Biomonitoring of Metals, Polybrominated Diphenyl Ethers, Polychlorinated Biphenyls, and Persistent Pesticides in Vietnamese Female Electronic Waste Recyclers

Urinary metals and their associations with DNA oxidative damage among e-waste recycling workers in Hong Kong

Recycling electronic waste (e-waste) poses risks of metal exposure, potentially leading to health impairments. However, no previous study has focused on this issue in Hong Kong. Therefore, from June 2021 to September 2022, this study collected urine samples from 101 e-waste workers and 100 office workers in Hong Kong to compare their urinary levels of metals using ICP-MS. Among the 15 included metals (with detection rates above the 70 % threshold), eight showed significantly higher urinary concentrations (unit: μg/g creatinine) in e-waste workers compared to office workers: Li (25.09 vs. 33.36), Mn (1.78 vs. 4.15), Ni (2.10 vs. 2.77), Cu (5.81 vs. 9.23), Zn (404.35 vs. 431.52), Sr (151.33 vs. 186.26), Tl (0.35 vs. 0.43), and Pb (0.69 vs. 1.16). E-waste workers in Hong Kong generally exhibited lower metal levels than those in developing regions but higher than their counterparts in developed areas. The urine level of 8-hydroxy-2-deoxyguanosine (8-OHdG) was determined by HPLC-MS/MS, and no significant difference was found between the two groups. Multiple linear regression models revealed no significant association between individual metal and urinary 8-OHdG concentrations. However, the metal mixture was identified to marginally elevate the 8-OHdG concentrations (1.12, 95 %CI: 0.04, 2.19) by quantile g‑computation models, with Mn and Cd playing significant roles in such effect. In conclusion, while the metal levels among Hong Kong e-waste workers compared favorably with their counterparts in other regions, their levels were higher than those of local office workers. This underscores the need for policymakers to prioritize attention to this unique industry.

E-waste in Vietnam: a narrative review of environmental contaminants and potential health risks

Informal electronic waste (e-waste) dismantling activities contribute to releasing hazardous compounds in the environment and potential exposure to humans and their health. These hazardous compounds include persistent organic pollutants (POPs), polycyclic aromatic hydrocarbons (PAHs) and heavy metals. This review searched papers addressing hazardous compounds emitted from e-waste recycling activities and their health effects in Vietnam. Based on the keywords searched in three electronic databases (PubMed, Psych Info, and Google scholar), we found 21 relevant studies in Vietnam. The review identifies extensive e-waste dismantling activities in Vietnam in the northern region. To measure the environmental exposure to hazardous compounds, samples such as e-waste recycling workshop dust, soil, air, and sediments were assessed, while human exposure levels were measured using participants' hair, serum, or breast milk samples. Studies that compared levels of exposure in e-waste recycling sites and reference sites indicated higher levels of PBDEs, PCBs, and heavy metals were observed in both environmental and human samples from participants in e-waste recycling sites. Among environmental samples, hazardous chemicals were the most detected in dust from e-waste recycling sites. Considering both environmental and human samples, the highest exposure difference observed with PBDE ranged from 2-48-fold higher in e-waste processing sites than in the reference sites. PCBs showed nearly 3-fold higher levels in e-waste processing sites than in reference sites. In the e-waste processing sites, age-specific higher PCB levels were observed in older recycler's serum samples. Among the heavy metals, Pb was highly detected in drinking water, indoor soil and human blood samples. While high detection of Ni in cooked rice, Mn in soil and diet, Zn in dust and As in urine were apparent. Exposure assessment from human biomonitoring showed participants, including children and mothers from the e-waste processing areas, had higher carcinogenic and non-carcinogenic risks than the reference sites. This review paper highlights the importance of further comprehensive studies on risk assessments of environmentally hazardous substances and their association with health outcomes at e-waste processing sites.

