Toxic metal levels in Nigerian electronic waste workers indicate occupational metal toxicity associated with crude electronic waste management practices

The poor management of electronic wastes (e-waste) in Nigeria exposes workers to toxic chemicals in waste electrical and electronic equipment. In this study, we evaluated the toxic metal levels in Nigerians occupationally exposed to e-waste. Whole blood levels of Lead (Pb), Mercury (Hg), Arsenic (As), Cadmium (Cd), and Chromium (Cr) were determined in Nigerian e-waste workers (n=63) and in age-matched non-exposed participants (n=41), using standard electrothermal atomic absorption spectrometry and inductively coupled plasma-mass spectrometry methods. The results showed statistically significant (p<0.01) elevated body burden of toxic metals in e-waste workers (Pb, 0.95 ± 0.00 µmol/L; Cr, 405.99 ± 6.34 µmol/L; Cd, 108.54 ± 1.60 nmol/L; As, 10.09 ± 0.01 µmol/L; and Hg, 25.02 ± 0.14 nmol/L) compared with non-exposed group ((Pb, 0.03 ± 0.00 µmol/L; Cr, 178.44 ± 5.99 µmol/L; Cd, 56.99 ± 1.42 nmol/L; As, 1.02 ± 0.0008 µmol/L; and Hg, 1.62 ± 0.0672 nmol/L). These data indicate that the elevated body burden of toxic metals in the e-waste exposed  population is an indication of occupational metal toxicity associated with crude e-waste management practices in Nigeria. In addition, the potential health implications of exposure to these toxic metals, such as chronic kidney disease, cancer; preceded by genome instability and depressed immune response were highlighted.Keywords: Metal toxicity, e-waste, Nigeria, Occupational exposure

Environmental cadmium exposure: a possible factor in the pathogenesis of preeclampsia

Cadmium is a toxic metal, an environmental contaminant and a multi-organ poison which has been implicated in the derangement of a number of biological and molecular systems. Exposure to cadmium is a serious global health threat particularly in developing countries and pregnant women are at great risk, This is because they have increased gastrointestinal absorption and retention of cadmium and the tendency for increased risk of complications owing to its toxic effects. Preeclampsia is a pregnancy complication characterized by the development of onset of hypertension and significant proteinuria after 20 weeks of gestation or during labour and/or within 48 hours of delivery. This pregnancy-specific syndrome is a leading cause of maternal death particularly in developing countries. Several reports have provided evidence of remote association between preeclampsia and cadmium but the mechanism of the involment of this toxic metal in this disease is still surrounded with uncertainty. Some possible mechanistic pathways such as induction of oxidative stress, acting as an antimetabolite to zinc and deregulation of epigenetic mechanisms have been elucidated in this article may be interconnected, work synergistically or act independently. However, pertinent to understand them in a bid to possibly prevent the disease or forestall its devastating consequences. Environmental cadmium exposure may be considered a factor that merits further serious attention in the continuous search for the precise an etiology of preeclampsia particularly in developing countries that experience uncontrolled cadmium release into the environment

Toxic metal levels in Nigerian electronic waste workers indicate occupational metal toxicity associated with crude electronic waste management practices

The poor management of electronic wastes (e-waste) in Nigeria exposes workers to toxic chemicals in waste electrical and electronic equipment. In this study, we evaluated the toxic metal levels in Nigerians occupationally exposed to e-waste. Whole blood levels of Lead (Pb), Mercury (Hg), Arsenic (As), Cadmium (Cd), and Chromium (Cr) were determined in Nigerian e-waste workers (n=63) and in age-matched non-exposed participants (n=41), using standard electrothermal atomic absorption spectrometry and inductively coupled plasma-mass spectrometry methods. The results showed statistically significant (p<0.01) elevated body burden of toxic metals in e-waste workers (Pb, 0.95 \ub1 0.00 \ub5mol/L; Cr, 405.99 \ub1 6.34 \ub5mol/L; Cd, 108.54 \ub1 1.60 nmol/L; As, 10.09 \ub1 0.01 \ub5mol/L; and Hg, 25.02 \ub1 0.14 nmol/L) compared with non-exposed group ((Pb, 0.03 \ub1 0.00 \ub5mol/L; Cr, 178.44 \ub1 5.99 \ub5mol/L; Cd, 56.99 \ub1 1.42 nmol/L; As, 1.02 \ub1 0.0008 \ub5mol/L; and Hg, 1.62 \ub1 0.0672 nmol/L). These data indicate that the elevated body burden of toxic metals in the e-waste exposed population is an indication of occupational metal toxicity associated with crude e-waste management practices in Nigeria. In addition, the potential health implications of exposure to these toxic metals, such as chronic kidney disease, cancer; preceded by genome instability and depressed immune response were highlighted

