Electronic Waste Recycling Research Articles

Risk assessment for sustainability in e-waste recycling in circular economy

E-waste is a hazardous concept for human health, environment and businesses, and therefore, risk assessment is essential to eliminate or reduce the negative effects of e-waste in a circular economy. Decision-making plays an important role during the risk assessment in e-waste recycling. This study aims to develop a decision tool under uncertain and risky conditions for achieving sustainability in electronic waste (e-waste) recycling in circular economy. Prospect theory and its aspects are integrated with the sustainability risk assessment in e-waste recycling. In order to evaluate the irrationality and risk attitudes of decision makers in a risky and uncertain environment, the prospect theory-based TODIM (acronym in Portuguese for interactive and multicriteria decision-making, i.e. Tomada de Decisao Interativa Multicriterio) method for a previous computer disassembly problem is used. Using prospect theory, the relationship between loss aversion, reference point, framing and two selves effect, and sustainability dimensions is presented with a sustainability risk assessment point of view. Further, tasks of computer disassembly processes are prioritized by considering risk factors. The results showed that random access memory modules, motherboard and power supply are the highest priority risks based on the evaluation of listed twelve sustainability risks. In this study, it is suggested that prospect theory is suitable for decisions under risk and uncertainty, and it is applicable to integrate sustainability risk assessment and prospect theory in order to fulfil the gap of knowledge. Relationship between prospect theory and sustainability risk assessment.

One-step recovery of REE oxalates in electro-leaching of spent NdFeB magnets

Recovery of rare-earth elements (REEs) from spent NdFeB magnets is receiving great attention because of high amount of neodymium and potential risk of environmental pollution. In this study, a novel environment-friendly hydrometallurgical route is proposed for efficient recovery of REEs during electrochemical leaching with sulfuric and oxalic acids. With proper adjustment of the electrolyte composition and operating conditions, effective separation of different elements is observed; a compact layer of REE oxalates in a purity of up to 93% is obtained on the cathode, while iron remains in the solution and as solid residue for further recovery. The mechanisms during the electro-leaching process were subsequently investigated and we propose that cathodic deposition of the REEs is due to electrostatic attraction of the REE-oxalate particles on the cathode. With this finding, selective recovery of REEs from spent magnets can be achieved. This study provides a new insight on electronic waste recycling by implementing principles of electrochemistry.

Micronutrient-rich dietary intake is associated with a reduction in the effects of particulate matter on blood pressure among electronic waste recyclers at Agbogbloshie, Ghana

BackgroundInformal recycling of electronic waste (e-waste) releases particulate matter (PM) into the ambient air. Human exposure to PM has been reported to induce adverse effects on cardiovascular health. However, the impact of PM on the cardiovascular health of e-waste recyclers in Ghana has not been studied. Although intake of micronutrient-rich diet is known to modify these PM-induced adverse health effects, no data are available on the relationship between micronutrient status of e-waste recyclers and the reported high-level exposure to PM. We therefore investigated whether the intake of micronutrient-rich diets ameliorates the adverse effects of ambient exposure to PM2.5 on blood pressure (BP).MethodsThis study was conducted among e-waste and non-e-waste recyclers from March 2017 to October 2018. Dietary micronutrient (Fe, Ca, Mg, Se, Zn, and Cu) intake was assessed using a 2-day 24-h recall. Breathing zone PM2.5 was measured with a real-time monitor. Cardiovascular indices such as systolic BP (SBP), diastolic BP (DBP), and pulse pressure (PP) were measured using a sphygmomanometer. Ordinary least-squares regression models were used to estimate the joint effects of ambient exposure to PM2.5 and dietary micronutrient intake on cardiovascular health outcomes.ResultsFe was consumed in adequate quantities, while Ca, Se, Zn, Mg, and Cu were inadequately consumed among e-waste and non-e-waste recyclers. Dietary Ca, and Fe intake was associated with reduced SBP and PP of e-waste recyclers. Although PM2.5 levels were higher in e-waste recyclers, exposures in the control group also exceeded the WHO 24-h guideline value (25 μg/m3). Exposure to 1 μg/m3 of PM2.5 was associated with an increased heart rate (HR) among e-waste recyclers. Dietary Fe intake was associated with a reduction in systolic blood pressure levels of e-waste recyclers after PM exposure.ConclusionsConsistent adequate dietary Fe intake was associated with reduced effects of PM2.5 on SBP of e-waste recyclers overtime. Nonetheless, given that all other micronutrients are necessary in ameliorating the adverse effects of PM on cardiovascular health, nutrition-related policy dialogues are required. Such initiatives would help educate informal e-waste recyclers and the general population on specific nutrients of concern and their impact on the exposure to ambient air pollutants.

