Impact of informal electronic waste recycling on metal concentrations in soils and dusts

Informal E-waste dismantling activities accelerated the releasing of liquid crystal monomers (LCMs) in Pakistan: Occurrence, distribution, and exposure assessment

Liquid crystal monomers (LCMs) are emerging contaminants characterized by their persistence, bioaccumulation potential, and toxicity. They have been observed in several environmental matrices associated with electronic waste (e-waste) dismantling activities, particularly in China. However, there is currently no information on the pollution caused by LCMs in other developing countries, such as Pakistan. In this study, we collected soil samples (n = 59) from e-waste dismantling areas with different functions in Pakistan for quantification analysis of 52 target LCMs. Thirty out of 52 LCMs were detected in the soil samples, with the concentrations ranging from 2.14 to 191 ng/g (median: 16.3 ng/g), suggesting widespread contamination by these emerging contaminants. Fluorinated LCMs (median: 10.4 ng/g, range: 1.27-116 ng/g) were frequently detected and their levels were significantly (P < 0.05) higher than those of non-fluorinated LCMs (median: 6.11 ng/g, range: not detected (ND)-76.7 ng/g). The concentrations and profiles of the observed LCMs in the soil samples from the four functional areas varied. The informal dismantling of e-waste poses a potential exposure risk to adults and infants, with median estimated daily intake (EDI, ng/kg bw/day) values of 0.0420 and 0.1013, respectively. Calculation of the hazard quotient (HQ) suggested that some LCMs (e.g., ETFMBC (1.374) and EDFPB (1.257)) may pose potential health risks to occupational workers and their families. Considering the widespread contamination and risks associated with LCMs, we strongly recommend enhancing e-waste management and regulation in Pakistan.

A comparative study on metal pollution from surface dust of informal and formal e-waste recycling sectors in national capital region of New Delhi and associated risk assessment

Electrical and electronic waste (e-waste) is considered as resource and secondary source of metals, and is being recycled for recovery of precious and base metals. But the processes of recycling and the waste generated during e-waste recycling in informal and formal sectors contribute toxic metals in to the environment. This work aimed to compare the environmental and health impacts of informal and formal e-waste recycling facilities at New Delhi and Bhiwadi Industrial area in India, respectively. Here, concentrations of Ba, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Sn, V, Zn, and Ag, and As in surface dust collected from informal and formal recycling sectors and their associated pollution, human health and ecological risk are presented. Metal concentrations were higher than the background levels in both sectors. Contamination factor (Cf), contamination degree (Cdeg), pollution load index (PLI), geo-accumulation index (Igeo) and enrichment factor (EnF) of metals indicated severe pollution levels in both sectors. However, contamination in informal sector was comparatively higher than the formal sector. Sampling sites in both sectors had very high ecological risk. Storage, dismantling/shredding and recycling techniques were contributors of metals in surface dust in formal sector whereas fumes deposition, re-suspension, and dried by-products during acid bath treatments were additional sources in informal sector. Metal pollution depends on metal(s), e-waste type(s) and recycling sector(s). Total non-carcinogenic health risk due to metals was 6.5E+00 and 6.0E+01 and 6.2E+00 and 5.5E+01 in adult and children in informal and formal sectors, respectively. Total carcinogenic risk was 3.3E-03 and 7.2E-03 in informal and formal sectors, respectively. Ingestion was major pathways of metals followed by dermal and inhalation and children were more prone to risk compared to adults. Formal sectors too cause metal pollution but to lesser degree compared to informal. More effective pollution control measures are required in formal sector to control environmental pollution.

Incorporating self-employed maintainers into WEEE formal recycling system: A system dynamic approach

The establishment and operation of a formal recycling system for waste electrical and electronic equipment is an important measure to reduce environmental hazards and improve the recycling of resources, but how to incorporate self-employed maintainers into the system has formed an important research gap. Based on the perspective of extended producer responsibility, we argue that self-employed maintainers are required to assume the corresponding environmental responsibility for the environmental externality caused by informal maintenance activities. Using qualitative structural analysis techniques of system dynamics approach with quantitative simulation analysis techniques, we construct an incentive model for self-employed maintainers' participation in formal recycling system, based on which we propose four incentive strategies. A simulation analysis is further conducted by using the case of waste mobile phones recycling in Qingdao to verify the effectiveness of our incentive model and strategies.

