E-waste Recycling Areas Research Articles

Investigating the spatial distribution of polychlorinated biphenyls in sediment in the Pearl River Delta, South China.

One hundred forty-three surface sediment (0-5 cm depth) samples were collected from locations representing industrialized areas, less-industrialized areas, and e-waste recycling areas in the Pearl River Delta (PRD). The spatial distribution of polychlorinated biphenyls (PCBs) and their potential adverse effects on aquatic organisms were investigated. The average PCB concentration in the less-industrialized areas (background) in the PRD was approximately 10 ng/g dry weight (dw), which was generally half that found in the industrialized areas (approximately 22 ng/g dw). Severe PCB contamination, with concentrations ranging from 1000 to 26500 ng/g dw, was found in pond sediments collected from e-waste recycling areas. It is very likely that such contamination would have had adverse effects on the aquatic biota there. PCBs in the e-waste recycling areas were dominated by penta- and hex-PCB congeners, which made them significantly different from those found in other regions, where tri- and tetra-PCB congeners were predominant. Higher abundances of less chlorinated congeners were seen in the less-industrialized areas compared to the industrialized areas. Differences in the transport abilities of different congeners, together with dechlorination of higher chlorinated congeners, is the most likely reasons for this.

Using Polychlorinated Naphthalene Concentrations in the Soil from a Southeast China E-Waste Recycling Area in a Novel Screening-Level Multipathway Human Cancer Risk Assessment.

Polychlorinated naphthalene (PCN) concentrations in the soil at an e-waste recycling area in Guiyu, China, were measured and the associated human cancer risk due to e-waste-related exposures was investigated. We quantified PCNs in the agricultural soil and used these concentrations with predictive equations to calculate theoretical concentrations in outdoor air. We then calculated theoretical concentrations in indoor air using an attenuation factor and in the local diet using previously published models for contaminant uptake in plants and fruits. Potential human cancer risks of PCNs were assessed for multiple exposure pathways, including soil ingestion, inhalation, dermal contact, and dietary ingestion. Our calculations indicated that local residents had a high cancer risk from exposure to PCNs and that the diet was the primary pathway of PCN exposure, followed by dermal contact as the secondary pathway. We next repeated the risk assessment using concentrations for other carcinogenic contaminants reported in the literature at the same site. We found that polychlorinated dibenzodioxins and dibenzofurans (PCDD/Fs) and PCNs caused the highest potential cancer risks to the residents, followed by polychlorinated biphenyls (PCBs). The relative importance of different exposure pathways depended on the physicochemical properties of specific chemicals.

Dioxins in breast milk of Chinese mothers: A survey 40 years after the e-waste recycling activities

In the past two decades, numerous studies on dioxin concentrations in breast milk have been conducted in China. However, information concerning dioxin concentrations in breast milk from women living in e-waste recycling sites remains limited. Thus, this study aimed to evaluate health risk owing dioxin intake in e-waste recycling areas in China. In 2015, 42 mothers were recruited from an e-waste recycling site, and the same number of mothers were recruited from a reference site. We collected 10-mL breast milk samples from each participant. Breast milk concentrations of polychlorinated dibenzo-p-dioxins (PCDDs)/polychlorinated dibenzofurans (PCDFs) were significantly higher in the exposed group than in the reference group. The total toxic equivalents (TEQ) of PCDDs/DFs were 9.68 pg/g lipid in the exposed group, a value two times higher than those in the reference group (4.18 pg/g lipid). The estimated daily intake (EDI) of PCDD/DFs was calculated to assess the risk of dioxins through breastfeeding. The infant EDI level was two times higher in the exposed group (54.21 pg TEQ/kg body wt/day) than in the reference group (23.41 pg TEQ/kg body wt/day). Our findings suggest that mothers and their breastfeeding infants living in an e-waste recycling site were exposed to higher dioxin concentrations than those living in a reference site.

