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

Abstract

Objective:

E-waste is rising. 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 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, 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, PCB81, PCB-114, PCB-156, PCB-157, PCB-189.

Conclusion:

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

As electronics generation increases and the practice of planned obsolescence becomes more common worldwide, the amount of electronics recycled has increased considerably. Unfortunately, while electronic waste recycling has afforded developing countries more economic opportunity, it may have also exposed workers to toxic chemicals.¹ A 2016 report on the rise of global e-waste shows that in 2016 alone, 44.7 million metric tons of electronic waste was generated. This was an increase of 8% since 2014.²

Metals, plastics, and other components of electronic waste (e-waste) are frequently recycled in developing countries, which have diverse occupational safety guidelines and different levels of attention to sustainability. In addition, while it is legal to export reusable or refurbished electronics to these countries, many non-functioning electronics are falsely classified as “used goods” to avoid the high costs of legitimate recycling.³ Of all the e-waste initially sent for recycling by developed countries, it has been estimated that 80% ends up being shipped to developing countries.⁴ There is a large informal sector that collects and manually dismantles e-waste to improve recovery of valuable metals, but lacks the ability to do so in a safe manner. This has the potential to harm the local environment, workers, and residents.⁵ E-waste recyclers can be exposed to toxic chemicals, such as metals and persistent halogenated organic pollutants (POPs), if the electronics are processed without adequate occupational safety measures. Toxic byproducts can also be released due to unsafe recycling methods, including acid baths, open-air burning, and chemical exposure of workers who lack personal protective gear.^4,6 In many areas, industrial and/or occupational safety protocols are often not in place or followed. In addition, the recycling facilities in these developing countries are often home-based or located in agricultural areas where toxic remnants from burning e-waste can seep into living spaces and food.

Electronic waste contains toxic compounds such as POPs or metals. If heat is used during recycling, e-waste can also generate other toxicants including dioxin-like chemicals (polyhalogenated dibenzo-p-dioxins, furans, and biphenyls). These chemicals have the potential for multiple adverse health effects. Health implications for people living near e-waste recycling facilities or centers include cancers, respiratory disorders, congenital abnormalities, endocrine disorders, and nervous system pathology.⁷ Evidence of exposure to chemicals secondary to e-waste recycling has been found in biological samples such as blood, breast milk, and placenta in individuals living near recycling sites. Sediment or soil near e-waste recycling facilities has also shown evidence of contamination.⁷

Highly toxic polyhalogenated dibenzo-p-dioxins and dibenzofurans are by-products of incineration and uncontrolled burning.⁸ The chemicals from e-waste do not only affect recyclers, but also their families, neighbors, and the environment. Other contaminants may contain toxic metals such as arsenic, lead, and mercury, as well as POPs, including organochlorine pesticides (eg, DDT), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs). Much of general population exposure to these toxic chemicals can be linked to micro-contamination of the food and water supply.⁹ Cancer, reproductive disorders, immunodeficiency, and developmental delays in children are only some of the health effects linked to PCBs, dioxins, and furans.¹⁰

In Vietnam, e-waste recycling is frequently home-based and/ or near agricultural areas, which can lead to human and environmental contamination. Some Vietnamese are already at risk for environmental health issues due to exposure to chemicals such as arsenic in the drinking water and rice, mercury in fish, and 2,3,7,8tetrachlorodibenzo-p-dioxin (TCDD) from Agent Orange in Southern Vietnam¹¹ (although our Vietnamese volunteers live in Northern Vietnam). Toxic equivalency factors (TEF) from the World Health Organization 2005 were used to estimate the total dioxin toxic equivalence (TEQ) found in our subjects.¹² WHO 2005 dioxin TEFs and calculated TEQs were used. Brominated dioxins and furans were given the same TEFs as WHO chlorinated 2005 TEFs.¹³