Soil heavy metal pollution from waste electrical and electronic equipment of repair and junk shops in southern Thailand and their ecological risk

The waste electrical and electronic equipment (WEEE) stream in Thailand shifted from exporting WEEE to recycling them in domestic enterprises after China's import restrictions on e-waste in 2018. This study aims to investigate the pollution status, pollution sources, and ecological risk of heavy metals from manual WEEE dismantling facilities (12 repair shops and 8 junk shops) in the Nakhon Si Thammarat province of southern Thailand by examining the concentrations of As, Cd, Ni, and Pb in the topsoil (0-15 cm) during the wet and dry seasons. The results revealed that the mean concentrations of all heavy metals were higher during the dry season than in the wet season. The concentrations of analyzed soil heavy metals decreased as the intensity of e-waste dismantling activities increased, with recycling sites > repair sites > control sites (no e-waste recycling activities). Only 10% of WEEE processing workshops (junk shops) had soil Pb and As concentrations that exceeded Thailand's residential soil quality standards. However, ecological indexing models based on the geo-accumulation index found that 75% of electric repair shops were contaminated with the analyzed heavy metals, particularly Pb. Moreover, the Nemerow integrated pollution index indicated that 16.7% of electric repair shops were on the pollution warning line. Our findings suggest that policymakers should promote ecological risk assessment as a method for mitigating the negative environmental impact of electronic repair businesses, which are widely dispersed in residential areas and tend to dominate the WEEE stream because of the circular economy concept of "right to repair", and highlight the decline of junk shops and e-waste dismantling villages for waste export resulting from China's ban.

Health Impact of Household Waste Burning in Khartoum State, Sudan

Background

Waste disposal and management is a global concern affecting both high- and low-income countries. This research assessed the health impact of burning household waste in Khartoum State, Sudan.

Methods

An online community-based cross-sectional study was implemented on a sample of 844 participants selected through a stratified random sampling technique across Khartoum State. The data were collected through a standardized pre tested online questionnaire. The data file was georeferenced through Google Earth Pro and analysed with SPSS 23 and ArcGIS 10.3. The data were summarized numerically and graphically. The appropriate frequency tables were used in ArcGIS to generate geographical distribution maps of household waste burning and predictive health risk maps of waste burning in Khartoum State. Statistical tests performed for association carried out were Chi-square and ANOVA. A binary regression analysis established the relationship between burning of household waste and its associated factors. All statistical tests were considered significant when p < 0.05.

Results

The practice of burning household waste was performed by 74.5% (619/831) of the participants with 50.8% (311/612) who reported burning the waste weekly. The health conditions related to household waste burning were predominately asthma (57.0%) and respiratory manifestations (38.0%). Of the ten contributing factors of health risks related to burning household waste, the two statistically significant were the frequency of waste collection (OR = 0.720, 95% [CI: 0.593-0.875], p = 0.001) and the place of waste disposal (OR = 0.791, 95% [CI: 0.651-0.961], p = 0.018).

Conclusion

The practice of burning household waste in Khartoum State was a public health concern. Sociodemographic and managerial factors exposing residents to health risks appeal political, health authorities and communities to establish a partnership to manage household waste for public safety and good quality of life.

Responsibility disengagement or sharing? Cooperative fulfilling mechanism of solid waste management in the remanufacturing supply chain

Due to limited resources and meager profits, collectors have insufficient motivation to fulfill their responsibilities, resulting in severe secondary pollution in the recycling process. Therefore, it is necessary to focus on the interests of collectors to motivate them to fulfill their solid waste management (SWM) responsibilities better. This paper focuses on remanufacturers' altruistic behavior in the context of collectors' compliance. Based on the Stackelberg game method, this paper constructs decision-making models for remanufacturers concerned or not concerned about the interests of collectors and compares the optimal decision-making outcomes of each model. The study finds that (1) based on remanufacturers' altruistic concerns, a coordination mechanism for sharing responsibility-fulfilling costs for collectors can motivate them to fulfill their responsibilities and improve the performance of the remanufacturing supply chain. (2) The proportion of the remanufacturer's share of the responsibility cost for the collector should not be too low, which is not conducive to encouraging the collector to fulfill the responsibility. However, the sharing proportion should not be too high, as this will increase the burden on the remanufacturer. This paper demonstrates the applicability of remanufacturers to moderately share responsibility costs for collectors to incentivize collectors to fulfill their responsibilities. The findings bridge the gap in research on SWM in remanufacturing supply chains. The management insights from this paper are expected to help remanufacturing supply chain companies establish a reuse behavior model that addresses the challenges that SWM faces to improve remanufacturing supply chain performance.