HBM4EU E-waste study: Assessing persistent organic pollutants in blood, silicone wristbands, and settled dust among E-waste recycling workers in Europe

E-waste recycling is an increasingly important activity that contributes to reducing the burden of end-of-life electronic and electrical apparatus and allows for the EU's transition to a circular economy. This study investigated the exposure levels of selected persistent organic pollutants (POPs) in workers from e-waste recycling facilities across Europe. The concentrations of seven polychlorinated biphenyls (PCBs) and eight polybrominated diphenyl ethers (PBDEs) congeners were measured by GC-MS. Workers were categorized into five groups based on the type of e-waste handled and two control groups. Generalized linear models were used to assess the determinants of exposure levels among workers. POPs levels were also assessed in dust and silicone wristbands (SWB) and compared with serum. Four PCB congeners (CB 118, 138, 153, and 180) were frequently detected in serum regardless of worker's category. With the exception of CB 118, all tested PCBs were significantly higher in workers compared to the control group. Controls working in the same company as occupationally exposed (Within control group), also displayed higher levels of serum CB 180 than non-industrial controls with no known exposures to these chemicals (Outwith controls) (p < 0.05). BDE 209 was the most prevalent POP in settled dust (16 μg/g) and SWB (220 ng/WB). Spearman correlation revealed moderate to strong positive correlations between SWB and dust. Increased age and the number of years smoked cigarettes were key determinants for workers exposure. Estimated daily intake through dust ingestion revealed that ΣPCB was higher for both the 50th (0.03 ng/kg bw/day) and 95th (0.09 ng/kg bw/day) percentile exposure scenarios compared to values reported for the general population. This study is one of the first to address the occupational exposure to PCBs and PBDEs in Europe among e-waste workers through biomonitoring combined with analysis of settled dust and SWB. Our findings suggest that e-waste workers may face elevated PCB exposure and that appropriate exposure assessments are needed to establish effective mitigation strategies.

Biomarkers of Organophosphate and Polybrominated Diphenyl Ether (PBDE) Flame Retardants of American Workers and Associations with Inhalation and Dermal Exposures

This study evaluated workers' exposures to flame retardants, including polybrominated diphenyl ethers (PBDEs), organophosphate esters (OPEs), and other brominated flame retardants (BFRs), in various industries. The study aimed to characterize OPE metabolite urinary concentrations and PBDE serum concentrations among workers from different industries, compare these concentrations between industries and the general population, and evaluate the likely route of exposure (dermal or inhalation). The results showed that workers from chemical manufacturing had significantly higher (p <0.05) urinary concentrations of OPE metabolites compared to other industries. Spray polyurethane foam workers had significantly higher (p <0.05) urinary concentrations of bis(1-chloro-2-propyl) phosphate (BCPP) compared to other industries. Electronic scrap workers had higher serum concentrations of certain PBDE congeners compared to the general population. Correlations were observed between hand wipe samples and air samples containing specific flame-retardant parent chemicals and urinary metabolite concentrations for some industries, suggesting both dermal absorption and inhalation as primary routes of exposure for OPEs. Overall, this study provides insights into occupational exposure to flame retardants in different industries and highlights the need for further research on emerging flame retardants and exposure reduction interventions.

Investigation of Urinary Metabolites of Organophosphate Esters in Hanoi, Vietnam: Assessment Exposure and Estimated Daily Intake

In recent years, organophosphate esters (OPEs) have become one of the most common additives in various consumer products worldwide, therefore the exposure and impact of OPEs on human health are drawing a lot of attention. In this study, three metabolites of OPEs including bis(1,3-dichloro-2-propyl) phosphate (BDCIPP), diphenyl phosphate (DPhP) and diethyl phosphate (DEP) were investigated in first-morning void urine samples taken from a population (age range: 3-76 years old) in Hanoi, Vietnam. The most dominant urinary OPE metabolite was DEP with the geometric mean of specific gravity adjust (SG-adjusted) concentration were 1960 ng mL-1 and detected frequency (DF) of 98%. Followed by DPhP (8.01 ng mL-1, DF: 100%) and BDCIPP (2.18 ng mL-1, DF: 51%). The results indicated that gender and age might have associations with the OPE metabolites variation in urine samples. The levels of OPE metabolites in urine samples from females were slightly higher than in males. An increase in age seems to have an association with a decrease in DPhP levels in urine. Exposure doses of parent OPEs were evaluated from the unadjusted urinary concentration of corresponding OPE metabolite. The estimated exposure doses of triethyl phosphate (TEP) (mean: 534,000 ng kg-1 d-1) were significantly higher than its corresponding reference dose, suggesting the high potential risk from the current exposure doses of TEP to human health. The results of this work provided the initial information on the occurrence of three OPE metabolites in urine from Hanoi, Vietnam and estimated exposure dose of corresponding parent OPEs.