Do E‐Waste Laws Create Behavioral Spillovers? Quasi‐Experimental Evidence from California

Many governing bodies have launched efforts to shape the operations of manufacturers, administration of civic entities, and behavior of individuals to limit waste generation. Typically, such efforts commence with the enactment of targeted legislations that create operational changes (e.g., recycling fees, collection centers) to the waste collection and disposal processes. For example, over 25 states in the United States have enacted legislations that aim to properly dispose used electronic and electrical goods (i.e., e‐waste) and divert such waste away from landfills. We argue that such legislations can have an impact that extends beyond just reducing e‐waste. This is because such laws may not only motivate individuals to restrict e‐waste but also induce broader behavioral spillovers that can prompt individuals to reduce waste in general. To explore this idea, we exploit a quasi‐experimental setup that arises from California's enactment of the Electronic Waste Recycling Act (EWRA). Specifically, a difference‐in‐differences analysis reveals that the introduction and implementation of the EWRA resulted in at least 4.93% reduction in municipal solid waste (MSW). A plausibility analysis illustrates that these MSW reductions are much larger than what can be attributed purely to the decline of e‐waste. Furthermore, we show that the effect of e‐waste laws is stronger when consumers have increased market access through (i) online connectivity and (ii) offline proximity. Our study informs policy makers on the effects of e‐waste legislation and the critical role of market access in enhancing the impact of such legislation.

The sustaining effects of e-waste-related metal exposure on hypothalamus-pituitary-adrenal axis reactivity and oxidative stress

Taizhou is one of the three largest electronic waste (e-waste) recycling locations in China. At present, to prevent the environmental problems stem from e-waste dismantling, the local government shut down all the industries in 2015. However, little is known to the sustaining effects of e-waste exposure on human health after the e-waste recycling factories were closed. In this study, we collected blood samples in the residents living near e-waste dismantling factories (exposed group) and a chosen reference area (reference group) for comparison in Taizhou in December 2017.17 metals were quantitatively determined in all blood samples. Among them, the concentrations of altogether 9 metals, including chromium (Cr), arsenic (As), cobalt (Co), nickel (Ni), silver (Ag), stannum (Sn), mercury (Hg), lanthanum (La) and cerium (Ce) were significant higher in the individuals in exposed group than in reference group. Hypothalamus-pituitary-adrenal axis (HPA axis) is critical endocrine system in regulating many physical functions. We found that the concentrations of hormones in HPA axis, including corticotropin releasing hormone (CRH), adrenocorticotropic hormone (ACTH) and cortisol, were higher in exposed group than in reference group. Moreover, we also observed significantly higher concentrations of biomarkers of oxidative stress (OS), including malondialdehyde (MDA) and 8-isoprostane (8-I), in exposed group compared with reference group even though the e-waste industries have been shut down for over 2 years. Meanwhile, the hormones in the HPA axis and the biomarkers of OS showed sinificantly positive correlation. The results of Pearson correlation and multiple linear regression showed that blood Cr and Ni positively correlated with the 3 hormones and 2 biomarkers of OS. Considering the relationship between Ni and Cr, HPA axis, OS, we speculated that high concentrations of Cr and Ni exposure could induce oxidative damage in e-waste exposure persons, and the regulations of HPA axis could play the important role during the process.