Heavy metals in indoor dust: Spatial distribution, influencing factors, and potential health risks

Given the large proportion of time that people spend indoors, the potential health risks posed by heavy metals in the indoor environment deserve greater attention. A global-scale assessment of heavy metal contamination in indoor dust was conducted in this study based on >127 articles published between 1985 and 2019. The pollution levels, spatio-temporal variations, sources, bioaccessibilities, influencing factors, and health risks of heavy metals associated with indoor dust were analyzed. Children's blood lead levels (BLLs) were also estimated using the integrated exposure uptake biokinetic model. The results indicated that the median concentrations of Cu and Zn in 71.9% and 71.0% of the study sites surpassed the corresponding permissible limits, 100 and 300 mg/kg, respectively; thus, their control should be given priority. Heavy metal concentrations in indoor dust from different areas of the world varied greatly, which was closely associated with the type of local human activities, such as mining, melting, e-waste recycling and Pb-related industries. The bioaccessibilities of some key elements, e.g., Pb, Cd, Cu, and Zn, in household dust were high. The levels of heavy metals in indoor dust were mainly affected by a combination of outdoor and indoor sources and related critical factors, and future studies should focus on quantifying the contributions of different sources. Based on the health risk assessment, dust Pb exposure is a major health concern in e-waste recycling areas, which warrants greater attention. 49.8%, 36.8% and 14.4% of study sites showed BLLs exceeding 35 μg/L (threshold limit in Germany), 50 μg/L (threshold limit in the USA), or 100 μg/L (threshold limit in China), respectively. Finally, Pb exposure from indoor dust represents a major contributor to children's blood Pb poisoning in many developing countries. This study details the overall heavy metal contamination status of indoor dust and provides insights for policymakers with respect to pollution prevention measures.

Simultaneous Determination of Multiple Classes of Phenolic Compounds in Human Urine: Insight into Metabolic Biomarkers of Occupational Exposure to E-Waste

A new method using solid-phase extraction (SPE) and high-performance liquid chromatography coupled with triple quadrupole mass spectrometry (HPLC-MS/MS) was established for simultaneously analyzing 35 types of phenolic compounds in human urine samples, including 12 hydroxyl polycyclic aromatic hydrocarbons (OH-PAHs), 16 brominated phenols (BRPs), 5 hydroxyl polybrominated diphenyl ethers (OH-PBDEs), triclosan, and tetrabromobisphenol A (TBBPA). The presence of NH4Ac in mobile phase played a crucial role in achieving good separation of isomers in HPLC-MS/MS analysis. The efficient SPE condition was obtained at pH 2 with a mixture eluent of methanol and dichloromethane. The recoveries of all analytes were 64.5%–143%, 56.2%–135%, and 52.5%–123% for low-, medium-, and high-spiked levels in a urine matrix, respectively, with less than 20% of RSDs of four of repetitive measurements. Moreover, the method was successfully applied to screen the potential urinary biomarker for population exposure to multipollutants from e-waste recycling areas, and 3,4-diBRP, 2,4,5-triBRP, 2,3,4,6-tetraBRP, and 2′-OH-BDE-28 were first tentatively detected in human urine. Specifically, 3,4-diBRP, 2,3,4,6-tetraBRP and, 2′-OH-BDE-28 were only detected in urine samples from e-waste dismantling workers, which should be considered as the urinary biomarkers for occupational exposure. Finally, this developed method will support a more comprehensive health risk assessment for human exposure to multipollutants.

Methylsiloxanes and Their Brominated Products in One e-Waste Recycling Area in China: Emission, Environmental Distribution, and Elimination.