The swelling performance of raw and modified bentonite of geosynthetic clay liner as the leachate barrier exposed to the synthetic E-waste leachate

Heavy metals are prevalent in electrical and electronic waste. The sealing of this type of waste disposal site is critical due to the existence of toxic materials. In this regard, Geosynthetic Clay Liners (GCLs) are widely used as one of the most common engineered barriers at disposal sites. Recently, attention has been drawn to modifying the bentonite of GCL with polymers to improve barrier performance against leachate. The aim of this study was to evaluate the swelling performance of the raw and modified GCL with a hydrophilic anionic polymer called CarboxyMethyl Cellulose (CMC) with weight percentages of 8, 10, and 12 of dried bentonite against synthetic heavy metals' leachate, containing copper and zinc, simultaneously and separately, based on ASTM D5890. It was found that adding this polymer could improve the swelling rate of the GCLs. The optimum CMC rate for modified GCLs exposed to the cationic solutions, including copper and zinc, was estimated at 10%. It could also be noted that the swell index of both natural and modified bentonites against solutions, including two cations of copper and zinc, simultaneously, was more sensitive to the changes in zinc ion concentration versus copper metal concentration.

Olive-tree polyphenols and urban mining. A greener alternative for the recovery of valuable metals from scrap printed circuit boards

Recycling printed circuit boards (PCBs) is becoming a source of precious metals and an alternative to conventional mining. This phenomenon is now known as "urban mining." In this work, a polyphenols-rich plant extract has been obtained from olive-tree leaves, and its ability to contribute to reducing four metals, namely, Ag, Cu, Cr, and Sn, that are present in scrap PCBs has been studied. Three reductants (NaBH₄, Fe°, and the olive-tree leaves extract) have been used to recover these valuable metals. An attempt has been made to minimize the concentration of the first two, replacing them with a natural, cheaper, and less toxic reductant. To achieve this goal, a computer-assisted factorial, composed, centered, orthogonal, and rotatable statistical design of experiments (FCCORD) has been used to build the experimental matrix to be carried out in the laboratory and, next, for the statistical treatment of the results. The results show that it is possible to achieve only a partial recovery of the four metals (silver, copper, chromium, and tin) from PCBs leachates by using sodium borohydride, iron, and the extract separately. In other words, none of these three reductants alone can completely remove any of the four metals in the leachate. Nevertheless, using the statistical design of experiments, the total recovery of the four metals has been achieved by combining the three reductants in the appropriate concentrations. Hence, polyphenols-rich plant extracts in general and olive-tree leaves extract in particular can be regarded as promising coadjuvants in the rising field of urban mining.

Novel insights into probabilistic health risk and source apportionment based on bioaccessible potentially toxic elements around an abandoned e-waste dismantling site

The study of potentially toxic element (PTE) hazards around e-waste recycling areas has attracted increasing attention but does not consider elemental bioaccessibility. Here, the respiratory and oral bioaccessibilities were incorporated into probabilistic health risk evaluation and source contribution apportionment. The results showed that soil Cd yielded the highest respiratory and oral bioaccessibility, whereas Cr in soils and vegetables attained the lowest oral bioaccessibility. When incorporating metal bioaccessibility into health risk assessment, a 48.3%-55.7% overestimation of non-cancer and cancer risks can be avoided relative to the risk assessment based on the total concentrations of PTEs. More importantly, priority control metals were misidentified without consideration of bioaccessibility. Cadmium, As, and Cr were screened as the priority metal(loid)s for targeted risk control based on the total PTEs, whereas Cd, Zn, and Cu were the priority metal(loid)s based on the bioaccessible PTEs. Furthermore, source apportionment revealed that >50% of oral bioaccessible Cd, Cu, Ni, Pb, and Zn in farmland were contributed by e-waste dismantling activities, whereas bioaccessible As and Cr mainly originated from agrochemical applications and natural sources, respectively. This study emphasizes the refinement of risk estimation and source apportionment through metal bioaccessibility adjustment, which facilitates the realistic assessment of adverse health effects in humans and the precise identification of high-risk sources.