Urinary calcium: a promising predictive biomarker for early recognition of environmental lead exposure in children

Background: In the continuous search for accessible, reliable and sensitive biomarkers for early detection of environmental lead exposure, authors determined the interaction between blood lead level (BLL), the conventional marker of lead exposure, and the indices of calcium and bone metabolism in children.Methods: This cross-sectional study involved 309 apparently healthy children from eight public primary schools in Ibadan, Nigeria who were classified as Elevated BLL (EBLL) and control based on standard cut-off for childhood BLL. BLL, serum Ca (tCa), phosphate, magnesium (Mg), 25-hydroxy-Vitamin D, alkaline phosphatase (ALP), urinary calcium (uCa) and urinary deoxypyridinoline (uDPD) were determined using AAS, HPLC and ELISA as appropriate. Bone-specific ALP (B-ALP) and ionized calcium (iCa) were calculated using standard formulae. Data analyses involved Student’s t-test, Pearson correlation and multivariate regression analysis. p0.05). BLL had significant positive correlation with uCa (r=0.176, p=0.002) (p0.05). BLL could be accounted for by uCa by applying the equation, BLL=0.329+0.324uCa.Conclusions: Urinary calcium could be a promising predictive biomarker for early recognition of significant environmental lead exposure in children

Assessment of Landfill-emitted Gaseous Pollutants and Particulate Matters in Alimosho Local Government of Lagos state, Nigeria

Information on landfill-emitted pollutants in Nigeria cities has consequently become a priority. This study was designed to assess the air quality of landfill sites and the nearby communities in the Alimosho Local Government Area of Lagos state, Nigeria. Five public landfills in use since about thirty years ago were chosen for this study. A lightly populated area, free from other sources of air pollution served as control. Target points for the study were the centre of landfill (CLF), 50M from CLF, 100M from CLF, and a radius of 100M away from landfill. Levels of selected gaseous pollutants (NO2, O3, H2S and CO) and particulate matters (PM2.5 and PM10) were determined in the landfill environments and control (unpolluted area), using Aeroqual Series 500 with sensors for NO2, O3, H2S, CO, PM2.5 and PM10. The result showed that levels of H2S were significantly (p<0.001) higher at the CLF, 50M from CLF and 100M from CLF compared with unpolluted area. There was no significant (p>0.05) difference when the level of H2S in 100M radius was compared with the unpolluted area. Levels of CO were significantly (p<0.001) higher at the CLF, 50M from CLF, 100M from CLF and 100M radius compared with unpolluted area. The levels of O3 were significantly (p<0.001) higher at the CLF, 50M from CLF, 100M from CLF and 100M radius compared with unpolluted area. Levels of VOC were significantly (p<0.001) higher at the CLF, 50M from CLF, 100M from CLF and 100M radius compared with unpolluted area. The levels of NO2 were significantly (p<0.001) higher at the CLF, 50M from CLF, 100M from CLF and 100M radius compared with the unpolluted area. The levels of PM2.5 increased significantly (p<0.001) at the CLF, 50M from CLF, 100M from CLF and 100M radius compared with the unpolluted area. The levels of PM10 were also significantly (p< 0.001) higher at the CLF, 50M from CLF, 100M from CLF and 100M radius compared with the unpolluted area. In conclusion, communities close to landfills may be polluted with toxic gases and particulate matters. Further investigation is needed to validate the safe distance of residential areas from landfills to avert the risks of toxicity associated with gaseous pollutants

