E-waste Site Research Articles

ASSESSMENT OF THE CONCENTRATION OF HEAVY METALS IN ELECTRONIC WASTE DUMP SITE IN ALABA INTERNATIONAL MARKET, LAGOS STATE

This research investigates the concentration of heavy metals (Pb, Cu, Cd, and Ni) at e-waste dump sites in Lagos, Nigeria. Measuring the concentration and distribution of heavy metals across different soil depths and comparing these concentrations in soil and water samples. For this purpose, 78 soil samples were taken from different sampling points, and analyses were carried out following standard procedures. The soil samples retrieved from the e-waste site consistently exhibit a sandy soil texture, as per the USDA classification system. It was found that Cu generally has the highest concentrations in the soil layers (2022.20-2312.67mgkg-1) while Cd generally has the least (16.32-22.62 mgkg-1). The elements observed for this study are Cu > Pd >Ni > Cd. Overall, this comprehensive study provides valuable insights into the environmental contamination and health risks posed by e-waste dump sites, emphasizing the need for effective management strategies to mitigate these risks and protect human health and the environment.

PBDEs and dechlorane plus contamination in community e-waste recycling: Environmental and health implications in Northeastern Thailand

Electronic waste (e-waste) poses significant environmental and health risks in Thailand due to both domestic production and international imports. A notable portion of this waste is processed in small-scale, community-based workshops, often located in poorer regions, where safety regulations are improperly enforced or entirely ignored. This study focuses on the Kalasin province in Northern Thailand, a region with numerous such workshops, where no comprehensive analysis of exposure to polybrominated diphenyl ethers (PBDEs) and dechlorane plus (DP) has been conducted. The study's objective was to quantify these toxic substances in environmental and biological samples to assess its contamination and human health risks. Environmental samples, including soil, dust, sediment, ash, eggs, crabs, snails, fish, and rice, were collected from e-waste processing sites and compared with control areas. Blood samples from e-waste workers and a control group were also analysed. Gas chromatography coupled with mass spectrometry operated in negative ion chemical ionization (GC-NCI-MS) was used to quantify PBDEs and DP isomers. Results showed significantly higher concentrations of these toxic compounds in e-waste sites compared to control areas. E-waste workers also had elevated levels of these substances in their blood, suggesting exposure through contaminated dust and food. These findings underscore the severe environmental contamination and health risks associated with improper e-waste management, highlighting the urgent need for regulatory measures and improved recycling practices to safeguard both environmental and public health.

Heavy metal contamination of the Nigerian environment from e-waste management: A systematic review of exposure pathway and attendant pathophysiological implications

Nigerian environment has become a depository of worrisome levels of toxicants including heavy metals. Electrical and electronic equipment which leads to the generation of e-waste is one of the considerable sources of environmental contaminants in Nigeria. This systematic review deployed Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) method to analyze various empirical and quantitative outputs on heavy metal components of e-waste management sites in Nigeria and investigated the distribution of heavy metals in several environmental matrices such as soil, water, surface dust, plant and blood of e-waste scavengers. Also, the probable environmental multi-transformation that ultimately potentiates the susceptibility of humans to the pathophysiological effects and genetic related disorders of exposure to heavy metal component of e-waste was discussed. The relative abundance of metals in soils due to inappropriate e-waste handling is given as follow: Fe>Cu>Pb>Zn>Mn>Co>Cr>Ni>As>Cd, in underground and surface water: Zn>Fe>Cu>Cr>Mn>Pb>Hg>Ni>Co>Cd>As; in surface dusts: Fe>Zn>Pb>Cu>Mn>Cr>Ni>Cd>Co; in plants: Pb>Cu>Mn>Zn>Ni>Cr>Cd obtained from the Nigerian environment. Moreso, the estimated abundance of heavy metals in the blood of e-waste scavengers is Nigeria is given as Cr>Cd>Hg>Zn>As>Pb>Cu>Mn>Fe. Conclusively, this study does not only show that various matrices of Nigerian environment is contaminated with heavy metal but also that the pattern of abundance differ in the environment and in biological systems with the latter having the abundance of Pb, Cr and Cd and the former having the abundance of Cu, Zn and Fe.

