Static and dynamic flow analysis of PBDEs in plastics from used and end-of-life TVs and computer monitors by life cycle in Korea

Release Behavior of Liquid Crystal Monomers from Waste Smartphone Screens: Occurrence, Distribution, and Mechanistic Modeling

Liquid crystal display (LCD) screens can release many organic pollutants into the indoor environment, including liquid crystal monomers (LCMs), which have been proposed as a novel class of emerging pollutants. Knowing the release pathways and mechanisms of LCMs from various components of LCD screens is important to accurately assess the LCM release and reveal their environmental transport behavior and fate in the ambient environment. A total of 47, 43, and 33 out of 64 target LCMs were detected in three disassembled parts of waste smartphone screens, including the LCM layer (LL), light guide plate (LGP), and screen protector (SP), respectively. Correlation analysis confirmed LL was the source of LCMs detected in LGP and SP. The emission factors of LCMs from waste screen, SP, and LGP parts were estimated as 2.38 × 10^-3, 1.36 × 10^-3, and 1.02 × 10^-3, respectively. A mechanism model was developed to describe the release behaviors of LCMs from waste screens, where three characteristics parameters of released LCMs, including average mass proportion (AP), predicted subcooled vapor pressures (P_L), and octanol-air partitioning coefficients (K_oa), involving coexistence of absorption and adsorption mechanisms, could control the diffusion-partitioning. The released LCMs in LGP could reach diffusion-partition equilibrium more quickly than those in SP, indicating that LCM release could be mainly governed through SP diffusions.

The Typical Polybrominated Diphenyl Ethers (PBDEs) and Heavy Metals Distributions in a Formal e-Waste Dismantling Site

Understanding the release of pollutants from the formal e-waste dismantling site could provide the basic information and potential risk to guide the normative regulation of the process. In this study, the distribution of typical polybrominated diphenyl ethers (PBDEs) and heavy metals in a relocating site of a formal e-waste dismantling company was firstly investigated down to the saturated zone, with a maximum depth of 3.0 m. The mean concentrations of Σ₁₃PBDEs were ranged from 2.815 to 7.178 ng/g, with a peak value of 7.178 ng/g in storage area. BDE-209 was the predominant congener of PBDEs in the soil, with the value ranged from 1.688 to 2.483 ng/g. A higher pollution of PBDEs and HMs was presented in the storage area. The risk assessment of PBDEs mostly posed a low environmental risk (RQ ≤ 0.01) and pentaBDE was found to be the most harmful driver for the potential environmental risk.

Comprehensive Identification of Liquid Crystal Monomers-Biphenyls, Cyanobiphenyls, Fluorinated Biphenyls, and their Analogues-in Waste LCD Panels and the First Estimate of their Global Release into the Environment

Our previous study demonstrated massive emissions of liquid crystal monomers (LCMs) from liquid crystal display (LCD)-associated e-waste dismantling; however, the compositions, priority list, and inventory of LCMs in waste LCD panels remain unknown. Herein, we conducted the first comprehensive identification covering a broader range of LCMs, including 21 biphenyls and analogues (BAs), 28 cyanobiphenyls and analogues (CBAs), and 44 fluorinated biphenyls and analogues (FBAs), in waste television/computer LCD panels. A total of 64 of the 93 target LCMs, including 19 BAs, 6 CBAs, and 39 FBAs, were widely detected in collected waste LCD panels. Approximately 10-18 of the 64 detectable LCMs were identified as the main compositions in various waste LCD panels, which contributed to >90% of the total LCMs. Total concentrations of FBAs in the television/computer LCD panel samples were comparable to those of BAs but much higher than those of CBAs, indicating FBAs and BAs being the commonly used LCM categories. The composition distribution of LCMs varied between television/computer LCDs and among different brands of television/computer LCDs. A preliminary estimate of the globally direct release of LCMs from waste television/computer LCD panels into various environmental compartments was about 1.07-107 kg/year, which will increase considerably in the near future.