Regulations in Vietnam related to e-waste recycling are limited, as there are no country wide standards that have been enforced by Vietnamese officials for home-based recycling operations. There are also no specific definitions as e-waste is listed under the hazardous waste index from Decision 23/2006/QD-BTNMT and identified as hazardous or non-hazardous by the National Technical Regulation 12/2006/QD-BTMNT.¹⁴ Waste import is prohibited under the Vietnamese Law on Environment Protection, but certain types of scrap materials (if used for industrial purposes) can be recycled in Vietnam.¹⁴ Additionally, there are increasing problems with electronic waste being illegally exported into Vietnam from other countries.¹⁵

These chemicals found in and around e-waste sites, especially those which are home based with little regard for chemical exposure, may leach into the water table and soil. This contaminates water, soil, and food sources such as fish, chicken, and pork. Because PBDD/Fs, PCDD/Fs, and dioxin-like PCBs persist and biomagnify up the food web, single source exposures for workers and others in or near e-waste sites have the potential to become multi-source exposures to those in the general population.

GOALS

Our previous publication reported the levels of PBDEs, PCBs, pesticides, and metals in these workers and non-recyclers.¹⁶ We reported that e-waste recyclers had significantly higher levels of PBDEs 47, 99, 100, 153, 154, 183, and 209, as well as elevated levels of PCBs 138/158 and 153 than non-recyclers. The lead levels in whole blood and urine were also higher in selected rural Vietnamese recyclers. Interestingly, methyl mercury was found to be higher in non-recyclers than recyclers. Arsenic was higher for both recyclers and non-recyclers in Vietnam than in the US general population.

Our goal for this publication is to present data on the exposure of dioxins, furans, and dioxin-like PCBs among the groups of selected rural Vietnamese female e-waste recyclers and non-recyclers and compare these findings to those observed in time-matched NHANES. In addition, the toxic equivalency levels were calculated to provide a better understanding of the potential for effects of these compounds in humans. This paper is also the first to look at polybrominated dioxins and furans in e-waste workers as well as non-recyclers. The results should contribute to a better understanding of the potential for health risks associated with e-waste recycling and support the need for legislation, regulations, protocols, or better enforcement of existing rules to reduce these environmental exposures.

The overall goals of this study are: (1) to present data on exposure of PBDD/Fs, PCDD/Fs, and dioxin like PCBs among rural Vietnamese female e-waste recyclers and non-recyclers; (2) to compare Vietnamese PBDD/F, PCDD/F, and dioxin-like PCB biomonitoring data to the well characterized US general population reported in the US National Health and Nutrition Examination Surveys (NHANES), as there is only limited information from Vietnam.^17–20

METHODS

This is a continuation of our previous study¹⁶ that took place in rural northern Vietnam in Hu’ng Ye?n Province, 45km southeast of Hanoi. The Ethics Board of the Hanoi School of Public Health and the Institutional Review Board (IRB) at the University of Texas Health Science Center Houston reviewed and approved the protocol for this study. Additionally, the Centers for Disease Control and Prevention (CDC) stated that as an agency, it was not involved in this research of human subjects.

Forty Vietnamese women who were home-based e-waste recyclers and had been recycling for at least 5 years were chosen from the B?i Dâu village/hamlet of the Mỹ Hào district. Twenty non-recyclers were recruited from a nearby commune, Cẩm Xá. To be included in this study, both recyclers and non-recyclers alike were required to self-report as “healthy.” Additionally, the non-recyclers could not have worked in e-waste recycling for the past 5 years. These are the same 60 women as those in our previously published study.¹⁶

Informed consent was obtained from all study participants prior to any questionnaires and sampling. Basic demographic information, such as birthdate, height, weight, and occupation were collected by the Vietnamese research staff and recorded on the questionnaire. All questionnaires were administered by native Vietnamese speakers; the questionnaires were in Vietnamese, and then translated by a Vietnamese partner into English. The CDC sent supplies, previously screened for chemical contamination and found to be acceptable, to Vietnam for collection of serum. After collection, specimens were frozen, maintained at −20 to −70°C and shipped on dry ice by express shipping service to the CDC in Atlanta, GA, USA. When received, CDC verified that all specimens were received frozen.