The present study investigated the sources and fates of methylsiloxanes and their brominated products in one e-waste recycling area of China. During thermal (30-1000 °C) recycling experiments for printed wiring boards (PWBs), besides volatile methylsiloxanes (D4, D5, and D6), their monobrominated products, that is, D3D(CH2Br), D4D(CH2Br), and D5D(CH2Br), were also found by quadrupole time-of-flight gas chromatography-mass spectrometry to have 2-3 orders of magnitude lower emissions (0.31-1.3 μg/g) than those (18.1-866 μg/g) of parent methylsiloxanes. Overall, the fastest emissions of methylsiloxanes and bromo-methylsiloxanes occurred at 300-400 and 400-500 °C, respectively, accounting for 35.3-51.0 and 39.4-82.1% of their total emission. In the e-waste recycling area, concentrations of D4-D6 were 1.1-75.0 μg/g dw [detection frequency (df) = 100%] in 31 dusts from PWB treatment workshops, while limits of detection (LOD) < 683 ng/g dw (df = 69-100%) in 48 surrounding soils were up to 3 orders of magnitudes higher than those in reference areas. Meanwhile, D3D(CH2Br)-D5D(CH2Br) were detected in both dusts (<LOD-1.2 μg/g dw, df = 48-52%) and soils (<LOD-70.3 ng/g dw, df = 23-77%) from the e-waste recycling area, but they were not present in reference samples. Simulating experiments showed that hydrolysis (9.07-378 d) and volatilization (8.55-1007 d) half-lives of monobrominated D4-D6 in soils were 1.6-5.0 times longer than those of their parent methylsiloxanes.

Human exposure levels of PAEs in an e-waste recycling area: Get insight into impacts of spatial variation and manipulation mode

Phthalic acid esters (PAEs) are one important category of additives in plastics, which are ubiquitous products of e-waste recycling areas, where PAEs are released to the environment intensively and higher exposure level is expected for the employees. This study investigated human exposure levels of PAEs in an e-waste recycling area (Ziya Circular Economy Park (ZCEP) in Tianjin, China) with intending to explore the impacts of residence spatial variation and dismantling manipulation mode. We collected 157 urine samples from three sites around ZCEP with different distances from the core dismantling site and urinary phthalate metabolites (mPAEs) concentrations were measured and were compared among these three sites. The exposure levels of PAEs exhibited spatial variation according to the distance from the core dismantling site, and urinary median ∑mPAEs concentrations (389 ng/mL) of the employees in ZCEP were significantly higher than those of residents in Ziya town (285 ng/mL) and the downtown of Jinghai district (207 ng/mL) (p < 0.05). Moreover, PAEs exposure levels were significantly affected by the manipulation modes in the e-waste recycling area and the urinary median ∑mPAEs concentrations in the employees of family workshops (401 ng/mL) were significantly higher than those in plants with centralized management (298 ng/mL). There were obvious differences on the urinary median mPAEs concentrations between subgroups based on age, BMI, and sex; however, no significant statistical associations were found between PAEs exposure levels and these socio-demographic indices (p > 0.05). Besides, there was no correlation between exposure levels of different PAEs and their physicochemical parameters like the logKow (p > 0.05).

Characterization and risk assessment of total suspended particles (TSP) and fine particles (PM2.5) in a rural transformational e-waste recycling region of Southern China.

In 2016, total suspended particles (TSP) and fine particles (PM2.5) were collected near four e-waste recycling parks in a region of Southern China. TSP and PM2.5 levels and composition around these industrial activities were determined and the potential risks for human health due to the exposure to toxic elements contained on fine particles (PM2.5) were evaluated. Levels of TSP and PM2.5 were lower with advanced recycling methods than with small recycling e-waste workshops operating in the sampling region. The main trace elements in particles were Cu, Pb, and Ti, the same as those detected before the transition to advanced dismantling methods in e-waste recycling. Significantly higher levels of Cu, Pb, Sn, Te, Tl and NH4+ in TSP and Cu and Te in PM2.5 were found in e-waste recycling areas than in BG site. Taking Cu as the indicative element emitted from e-waste recycling activities, significant high positive correlations between Cu and W, and Cu and Te were found. These elements are present and can be released from electrical and electronical components during e-waste recycling processes. Exposure to elements for the population living near these e-waste recycling parks means carcinogenic risks above the acceptable threshold (>10-5).

Impact of informal e-waste recycling on human health

Increasing e-waste has become a major problem for global environment and public health. In the process of dismantling and recycling of disordered electronic waste, heavy metals such as lead and brominated flame retardants and organic substances are released into environmental media such as air, soil, dust and water, which is harmful to the health of local residents. Taking an e-waste dismantling area in Guangdong Province as an example, this paper reviews exposure levels of heavy metals and organic matters in e-waste recycling areas in China, as well as the health effects of local residents. Previous studies have found that e-waste recycling activities led to serious environmental pollution and high exposure levels of heavy metals and organic matters in local residents, which has a certain impact on the physiological functions of various human systems. The establishment of a centralized dismantling zone can effectively reduce the load level of various pollutants.