The global distribution of epidemiological studies involving waste pickers: A systematic review

Waste pickers, who work with the collection of recyclable materials in search of a source of income, are subject to various risks and diseases that are very well researched. The aim of this systematic review was therefore to identify and analyze the results of epidemiological research on waste pickers over the last 20 years as well as to investigate the geographical distribution and quality of these studies. The studies were selected from the literature by creating search keys with representative keywords in different databases. This systematic review exceptionally includes research qualified according to the Strengthening the Reporting of Observational Studies in Epidemiology guidelines. In total, 61 epidemiological studies with waste pickers were found in 15 different countries, with the largest number of studies carried out in the American continent compared to the African and Asian, respectively. Regarding the quality, 91.80 % were classified as excellent and 8.20 % as good. Although the results show a significant number of epidemiological studies with waste pickers, demonstrating scientific evidence, that there is still a lack of research focusing on waste pickers in different work scenarios, from different health perspectives and in different parts of the world, and it is not possible to highlight the trends in health research for this profession.

Systematic Review and Meta-Analysis of Mercury Exposure among Populations and Environments in Contact with Electronic Waste

Electronic waste (e-waste) recycling releases mercury (Hg) into the environment, though to our knowledge Hg levels at such sites have yet to be examined on a worldwide basis. A systematic review of scientific studies was conducted to extract, analyze, and synthesize data on Hg levels in e-waste products, environments near recycling sites, and in people. Data were extracted from 78 studies from 20 countries, and these included Hg levels in 1103 electrical and electronic products, 2072 environmental samples (soil, air, plant, food, water, dust), and 2330 human biomarkers (blood, hair, urine). The average Hg level in products was 0.65 μg/g, with the highest levels found in lamps (578 μg/g). Average soil and sediment Hg levels (1.86 μg/g) at e-waste sites were at least eight times higher than at control sites. Average urinary Hg levels (0.93 μg/g creatinine) were approximately two-fold higher among e-waste workers versus control groups. Collectively, these findings demonstrate that e-waste recycling may lead to Hg contamination in environments and human populations in close proximity to processing sites. These findings contribute to a growing knowledge base of mercury exposure through diverse source-exposure pathways, and the work has potential policy implications in the context of the Minamata Convention.

Biomonitoring of Polybrominated Dioxins & Furans, Polychlorinated Dioxins & Furans, and Dioxin Like Polychlorinated Biphenyls in Vietnamese Female Electronic Waste Recyclers

OBJECTIVE

E-waste is rising globally. This is a follow up to our study reporting metals/polybrominated diphenyl ethers (PBDE's)/polychlorinated biphenyls (PCBs) in female e-waste recyclers. Here we report polybrominated, polychlorinated dioxins/furans, and dioxin-like polychlorinated biphenyls in these same workers.

METHODS

Female Vietnamese recyclers and non-recyclers recruited; blood samples collected. Polybrominated, polychlorinated dioxins/furans, and dioxin-like polychlorinated biphenyls levels compared in recyclers, non-recyclers, and National Health and Nutrition Examination Surveys (NHANES).