Impact of anthropogenic activities on atmospheric chlorinated paraffins in Ghana using polyurethane foam disk - passive air sampler

Chlorinated paraffins (CPs) are a global concern due to their high production, ubiquity in the environment and potential toxicity. In Ghana, there is a significant research gap on the concentration and sources of CPs in the air, as well as insufficient regular monitoring programs to track CP levels over time. This study utilized polyurethane foam-based passive air samplers (PUF-PAS) to examine the concentrations, sources and potential human health risks of CPs in the atmosphere surrounding e-waste sites, urban areas, commercial areas and control/background areas in Ghana. The medium-chain CPs (MCCPs) dominated with an average concentration of 26.0 ± 40.1 ng/m3 and ranged from 1.78 to 240 ng/m3. Short-chain CPs (SCCPs) ranged from 0.05 to 15.2 ng/m3 and had an average concentration of 3.48 ± 3.99 ng/m3. The very short-chain CPs (C9-CPs), had an average concentration of 0.544 ± 0.524 ng/m3 and ranged from 0.091 to 2.14 ng/m3. MCCPs exceeded SCCPs by a factor of 7.5 and C9-CPs by a factor of 48. C14Cl8 was the dominant congener in MCCPs and C10Cl7 was also the dominant congener in SCCPs. E-waste was the main contributor to SCCPs and MCCPs (>30 %) in Ghana. The assessed non-cancer risks associated with CP exposure were within acceptable ranges. For cancer risk, MCCPs indicated high potential health risk but C9-CPs and SCCPs showed low risk. To the best of our knowledge, this is the first study on CPs in Ghana's atmosphere, and e-waste was identified as the country's main source of CPs. This study will help regulatory bodies create policies and procedures to control the use and disposal of chlorinated paraffins.

Spatial distribution and health risks assessment of heavy metals in e-waste dumping sites from Pakistan.

The present study focused on to determine the concentration and health risk of heavy metals (Cu, Pb, Zn, Cd, Hg, Cr) in e-waste contaminated soils collected from different provinces of Pakistan. Further, the impact of heavy metals on soil enzyme activities and microbial community was also investigated. The concentration (mg/kg) of Hg, Zn, Fe, Cu, Pb, Cd, and Cr ranged between 0-0.258, 2.284-6.587, 3.005-40.72, 8.67-36.88, 12.05-35.03, 1.03-2.43, and33.13-60.05, respectively. The results revealed that Lahore site of Punjab province indicated more concentration of heavy metals as compared to other sites. The level of Cr at all sites whereas Hg at only two sites exceeds the World Health Organization standards (WHO) for soil. Soil enzyme activity exhibited dynamic trend among the sites. Maximum enzyme activity was observed for urease followed by phosphatase and catalase. Contamination factor (Cf), Pollution load index (PLI), and geo-accumulation index (Igeo) results showed that all the sites are highly contaminated with Cu, Cd, and Pb. Hazard index (HI) was less than 1 for children and adults suggesting non-carcinogenic health risk. Principle component analysis results depicted relation among Cr, Fr, catalase, and actinomycetes; Cd, OM, urease, and bacteria, and Pb, Cu, Zn, Hg, and phosphatase, suggesting soil enzymes and microbial community profiles were influenced by e-waste pollution. Therefore, there is a dire need to introduce sustainable e-waste recycling techniques as well as to make stringent e-waste management policies to reduce further environmental contamination.

A Review of the Association between Exposure to Flame Retardants and Thyroid Function.