An overview study on management and implementation of WEEE in China

Waste electrical and electronic equipment (WEEE) which contains various valuable and harmful materials is an inevitable waste in modern society. In order to resolve the pollution problems associated with WEEE treatment, a WEEE management system has been established in China. The main role of importers and manufacturers of electrical and electronic equipment (EEE) is to pay the treatment fees to facilitate the WEEE recycling in China. The announced treatment and subsidy fee is given by set, not by the weight of WEEE. There is no lesser green treatment fee for the producers which can produce environmentally friendly EEE in China. Also, the recovery of refrigerants from the foaming agent of refrigerators is not required in China. In total, 45 million sets of recycled WEEE were certified in 2020, a year that contains the most updated data. Among them, 48%, 14%, 20%, 10% and 8% are for TV, refrigerator, washing machine, computer and air conditioners, respectively. The spatial analysis indicates that the WEEE recycling activities are mainly concentrated on the mid-east and east regions of China. It also can be concluded that the certified amount of each province has higher positive correlation with provincial population than provincial GDP per capita and green recovery rate. It also clearly notes that the amount of recycled air conditioner is the lowest for each province. Thus, more effort should be conducted to increase the recycling of scrapped air conditioner in China.

Digital environment: An evolutionary component in environmental health

The COVID-19 pandemic has hastened the progress of digitalization where the public is forced to embrace paradigm shifts on how we function in a digital society. The way we work, learn, live, and play daily has drastically changed with the revolution of digital systems from their analog predecessor. This transformation warrants the digital environment as a social determinant of health. It comprises the whole continuum from the tangible aspects of the computing devices, their programing and information system, the network technologies connecting them, and the product of interactivity between people to people and people to the digital interface. Despite permeating the everyday life of each level of society, the digital environment has yet to be scrutinized comprehensively in terms of health. A review of the literature produces fragmented results where different specialties within and beyond the medical field lay claim to the various aspects of digitalization. We proposed five domains within the digital environment namely digital transformation, digital health, digital technology, digital identity, and digital media that exerts diversified pressure on the digital environment through human activities. Their subjacent linkage to human health and environmental impact is further discussed by using the DPSEEA framework. Challenges that crossed all domains were discussed including the widening gap of inequalities secondary to the limited availability of, and accessibility to digitalization. Considering the rapid speed at which we propel to a fully immersive virtual world, a timely transformation of environmental health to include the digital environment as part of its main components is inevitable.

Effects of Artificial Sweat Formulation and Extraction Temperature on Estimation of the Dermal Bioaccessibility of Potentially Toxic Elements in a Contaminated Soil from an E-Waste Recycling Site

Informal recycling of electronic waste leads to soil contamination that can impact human health. To accurately assess exposure to potentially toxic elements (PTE) in soil it is necessary to consider their bioavailability through ingestion, inhalation and dermal contact. However, bioaccessibility tests that estimate dermal absorption following adhesion of contaminated soil particles to skin are not well established. In this study the concentrations of As, Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn were estimated in the <45 µm particle size fraction of a bulk composite soil from an e-waste recycling site using five different artificial sweat formulations. Extractions were performed at temperatures ranging from 17 to 47 °C to investigate the effect of ambient temperature on bioaccessibility. Results obtained using the different artificial sweats were not consistent with one another. In particular, the NIHS 96-10 formulation solubilized larger amounts of analytes (ranging from 6.3 times the next most effective extractant for Cu to 1700 times the next most effective for Pb). There was a general increase in release of PTE with increasing temperature, except for As. Although trends varied between analytes and formulations, this highlights the need to consider ambient temperature when estimating dermal bioaccessibility of PTE in soil.

Mobility, spatial variation and human health risk assessment of mercury in soil from an informal e-waste recycling site, Lagos, Nigeria