Elevated lead levels from e-waste exposure are linked to sensory integration difficulties in preschool children

Exposure to lead is associated with adverse effects on neurodevelopment. However, studies of the effects of lead on sensory integration are few. The purpose of this research is to investigate the effect of lead exposure on child sensory integration by correlating the blood lead levels of children with sensory processing measures. A total of 574 children, from 3 to 6 years of age, 358 from an electronic waste (e-waste) recycling town named Guiyu, and 216 from Haojiang, a nearby town with no e-waste recycling activity, were recruited in this study. The median blood lead level in Guiyu children was 4.88 μg/dL, higher than the 3.47 μg/dL blood lead level in Haojiang children (P < 0.001). 47.2% of Guiyu children had blood lead levels exceeding 5 μg/dL. The median concentration of serum cortisol, an HPA-axis biomarker, in Guiyu children was significantly lower than in Haojiang, and was negatively correlated with blood lead levels. All subscale scores and the total score of the Sensory Processing Measure (Hong Kong Chinese version, SPM-HKC) in Guiyu children were higher than Haojiang children, indicating greater difficulties, especially for touch, body awareness, balance and motion, and total sensory systems. Sensory processing scores were positively correlated with blood lead, except for touch, which was negatively correlated with serum cortisol levels. Simultaneously, all subscale scores and the total SPM-HKC scores for children with high blood lead levels (blood lead > 5 μg/dL) were higher than those in the low blood lead level group (blood lead < 5 μg/dL), especially for hearing, touch, body awareness, balance and motion, and total sensory systems. Our findings suggest that lead exposure in e-waste recycling areas may result in a decrease in serum cortisol levels and an increase in child sensory integration difficulties. Cortisol may be involved in touch-related sensory integration difficulties.

Cardiovascular endothelial inflammation by chronic coexposure to lead (Pb) and polycyclic aromatic hydrocarbons from preschool children in an e-waste recycling area

Lead (Pb) and polycyclic aromatic hydrocarbon (PAH) exposure is positively associated with cardiovascular disease (CVD), and the possible potential mechanism may be caused by damage to the endothelium by modulation of inflammatory processes. No comprehensive research shows co-exposure of Pb and PAH on cardiovascular endothelial inflammation in electronic waste (e-waste) exposed populations. Given this, the aim of this study is to provide evidence for a relationship between Pb and PAH co-exposure and cardiovascular endothelial inflammation, in an e-waste-exposed population, to delineate the link between a potential mechanism for CVD and environmental exposure. We recruited 203 preschool children (3–7 years) were enrolled from Guiyu (e-waste-exposed group, n = 105) and Haojiang (reference group, n = 98). Blood Pb levels and urinary PAH metabolites were measured. Percentages of T cells, CD4+ T cells and CD8+ T cells, complete blood counts, endothelial inflammation biomarker (serum S100A8/A9), and other inflammatory biomarkers [serum interleukin (IL)-6, IL-12p70, gamma interferon-inducible protein 10 (IP-10)] levels were evaluated. Blood Pb, total urinary hydroxylated PAH (ΣOHPAH), total hydroxynaphthalene (ΣOHNap) and total hydroxyfluorene (ΣOHFlu) levels, S100A8/A9, IL-6, IL-12p70 and IP-10 concentrations, absolute counts of monocytes, neutrophils, and leukocytes, as well as CD4+ T cell percentages were significantly higher in exposed children. Elevated blood Pb, urinary 2-hydroxynaphthalene (2-OHNap) and ΣOHFlu levels were associated with higher levels of IL-6, IL-12p70, IP-10, CD4+ T cell percentages, neutrophil and monocyte counts. Mediator models indicated that neutrophils exert the significant mediation effect on the relationship between blood Pb levels and S100A8/A9. IL-6 exerts a significant mediation effect on the relationship between blood Pb levels and IP-10, as well as the relationship between urinary ΣOHFlu levels and IP-10. Our results indicate that children with elevated exposure levels of Pb and PAHs have exacerbated vascular endothelial inflammation, which may indicate future CVD risk in e-waste recycling areas.