Understanding the factors for increased informal electronic waste recycling in Kumasi, Ghana

ABSTRACT The purpose of this paper is twofold: to explore the factors influencing the emergence and growth of informal e-waste activities and to examine workers’ motivation for involvement in informal e-waste activities. Semi-structured interviews and observations among actors in the recently established Dagomba-Line e-waste site in Kumasi, Ghana were employed to gather relevant data. Emergence and growth of e-waste activities are largely influenced by spatial, political, socio-cultural and economic factors. The reuse and open disposal of e-waste are the common practices due to the cost of transportation to a final disposal site. Similar to findings at the well-established Agbogbloshie e-waste site, also in Ghana, scavengers are found at the bottom of the e-waste financial ladder. The major motivating factor for engaging in e-waste handling is poverty. Additionally, some respondents mentioned the lucrative nature of the activity, landlessness, and peer influence as a motivation. The results showed that younger workers (below 35 years) were more likely to be engaged in the activity for reasons of peer influence and poverty and major source of livelihood . The paper recommends that policy and planning should reflect ways of delivering and creating stable socio-economic conditions that promote an inclusive and sustainable development.

Influence of metals from e-waste dismantling on telomere length and mitochondrial DNA copy number in people living near recycling sites

Metals are the primary toxicants released by electronic waste (e-waste) recycling, but their adverse effects on people working in e-waste recycling or living near e-waste sites have not been studied well. Taizhou is one of the three largest e-waste recycling locations in China. Atpresent, to prevent the environmental problems stem from e-waste dismantling, the local government has shut down all the industries in 2015. In this study, we collected blood samples of residents living near e-waste dismantling factories, and in matched reference areas in Taizhou, in December 2017, after the factories have been shut down for two years. Seventeen metals were quantified in all blood samples. Among them, the concentrations of arsenic (As), nickel (Ni), silver (Ag), lanthanum (La), and Cerium (Ce) were statistically significant higher in individuals in e-waste recycling locations than those in reference location. Length of telomere (LOT) and mitochondrialDNA copy number (MCN) were measured in blood as a marker of human health. In the e-waste dismantling location, the level LOT and MCN were elevated in resident living near e-waste sites (RE) and former working in e-waste recycling (OE) than residents living in the reference area (RF). Furthermore, Pearson correlation and multiple linear regression analysis between the changed metals and LOT, MCN in blood were performed. In RE and OE, the concentration of Ni significantly positively correlated with MCN; in OE, the Ni level significantly positively correlated with MCN and LOT. Considering that the high level of Ni, TL and mtDNA were correlated with the risk of cancer, we speculated that e-waste exposure elevate the risk of cancer, and Ni that has long been present in the body was the potential hazardous element causing cancer.

Interaction type of tetrabromobisphenol A and copper manipulates ammonia-oxidizing archaea and bacteria communities in co-contaminated river sediments

The combined contamination of brominated flame retardants (BFRs) and heavy metals in electronic waste (e-waste) recycling and disposal areas has been a serious concern owing to their environmental persistence and chronic toxicities. Ammonia oxidizers, e.g., ammonia-oxidizing archaea (AOA) and bacteria (AOB) play essential roles in nitrogen cycling and can serve as ideal indicators that reflect the changes in sediment health in response to environmental variables. There is currently very little information available on the combined toxic effects of BFRs and heavy metals on AOA and AOB communities. In this study, two typical e-waste pollutants, tetrabromobisphenol A (TBBPA) and copper (Cu), were selected as target contaminants to investigate the individual and combined effects of both pollutants on AOA and AOB communities in river sediments. Respective treatments of TBBPA (1, 10, and 20 mg/kg wet weight), Cu (100 mg/kg wet weight) and their combined treatments (weight ratios of 1:100, 1:10, and 1:5) were performed in laboratory experiments. High-throughput sequencing was applied to explore the response of ammonia oxidizers to TBBPA and Cu. The interaction types of TBBPA and Cu were calculated by the directional classification system to reveal the individual and combined toxicities of both contaminants to the ammonia oxidizers. On days 15 and 30, the dominant interaction type of TBBPA and Cu was synergistic (62.50%), and the combined contamination exacted selective pressure and inhibition on the AOB and AOA communities. On days 45 and 90, the interaction type shifted to be antagonistic (83.33%), with both the AOB and AOA communities gradually reaching stable population equilibria. The alteration of the interaction type is attributed to the elevated TBBPA/Cu tolerance as the incubation time increased. This study disclosed the interaction types of TBBPA and Cu in contaminated river sediments, and revealed that the combined effect could potentially manipulate AOB and AOA communities.

Exposure to Heavy Metals in Electronic Waste Recycling in Thailand.