Flame retardants have been shown to cause widespread physiological effects, in particular on endocrine organs such as the thyroid. This review aims to provide an overview of the literature on the association between flame retardants and thyroid function within humans. A search in the National Library of Medicine and National Institutes of Health PubMed database through January 2024 yielded 61 studies that met the inclusion criteria. The most frequently analyzed flame retardants across all thyroid hormones were polybrominated diphenyl ethers (PBDEs), in particular BDE-47 and BDE-99. Ten studies demonstrated exclusively positive associations between flame retardants and thyroid stimulating hormone (TSH). Six studies demonstrated exclusively negative associations between flame retardants and TSH. Twelve studies demonstrated exclusively positive associations for total triiodothyronine (tT3) and total thyroxine (tT4). Five and eight studies demonstrated exclusively negative associations between flame retardants and these same thyroid hormones, respectively. The effect of flame retardants on thyroid hormones is heterogeneous; however, the long-term impact warrants further investigation. Vulnerable populations, including indigenous people, individuals working at e-waste sites, firefighters, and individuals within certain age groups, such as children and elderly, are especially critical to be informed of risk of exposure.

Contamination characteristics and dietary intake risk of brominated flame retardants in fishes around a typical e-waste dismantling site in Southern China

Polybrominated diphenyl ethers (PBDEs) and their substitutes, novel brominated flame retardants (NBFRs), are ubiquitously present in the aquatic environment of electronic waste (e-waste) dismantling region, leading to their inevitable absorption and accumulation by aquatic organisms, which can be transferred to human via directly aquatic product consumption or through food chain, thereby posing potential health risks. This study focused on fish samples from Guiyu and its surrounding areas, and found the total PBDEs concentrations were 24–7400 ng/g lw (mean: 1800 ng/g lw) and the total NBFRs concentrations were 14 to 2300 ng/g lw (mean: 310 ng/g lw).Significant positive correlations were found among PBDE congeners, among different NBFRs, and between NBFRs and commercial PBDEs that they replace. ΣPBDEs and ΣNBFRs in the intestine were 620–350,000 and 91–81,000 ng/g lw (mean: 83000 and 12,000 ng/g lw, respectively), significantly exceeding those in the gills, where ΣPBDEs and ΣNBFRs were 14–37,000 and 39–45,000 ng/g lw (mean: 9200 and 2400 ng/g lw, respectively). The ΣPBDEs and ΣNBFRs showed no non-carcinogenic risks to the target population through dietary intake. Despite the significantly higher daily intake of decabromodiphenyl ethane (DBDPE) compared to decabromodiphenyl ether (BDE209), the non-carcinogenic risk associated with BDE209 remained higher than that of DBDPE. Our findings can assist researchers in understanding the presence of BFRs in aquatic organisms, inhabiting e-waste dismantling areas, and in evaluating the associated health risks posed to humans through dietary exposure.

Investigating the distribution of microplastics in soils from e-waste dismantling sites and their adsorption of heavy metals.

Microplastics are characterized by strong hydrophobicity, large specific surface area. In addition to the pollutant they contain, the heavy metals adsorbed on the surface of microplastics can migrate or be transformed with them into the environmental medium, which is potentially harmful to humans. The distribution characteristics of microplastics in contaminated soil at the e-waste dismantling site were studied. The study investigated the adsorption characteristics of polyvinyl chloride (PVC), polypropylene (PP) and acrylonitrile-butadiene-styrene (ABS) on copper (Cu), zinc (Zn) and lead (Pb). It analysed the influence of various factors on the adsorption process of heavy metals, the adsorption law of microplastics on some of the heavy metals in the environment, and the risk of heavy metal release from microplastics to soil. The results showed that ABS and PP were the main microplastics in the contaminated soil. Among them, black, white and transparent microplastics accounted for 89.91%. The shape of microplastics is mainly granular, and microplastics with a particle size of 1-2 mm accounted for the largest proportion. Further studies showed that plastic particles made of ABS, PP and PVC also have the adsorption capacity for different types of heavy metals in soil, and the trends of adsorption capacity are: PP>PVC>ABS. When PP does not reach adsorption equilibrium in the adsorption process, the smaller the particle size and the more added amount, the greater the adsorption capacity. This is because the smaller the particle size of the microplastic is, the more adsorption points it can provide, increasing its ability to adsorb heavy metal ions.