A few dioxin-like PCBs from our previous study, the mono-ortho PCBs, were also included in this paper as they have TEF values.¹² Dioxin toxic equivalency factors (TEFs) were used to calculate the total dioxin toxic equivalents (TEQs). The brominated dioxin or furan toxic equivalency factors used¹³ were the same as the TEFs for the chlorinated compounds. We measured blood levels of both chlorinated and brominated dioxins and dioxin-like compounds from female e-waste recyclers and non-recyclers. This data was compared with the levels in women from the US general population, using data from the NHANES to provide comparison. Our study is the first to compare dioxin TEQs between Vietnamese female recyclers and non-recycling women to a representative US female general population.

The following congeners were measured in both the recyclers and the non-recyclers: polybrominated dioxins (12378-PBDD; 12347-HxBDD/123678-HxBDD; 123789-HxBDD; 2378-TBDD); polybrominated furans (2378-TBDF; 12378-PBDF; 23478-PBDF; 123478-HxBDF); polychlorinated dioxins (2378-TCDD; 12378-PCDD; 123478-HxCDD; 123678-HxCDD; 123789-HxCDD; 1234678-HpCDD; OCDD); polychlorinated furans (2378-TCDF; 12378-PCDF; 23478-PCDF; 123478-HxCDF; 123678-HxCDF; 123789-HxCDF; 234678-HxCDF; 1234678-HpCDF; 1234789-HpCDF; OCDF); non-ortho-substituted polychlorinated biphenyls (PCB-77-, 81, 126, and 169; and mono-ortho-substituted PCBs (PCB-105, 114, 118, 123, 156, 1517, 167, and −189). Forty ortho-PCBs were reported in our earlier paper; here, only the non-ortho- and mono-ortho-substituted PCBs were examined, as they have dioxin-like toxicities.¹²

LABORATORY ANALYSIS

Chemists at the laboratory of the CDC’s National Center for Environmental Health (NCEH) used gas chromatography/isotope dilution high-resolution mass spectrometry (GC/ID-HRMS) to measure PBDDs, PBDFs, PCDDs, PCDFs, and the non-ortho substituted (coplanar polychlorinated biphenyls, cPCBs) in serum. Serum samples were spiked with ¹³C₁₂- labeled internal standards and the analytes of interest were isolated using C₁₈ solid phase extraction (SPE) followed by a multi-column automated cleanup and enrichment procedure using a Fluid Management System (Watertown, MA) Power-Prep/6. The analytes were chromatographed on a DB-5ms capillary column(30m × 0.25mm × 0.25mm film thickness) using a Thermo Scientific TRACE 1310 gas chromatograph and measured using a Thermo Scientific (Bremen, Germany) DFS mass spectrometer operated in electron impact (EI) mode using selected ion monitoring (SIM) at 10,000 resolving power. Analytes were quantified by ID-HRMS and the concentration of each analyte was calculated from an individual linear calibration curve. Each analytical run was blinded to the analyst and consisted of eight unknown serum samples, two method blanks, and two quality control samples. All data were reviewed using comprehensive quality assurance and quality control (QA/QC) procedures. The analytical results were reported on both a whole-weight and lipid-adjusted basis mass concentration. Serum total lipids were determined using an enzymatic “summation” method.²² The WHOTEFs^12,13 were used to calculate the TEQ’s for each individual congener. Detection limits, on a whole weight and lipid adjusted basis, were reported for each analyte and corrected for sample weight and lipid concentration.^12,22–26

The same method for the brominated dioxins and furans was used as for the chlorinated compounds, monitoring for different masses using different GC settings (personal communication, Andrea Sjödin).^27,28