RESULTS

Recyclers >non-recyclers: 12378-PBDD, 2378-TBDF, 12378-PCDF, 123478-HxCDF, 123678-HxCDF, 1234678-HpCDF, PCB-126. Non-recyclers >NHANES: 123478-HxCDF, 123678-HxCDF, 234678- HxCDF, PCB-126, PCB-169. NHANES >non-recyclers: 12378-PCDD, 123478-HxCDD, 123678-HxCDD, 123789-HxCDD, 1234678-HpCDD, 123789-HxCDF, 1234678-HpCDF, 1234789-HpCDF, OCDF, PCB-81, PCB-114, PCB-156, PCB-157, PCB-167, PCB-189. Recyclers >NHANES: S: 2378-TeCDF, 12378-PCDF, 23478-PCDF, 123478-HxCDF, 123678- HxCDF, 234678-HxCDF, PCB-126. NHANES >recyclers: 12378-PCDD, 123478-HxCDD, 123678-HxCDD, 123789-HxCDD, 1234678-HpCDD, OCDD, 123789-HxCDF, 1234678-HpCDF, 1234789-HpCDF, OCDF, PCB- 81, PCB-114, PCB-156, PCB-157, PCB-189.

CONCLUSION

12378 PCDD, 2378-TCDD, PCB 126 makeup most total dioxin equivalences (TEQs) in AQ5 these workers, indicating increased exposure; remediation indicated.

Formal waste treatment facilities as a source of halogenated flame retardants and organophosphate esters to the environment: A critical review with particular focus on outdoor air and soil

Extensive use of halogenated flame retardants (HFRs) and organophosphate esters (OPEs) has generated great concern about their adverse effects on environmental and ecological safety and human health. As well as emissions during use of products containing such chemicals, there are mounting concerns over emissions when such products reach the waste stream. Here, we review the available data on contamination with HFRs and OPEs arising from formal waste treatment facilities (including but not limited to e-waste recycling, landfill, and incinerators). Evidence of the transfer of HFRs and OPEs from products to the environment shows that it occurs via mechanisms such as: volatilisation, abrasion, and leaching. Higher contaminant vapour pressure, increased temperature, and elevated concentrations of HFRs and OPEs in products contribute greatly to their emissions to air, with highest emission rates usually observed in the early stages of test chamber experiments. Abrasion of particles and fibres from products is ubiquitous and likely to contribute to elevated FR concentrations in soil. Leaching to aqueous media of brominated FRs (BFRs) is likely to be a second-order process, with elevated dissolved humic matter and temperature of leaching fluids likely to facilitate such emissions. However, leaching characteristics of OPEs are less well-understood and require further investigation. Data on the occurrence of HFRs and OPEs in outdoor air and soil in the vicinity of formal e-waste treatment facilities suggests such facilities exert a considerable impact. Waste dumpsites and landfills constitute a potential source of HFRs and OPEs to soil, and improper management of waste disposal might also contribute to HFR contamination in ambient air. Current evidence suggests minimal impact of waste incineration plants on BFR contamination in outdoor air and soil, but further investigation is required to confirm this.

Polybrominated diphenyl ethers in serum from residents living in a brominated flame retardant production area: Occurrence, influencing factors, and relationships with thyroid and liver function

Polybrominated diphenyl ethers (PBDEs) have been used as flame retardants (FRs) in China for decades, even after they were identified as persistent organic pollutants. In this study, serum samples were collected from 172 adults without occupational exposure who were residents of a well-known FR production region (Laizhou Bay, north China), and PBDE congeners were measured to assess their occurrence, congener profile and influencing factors in serum. Moreover, the relationships between serum concentrations of PBDEs and thyroid/liver function indicators were analyzed to evaluate whether human exposure to PBDEs would lead to thyroid/liver injury. All 8 PBDE congeners were detected at higher frequencies and serum concentrations than those found in general populations. The median levels of ∑PBDEs, BDE-209 and ∑_3-7PBDEs (sum of tri-to hepta-BDEs) were 64.5, 56.9 and 7.2 ng/g lw (lipid weight), respectively, which indicated that deca-BDE was the primarily produced PBDE in Laizhou Bay and that the lower brominated BDEs were still ubiquitous in the environment. Gender was a primary influencing factor for some BDE congeners in serum; their levels in female serum samples were significantly lower than those in male serum samples. Serum PBDE levels showed a downward trend with increased body mass index (BMI), which might reflect the increasing serum lipid contents. Serum levels of some BDE congeners were significantly positively correlated with certain thyroid hormones and antibodies, including free triiodothyronine (fT3), total triiodothyronine (tT3), total thyroxine (tT4) and thyroid peroxidase antibody (TPO-Ab). Levels of some congeners were significantly negatively correlated with some types of serum lipid, including cholesterol (CHOL), low density lipoprotein (LDL) and total triglyceride (TG). Other than serum lipids, only two liver function indicators, total protein (TP) and direct bilirubin (DBIL), were significantly correlated with certain BDE congeners (BDE-100 and BDE-154). Our results provide new evidence on the thyroid-disrupting and hepatotoxic effects of PBDEs.