Academic urban legend, Agbogbloshie: Sweeping away the "World's Largest E-Waste Dumpsite"

Agbogbloshie, once an internationally recognised toxic e-waste site, was thrust into prominence by sensationalised media and literature. Despite various e-waste initiatives by the government and development partners, the municipality unexpectedly demolished the site in 2021. This action can be attributed partly to the municipality's inability to effectively manage informality, and partly to the propagation of questionable ‘facts’ based on inadequate data, journalistic views, and distortions, which fueled an urban myth and intensified extreme perceptions about Agbogbloshie and its policy trajectory. The emergence and downfall of this academic urban legend are demonstrated through an examination of Wikipedia activity related to the Agbogbloshie page, Google citations, other digital traces, and publication patterns. The Agbogbloshie case highlights the risks of globalizing extreme urban cases, underscores the need for more consistent and aligned urban policies and actions in Accra that are not only consistent and aligned but also cognizant of the complexities of informality, viewing it as a manifestation of underlying socio-economic challenges. It also calls for strategies that avoid displacement and fragmentation, recognising the potential hazards of relocating informal challenges to other urban and peri-urban areas following slum demolitions.

Cross-shift changes in pulmonary function and occupational exposure to particulate matter among e-waste workers in Ghana.

Little is known on the association between cross-shift changes in pulmonary function and personal inhalation exposure to particulate matter (PM) among informal electronic-waste (e-waste) recovery workers who have substantial occupational exposure to airborne pollutants from burning e-waste. Using a cross-shift design, pre- and post-shift pulmonary function assessments and accompanying personal inhalation exposure to PM (sizes <1, <2.5 μm, and the coarse fraction, 2.5-10 μm in aerodynamic diameter) were measured among e-waste workers (n = 142) at the Agbogbloshie e-waste site and a comparison population (n = 65) in Accra, Ghana during 2017 and 2018. Linear mixed models estimated associations between percent changes in pulmonary function and personal PM. Declines in forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) per hour were not significantly associated with increases in PM (all sizes) among either study population, despite breathing zone concentrations of PM (all sizes) that exceeded health-based guidelines in both populations. E-waste workers who worked "yesterday" did, however, have larger cross-shift declines in FVC [-2.4% (95%CI: -4.04%, -0.81%)] in comparison to those who did not work "yesterday," suggesting a possible role of cumulative exposure. Overall, short-term respiratory-related health effects related to PM exposure among e-waste workers were not seen in this sample. Selection bias due to the "healthy worker" effect, short shift duration, and inability to capture a true "pre-shift" pulmonary function test among workers who live at the worksite may explain results and suggest the need to adapt cross-shift studies for informal settings.

Screening legacy and emerging organic pollutants in the contaminated soil of Dhaka, Bangladesh