Costs and benefits of recycling PVC contaminated with the legacy hazardous plasticizer DEHP

Reusing materials is an attractive option for circular economy and can also reduce emissions of greenhouse gases and pollutants. However, recycling raises questions regarding the potential risks to human health or the environment when hazardous legacy chemical additives of materials are also recycled, instead of the recent and less hazardous additives of virgin materials. To address this trade-off, this study developed a model to calculate the total external cost of material supply, considering the health and environmental impacts of all industrial steps (e.g. virgin material production, incineration, and recycling), and the health effects of recycling chemicals present in the material. The model is coupling material flow analysis, life-cycle analysis, and environmental economics to compare different recycling policies. It is applied for all illustrative purposes to soft PVC and DEHP in France. Results show that recycling of materials is in the long-term positive despite the prolongation of the presence of hazardous additives in materials. The time when the recurring environmental benefits of recycling offset the negative impacts on human health of recycling the additives is very sensitive to the health impact of additives. This approach can improve the harmonization between recycling and circular economy policies, and as a framework to confirm the relevance and size treatments to remove additives from materials during recycling.

Transfer of POP-BFRs within e-waste plastics in recycling streams in China

Due to the rapid increase of e-waste plastics and the national policy's strong preference for mechanical recycling, a substantial amount of POP-BFRs is flowing into recycling streams in China. Therefore, confronting with the worldwide prohibition in manufacturing and consumption, identifying the transfer and inventory of POP-BFRs in recycling stage has become the key to their effective management and elimination. In this study, the level of PBDEs in e-waste housings, recycled plastics and daily-use products from recycling facilities and the commodity market was determined, and a gradual decrease of PBDEs was observed along with the downstream life cycle, indicating that recycling is a crucial medium of POP-BFRs transferred from their original use to an expansive reutilization market. Based on that, an extrusion experiment was conducted to imitate the mechanical recycling of e-waste plastics. It was found that, about 77% of PBDEs and 39% of HBCD were retained in recycled materials, with levels comparable to those in the products from recycling manufacturers and the consumer market. Mechanical recycling had no effect on the predominance of highly brominated BDE congeners, and no obvious transformation from higher to lower brominated diphenyl ethers was observed in recycled materials under thermal conditions; however, the isomerization of γ-HBCD brought about a noticeable increase in the relative abundance of α-HBCD. According to a Monte Carlo method estimation by using the transfer rate, approximately 235-687.8 tons of PBDEs have entered into recycling streams annually in the most recent five years. The field survey, laboratory findings and model evaluation results obtained in this study would not only contribute to a broader understanding of POP-BFRs sources and impact scopes posed on human health and the environment, but also provide a basis for developing effective strategies to manage POP-BFRs from the recycling perspective.

Occurrence, levels and profiles of brominated flame retardants in daily-use consumer products on the Chinese market

With the global phasing-out of POP-BFRs (brominated flame retardants restricted under the Stockholm Convention on Persistent Organic Pollutants), the main challenge for their environmentally sound management has shifted from manufacturing and consumption to their recycling and disposal. For the end-of-life products containing POP-BFRs, material recycling and reuse in new articles is the favorite approach widely adopted by recyclers. This would result in POP-BFRs being transferred into daily-use consumer products. To identify the possible reservoirs of POP-BFRs in consumer products on the Chinese market, 120 samples were screened for Br by using a portable X-ray fluorescence (XRF) spectrometer, and the three traditional BFRs, i.e., polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCD) and tetrabromobisphenol A (TBBPA), were analyzed in 15 Br-positive samples. The results showed that 36.7% of products contained at least one test point positive for Br, and higher detection frequencies were found in electric appliances and toys. The concentrations of ∑BFRs ranged from 0.48 to 73.82 mg kg-1 with a general contribution in the order of ∑PBDEs > TBBPA > HBCD. BDE-209 was the dominant congener among PBDEs in most investigated samples, accounting for 48.18-99.36%. Relatively high proportions of the more bioaccumulative and toxic substances of lower brominated PBDE congeners and α-HBCD in products may increase the adverse impacts on the environment and human health. The obtained results will be helpful to understand the downstream flow of POP-BFRs with great significance to the control on their unintended contamination in daily life.

Polybrominated diphenyl ethers (PBDEs) in dust in typical indoor public places in Hangzhou: Levels and an assessment of human exposure