Human exposure to halogenated and organophosphate flame retardants through informal e-waste handling activities - A critical review

Informal electrical and electronic waste (e-waste) handling activities constitute a potentially important source of halogenated (HFRs) and organophosphate flame retardants (OPFRs) to the environment and humans. In this review, two electronic databases (ScienceDirect and Web of Science Core Collection) were searched for papers that addressed this topic. A total of 82 relevant studies (including 72 studies selected from the two databases and 10 studies located from the references of the first 72 selected studies) were identified that reported on human external and internal exposure to HFRs and OPFRs arising as a result of informal e-waste handling activities. Compared to the general population, higher levels of external exposure (i.e., inhalation, ingestion, and dermal absorption) and internal exposure (i.e., blood serum, hair, breast milk, urine, and other human matrices) to HFRs and OPFRs were identified for e-waste recyclers and residents inhabiting e-waste dismantling and recycling zones, especially for younger adults and children. Food intake and dust ingestion were the dominant exposure pathways for the majority of brominated flame retardants (BFRs) and dechlorane plus (DP); while inhalation was identified as the most significant pathway of human exposure to OPFRs in informal e-waste sites. The majority of research to date has focused on China and thus future studies should be conducted in other regions such as Africa and South Asia. Other suggested foci of future research are: examination of exposure via dermal contact with e-waste, dietary exposure of local populations to OPFRs, confirmation of the existence of and cause(s) of the higher body burdens of females compared with males amongst populations impacted by informal e-waste handling, and characterisation of exposure of such populations to chlorinated paraffins.

Arsenic burden in e-waste recycling workers - A cross-sectional study at the Agbogbloshie e-waste recycling site, Ghana

The export of e-waste from industrialized to developing countries has led to the formation of a large-scale informal e-waste recycling sector in Accra, Ghana. During recycling processes, workers are exposed to several hazardous substances, such as heavy metals. As a common component of e-waste, inorganic arsenic can be released during e-waste recycling processes. The aim of this study was to assess the exposure to inorganic arsenic species in e-waste workers compared to a control group. N = 84 e-waste workers and n = 94 control subjects were included in this analysis. Inorganic arsenic species were determined in urine samples using HPLC-ICP-MS. E-waste workers showed higher median concentrations of As(III), As(V), MMA, DMA and the sum of inorganic arsenic in comparison to the control group. More than 80% of the e-waste workers exceeded the acceptable concentration (14 μg/L), which was significantly higher in comparison to the control group (70%). The tolerable concentration (40 μg/L) was exceeded in 17.2% of the participants, meaning a statistically relevant risk of developing cancer due to arsenic exposure throughout their (working) life. In conclusion, the exposure to inorganic arsenic is not only a problem of informal e-waste recycling, but a major public health concern that needs further investigation.

