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Pesticide residues and heavy metal content of cassava, yam, cocoyam, potato, water yam and carrot were evaluated by gas chromatography-mass spectrometry and atomic absorption spectroscopy. The detected pesticide residues in the samples were 2,4-dichlorophenoxyacetic acid, glyphosate, hexachlorobenzene (HCB), dichlorobiphenyl, aldrin, endosulfan, profenofos, g-chlordane, carbofuran, biphenyl, heptachlor, lindane and t-Nonachlor. The concentration of HCB ranged between 0.0799 ± 0.06 mg/kg and 0.1596 ± 0.00 mg/kg, which was greater than the permitted maximum limit of 0.5 mg/kg established by the US Environmental Protection Agency. The concentration of aldrin and profenofos detected was lower than the predetermined maximum allowed limits. Endosulfan concentrations in cocoyam (0.2500 mg/kg) and potato (0.3265 mg/kg) were higher than the limits allowed by the Canadian Department of Industrial Research. The heavy metals detected in these samples include cobalt, nickel, lead, manganese, chromium, arsenic and mercury in at least one of the samples evaluated. There was not much difference between the concentration of cobalt in yam (0.036 mg/kg) and the maximum allowed concentration (0.043 mg/kg). Lead was detected in potatoes and carrots but was below detectable concentration in cassava, yam, cocoyam and water yam. Similarly, cocoyam was found to have a significant mercury content (0.658 mg/kg), but mercury content was below detectable concentrations in cassava, yam and water yam. [ABSTRACT FROM AUTHOR]

The attendant effects of urbanization on the environment and human health are evaluable by measuring the potentially harmful element (PHE) concentrations in environmental media such as stream sediments. To evaluate the effect of urbanization in Osogbo Metropolis, the quality of stream sediments from a densely-populated area with commercial/industrial activities was contrasted with sediments from a sparsely-populated area with minimal anthropogenic input.Forty samples were obtained: 29 from Okoko stream draining a Residential/Commercial Area (RCA, n = 14) and an Industrial Area (IA, n = 15), and 11 from Omu stream draining a sparsely-populated area (SPA). The samples were air-dried, sieved to < 75 micron fraction, and analysed for PHEs using inductively-coupled plasma atomic emission spectrometry (ICP-AES). Index of geoaccumulation (I geo ), pollution index (PI), ecological risk factor (Er) and index (ERI) were used for assessment. Inter-elemental relationships and source identification were done using Pearson's correlation matrix and principal component analysis (PCA).PHE concentrations in the stream sediments were RCA: Zn > Pb > Cu > Cr > Sr > Ni > Co, IA: Zn > Cr > Ni > Co > Pb > Cu > Sr and SPA: Zn > Co > Cr > Cu > Sr > Ni > Pb. I geo calculations revealed moderate-heavy contamination of Cu, Pb and Zn in parts of RCA, moderate-heavy contamination of Zn in IA while SPA had moderate contamination of Co and Zn. PI values revealed that stream sediments of RCA are extremely polluted, while those of IA and SPA are moderately and slightly polluted, respectively.The pollution of the stream sediments in RCA and IA is adduced to anthropogenic activities like vehicular traffic, automobile repairs/painting, blacksmithing/welding and metal scraping. In SPA however, the contamination resulted from the application of herbicides/fertilizers for agricultural purposes., (© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)

Cowpea (Vignus unguiculata) is a source of plant protein that is widely consumed by the Nigerian populace. The aim of the study was to evaluate the health risk of heavy metals in two cowpea types sold in Gwagwalada Market, Nigeria. The concentrations of five heavy metals nickel (Ni), cadmium (Cd), manganese (Mn), cobalt (Co), and chromium (Cr) were assessed in the cowpea types. Samples of each type were randomly purchased and the heavy metal concentrations (mg/kg) were analyzed with an atomic absorption spectrophotometer. The concentrations of the heavy metals in mg/kg dry weight of the brown type were as follows: Ni (2.45 ± 0.87), Cd (0.26 ± 0.10), Mn (9.11 ± 1.80), and Co (1.67 ± 0.20), while the concentrations for the white type were: Ni (4.55 ± 1.21), Cd (0.27 ± 0.13), Mn (9.17 ± 1.50), and Co (1.09 ± 0.15). The level of Cr was below detection in all the samples analyzed. However, the levels of Ni, Mn, and Co investigated were all below the permissible limits set by FAO/WHO. The Cd concentrations of both cowpea types exceeded the FAO/WHO permissible limit of 0.2 mg/kg for cowpea. Determined heavy metal concentrations were used for potential health risk assessment in adults and children. The target hazard quotient and hazard index were >1 for Co, while the target cancer risk of Ni subsulfide for the cowpea types exceeded 10−4, and these results are causes for concern. It is recommended that the concentrations of the heavy metals in cowpea sold in Nigerian markets should be monitored regularly in order to avert their detrimental effects on consumers. [ABSTRACT FROM AUTHOR]