The current understanding of the legacy and emerging organic pollutants in the soil of Bangladesh remains limited. Inadequate disposal practices, particularly in e-waste, landfills, and industrial operations, may lead to the pervasive presence of persistent organic pollutants (POPs) and polycyclic aromatic hydrocarbons (PAHs) in the country. This study aimed to systematically investigate the concentrations, sources, and risk assessment of halogenated flame retardants (HFRs), polychlorinated biphenyls (PCBs), polychlorinated naphthalenes (PCNs), organochlorine pesticides (OCPs), chlorinated paraffins (CPs), and PAHs in the contaminated soil of Dhaka's dumpsites, e-waste, and industrial areas collected in 2017. The total concentration of investigated pollutants averaged at 4790 ± 4040 ng g−1 dw, with the following order: ∑44CPs (4110 ± 4140 ng g−1 dw) > ∑16PAHs (422 ± 491 ng g−1 dw) > ∑16HFRs (190 ± 538 ng g−1 dw) > ∑209PCBs (43.5 ± 73.5 ng g−1 dw) > ∑50PCNs (17.7 ± 21.0 ng g−1 dw) > ∑27OCPs (9.41 ± 9.61 ng g−1 dw). The e-waste site exhibited the highest total concentration of the target pollutants, reaching 12,700 ng g−1 dw. CPs were the predominant contributors, accounting for averages of 81.8%, 70.5%, and 68.5% to waste landfills, e-waste, and industrial sites, respectively. A comprehensive analysis of 209 PCB congeners revealed their primary origin from Aroclor PCBs, with minor contributions from unintentionally produced PCBs. The highest incremental lifetime carcinogenic risk (ILCR) occurred in e-waste sites, contributed by dioxin-like PCBs, with a maximum value of 5.9 × 10−5 for adults, exceeding the limit 1.0 × 10−6 set by the U.S. EPA. The non-carcinogenic hazard quotients (HQs) were much lower, suggesting no significant risk from the investigated pollutants. Our findings highlight the importance of proper waste management and regulated e-waste recycling to mitigate potential hazardous risks to the Bangladeshi population.

Lagging pollution of polycyclic aromatic hydrocarbons in the rebuilt e-waste site: From the perspective of characteristics, sources, and risk assessment

Little information is known regarding how the lagged pollution of polycyclic aromatic hydrocarbon (PAH) influenced the environment and human health after an e-waste dismantling site was rebuilt. This study investigated the characteristics, sources, and risk assessment of PAHs in a rebuilt e-waste site and its surrounding farmland by analyzing the samples of soil, dust, water, and vegetable. Concentrations of PAHs in soil, vegetable and water in the rebuilt site were relatively higher than in its surrounding farmland. The concentrations in surface soils, soil columns, dust, vegetables, and water varied from 55.4 to 3990 ng g−1, 1.65 to 5060 ng g−1, 2190 to 2420 ng g−1, 2670 to 10,300 ng g−1, and 46.8 to 110 μg L−1 in the e-waste site, respectively. On the farmland, PAH concentrations in surface soils, vegetables, and water ranged from 41.5 to 2760 ng g−1, 506 to 7640 ng g−1, and 56.6 to 89.2 μg L−1, respectively. A higher proportion of high-molecular-weight PAHs (HMW-PAHs) appeared in all multimedia compared with low-molecular-weight PAHs (LMW-PAHs). Diagnostic ratio together with positive matrix factorization (PMF) revealed that vehicle emission was the primary source in this area, and the activity of e-waste disposal was another important source in the rebuilt e-waste site. Based on the deterministic health risks, people working in the reconstructed e-waste site were exposed to low risks, whereas the residents living near the surrounding farmland were exposed to low risk. Sensitivity analyses indicated that exposure frequency and PAH concentrations were the main factors that influenced exposure risk. This study provides valuable insight into the comprehension of the lagging pollution effects of PAH on the environment and human health after the e-waste site was rebuilt.

Tetrabromobisphenol-A/S and their derivatives in surface particulates from workshop floors of three representative e-waste recycling sites in China

Surface particulates collected from the workshop floors of three major e-waste recycling sites (Taizhou, Qingyuan, and Guiyu) in China were analyzed for tetrabromobisphenol A/S (TBBPA/S) and their derivatives to investigate the environmental pollution caused by e-waste recycling activities. Mean concentrations of total TBBPA/S analogs in surface particulates were 31,471–116,059 ng/g dry weight (dw). TBBPA, TBBPA-BGE, and TBBPA-BDBPE were the most frequently detected in particulates with average concentration ranges of 17,929–78,406, 5601–15,842, and 5929–21,383 ng/g dw, respectively. Meanwhile, TBBPA, TBBPA-BGE, and TBBPA-BDBPE were the most abundant TBBPA/S analogs, accounting for around 96% of the total. The composition profiles of TBBPA/S analogs differed significantly among three e-waste sites. Similarly, principal component analysis uncovered different pollution patterns among different sites. The discrepancy in the profiles of TBBPA/S analogs largely relied on the e-waste types recycled in different areas. E-waste recycling led to the release of TBBPA/S analogs, and TBBPA/S analogs produced differentiation during migration from source (surface particulates) to nearby soil. More researches are necessary to find a definite relationship between pollution status and e-waste types and study differentiation behavior of TBBPA/S analogs in migration and diffusion from source to environmental medium.