Development and Validation of an RP-HPLC Method for the Quantitative Analysis of Triclosan in Human Urine

Triclosan (TCS), a synthesized chlorinated phenolic compound, is commonly utilized in consumable products as an antimicrobial agent. TCS has sparked widespread awareness because of its toxicity and possible negative effect on public health in recent years. In this study, a highly sensitive, fast, and cost-effective isocratic reversed-phase high-performance liquid chromatography (RP-HPLC) method coupled with solid-phase extraction for analysis of triclosan in human urine samples was developed. The method utilized methanol and water in a ratio of 90 : 10 as the mobile phase on a Phenomenex Luna 3 µm C18(2) 100 Å, 150 × 4.60 mm stationary phase, with a runtime of 5 minutes. The method showed good resolution of triclosan in the presence of the sample matrix. Validation of the method was performed according to the International Council for Harmonization of Technical Requirements for Pharmaceuticals for Human Use (ICH). Linearity was tested over a range of 0.00625 µg/mL to 6.4 µg/mL, as accuracy recorded a recovery of 89.25%, 91.0%, and 92.75%. Limits of detection (LOD) and quantification (LOQ) were obtained to be 0.0173 µg/mL and 0.0525 µg/mL, respectively. The method proved to be robust over a temperature range of 26°C, 30°C, and 35°C and a flow rate of 0.5 ml, 1.0 ml, and 1.5 ml. The developed method was employed to detect and quantify triclosan in 153 urine samples, comprising 60 samples from Ibadan, Nigeria, and 93 samples from Kumasi, Ghana. Triclosan was detected in a total of 52 samples with an average content of 0.054588 µg/ml. This method can therefore be used for the routine analysis of triclosan in urine samples

Rising environmental cadmium levels in developing countries: Threat to genome stability and health

Cadmium (Cd) is a ubiquitous environmental pollutant of increasing worldwide concern. It is thought to be of greater concern to rapidly industrializing developing countries because of the increasing pace of industrial activities in these countries with increasing consumption and release into the environment. Traditionally, health concerns in exposed human populations have revolved around the association of Cd with bone disease, emphysema and possibly hypertension. Accumulating evidence suggest that Cd is involved in the disruption of many genomic processes, the mechanisms of which are being gradually understood. Changes in DNA Methylation may be induced by cadmium leading to epigenetic alterations. Additionally, though Cd is not thought to induce reactive oxygen species (ROS) directly because it is not capable of accepting or donating electrons under physiological conditions, 8-hydroxy deoxyguanosine (8-OHdG) (a marker of oxidative stress to DNA and a risk factor for cancer among others) has been shown to be elevated in the DNA of testes from rats treated with cadmium chloride, at least in part because Cd inhibits DNA repair mechanisms. Cadmium is also a metabolic antagonist to Zinc (Zn), an important micronutrient involved in numerous molecular activities. This antagonism alters the physiological stoichiometric relationship between Cd and Zn leading to high Cd/Zn ratio, one consequence of which is high error rate and lack of efficient DNA repair systems leading to high mutation and genome instability culminating in many carcinogenic states, particularly prostate carcinogenesis. Cadmium has also been shown to replace Zn in the tumor suppressor protein, p53 thereby impairing p53's DNA binding activity and associated repair processes. The expression of the p53 protein is significantly depressed by cadmium. Although the rising level of Cd in the environment is widely acknowledged, the occult threat it poses to genome stability largely through inhibition of normal DNA damage repair, oxidative stress and apoptosis and health is poorly recognized. This paper examines the involvement of Cd in the molecular pathways of human disease, providing insight for the prevention of genome instability and associated disease susceptibility particularly cancer across populations through micronutrient intervention, aiding upregulation of the antioxidant defense and DNA repair systems