and CR_dermal), accounting for 99.84% and 97.04% of lifetime cancer risk in children and adults, respectively. The contamination level of Cd recorded is of great concern and signifies very strong contribution from anthropogenic sources.

CONCLUSION

This study has further revealed the levels of HMs in typical African residential settings that could be used by relevant stakeholders and policy makers in developing lasting control measures.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s40201-021-00778-8.

Adverse health and environmental outcomes of cycling in heavily polluted urban environments

Cycling is a healthy habit; however, are its benefits outweighing risks when biking in heavily trafficked and air-polluted cities? Research involved studying contamination with traffic-related elements of dust collected from bike paths located in top trafficked cities of Europe in Poland. Human health risk was assessed via inhalation and ingestion pathways for adults and children. Bike path dust was heavily contaminated with Zn, Cd (Geoaccumulation index Igeo 4) and Pb (Igeo 3), sourced predominantly from nonexhaust car emissions. The concentrations of metals in dust decreased in the following descending order: Zn > Mn > Cu > Pb > Cr > Cd. A fractionation study revealed that Zn and Cd are almost entirely bioavailable (Mobility factor MF above 90%), causing hazards to humans and the environment. The highest congested intersections result in more TRAP-contaminated dust deposited on bike paths, which is easily resuspended, posing a health risk for cyclists or pedestrians. Avoiding cycling in proximity to heavily trafficked routes should be considered, when possible, as well as physical removal of dust by wet sweeping to limit dust resuspension.