Bioaccessibility of halogenated flame retardants and organophosphate esters in settled dust: Influences of specific dust matrices from informal e-waste and end-of-life vehicle processing areas in Vietnam

Bioaccessibility of halogenated flame retardants (HFRs) and organophosphorus esters (OPEs) is necessarily investigated to provide more accurate risk assessment and information about absorption behavior of these pollutants. In this study, total and bioaccessible concentrations of HFRs (including legacy and alternative substances) and OPEs were determined in settled dust samples collected from Vietnamese e-waste and end-of-life vehicle (ELV) processing areas. Concentrations of both HFRs and OPEs were significantly higher in the e-waste dust than ELV dust. Bioavailability of HFRs and OPEs in dust was determined by using an in vitro assay with human-simulated digestive fluids, dialysis membrane, and Tenax® TA sorptive sink. Bioaccessibility of HFRs was markedly lower than that of OPEs, which could be largely due to higher hydrophobicity of HFRs compared to OPEs. Bioaccessibility of almost hydrophobic compounds were markedly lower in the e-waste dust (containing micronized plastic debris) than in the ELV dust (containing oily materials), suggesting the influence of specific dust matrices on pollutant bioaccessibility. Although the daily uptake doses of selected HFRs and OPEs from dust were markedly higher in the e-waste sites compared to the ELV sites, the direct exposure risk was not significant. Our results suggest that bioaccessibility can partly explain the differences between dust and uptake profiles, which may relate to accumulation profiles of HFRs and OPEs in human samples.

Preferential association of PBDEs and PAHs with mineral particles vs. dissolved organic carbon: Implications for groundwater contamination at e-waste sites

Polybrominated biphenyl ethers (PBDEs) and polycyclic aromatic hydrocarbons (PAHs) are commonly detected contaminants at e-waste recycling sites. Against the conventional wisdom that PBDEs and PAHs are highly immobile and persist primarily in shallow surface soils, increasing evidence shows that these compounds can leach into the groundwater. Herein, we compare the leachabilities of PBDEs vs. PAHs from contaminated soils collected at an e-waste recycling site in Tianjin, China. Considerable amounts of BDE-209 (0.3–2 ng/L) and phenanthrene (42–106 ng/L), the most abundant PBDE and PAH at the site, are detected in the effluents of columns packed with contaminated soils, with the specific concentrations varying with hydrodynamic and solution chemistry conditions. Interestingly, the leaching potential of BDE-209 appears to be closely related to the release of colloidal mineral particles, whereas the leachability of phenanthrene correlates well with the concentration of dissolved organic carbon in the effluent, but showing essentially no correlation with the concentration of mineral particles. The surprisingly different trends of the leachability observed between BDE-209 and phenanthrene is counterintuitive, as PBDEs and PAHs often co-exist at e-waste recycling sites (particularly at the sites wherein incineration is being practiced) and share many similarities in terms of physicochemical properties. One possible explanation is that due to its extremely low solubility, BDE-209 predominantly exists in free-phase (i.e., as solid (nano)particles), whereas the more soluble phenanthrene is mainly sorbed to soil organic matter. Findings in this study underscore the need to better understand the mobility of highly hydrophobic organic contaminants at contaminated sites for improved risk management.