Statistical Analysis

Data analysis was performed using SPSS, v. 25.0 (IBM Corp, Armonk, NY). Any data that was transcribed by hand for statistical analysis was checked by at least three team members. All concentrations with less than the limit of detection (LOD) were substituted with LOD divided by the square root of two during statistical analysis. The LOD varies per sample depending on the amount of analyte and the total amount of serum. Missing factors were dealt with via listwise deletion. Statistical significance between e-waste recyclers and none-waste recyclers was assessed with the geometric means test using the SPSS procedure for the Wilcoxon Rank-Sum test (nonparametric test/2 independent samples/Mann–Whitney U test type), with the exact p-option enabled because of the number of subjects in this occupational study (40 e-waste recyclers and 20 non-recyclers). Geometric means for NHANES were determined by first downloading raw SAS data from NHANES 2007–2008 DOXPOL_E.XPT and uploading it into SPSS, then following the same procedure for determining geometric means as with the Vietnamese population, taking into consideration group stratification of NHANES data in order to only include women. We did not do this for PBDD/Fs because NHANES does not include these congeners. Statistical significance between the groups were assessed by finding the geometric mean and 95% confidence interval (CI) and comparing for overlap. Calculations were not performed for any analyte with less than 60% detectionrates, other than the polybrominated compounds. This cutoff was chosen to assure the data would be based on clearly detectable results. The choice to use LOD/√2 and the cutoff of 60% detection rates were the same as used by NHANES. We calculated total TEQ with the following formula: TEQ=sum of TEF × concentration of each congener.¹²

RESULTS

There were no significant differences in mean age, weight, and body mass index (BMI) between the e-waste workers and non-recyclers. All e-waste recyclers reported “farmer” and “e-waste recycler” as their primary occupation, whereas the non-recycler group included occupations of farmer, tailor, mason, nurse, student, and accountant (see Table 1). Arithmetic means for continuous demographic variables in Table 1 are nonsignificant by two sample t tests, supporting our use of a nearby village as a control.

TABLE 1.

Demographics

Demographic	Recyclers (n = 40)	Non-recyclers (n = 20)
Average age (mean and range)	37.3 (19–50)	36.4 (18–52)
Sex	100% female	100% female
Smoking status	100% non-smoker	100% non-smoker
Average weight (mean and range)	50.9 kg (40–72 kg)	51.5 kg (44–70 kg)
Height (mean and range)	1.56 m (1.45–1.65m)	1.57 m (1.5–1.64m)
BMI (mean and range)	21.0 (16.6–30.4)	20.8 (17.9–27.3)
Occupations	Farmer/E-waste recycler	Farmer, tailor, mason, nurse, student, accountant
Stated years recycling (mean and range)	5.5 (1 –20)	None for the past 5 years

Supplemental Table 1, http://links.lww.com/JOM/B66 shows significant values based on geometric means of the recyclers and non-recyclers, as well as a comparison of both groups to NHANES. The data are presented as lipid normalized serum data for polyhalogenated dioxins and furans, and PCBs. A detailed comparison for each congener of the mean, median, etc. is shown in Supplemental Table 2, http://links.lww.com/JOM/B67.

Significant differences between non-recycler and recycler concentration (ppt lipid) were seen in the following: in the polybrominated dioxins, 12378-PBDD with non-recyclers at median 0 (and geometric mean less than LOD) and recyclers at median 0 (but with geometric mean at 5.71) (P value 0.0419); in the polybrominated furans, 2378-TBDF with non-recyclers at 0 (with geometric mean at less than LOD) and recyclers at 0 (but with geometric mean at 7.54) (P value 0.0267). Of the polychlorinated furans, 12378-PCDF with non-recyclers lower at 1.303 and recyclers at 2.609 (P value 0); 123478-HxCDF, with non-recyclers lower at 3.728 and recyclers at 4.682 (P value 0.0438); 123678-HxCDF with non-recyclers lower at 4.135 and recyclers at 6.128 (P value at 0.0095); 1234678-HpCDF with non-recyclers lower at 0 and recyclers at 5.851 (P value 0.0015); and finally, of the non-ortho-substituted polychlorinated biphenyls, PCB-126 with non-recyclers lower at 21.99 and recyclers at 28 (P value 0.0438). Multivariate logistic regression predicting case versus control was used to investigate the effect of Age and BMI as well as combinations of these variables. A strong positive interaction was found between 123478-HxCDF and 1234678-HpCDF. Age and BMI where not significant in the multivariate model.

When comparing non-recyclers to NHANES, significant differences where NHANES was higher were seen in the following polychlorinated dioxins: 12378-PCDD with non-recyclers lower at 2.591 and NHANES at 3.56 (P value 0.007); 123478-HxCDD with non-recyclers lower at 0 and NHANES at 2.4 (P value <0.0001); 123678-HxCDD with non-recyclers lower at 0 and NHANES at 19.7 (P value <0.0001); 123789-HxCDD with non-recyclers lower at 1.451 and NHANES at 3.37 (P value <0.0001); 1234678-HpCDD with non-recyclers lower 7.921 and NHANES at 22.95 (P value 0.0002).