Spatial variations and mobility of mercury (Hg) and Hg associations with other potentially toxic elements (PTEs) were studied in soil samples from Alaba, the largest e-waste recycling site in Nigeria and West Africa. Total Hg concentration was determined in surface soil samples from various locations using cold vapour atomic absorption spectrometry (CVAAS) following microwave-assisted acid extraction, while sequential extraction was used to determine operationally defined mobility. The concentrations of the PTEs arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), manganese (Mn), mercury (Hg), nickel (Ni), lead (Pb) and zinc (Zn) metals were determined using inductively coupled plasma mass spectrometry (ICP-MS) following microwave-assisted digestion with aqua regia. Total Hg concentration ranged from < 0.07 to 624 mg/kg and was largely dependent on the nature and intensity of e-waste recycling activities carried out. Mobile forms of Hg, which may be HgO (a known component of some forms of e-waste), accounted for between 3.2 and 23% of the total Hg concentration, and were observed to decrease with increasing organic matter (OM). Non-mobile forms accounted for >74% of the total Hg content. In the main recycling area, soil concentrations of Cd, Cd, Cu, Hg, Mn, Ni, Pb and Zn were above soil guideline values (Environment Agency in Science Report, 2009; Kamunda et al., 2016). Strong associations were observed between Hg and other PTEs (except for Fe and Zn) with the correlational coefficient ranging from 0.731 with Cr to 0.990 with As in April, but these correlations decreased in June except for Fe. Hazard quotient values > 1 at two locations suggest that Hg may pose health threats to people working at the e-waste recycling site. It is therefore recommended that workers should be investigated for symptoms of Hg exposure.

A cost-benefit analysis of the downstream impacts of e-waste recycling in Pakistan

This paper presents downstream cost-benefit analysis for electronic waste (e-waste) recycling workers in Pakistan, a country that both generates large quantities of e-waste domestically and imports a significant amount from developed countries. Financial cost-benefit elements - reduction in productive capacity, lost wages, medical expenses, wages (and meals) and non-financial cost-benefit elements - opportunity cost, cost of illiteracy and value of life have been quantified. Primary data collected on site was analyzed using quantitative and qualitative methods. The estimated total net economic cost to recycling workers is between Rs.34,069 and Rs.85,478 (US$ 203-510¹) per month or an average of Rs.50,363 (US$ 300) per worker. This main finding suggests that cost exceeds by 2.6-4.7 times the estimated economic benefits derived by these workers. Related qualitative data suggests government and owners of recycling businesses are largely blind to many of the less visible costs of this industry, while recycling workers and their families appear trapped in a vicious cycle of poverty. Understanding that what can be measured can be managed and improved, a systematic assessment of informal recycling based on identified impact factors may help mitigate and ideally also motivate a shift towards formal processing that would reduce the downstream negative impacts, both visible and hidden.

Global occurrence, chemical properties, and ecological impacts of e-wastes (IUPAC Technical Report)

The waste stream of obsolete electronic equipment grows exponentially, creating a worldwide pollution and resource problem. Electrical and electronic waste (e-waste) comprises a heterogeneous mix of glass, plastics (including flame retardants and other additives), metals (including rare Earth elements), and metalloids. The e-waste issue is complex and multi-faceted. In examining the different aspects of e-waste, informal recycling in developing countries has been identified as a primary concern, due to widespread illegal shipments; weak environmental, as well as health and safety, regulations; lack of technology; and inadequate waste treatment structure. For example, Nigeria, Ghana, India, Pakistan, and China have all been identified as hotspots for the disposal of e-waste. This article presents a critical examination on the chemical nature of e-waste and the resulting environmental impacts on, for example, microbial biodiversity, flora, and fauna in e-waste recycling sites around the world. It highlights the different types of risk assessment approaches required when evaluating the ecological impact of e-waste. Additionally, it presents examples of chemistry playing a role in potential solutions. The information presented here will be informative to relevant stakeholders seeking to devise integrated management strategies to tackle this global environmental concern.

Free, open, quantitative and adaptable digital soil map data and database for Nigeria

Nigeria's digital soil map (DSM) and database is the most comprehensive and detailed source of quantitative information on the country's soil distribution. Digital cartography and geographic information system (GIS) operations were methods used in producing the DSM and database. We obtained analogue soil data in 8 hard copy maps (each at a displayable scale of 1: 650,000) from the Federal Department of Agricultural Land Resources (FDALR), which archived the result of Nigeria's reconnaissance soil survey. The survey started in 1985 and by 1990; it has completed the compilation of hard copy maps that outline Nigeria's major soil distribution. Our experimental design begins with electronic scanning of these paper maps. We set the scanning system to 500 dpi, creating high-resolution raster images, which were imported into ESRI ArcGIS software, for orthorectification by geo-referencing to WGS 1984 geographic coordinate system. We applied a spatial processing tool on the orthorectified images and created a geometrically-seamless mosaicked raster image for the soil data of the whole Nigeria. Using GIS on-screen digitization – with optimal snapping tolerance – we created vector polygons (spatial data) of soil components (mapping units). Finally, we coded the metadata (attributes) of Nigeria's soil distribution into Microsoft EXCEL spreadsheet, which we linked to the soil spatial data. The combined spatial and attribute soil data forms the soil database for Nigeria and provides, on-demand, vital soil information, such as thematic maps of soil characteristics. The department of Geoinformatics and surveying University of Nigeria, Enugu Campus (UNEC) is the major repository of Nigeria's DSM and database.