Simultaneous targeted and non-targeted analysis of plastic-related contaminants in e-waste impacted soil in Agbogbloshie, Ghana

An LC-MS based analytical method was developed and validated for the simultaneous targeted analysis and suspect screening of plastic-related contaminants in e-waste impacted soils. Satisfactory recoveries (97 ± 13 %) were achieved using ultrasound-assisted extraction for 14/15 of the targeted analytes (7 bisphenols and 8 plasticizers) in a range of agricultural and non-agricultural soils. The method was applied to 53 soil samples collected in May 2015 in the region of Agbogbloshie (Ghana) at e-waste facilities (incl. Dump, trade, and burn sites), neighboring non-agricultural (incl. upstream, downstream, and community) and agricultural fields, and at two control agricultural sites away from e-waste recycling facilities. Bisphenol A (BPA) and bis(2-ethylhexyl) phthalate (DEHP) were the two dominant contaminants in e-waste soil (with concentrations up to 48.7 and 184 μg g−1, respectively), especially at the trade site, where e-waste was sorted and dismantled. The non-targeted workflow was successfully applied to identify additional plastic-related contaminants previously unreported in e-waste impacted soils, including bis(2-propylheptyl) phthalate, diisononyl phthalate, trioctyl trimellitate, 4-dodecylbenzenesulfonic acid, perfluorooctanesulfonic acid, perfluorobutanesulfonic acid, diphenyl phosphate, and triethylene glycol monobutyl ether. The agricultural soils surrounding the e-waste sites were also contaminated by plastic-related chemicals (especially DEHP), highlighting the impact of e-waste activities on the surrounding agricultural system.

Ecotoxicity of heavy metals in soil around long-term e-waste recycling sites in Tema and Ashaiman areas of Ghana.

The effect of e-waste recycling activities on the prevalence of metals (Cd, Cu, Hg, Ni, Pb, and Zn) and a metalloid (As) in soil was assessed for four e-waste sites in Ghana. Samples of top- and subsoil were collected from dismantling and burning sections, and the prevalence and the distribution of selected metals were determined using atomic absorption spectroscopy. The concentrations of the metals analyzed were above the background concentrations except for Cd, which was detected at a comparable level to the background levels. Levels of Cu and Pb increased with increasing soil depth. Cd, Zn, As, and Ni levels decreased with increasing soil depth. However, Hg levels showed no recognizable trend in its distribution relative to soil depth. The pollution indices evaluated revealed deterioration of the soil quality at the e-waste sites. Pollution indices are used to categorize soil pollution levels based on cut-off values. Geo-accumulation indices suggested that the soil was very highly polluted with Pb, highly polluted with Cu, and moderately polluted with As, Hg, Cd, and Zn. The enrichment factor values indicated that soil from the studied sites was very highly enriched with Pb (i.e., EF of 9.60 to 63.14; median being 28.51) and significantly enriched with Cu and Hg (i.e., EF of 3.09 to 21.86; median 7.72 for Cu and EF of 1.48 to 25.5; median 10.57 for Hg). The contamination factor analysis revealed very high contamination of soils with Pb. The metals Cu, Zn, As, Ni, Cd, and Hg exhibited moderate to considerable contamination. This study is part of the continuous effort to assist policymakers with scientific information needed to influence policy decisions on environmental management in Ghana.

A review of heavy metal risks around e-waste sites and comparable municipal dumpsites in major African cities: Recommendations and future perspectives

In Africa, the effects of informal e-waste recycling on the environment are escalating. It is regularly transported from developed to developing nations, where it is disassembled informally in search of precious metals, thus increasing human exposure to harmful compounds. Africa has a serious problem with e-waste, as there are significant facilities in Ghana and Nigeria where imported e-waste is unsafely dismantled. however, because they are in high demand and less expensive than new ones, old electronic and electrical items are imported in large quantities, just like in many developing nations. After that, these objects are frequently scavenged to recover important metals through heating, burning, incubation in acids, and other techniques. Serious health hazards are associated with these activities for workers and individuals close to recycling plants. At e-waste sites in Africa, there have been documented instances of elevated concentrations of hazardous elements, persistent organic pollutants, and heavy metals in dust, soils, and vegetation, including plants consumed as food. Individuals who handle and dispose of e-waste are exposed to highly hazardous chemical substances. This paper examines heavy metal risks around e-waste sites and comparable municipal dumpsites in major African cities. Elevated concentrations of these heavy metals metal in downstream aquatic and marine habitats have resulted in additional environmental impacts. These effects have been associated with unfavourable outcomes in marine ecosystems, such as reduced fish stocks characterized by smaller sizes, increased susceptibility to illness, and decreased population densities. The evidence from the examined studies shows how much e-waste affects human health and the environment in Africa. Sub-Saharan African nations require a regulatory framework that includes specialized laws, facilities, and procedures for the safe recycling and disposal of e-waste.