Serum concentrations of bisphenol A and its alternatives in elderly population living around e-waste recycling facilities in China: Associations with fasting blood glucose

In the present study, concentrations of bisphenol A (BPA) and its six alternatives were quantified in serum samples collected from elder population living around an e-waste recycling facilities as well as an reference area in China. BPA, bisphenol AF (BPAF), and bisphenol F (BPF) were frequently detected (detection rates: > 65%) in serum samples collected from residents living near e-waste dismantling facilities, with geometric mean (GM) concentrations of 3.2, 0.0074, and 0.062 ng/mL, respectively. The detection frequencies of other four bisphenols (BPs) in serum samples were lower than 25%, regardless of the sampling areas. Significant difference (Mann−Whitney U−test, p < 0.05) was observed in the serum concentration of BPA, but not BPAF and BPF, between the e-waste recycling and reference areas. This finding indicated e-waste dismantling activities are correlated with human BPA exposure. Significant higher (p < 0.05) detection rates of donors who had abnormal fasting blood glucose (FBG) levels were found in e-waste recycling areas (45%) than those found in reference area. Our results suggested BPA and BPAF exposure might associated with abnormal FBG in participants living in e-waste sites. To our knowledge, this study is first determination of BPs in serum samples and assessment of health risk of elderly people from BPs exposure in e-waste dismantling area.

Occurrence of organophosphorus flame retardants and plasticizers in wild insects from a former e-waste recycling site in the Guangdong province, South China

Due to the fast growth of the electronic industry, a large quantity of electronic waste (e-waste) is generated worldwide and then often inappropriately dismantled and disposed of. In a pilot study, the occurrence of organophosphorus flame retardants and plasticizers (PFRs) was investigated for the first time in several wild insect species collected from a former e-waste recycling site in the Guangdong province, South China. TEHP was the most abundant PFR (average concentration of 5.8 ng/g ww), followed by TPHP (2.5 ng/g ww), TCIPP (2.2 ng/g ww), TCEP (0.8 ng/g ww), EHDPHP and TCP (both 0.1 ng/g ww). Dragonfly nymphs were the most contaminated insects, with total PFR concentrations of 68 ng/g ww, followed by moth adults (26 ng/g ww) and terrestrial stinkbug (17 ng/g ww). The different contamination patterns observed in the analyzed insects could be explained by their different habitats and feeding habits. This study shows that e-waste recycling areas can be an important local source of contamination with PFRs, mainly caused by inadequate recycling activities.

Chlorinated flame retardant Dechlorane Plus: environmental pollution in China

Dechlorane Plus (DP) is a chlorinated flame retardant that is currently in intensive use and has been detected extensively in the environment. In China, the temporal and spatial distribution of DP is characterized by sources of point emissions in the south and diffusion to the north and west, including to remote, high-elevation areas, which are characterized by different climatic conditions and topographies. Thus, relatively high and low concentrations of DP have been observed in areas without significant nearby pollution sources. High DP concentrations have been observed in South China because of the recycling of large amounts of electronic waste and the presence of a DP factory. DP in urban areas is not influenced by atmospheric transportation, whereas DP in rural areas originates from atmospheric transmission from specific sources, such as e-waste recycling areas, which vary seasonally. Furthermore, DP in Chinese forest soils has been observed to preferentially accumulate in the mineral horizon due to leaching by precipitation as well as erosion by weathering in the organic horizon. Although the hazard quotient (HQ) has been estimated to be far from 1 for DP manufacturing operators, the HQ might not reveal deleterious effects on humans. Extremely high DP concentrations have been observed in serum samples from DP manufacturing operators in China. Moreover, different isomer-specific accumulation in terrestrial species, except for aquatic biota, shows that syn-DP is preferentially accumulated. Finally, to achieve better understanding of the mechanisms of DP degradation both in nature and in organisms, further laboratory study is needed.