A comprehensive analysis of e-waste legislation worldwide

The improper disposal and informal processing of e-waste have raised serious concerns for the environment and human health worldwide. A variety of legislative frameworks have been implemented to regulate e-waste management and upcycling in order to prevent environmental pollution and adopt resource reuse. Current e-waste legislation in different countries mostly include restrictions on e-waste import/export, regulations for recycling specific categories of e-waste, and Extended Producer Responsibility (EPR). This article serves as a comprehensive commentary to weigh the advantages and drawbacks of the different e-waste legislation enforced around the world. Though each country's e-waste legislation is enframed to address the country-specific problems, the legislation is mostly not holistic, leading to different management issues. A variety of e-waste management issues prevalent in most countries (with e-waste specific legislation) have been listed and categorized for better understanding of the status quo. Further, the article proposes a generic e-waste management model catering to requirements of countries around the world. The implementation of such a model for Europe, China, India, Japan, South Korea, Taiwan, and Australia has been illustrated to show that the model can suit both developed and developing countries with contrasting e-waste management issues. The challenges that would arise in implementing an effective legislation and mechanisms for overcoming these challenges have also been discussed. To conclude, the role of governing bodies in tackling the future e-waste problems has been highlighted. In total, the article promotes scaling up the feasibility and efficacy of the implementation of e-waste policies across the globe in the coming years.

Impact of bonfires on soil properties in an urban park in Vilnius (Lithuania)

Lighting bonfires in urban parks is a widespread practice. However, few studies have examined their impact on soil properties. The aim of this study was to analyze the impact of bonfires on the soil properties of an urban park in Vilnius, Lithuania. The properties studied were soil water repellency (SWR), aggregate stability (AS), soil organic matter (SOM) content, total nitrogen (TN), inorganic carbon (IC), pH, electrical conductivity (EC), extractable calcium (Ca), magnesium (Mg), sodium (Na), potassium (K), aluminum (Al), manganese (Mn), iron (Fe), zinc (Zn), copper (Cu), boron (B), chromium (Cr), available phosphorus (P), silicon (Si) and sulfur (S). Soil ratios calculated were carbon/nitrogen ratio (C/N), Ca + Mg/(Na + K)^1/2 (SPAR), Ca:Al and Ca:Mg. Three areas were studied: Site 1) Pinus sylvestris L. and Quercus robur L.; Site 2) Aesculus glabra Wild.; and Site 3) Pinus sylvestris L. and Acer plantanoides L. At each site, 20 samples were collected (10 within the bonfire area, 10 from a control area). The results showed significantly higher values of SOM, IC, pH, EC, Ca, Mg, Na, K, P, Al, Zn, Cu, Cr, S, C/N ratio, Ca:Al ratio and Ca:Mg ratio in bonfire soils than in control unburned soils. In bonfire soils, significantly lower values were recorded of SWR, AS, TN, SOM, Al, Mn, Fe, Cr, S and SPAR comparing to control soils. Most affected area by the bonfire was Site 1, which presented a marked increase in heavy metal content comparing to the control. The impact of soil heating was evident in AS, IC, pH, extractable Ca, Mg, Na, K, P, Al, Zn, Cu, Cr, S, and in its ratios. Protective measures are needed to limit bonfires and prohibit the burning of hazardous materials.

Soil elemental concentrations, geoaccumulation index, non-carcinogenic and carcinogenic risks in functional areas of an informal e-waste recycling area in Accra, Ghana