Spatial distribution of potentially toxic elements in e-waste contaminated site at Akwatia-Line, Kumasi, Ghana

E-waste processing sites abound with potentially toxic elements (PTE) that negatively affect the environment and human health. The study determined the presence of selected PTE (Cu, Zn, Pb, Hg, and Al) and their spatial distribution in an e-waste processing site in a developing country setting. pH, moisture, organic matter/carbon, and particle size were determined in 30 soil samples. The spatial position of each sampling point was picked with a GPS device, and the area was mapped in a GIS environment. The concentrations of PTE were determined with an atomic absorption spectrophotometer. Findings from the study indicate that the soil is polluted with PTE, rich in organic carbon/matter but has low pH. The Geoaccumulation Indices ranged from unpolluted (Al) to strongly/extremely polluted (Cu). Pollution Load Index showed about 77 % of the samples as extremely/heavily polluted, 10 % as heavily polluted, and 13 % as moderately polluted. Contamination Factors of Zn, Pb, and Cu were very high but considerably low for Hg and Al. Regular monitoring and remediation are required for the soil to be restored and put into productive use.

Assessment of legacy and alternative halogenated organic pollutants in outdoor dust and soil from e-waste sites in Nigeria: Concentrations, patterns, and implications for human exposure

E-waste is often processed informally, particularly in developing countries, resulting in the release of harmful chemicals into the environment. This study investigated the co-occurrence of selected persistent organic pollutants (POPs), including legacy and alternative halogenated flame retardants (10 polybrominated diphenyl ethers (PBDEs), decabromodiphenyl ethane (DBDPE), syn and anti-dechlorane plus (DP)), 32 polychlorinated biphenyls (PCBs) and 12 organochlorine pesticides (OCPs), in 20 outdoor dust and 49 soil samples from 7 e-waste sites in Nigeria. This study provides the first report on alternative flame retardants (DBDPE and DP) in Nigeria. The total concentration range of the selected classes of compounds was in the order: ∑10PBDEs (44–12300 ng/g) > DBDPE (4.9–3032 ng/g) > ∑2DP (0.7–278 ng/g) > ∑32PCBs (4.9–148 ng/g) > ∑12OCPs (1.9–25 ng/g) for dust, and DBDPE (4.9–9647 ng/g) > ∑10PBDEs (90.3–7548 ng/g) > ∑32PCBs (6.1–5025 ng/g) > ∑12OCPs (1.9–250 ng/g) > ∑2DP (2.1–142 ng/g) for soil. PBDEs were the major contributors to POP pollution at e-waste dismantling sites, while PCBs were the most significant contributors at e-waste dumpsites. DBDPE was found to be significantly associated with pollution at both e-waste dismantling and dumpsites. Estimated daily intake (EDI) via dust and soil ingestion and dermal adsorption routes ranged from 1.3 to 2.8 ng/kg bw/day and 0.2–2.9 ng/kg bw/day, respectively. In the worst-case scenario, EDI ranged from 2.9 to 10 ng/kg bw/day and 0.8–5.8 ng/kg bw/day for dust and soil, respectively. The obtained intake levels posed no non-carcinogenic risk, but could increase the incidence of cancer at some of the studied e-waste sites, with values exceeding the USEPA cancer risk lower limit (1.0 × 10−6). Overall, our results suggest that e-waste sites act as emission point sources of POPs.