Electronic waste recycling can release heavy metals into the environment and cause adverse health effects. We assessed the association between exposure to heavy metals from electronic waste recycling and the prevalence of asthma in a nested case-control study of 51 subject pairs with and without asthma. House dust, airborne dust, blood, and urine were collected from residents of two neighboring sites in Ubon Ratchathani province, Thailand. Multiple electronic waste-handling activities are conducted in the first site, while the second site is mostly agricultural. Concentrations of chromium, mercury, nickel, and lead in house dust and airborne dust were higher in the electronic waste-handling site (p < 0.05), but levels of exposure were similar in subjects with and without asthma. Although we did not find an association between exposure to these metals and the prevalence of asthma, control measures should be implemented to reduce health risks from long-term exposure to heavy metals.

O2O Recycling Closed-Loop Supply Chain Modeling Based on Classification Process considering Environmental Index

“O2O” (online to offline) classification recycling is a new recycling mode. It is premised on the double lines of online service platform and offline recycling service system, thus forming a pattern of online disposal and offline trading. This mode is capable of integrating upstream and downstream resources on the network platform, creating a recycling and processing mode for the entire industry chain of waste sorting, and developing a circular development mode featuring “resources-products-waste-renewable resources” to realize the recycling of resources. In this paper, the abovementioned recycling mode is constructed using the dynamic method. Taking the recycling of electronic waste (e-waste) as an example, on the basis of the original recycling, an online recycling mode is added and the e-waste is reprocessed by means of classification. Besides, the final process of manufacturing is put into the market for new products. By comparing the efficiency of different classification processing channels and the efficiency of O2O recycling, it was found out that the higher the product quality, the higher the recycling efficiency, and the efficiency of online recycling was concluded due to offline recycling. The system effect is evaluated according to the environmental index. In addition, this paper demonstrates the applicability of the mode by introducing Gree Corp. The results of this research are believed as contributory to improving the efficiency of recycling and remanufacturing at corporate level. It also provides a valuable reference for the improvement of e-waste management work for governments both in China and other countries.

Metal Levels, Genetic Instability, and Renal Markers in Electronic Waste Workers in Thailand.

Background: Informal electronic waste (e-waste) recycling is an increasingly important industry worldwide. However, few studies have studied the health risks in this group of workers. Objective: To assess the associations between occupational exposures to metals and genetic instability and renal markers among e-waste recycling workers. Methods: We recruited informal e-waste recycling workers from a community in northeastern Thailand. Participants completed a questionnaire, several health measurements, and provided urine and blood samples, which we then analyzed for a number of metals including lead (Pb), cadmium (Cd), and manganese (Mn). Samples were analyzed for a marker of RNA and DNA damage (ie, oxidative stress), 8-hydroxy-2'-deoxyguanosine (8-OHdG). Glomerular filtration rate (GFR) and fractional excretion of calcium (FECa%) were measured as markers of renal function. Correlations and regression models were used to assess associations between these various factors. Results: We found significantly higher levels of Cd and Pb in blood of men compared with those in women. Men who worked >48 hours/week had significantly higher levels of 8-OHdG compared with men who worked ≤48 hours/week. Smoking was significantly associated with higher blood Pb and Cd concentrations among men. Conclusion: Our results suggest gender differences in both blood concentrations of metals associated with e-waste recycling and smoking and highlight potentially elevated oxidative stress associated with longer work hours. Health promotion efforts are needed among informal e-waste recyclers to reduce possible risks of renal damage and cancer.

The Impact of Green Information on the Participation Intention of Consumers in Online Recycling: An Experimental Study

The rapid growth of electronic waste around the world has led to increased recycling problems. With the development of information technology, e-commerce has become a new trend in electronic waste recycling. This research designs two experiments to study the effect mechanism of green information on participation intention (PI) for online recycling websites. We found that providing green information can increase the PI of consumers, including environmental knowledge of product recycling (EKPR) and environmental corporate social responsibility (ECSR). Green perceived value (GPV) and green trust (GT) play mediating roles on the impact of green information on PI. In addition, the recycling platform reputation (RPR) plays a moderating role in the effect of ECSR on GT. Theoretical and managerial implications, along with avenues for future research, are discussed.