Understanding the impact of natural and modified environment on human health is a subject within the scope of medical geology. Ameka and its environs in southeastern Nigeria is known for intensive mining and agricultural activities that frequently predispose water resources to pollution by environmentally sensitive elements (ESEs). The present study analyzed the groundwater quality and associated probabilistic human health risks due to ESEs in Ameka area, using multiple indices and a novel health risk assessment framework, HHRISK. Entropy-weighted water quality index and other geochemical evaluation indices (including pollution index, enrichment factor, index of geoaccumulation, pollution index of groundwater, and quantification of contamination) revealed that all the groundwater samples from hand-dug wells and boreholes were extremely polluted and hence unsuitable for drinking. The HHRISK model was utilized for ingestion and dermal exposure routes assessments. Results showed that all the samples pose very high carcinogenic and non-carcinogenic health risks. With respect to aggregated non-carcinogenic HHRISK, the order of health threat impact of the ESEs for children and adult populations is predicted as Cd > As > Se > Co > Ni > Pb > Mn > Zn > Cu > Fe. However, aggregated cancer risk for both populations followed the trend Ni > Cd > As > Pb. Furthermore, cumulative non-carcinogenic risk (HRQcum) and carcinogenic risk (CRcum) scores (for children and adults) exceeded standard limits in all the samples. However, the scores obtained for the adults were generally lower, implying that the children population is more vulnerable to both non-carcinogenic and carcinogenic health risks. Thus, there is urgent need to adopt environmentally-friendly pollution mitigation measures in the Ameka area. [ABSTRACT FROM AUTHOR]

Industrial evolution in developing countries, most especially Nigeria in the last century, has resulted in geometrical increase in waste generation compared to the arithmetic progress in management methods, thereby creating the problem of effective waste management and disposal. Wastes generated from industries have become a major source of pollution of groundwater when contaminants become leached into the groundwater. Water samples collected from 44 wells within 25 m radius from six refuse dump sites within Lagos metropolis during the months of February and September, 2006 were analyzed for nine heavy metals, namely, Lead (Pb), Chromium (Cr), Zinc (Zn), Cadmium (Cd), Nickel (Ni), Cobalt (Co), Iron (Fe), Manganese (Mn) and Copper (Cu), using AAS according to standard procedures. The results showed elevated concentrations of most heavy metals determined. Pb, Cd, Mn and Fe have their concentrations clearly above the World Health Organization (WHO) and Standard Organization of Nigeria (SON) recommended limit for potable water, showing contamination from the refuse dumps, while the concentrations of Cu and Zn were below toxic levels for drinking water in all the samples. Co was not detected in most of the samples, while the concentration of Ni detected was also quite low except at one of the sites where it was above the recommended level. [ABSTRACT FROM AUTHOR]

More still needs to be learned regards the relative contamination of heavy metals and pesticide residues, particularly those found in widely consumed Nigerian food crops like cereals, vegetables, and tubers. In this current study, the heavy metals and pesticide residues detectable in widely consumed Nigerian food crops were respectively quantified using atomic absorption spectroscopy (AAS) and gas chromatography (GC). Specifically, the widely consumed Nigerian food crops included cereals (rice, millet, and maize), legume (soybean), tubers (yam and cassava), as well as leaf (fluted pumpkin, Amaranthus leaf, waterleaf, and scent leaf) and fruit vegetables (okro, cucumber, carrot, and watermelon). Results showed that the detected heavy metals included arsenic (As), cadmium (Cd), chromium (Cr), cobalt (Co), iron (Fe), lead (Pb), manganese (Mn), mercury (Hg), and nickel (Ni), whereas the pesticide residues included Aldrin, Carbofuran, g-chlordane, Chlorpyrifos, DichloroBiphenyl, Dichlorodiphenyldichloroethane (DDD), Dichlorodiphenyltrichloroethane (DDT), Dichlorvos, Endosulfan, Heptachlor, Hexachlorobenzene (HCB), Isopropylamine, Lindane, t-nonachlor, and Profenofos. Across the studied food crops, the concentrations of heavy metals and pesticides were varied, with different trends as they largely fell below the established maximum permissible limits, and with some exceptions. Our findings suggest there could be a somewhat gradual decline in the concentration of the heavy metals and pesticide residues of these studied food crops when compared to previously published reports specific to Nigeria. To help substantiate this observation and supplement existing information, further investigations are required into the concentration of these heavy metals and pesticide residues specific to these studied food crops at other parts of the country. [ABSTRACT FROM AUTHOR]