Elevated biomarkers of sympatho-adrenomedullary activity linked to e-waste air pollutant exposure in preschool children

Air pollution is a risk factor for cardiovascular disease (CVD), and cardiovascular regulatory changes in childhood contribute to the development and progression of cardiovascular events at older ages. The aim of the study was to investigate the effect of air pollutant exposure on the child sympatho-adrenomedullary (SAM) system, which plays a vital role in regulating and controlling the cardiovascular system. Two plasma biomarkers (plasma epinephrine and norepinephrine) of SAM activity and heart rate were measured in preschool children (n = 228) living in Guiyu, and native (n = 104) and non-native children (n = 91) living in a reference area (Haojiang) for >1 year. Air pollution data, over the 4-months before the health examination, was also collected. Environmental PM2.5, PM10, SO2, NO2 and CO, plasma norepinephrine and heart rate of the e-waste recycling area were significantly higher than for the non-e-waste recycling area. However, there was no difference in plasma norepinephrine and heart rate between native children living in the non-e-waste recycling area and non-native children living in the non-e-waste recycling area. PM2.5, PM10, SO2 and NO2 data, over the 30-day and the 4-month average of pollution before the health examination, showed a positive association with plasma norepinephrine level. PM2.5, PM10, SO2, NO2 and CO concentrations, over the 24 h of the day of the health examination, the 3 previous 24-hour periods before the health examination, and the 24 h after the health examination, were related to increase in heart rate. At the same time, plasma norepinephrine and heart rate on children in the high air pollution level group (≤50-m radius of family-run workshops) were higher than those in the low air pollution level group. Our results suggest that air pollution exposure in e-waste recycling areas could result in an increase in heart rate and plasma norepinephrine, implying e-waste air pollutant exposure impairs the SAM system in children.

PBDE emission from E-wastes during the pyrolytic process: Emission factor, compositional profile, size distribution, and gas-particle partitioning.

Polybrominated diphenyl ether (PBDE) pollution in E-waste recycling areas has garnered great concern by scientists, the government and the public. In the current study, two typical kinds of E-wastes (printed wiring boards and plastic casings of household or office appliances) were selected to investigate the emission behaviors of individual PBDEs during the pyrolysis process. Emission factors (EFs), compositional profile, particle size distribution and gas-particle partitioning of PBDEs were explored. The mean EF values of the total PBDEs were determined at 8.1 ± 4.6 μg/g and 10.4 ± 11.3 μg/g for printed wiring boards and plastic casings, respectively. Significantly positive correlations were observed between EFs and original addition contents of PBDEs. BDE209 was the most abundant in the E-waste materials, while lowly brominated and highly brominated components (excluding BDE209) were predominant in the exhaust fumes. The distribution of total PBDEs on different particle sizes was characterized by a concentration of finer particles with an aerodynamic diameter between 0.4 μm and 2.1 μm and followed by less than 0.4 μm. Similarly, the distribution of individual species was dominated by finer particles. Most of the freshly emitted PBDEs (via pyrolysis) were liable to exist in the particulate phase with respect to the gaseous phase, particularly for finer particles. In addition, a linear relationship between the partitioning coefficient (KP) and the subcooled liquid vapor pressure (PL0) of the different components indicated non-equilibrium gas-particle partitioning during the pyrolysis process and suggested that absorption by particulate organic carbon, rather than surface adsorption, governed gas-particle partitioning.

E-Waste Driven Pollution in Pakistan: The First Evidence of Environmental and Human Exposure to Flame Retardants (FRs) in Karachi City.