Emission characteristics of polybrominated diphenyl ethers from the thermal disassembly of waste printed circuit boards

Thermal disassembly is prevalently applied for the removal of electronic components on waste printed circuit boards (WPCBs), and temperature is an important factor influencing the pollutant emission process. The emission characteristics of polybrominated diphenyl ethers (PBDEs) to the environment under thermal stress were investigated by conducting both bench-scale experiments and pilot-scale experiments over a temperature range from 100 to 260 °C. Bench-scale experiments showed that the emission factors (EFs) for ∑39PBDEs from WPCB powder were obviously higher than those from WPCB fragments. Mono-to tri-BDEs predominated the PBDEs emission at each temperature, and the EFs for the mono-to tri-BDEs from WPCB powder ranged from 232 to 3280 ng/g, respectively. Pilot-scale experiments were done to study the particulate matter (PM) and PBDEs emitted from WPCBs mounted with electronic components using a thermal disassembly machine. The mass of the PM and PBDEs released from WPCBs during heating increased with increasing temperature. A bimodal distribution pattern for the PM with peaks at diameters of 0.4–0.7 and 5.8–9.0 μm was observed. The values of the EFs for ∑39PBDEs varied from 6.41 to 674 ng/g, which were comparable with those calculated from WPCB fragments in the bench-scale experiments. The mass distribution of the ∑39PBDEs in the PM predominated in the size fraction of >9.0 μm and 0.7–1.1 μm at 100 and 260 °C, respectively. The highly brominated PBDEs (hexa- and hepta-BDEs) had a mass median aerodynamic diameter (MMAD) greater than 2.5 μm, while the lightly brominated PBDEs (mono-to penta-BDEs) were mainly distributed in finer particles, with a MMAD of less than 2.5 μm. The particle size distribution of PBDEs was significantly correlated with the distribution of organic carbon (OC) in PM. All these results can provide basic data for gas pollution related to PBDEs and its control for electronic waste recycling.

Underlying factors behind the low participation rate in electronic waste recycling

This study aims to understand influential factors for Jakarta’s residents to participate in a formal electronic waste recycling programme. It questions the efficacy of providing facilities to collect electronic waste despite the lack of legislated regulations or policies. Using the goal-framing theory as a foundation, a survey conducted on 208 respondents in 2018 revealed that selling obsolete electronic devices to peddlers or retaining them at home were standard practices in society, and only 2% of respondents recycled their electronic waste at formal facilities. The results show that electronic waste recycling intention correlates highest with information and convenience, 0.521 and 0.411, respectively. While knowledge has the least correlative value with attitude and intention, that is 0.204 and 0.240. It clarifies that the normative goal is weaker than hedonic and gain goals. Respondents had enough awareness about the hazards of electronic waste. However, their behaviour did not exhibit it. It is imperative to lessen the gap between normative and hedonic goals by campaigning continuously and place the facilities at easily accessible locations to increase recycling participation. Furthermore, collecting electronic waste requires a collaboration between the government and electronics businesses, and must be supported by a legal framework.

Birth outcomes associated with maternal exposure to metals from informal electronic waste recycling in Guiyu, China

BackgroundInformal electronic waste (e-waste) recycling is a rapidly growing industry. Informal e-waste recycling creates a mixture of chemicals that can be harmful to humans, especially vulnerable populations like pregnant women and young children. ObjectivesWe aimed to analyze the associations between birth outcomes and living in a community with a history of informal e-waste recycling. MethodsThe e-waste Recycling Exposure and Community Health (e-REACH) Study enrolled pregnant women in Guiyu, an informal e-waste recycling site (n = 314), and an unexposed control site (Haojiang) (n = 320) at delivery. We analyzed maternal whole blood samples for lead (Pb), cadmium (Cd), chromium (Cr), and manganese (Mn). We captured data in newborns on birth weight, birth length, head circumference, body mass index (BMI), and Ponderal Index (PI). We compared the birth outcomes between sites after adjustment for covariates, and examined the associations with individual and the mixture of metals. ResultsThe neonates from Guiyu had smaller head circumference (adj β −1.96 cm, 95% CI −2.39, −1.52), BMI (adj β −0.77 kg/m2, 95% CI −1.03, −0.51), and PI (adj β −2.01 kg/m3, 95% CI −2.54, −1.47). Birth weights were lower in Guiyu compared to Haojiang, but the difference was not significant (β −51, 95% CI −132, 29). Cumulative exposure to metals was related to lower head circumference, BMI, and PI, but not related to birth weight. DiscussionWe observed slight and statistically significant differences in the head size, BMI, and PI of neonates, but not birth weight, from Guiyu when compared to neonates from Haojiang. Cumulative metal exposure may partially account for the findings.