Significant differences between non-recyclers and NHANES were seen in the following polychlorinated furans: 123478-HxCDF with non-recyclers higher at 3.728 and NHANES at 2.8 (P value 0.0065); 123678-HxCDF with non-recyclers higher at 4.135 and NHANES at 2.88 (P value 0.026); 123789-HxCDF with nonrecyclers lower at 0 and NHANES at 0.08825 (P value 0.0015); 234678-HxCDF with non-recyclers higher at 1.466 and NHANES at 0.06065 (P value <0.0001); 1234678-HpCDF with non-recyclers lower at 0 and NHANES at 7.535 (P value 0.0015); 1234789-HpCDF with non-recyclers lower at 0 and NHANES at 0.0848 (P value 0.0002); OCDF with non-recyclers lower at 0 and NHANES at 2.51 (P value 0.0113).

Of the non-ortho-substituted PCBs, the following showed significant differences between non-recyclers and NHANES: PCB-81 with non-recyclers lower at 0 and NHANES at 2.005 (P value 0.0002); PCB-126 with non-recyclers higher at 21.99 and NHANES at 12.4 (P value 0.026); PCB-169 with non-recyclers higher at 16.3 and NHANES 11.2 (P value 0.0053).

Of the mono-ortho-substituted PCBs, the following showed significant differences between non-recyclers and NHANES: PCB-114 with non-recyclers lower at 0 and NHANES at 0.3277 (P value 0.001); PCB-156 with non-recyclers lower at 1.3 and NHANES at 2.353 (P value 0.0608); PCB-157 with non-recyclers lower at 0 and NHANES 0.4983 (P value 0.0188); PCB-167 with non-recyclers lower at 0 and NHANES at 0.6203 (P value 0.0173); PCB-189 with non-recyclers lower at 0 and NHANES at 0.1905 (P value <0.0001).

When comparing recyclers to NHANES, there were significant differences in the following polychlorinated dioxins: 12378-PCDD with recyclers lower at 1.9665 and NHANES at 3.56 (P value 0.0004). 123478-HxCDD with recyclers lower at 0 and NHANES at 2.4 (P value <0.0001); 123678-HxCDD with recyclers lower at 0 and NHANES at 19.7 (P value <0.0001); 123789-HxCDD with recyclers lower at 0.8384 and NHANES at 3.37 (P value <0.0001); 1234678-HpCDD with recyclers lower at 7.404 and NHANES at 22.95 (P value <0.0001); and OCDD with recyclers lower at 107.7 and NHANES at 212.5 (P value <0.0001).

Of the polychlorinated furans, the following showed significant differences: 2378-TCDF with recyclers higher at 1.508 and NHANES at 0.117 (P value 0.0001); 12378-PCDF with recyclers higher at 2.609 and NHANES at 0.238 (P value <0.0001); 23478-PCDF with recyclers higher at 6.28 and NHANES at 3.79 (P value 0.0031); 123478-HxCDF with recyclers higher at 4.682 and NHANES at 2.8 (P value 0.0002); 123678-HxCDF with recyclers higher at 6.128 and NHANES at 2.88 (P value <0.0001); 123789-HxCDF with recyclers lower at 0 and NHANES at 0.08825 (P value 0.0002); 234678-HxCDF with recyclers higher at 1.6465 and NHANES at 0.06065 (P value 0.0003); 1234678-HpCDF with recyclers lower at 5.851 and NHANES at 7.535 (P value 0.0335); and 1234789-HpCDF with recyclers lower at 0 and NHANES at 0.0848 (P value 0.0035); and OCDF with recyclers lower at 0 and NHANES at 2.51 (P value <0.0001).

Of the non-ortho-substituted polychlorinated biphenyls, the following showed significant differences: PCB-81 with recyclers lower at 0 and NHANES at 2.005 (P value 0.0009); PCB-126 with recyclers higher at 28 and NHANES at 12.4 (P value 0.0002).