Human exposure to PBDEs in e-waste areas: A review

Polybrominated biphenyl ethers (PBDEs) are commonly added to electronic products for flame-retardation effects, and are attracting more and more attentions due to their potential toxicity, durability and bioaccumulation. This study conducts a sysmtematic review to understand the human exposure to PBDEs from e-waste recycling, especially exploring the exposure pathways and human burden of PBDEs as well as investigating the temporal trend of PBDEs exposure worldwide. The results show that the particular foods (contaminated fish, poultry, meat and breast milk) ingestion, indoor dust ingestion and indoor air inhalation may be key factors leading to human health risks of PBDEs exposure in e-waste recycling regions. Residents and some vulnerable groups (occupational workers and children) in e-waste recycling areas may face higher exposure levels and health risks. PBDE exposure is closely related to exposure level, exposure duration, e-waste recycling methods, and dietary customs. High levels of PBDEs are found in human tissues (breast milk, hair, blood (serum), placenta and other tissues) in e-waste areas, at far higher levels than in other areas. Existing data indicate that PBDE exposure levels do not present any apparent downward trend, and will possibly cause serious human diseases. More epidemiological studies are still needed to provide a solid basis for health risk assessment.

Polybrominated diphenyl ethers and decabromodiphenyl ethane in paired hair/serum and nail/serum from corresponding chemical manufacturing workers and their correlations to thyroid hormones, liver and kidney injury markers

We detected the polybrominated diphenyl ethers (PBDEs) or decabromodiphenyl ethane (DBDPE) in paired hair-serum and nail-serum samples collected from the corresponding chemical manufacturing workers. The levels of decabrominated diphenyl ether (BDE-209) or DBDPE in the serum, hair and nail samples were all significantly higher than those reported in other studies, and the "work place" (pretreatment or posttreatment workshop) was the primary influencing factor that affected the levels of specific BFRs in vivo. For BDE-209 workers, the BDE-209 in both the hair and nail samples were significantly and positively related to the BDE-209 in the serum, indicating that both hair and nails can be used as noninvasive biomatrices to reflect internal exposure to BDE-209. In DBDPE workers, hair rather than nails was more suitable for use as a noninvasive biomatrix to infer the DBDPE exposure level. A series of serum biomarkers reflecting thyroid hormones and liver and kidney injuries were tested to calculate the correlations between hair or nail BFR levels and the levels of the biomatrices. The BDE-209 in the hair samples was significantly and positively correlated with the total protein (TP), and the nail BDE-209 level was significantly and positively related to the total bilirubin (TBIL), indirect bilirubin (IDBIL) and uric acid (UA). The DBDPE in hair was significantly and positively correlated with the thyroid hormones free triiodothyronine (fT3) and total triiodothyronine (tT3) and kidney injury markers, including blood urea nitrogen (BUN), creatinine (CRE) and cystatin C (Cys-C). In addition, the nail DBDPE levels were significantly and positively correlated with the albumin/globulin (A/G), BUN, CRE and Cys-C but negatively correlated with the TP and globulin (GLO). Our findings provide preliminary evidence that hair and nails can be used as noninvasive biomatrices for assessing internal BFR exposure and health damage in occupational workers.

A Review of Biomarkers Used for Assessing Human Exposure to Metals from E-Waste

Electronic waste recycling presents workers and communities with a potential for exposures to dangerous chemicals, including metals. This review examines studies that report on blood, hair, and urine biomarkers of communities and workers exposed to metals from e-waste. Our results from the evaluation of 19 publications found that there are consistently elevated levels of lead found in occupationally and non-occupationally exposed populations, in both the formal and the informal e-waste recycling sectors. Various other metals were found to be elevated in different exposure groups assessed using various types of biomarkers, but with less consistency than found in lead. Antimony and cadmium generally showed higher concentrations in exposed groups compared to reference group(s). Mercury and arsenic did not show a trend among exposure groups due to the dietary and environmental considerations. Observed variations in trends amongst exposure groups within studies using multiple biomarkers highlights the need to carefully select appropriate biomarkers. Our study concludes that there is a need for more rigorous research that moves past cross-sectional study designs, involves more thoughtful and methodical selection of biomarkers, and a systematic reporting standard for exposure studies to ensure that results can be compared across studies.