Process integration of E-waste carbonization and High-gravity rotating packed bed for optimal gold recovery and the fine particles reduction

Urban mining that uses an electronic waste recycling process is an emerging industry that is used to recover several high-value precious metals to reduce natural degradation and depletion. To obtain these precious metals more effectively, integrated circuit (IC) chips are pretreated using a carbonization process. In this study, the gold stripping efficiency for various types of IC chips was evaluated. To reduce the carried fine particle emitted from the exhaust gas of the carbonization process, a high-gravity rotating packed bed (HiGee RPB) generating micro-mixing the gas and liquid phases under a centrifugal force was applied. The performance in terms of particle removal efficiency under different high-gravity factor and gas-to-liquid ratio was determined. The result indicated that a pyrolysis temperature of 800 °C gives the maximum gold stripping efficiency of 99.8% and a minimum particle concentration of 23 mg m−3. The particle removal efficiency increased as the high-gravity factor and liquid flow rate increased. An empirical model is used to describe the particle collection mechanism based on the experiment data and control variables. The mechanism includes Brownian diffusion, inertial impaction and interception, which affect the removal efficiency for different particle sizes. Finally, the process was optimized in terms of the removal efficiency and the energy consumption using a response surface model. A minimum level of energy consumption with a particle emission concentration of 16.9 mg m−3 is necessary for the IC chip carbonization process.

‘The biggest challenge is that we have to tell people how to sort.’ Waste management and the processes of negotiation of environmental citizenship in Slovenia

ABSTRACTThis article departs from the concept of environmental citizenship. Focus is on the experiences of representatives for Slovenian municipal waste management companies and business sector service companies engaged in the collection and recycling of electronic waste, and their attempts to increase the amount of separately collected municipal waste. They do so by engaging the Slovenian citizens to undertake separate sorting. Theoretically, the focus is on the processes of negotiating citizen engagement and, more specifically, attempts to incentivise the separate sorting of municipal waste which, it is argued, also helps foster the image of a particular kind of citizen. This article understands the informants’ experiences as being intimately linked to, and constitutive of, contemporary waste management discourses where attention is increasingly paid to the activities and behaviours of individual citizens. Noteworthy, while the concept of environmental citizenship can be said to allow citizens to practise sustainability (a concept that is otherwise seemingly quite abstract), the waste management policies of today seem to be increasingly relying on this active citizenship. It is at the intersection of these phenomenon that the negotiation practices of Slovenian waste management authorities happen.

Advances in bioleaching of copper and nickel from electronic waste using Acidithiobacillus ferrooxidans: evaluating daily pH adjustment

The waste stream of electrical and electronic equipment is three times faster than other municipal waste streams. Recycling of electronic waste is necessary for both reducing environmental pollution and saving natural ores. Bioleaching is known as an efficient technology for metal leaching. In most of the previous studies on the bioleaching of electronic waste, the pH of the process was adjusted daily under the optimal pH of the bacterium growth. Using acid causes increasing process costs and unsustainability of the process. In this work, the effect of daily pH adjustment on the bioleaching efficiency of electronic waste using adapted Acidithiobacillus ferrooxidans was studied. Simultaneously, Cu and Ni leaching efficiency, bacterial growth characteristics, and chemical characteristics (including field emission scanning electron microscopy, Fourier transform infrared spectrometer, and X-ray diffraction) were discussed. The results showed that at a pulp density of 1.5% (w/v) with pH adjustment, the maximum leaching efficiency of Cu and Ni was, respectively, about 90% and 88%, while for the sample without pH adjustment, the maximum leaching efficiency of Cu and Ni was, respectively, 100% and 92%. All the results confirmed pH adjustment of the bioleaching solution is not necessary and even reduces the process efficiency.

Multi-exposures to suspected endocrine disruptors in electronic waste recycling workers: Associations with thyroid and reproductive hormones.