This study assesses the distribution, contamination and human health risks of major, minor and trace elements in the topsoil and subsoil of two informal e-waste recycling sites in Accra, Ghana. Metal concentrations in Agbogbloshie exceeded the Dutch Soil intervention values with exceedances of 72%, 57%, 57%, 38%, 16%, 2% for Cu, Zn, Pb, Ba, Cd and As respectively. Metal concentrations in Ashaiman exceeded the Dutch Soil intervention values with exceedances of 62%, 57% and 46% for Cu, Zn and Pb respectively. Geoaccumulation indices indicated that the topsoils of the burn area and dismantling areas of Agbogbloshie e-waste recycling site were strongly contaminated by Pb and uncontaminated by Cr, Fe, As and Ba. Lead (Pb) contributed greatly to non-carcinogenic ingestion hazard quotient for residents living near Agbogbloshie and Ashaiman e-waste recycling sites while arsenic (As) presented carcinogenic risks to children from the dismantling area topsoils. Non-carcinogenic risks from ingestion were significant with children being more susceptible to non-carcinogenic ingestion risks than adults. Non-carcinogenic risks from dermal exposure were negligible. Hazard quotients of Pb for children in burn area topsoils and dismantling area topsoils were 7.4-7.6-fold greater than that for adults. The mean geoaccumulation indices values of Pb and Cu indicated extreme contamination of topsoils with these elements. A "novel environmental assessment tool" based on the Agency for Toxic Substances and Disease Registry (ASTDR) total impact points confirmed Pb and Cu as the most toxic elements.

Health risk assessment of cadmium, chromium and nickel from car paint dust from used automobiles at auto-panel workshops in Nigeria

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Fairly used vehicular importation into Nigeria is reputed to be the highest in Africa.

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Most modern cars/vehicles are fitted with some electronic, electrical devices and mechanical components that contain heavy metals.

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Due to prevailing economic hardship and the fact that new vehicles are out of reach of average Nigerians, the vehicles are taken to the automobile workshops for total overhaul and refurbishing.

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Metal values of soil from all the workshops were higher than that of paint dust matrix, this can be attributed to the fact that as vehicles are repaired and taken away, more are brought into the workshops for repair.

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For cadmium and chromium, children are marginally at risk of cancer than adult through ingestion, while dermal contact does not pose any serious threat.

Nigeria’s economic problems which inhibited local production has resulted in massive importation of used automobiles. Most of these automobiles need some repairs and reworking, having outlived their lifespan in the manufacturer’s country. This study centers on the human carcinogenic and non-carcinogenic health risk assessment of cadmium, chromium and nickel exposures from reworking of imported used vehicles. Scraped car paint dusts from 56 Japanese made cars were collected from 8 different panel beating (body works) workshops (A–H) in Southeastern Nigeria. They were homogenized, mixed, divided into fine particles, filtered and digested by standard method. The filtrates were assayed for cadmium, chromium and nickel with atomic absorption spectrophotometry (AAS, 200A), workshops F and D have the highest concentration (mg/kg) of Cd (3.58 ± 0.02) and (3.36 ± 0.04) and higher than levels in workshops A, B, C, E, G and H. Chromium (mg/kg) in workshops F and G were (2.87 ± 0.04) and (2.95 ± 0.06) and higher than the other workshops. Nickel in workshop A (3.84 ± 0.04) is close to other workshop values. The highest hazard quotients for adults were cadmium in workshops B (1.37E-01), D (1.69E-01), E (1.79E-01) (inhalation), chromium [workshops G (5.45E-02), F (5.29E-02) and C (5.24E-02) inhalation]. Nickel -workshop A (5.9E-03) for children (inhalation). HQ in children through ingestion is cadmium (3.72E-04) workshop F and ingestion- 3.21E-01(workshop F) while nickel is 1.06E-02 (workshop A).The highest cancer risks were in exponents -4,-7 and -8 (adult) and -3, -6 and -9 (children) for workshops A–H through inhalation, ingestion and dermal contact, exposures to scrap car paint dust may be of significant public health importance in Nigeria as it can add to body burden of some carcinogenic heavy metals.

Magnetic field enhance decontamination efficiency of Noccaea caerulescens and reduce leaching of non-hyperaccumulated metals

Hyperaccumulators can accumulate high amounts of specific metals and have been widely used to remediate metal polluted soil. However, organic acid secretion and soil acidification (two important mechanisms for hyperaccumulators to mobilize and extract metals) can also activate non-hyperaccumulated metals and then increase the leaching risk. The decontamination efficiency and leaching risk of using Noccaea caerulescens (formerly Thlaspi caerulescens) and Thlaspi arvense were compared in the present study. Although N. caerulescens accumulated significantly more Cd and Zn than T. arvense, it increased the leaching risk of Pb and Cu as well. Under magnetic fields of 30, 60, 120 and 150 mT, the biomass production of N. caerulescens was increased by 18.5, 48.9, 80.4, and 29.3% respectively, but decreased by 21.7% under 400 mT. Comparing with the control, plants raised from seeds pre-treated by magnetic fields accumulated 37.8-250.1% more metals and reduced the leachate volume and leached metals by 1.1-32.9% and 4.6-48.1% respectively. Considering remediation efficiency, environmental risk alleviation and energy consumption, N. caerulescens treated by 120 mT magnetic field is suited to remediate multi-metal polluted soil.