Of the mono-ortho-substituted PCBs, the following showed significant differences: PCB-114 with recyclers lower at 0 and NHANES at 0.3277 (P value <0.0001); PCB-156 with recyclers lower at 1.1 and NHANES at 2.353 (P value 0.0029); PCB-157 with recyclers lower at 0 and NHANES at 0.4983 (P value 0.0071); and PCB-189 with recyclers lower at 0 and NHANES at 0.1905 (P value <0.0001).

Toxic equivalency has traditionally been determined using the 2005 World Health Organization Toxic Equivalency Factors for dioxins.¹² In this document, the following are used to determine toxic equivalency: chlorinated dibenzo-p-dioxins, chlorinated dibenzofurans, non-ortho-substituted PCBs, and mono-ortho-substituted PCBs. Additionally, we included PBDDs/Fs in our analysis based on conclusions drawn from a 2011 expert consultation between the WHO and UNEP.¹³ Because burning of e-waste has been shown to generate PBDD/Fs,¹⁶ it is important to consider them in calculating the total TEQ. Van den Berg et al¹³ recommend adding polybrominated diphenyl-p-dioxins and polybrominated diphenyl furans to better calculate TEQs.

Table 2 shows total TEQs including brominated dioxins and furans for our study participants. Total PBDD TEQ in non-recyclers was 19.456 and 48.80% of the total dioxin load and in recyclers, it was 14.292 and 43.78% of the total dioxins. Total PBDF TEQ in non-recyclers was 11.1892 and 28.06% of total dioxin load and recyclers were 8.4995 and 26.03% of the total dioxin load. Total PCDD TEQ in non-recyclers was 3.918441 and 9.83% total dioxin load. Total PCDD TEQ in recyclers was 3.632445 with 11.13% total dioxin load. Total PCDF TEQ in non-recyclers was 2.745137 and 6.89% and in recyclers it was 3.338824 and 10.23%. Total nos-PCBs in non-recyclers was 2.558053 and 6.42% and recyclers was 2.883223 and 8.83%. Total mos-PCB in non-recyclers was 0.00264 and 0.01% and in recyclers 0.002682 and 0.01%. Total PBDD and PBDF TEQ in non-recyclers was 30.6452 and 76.86% and in recyclers 22.7935 and 69.81%. Total PCDD and PCDF TEQ in non-recyclers were 6.663578 and 16.71% and in recyclers 6.971269 and 21.35%. Total PCB TEQ in non-recyclers was 2.560693 and 6.42% and in recyclers 2.885905 and 8.84%. Total TEQ in non-recyclers was 39.869471 at 100.00% and in recyclers 32.650674 at 100.00%.

TABLE 2.

Total TEQs Including Brominated Chemicals

Compound	Non-recycler Geometric Means TEQ	% of Total Dioxin	Recycler Geometric Means TEQs	% of Total Dioxin
Total PBDD’s TEQ	19.456	48.80	14.294	43.78
Total PBDF’s TEQ	11.190	28.06	8.4995	26.03
Total PCDDs TEQ	3.9184	9.83	3.6325	11.13
Total PCDFs TEQ	2.7451	6.89	3.3388	10.23
Total NOS-PCBs TEQ	2.5581	6.42	2.8832	8.83
Total MOS-PCBs TEQ	0.0026	0.01	0.0027	0.01
Total PBDD/PBDFs TEQ	30.645	76.86	22.794	69.81
Total PCDD/PCDFs TEQ	6.6636	16.71	6.9713	21.35
Total PCBs TEQ	2.5607	6.42	2.8860	8.84
Total TEQs	39.869	100.00	32.651	100.00

For non-recyclers the total TEQ was driven mainly by Total PBDDs/PBDFs which was 76.86% of total dioxin, with PCDDs/PCDFs contributing 16.71% and PCBS contributing 6.42%. Of note, there was an apparent outlier in the non-recyclers that may have contributed to the increased TEQ of non-recyclers. For recyclers, total TEQ was also driven by total PBDDs/PBDFs at 69.81%, but with a higher influence of PCDDs and PCDFs at 21.35% and PCBs at 8.84%.