Electronic waste recycling (e-recycling) exposes workers to substances such as flame retardants and metals. Some of them are known or suspected endocrine disruptors that could affect hormonal homeostasis and eventually result in adverse health outcomes. Our aim was to measure biological concentrations of organophosphate ester (OPE) metabolites, polybrominated diphenyl ethers (PBDEs), mercury, lead and cadmium in e-recycling workers, and to explore associations with thyroid and sexual hormones. In a cross-sectional study, end-of-shift blood and urine spot samples were collected from 23 women and 77 men in six e-recycling facilities and one commercial recycling facility. Urinary concentrations of 15 OPE metabolites and mercury, and blood concentrations of 12 PBDE congeners, lead, cadmium, and thyroid (thyroxine [T4], triiodothyronine [T3], thyroid stimulating hormone [TSH]) and sexual (testosterone [T], estradiol, Follicle Stimulating Hormone [FSH], Luteinizing hormone [LH]) hormones were measured. E-recycling workers had higher concentrations of BDE209, all OPE metabolites, and lead than commercial recycling workers. In e-recycling workers, plasma geometric mean concentration of BDE209 was 18ng/g lipids (geometric standard deviation [GSD]: 2.8) vs.1.7ng/g lipids (GSD: 2.8) in commercial recycling, and urinary geometric mean concentration of diphenyl phosphate (DPhP), a major metabolite of triphenyl phosphate, was 1.7ng/ml (GSD: 2.5), vs. 0.95ng/ml (GSD: 2.0). In men, a two-fold increase in BDE209 was associated with 3.1% (95% Confidence interval: 0.07, 6.1) higher levels of total T4, and a two-fold increase in tert-butyl diphenyl phosphate (tb-DPhP) was associated with 18% (-29, -4.7) lower total T, 18% (-27, -6.9) lower free T and 13% (-25, 0.70) lower free T/estradiol ratio. In women, a two-fold increase in BDE153 was associated with 10% (-17, -3.2) lower free T3. To our knowledge, this is the first study to show associations between OPE metabolites and sex hormones in adults. Although some of our results are not conclusive and need replication, they suggest that prudent avoidance should be applied in risk management of flame retardants.

Occupational and dietary differences in hydroxylated and methoxylated PBDEs and metals in plasma from Puget Sound, Washington, USA region volunteers

Electronic waste (E-waste) recycling is a rapidly growing occupation in the USA with the potential for elevated exposure to flame retardants and metals associated with electronic devices. We previously measured polybrominated diphenyl ethers (PBDEs) in plasma from E-waste workers and found them similar to non-E-waste workers. This study focused on structurally related PBDE derivatives, the hydroxylated (OH-PBDEs) and methoxylated (MeO-PBDEs) forms along with metals known to occur in E-waste. Humans can metabolize PBDEs and some MeO-PBDEs into OH-PBDEs, which is a concern due to greater health risks associated with OH-PBDEs. We measured 32 different OH-PBDEs and MeO-PBDEs in plasma samples provided by 113 volunteers living in the greater Puget Sound region of Washington State, USA. We measured 14 metals in a subset of 10 E-waste and 10 non-E-waste volunteers. Volunteers were selected based on occupational and dietary habits: work outdoors and consume above average amounts of seafood (outdoor), electronic waste recycling (E-waste) or non-specific indoor occupations (indoor). A two-week food consumption diary was obtained from each volunteer prior to blood sampling. OH-PBDEs were detected in all volunteers varying between 0.27 and 102 ng/g/g-lipid. The MeO-PBDEs were detected in most, but not all volunteers varying between n.d. – 60.4 ng/g/g-lipid. E-waste recyclers had OH-PBDE and MeO-PBDE plasma levels that were similar to the indoor group. The outdoor group had significantly higher levels of MeO-PBDEs, but not OH-PBDEs. Comparison of plasma concentrations of BDE-47 with its known hydroxylated metabolites suggested OH-PBDE levels were likely determined by biotransformation and at least two subpopulations identified differing in their apparent rates of OH-PBDE formation. The metals analysis indicated no significant differences between E-waste workers and non-E-waste workers. Our results indicate E-waste workers do not have elevated plasma levels of these contaminants relative to non-E-waste workers.