Informal e-waste recycling activities have been shown to be a major emitter of organic flame retardants (FRs), contributing to both environmental and human exposure to laborers at e-waste recycling sites in some West African countries, as well as in China and India. The main objective of this study was to determine the levels of selected organic FRs in both air and soil samples collected from areas with intensive informal e-waste recycling activities in Karachi, Pakistan. Dechlorane Plus (DP) and "novel" brominated flame retardants (NBFRs) were often detected in high concentrations in soils, while phosphorus-based FRs (OPFRs) dominated atmospheric samples. Among individual substances and substance groups, decabromodiphenyl ether (BDE-209) (726 ng/g), decabromodiphenyl ethane (DBDPE) (551 ng/g), 1,2-bis(2,4,6-tribromophenoxy) ethane (BTBPE) (362 ng/g), and triphenyl-phosphate (∑TPP) (296 ng/g) were found to be prevalent in soils, while OPFR congeners (5903-24986 ng/m3) were prevalent in air. The two major e-waste recycling areas (Shershah and Lyari) were highly contaminated with FRs, suggesting informal e-waste recycling activities as a major emission source of FRs in the environment in Karachi City. However, the hazards associated with exposure to PM2.5 appear to exceed those attributed to exposure to selected FRs via inhalation and soil ingestion.

E-waste: the problem persists after recycling

e-waste: the problem persists after recycling

Pollution Status and Human Exposure of Decabromodiphenyl Ether (BDE-209) in China.

Decabromodiphenyl ether (BDE-209/decaBDE) is a high-production-volume brominated flame retardant in China, where the decaBDE commercial mixture is manufactured in Laizhou Bay, Shandong Province, even after the prohibition of penta- and octaBDE mixtures. The demand for flame retardants produced in China has been increasing in recent years as China not only produces electronic devices but also has numerous electronic waste (e-waste) recycling regions, which receive e-wastes from both domestic and foreign sources. High concentrations of BDE-209 have been observed in biotic and abiotic media in each of the different areas, especially within the decaBDE manufacturers and e-waste recycling areas. BDE-209 has been viewed as toxic and bioaccumulative because it might debrominate to less brominated polybrominated diphenyl ethers (PBDEs) (lower molecular weight and hydrophobicity), which are more readily absorbed by organisms. The highest concentration of PBDEs in dust within urban areas reached 40 236 ng g–1 in the Pearl River Delta, and BDE-209 contributed the greatest proportion to the total PBDEs (95.1%). Moreover, the maximum hazard quotient was found for toddlers (0.703) for BDE-209, which was close to 1. This suggests that exposure to BDE-209 might lead to increased potential for adverse effects and organ harm (e.g., the lungs) through inhalation, dust ingestion, and dermal absorption, especially for the group of toddlers compared to others. In daily food and human tissues, the amount of BDE-209 was also extensively detected. However, the toxicity and adverse effect of BDE-209 to humans are still not clear; thus, further studies are required to better assess the toxicological effects and exposure scenarios, a more enhanced environmental policy for ecological risks regarding BDE-209 and its debrominated byproducts in China.

Comparison of soil heavy metal pollution caused by e-waste recycling activities and traditional industrial operations.

The traditional industrial operations are well recognized as an important source of heavy metal pollution, while that caused by the e-waste recycling activities, which have sprouted in some developing countries, is often overlooked. This study was carried out to compare the status of soil heavy metal pollution caused by the traditional industrial operations and the e-waste recycling activities in the Pearl River Delta, and assess whether greater attention should be paid to control the pollution arising from e-waste recycling activities. Both the total contents and the chemical fractionation of major heavy metals (As, Cr, Cd, Ni, Pb, Cu, and Zn) in 50 surface soil samples collected from the e-waste recycling areas and 20 soil samples from the traditional industrial zones were determined. The results show that the soils in the e-waste recycling areas were mainly polluted by Cu, Zn, As, and Cd, while Cu, Zn, As, Cd, and Pb were the major heavy metals in the soils from the traditional industrial zones. Statistical analyses consistently show that Cu, Cd, Pb, and Zn in the surface soils from both types of sites were contributed mostly by human activities, while As, Cr, and Ni in the soils were dominated by natural background. No clear distinction was found on the pollution characteristic of heavy metals in the surface soils between the e-waste recycling areas and traditional industrial zones. The potential ecological risk posed by heavy metals in the surface soils from both types of sites, which was dominated by that from Cd, ranged from low to moderate. Given the much shorter development history of e-waste recycling and its largely unregulated nature, significant efforts should be made to crack down on illegal e-waste recycling and strengthen pollution control for related activities.