Differential DNA methylation in newborns with maternal exposure to heavy metals from an e-waste recycling area

This study explored the effects of maternal exposure to e-waste environmental heavy metals on neonatal DNA methylation patterns. Neonatal umbilical cord blood (UCB) samples were collected from participants that resided in an e-waste recycling area, Guiyu and a nearby non-e-waste area, Haojiang in China. The concentrations of UCB lead (Pb), cadmium (Cd), manganese (Mn) and chromium (Cr) were measured by graphite furnace atomic absorption spectrometry. Epigenome-wide DNA methylation at 473, 844 CpG sites (CpGs) were assessed by Illumina 450 K BeadChip. The differential methylation of CpG sites from the microarray were further validated by bisulfite pyrosequencing. Bioinformatics analysis showed that 125 CpGs mapped to 79 genes were differential methylation in the e-waste exposed group with higher concentrations of heavy metals in neonatal UCB. These genes mainly involve in multiple biological processes including calcium ion binding, cell adhesion, embryonic morphogenesis, as well as in signaling pathways related to NFkB activation, adherens junction, TGF beta and apoptosis. Among them, BAI1 and CTNNA2 (involving in neuron differentiation and development) were further verified to be hyper- and hypo-methylated, respectively, which were associated with maternal Pb exposure. These results suggest that maternal exposure to e-waste environmental heavy metals (particularly lead) during pregnancy are associated with peripheral blood differential DNA methylation in newborns, specifically the genes involving in brain neuron development.

Health Risks of Polybrominated Diphenyl Ethers (PBDEs) and Metals at Informal Electronic Waste Recycling Sites

Concerns about the adverse public health consequences of informal electronic waste (e-waste) recycling are increasing. This study adopted a cross-sectional study design to gain insights into health risks (cancer and non-cancer risks) associated with exposure to e-waste chemicals among informal e-waste workers via three main routes: Dermal contact, ingestion, and inhalation. The e-waste chemicals (PBDE and metals) were measured in the dust and top soils at e-waste sites (burning, dismantling, and repair sites). Adverse health risks were calculated using the EPA model developed by the Environmental Protection Agency of the United States. The concentrations of the e-waste chemicals and the health risks at the e-waste sites increased as the intensity of the e-waste recycling activities increased: control sites < repair sites < dismantling sites < burning sites. Dermal contact was the main route of exposure while exposure via inhalation was negligible for both carcinogenic and non-carcinogenic risks. Cumulative health risks via all routes of exposure (inhalation, ingestion, and dermal contact) exceeded the acceptable limits of both non-cancer effects and cancer risk at all e-waste sites. This indicates that overall the e-waste workers are at the risk of adverse health effects. Therefore, the importance of occupational safety programs and management regulations for e-waste workers cannot be over emphasised.

Hydrophobic Organic Pollutants in Soils and Dusts at Electronic Waste Recycling Sites: Occurrence and Possible Impacts of Polybrominated Diphenyl Ethers

Concerns about the adverse consequences of informal electronic waste (e-waste) recycling is increasing, because e-waste contains some hazardous substances such as polybrominated diphenyl ethers (PBDEs) which is used as flame retardants in electronics. There is dearth of information on the concentrations of PBDEs and the pattern of distribution at the various e-waste recycling sites in Nigeria. This study therefore measured the concentrations of 13 PBDE congeners, in top soils (0–10 cm) and in various dust samples from different e-waste recycling sites (burning, dismantling, repair). PBDE concentrations at e-waste sites were compared with the concentrations in samples from corresponding control sites in three study locations in Nigeria (Lagos, Ibadan, and Aba). There were significant differences in the level of PBDEs congeners between each of the e-waste recycling sites and the corresponding control sites. The levels of PBDEs at the e-waste recycling sites exceeded the levels at the controls sites by a factor of 100 s to 1000 s. In general, PBDE concentrations at the e-waste sites decreased with the intensity of the e-waste recycling activities: burning sites > dismantling sites > repair sites > control sites. Our results suggest that the informal e-waste recycling has negative impacts on the enviroment and human health.