DISCUSSION

We expected to find significant elevations in the dioxins, furans, and PCBs of the Vietnamese e-waste recycler group compared with the non-recyclers. These women working in e-waste recycling may not have adequate personal protective equipment to reduce exposure to toxic chemicals. Figure 1 is a photograph of a typical work situation for the e-waste recyclers that was taken while collectingdataforthestudy.Whilealle-wasterecyclersstatedthattheywore cloth mask, gloves, and special shoes as personal protective equipment on the questionnaire, this is not the case as shown.

FIGURE 1.

E-waste recycling women from rural northern Vietnam.

12378-PCDD, 2378-TCDD, 23478-PCDF, and PCB 126 account for the majority of the total dioxin toxic equivalency for e-waste recyclers, with each contributing more than 10% of the total body TEQ. Together, these four congeners constitute 74.2% of the total TEQ burden not including PBDD/Fs in recyclers, and 73.6% of those in non-recyclers. In NHANES data, 23478-PCDF and PCB126 together comprised of 79.2% of the total TEQ burden, while 12378-PCDD and 23478-PCDF were not calculated because there was too high a proportion below the limit of detection to provide valid results.²⁰ Another study located in Lisbon, Portugal near waste incinerators show a similar profile where the 12378-PCDD, 2378-TCDD, 23478-PCDF, and 123678-HCDD altogether account for 84% of the total identified dioxin body burden.²⁵

We predicted that the levels of dioxin equivalents (TEQs) would be higher in the Vietnamese women than the US women sampled in NHANES. However, the data show that for almost all the congeners that were statistically different between the two countries, the values in the US general population were higher than in our measured Vietnamese population. This could be attributed to the fact that our Vietnamese samples were taken from people that lived in rural areas albeit with additional exposure to occupational toxicants. It is likely that the NHANES data was taken from more urban areas in the United States, as people in urban areas may be exposed to higher concentrations of dioxin-like chemicals.

TEQs indicated that if brominated chemicals were excluded, the recyclers would have a higher exposure to dioxins. However, the elevated level of non-recyclers to brominated chemicals seems to indicate that there is an unknown exposure of these women and should be studied further. From the individual measurements, there were a few non-recyclers with brominated chemical measurements much higher than others in their group. We speculate that it is possible that some of the non-recyclers may have not been completely truthful about their e-recycling exposure in order to receive the modest compensation for their participation in this survey.

CONCLUSION

The female Vietnamese recyclers in our study have higher dioxin than the non-recyclers. This is not unexpected as the data from male recyclers in several countries has demonstrated. Thus, e-waste recycling conducted in the homes of Vietnamese women may lead to increased exposure to dioxin-like components. Occupational and environmental remediation is recommended; improved occupational protocols and enforcement of these standards should reduce some chemical exposures of recycling workers.

This is one case study only, encompassing data from only one district in Northern Vietnam. These data are not meant to show representative values for all or even “typical” recyclers and non-recyclers, but rather the findings in this group of recyclers and their non-recyclers. With different e-waste being recycled at different times, different measured levels and TEQs would be expected to be found. However, a pilot study we conducted in other villages in Vietnam did find higher dioxin-like activity, as measured by the CALUX bioassay, in 10 recycling women than in 10 non-recyclers.²⁶

This study contributes to the information on occupational exposure risks for e-waste recyclers, as well as ordinary women in rural northern Vietnam who are exposed to the environmental effects of the unsafe workplace. Further research should also focus on practical methods of decreasing exposure to recycling workers and others who may have been exposed, including family members of recyclers when recycling is performed at home-based facilities. Recycling of e-waste can improve sustainability of environmental resources and provide income for workers and their families, but it may also be a source of toxic chemical exposure. A balance seems indicated. Further research is indicated at other recycling facilities. Contamination of children and other relatives in home-based e-waste recycling should also be investigated. The fact that all of the Vietnamese women in our study have lower dioxin levels than that of the US NHANES population may reflect the rural nature of our study population. Finally, research is indicated to determine both the short- and long-term health effects of occupational and environmental exposures.