Polybrominated diphenyl ethers (PBDEs) are organic pollutants (POPs) with the characteristics of environmental persistence, long-distance transmission in nature, biological accumulation and toxic effects on human health. To investigate the level of contamination due to PBDEs in typical indoor public places in Hangzhou, dust samples were collected from ten supermarkets, three electronic markets and five different areas throughout one commodity market. Based on sample pretreatment and GC-ECD instrumental analysis, the contamination characteristics, sources and the influencing factors of 14 PBDE congeners were analyzed. The results revealed that the mean of ∑₁₄PBDEs in dust in the supermarkets and electronic markets was 546.13 ng/g and 1140.05 ng/g, respectively, while in the commodity market the mean was 1005.42 ng/g and varied in the five different areas as follows: shoe areas (1367.22 ng/g) > parking lot (1001.05 ng/g) > waiting halls (970.31 ng/g) > packet areas (933.23 ng/g) > curtain areas (755.28 ng/g). The high levels of PBDE were attributed to the quantity of electrical appliances in the supermarkets (r = 0.708^*, p < 0.05) and the electronic markets (r = 0.799^**, p < 0.05) through Spearman correlation coefficient analysis. BDE-209 was the dominant congener, accounting for 53.72% in supermarkets and 64.25% in electronic markets. The calculated inhalation exposure revealed that the exposure level of PBDEs varied in supermarkets, electronic markets and commodity markets, with values of 0.476 ng/day/kg, 0.993 ng/day/kg and 0.876 ng/day/kg, respectively. Moreover, BDE-209's contribution to the total intake of PBDEs was the highest, with a value of 0.072-0.970 ng/day/kg, while the value of BDE-183 was the lowest, with a value of 0-0.020 ng/day/kg. The exposure level of PBDEs in the studied indoor public places was lower than the reference dose of EPA.

Tracing perfluoroalkyl substances (PFASs) in soils along the urbanizing coastal area of Bohai and Yellow Seas, China

With the shift of fluorine chemical industry from developed countries to China and increasing demand for fluorine chemical products, occurrence of perfluoroalkyl substances (PFASs) in production and application areas has attracted more attention. In this study, 153 soil samples were collected from 21 cities along the urbanizing coastal area of the Bohai and Yellow Seas. PFASs in this area were relatively higher, compared with other study areas. The concentrations ranged from 2.76 to 64.0 ng g^-1, and those in most sites were between 2.76 and 13.9 ng g^-1, with a predominance of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS). Among the 21 coastal cities, contaminations of PFASs in Zibo, Nantong and Binzhou were elevated, which was likely affected by local fluorine chemical plants, equipment manufacturing and chemical industry, respectively. The total emissions of PFOA and PFOS were similar, with amount of 4431 kg and 4335 kg, respectively. Atmospheric deposition was the largest source, accounting for 93.2% of total PFOA and 69.6% of PFOS, respectively. In addition, due to application of aqueous film-forming foams (AFFFs) and sulfluramid, disposal of sewage sludge and stacking of solid waste, emission of PFOA and PFOS to soil was 1617 kg, accounting for 9.29% of the whole China. In general, pollution in Jiangsu, Shandong and Tianjin was more serious than those in Liaoning and Hebei, which was consistent with industrialization level and size of industrial sectors emitting PFASs.

Carcinogenic activity of pentabrominated diphenyl ether mixture (DE-71) in rats and mice

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Pentabrominated diphenyl ether (PBDE) mixture was a multispecies carcinogen causing liver tumors in male and female rats and mice.

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Hras or Ctnnb1 mutations characterized the PBDE-induced liver tumors.

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PBDE-induced liver tumors increased with increasing PBDE exposure.

Pentabrominated diphenyl ether (PBDE) flame retardants have been phased out in Europe and in the United States, but these lipid soluble chemicals persist in the environment and are found human and animal tissues. PBDEs have limited genotoxic activity. However, in a 2-year cancer study of a PBDE mixture (DE-71) (0, 3, 15, or 50 mg/kg (rats); 0, 3, 30, or 100 mg/kg (mice)) there were treatment-related liver tumors in male and female Wistar Han rats [Crl:WI(Han) after in utero/postnatal/adult exposure, and in male and female B6C3F1 mice, after adult exposure. In addition, there was evidence for a treatment-related carcinogenic effect in the thyroid and pituitary gland tumor in male rats, and in the uterus (stromal polyps/stromal sarcomas) in female rats. The treatment-related liver tumors in female rats were unrelated to the AhR genotype status, and occurred in animals with wild, mutant, or heterozygous Ah receptor. The liver tumors in rats and mice had treatment-related Hras and Ctnnb mutations, respectively. The PBDE carcinogenic activity could be related to oxidative damage, disruption of hormone homeostasis, and molecular and epigenetic changes in target tissue. Further work is needed to compare the PBDE toxic effects in rodents and humans.

Life cycle analysis of perfluorooctanoic acid (PFOA) and its salts in China

China has been the largest producer and emitter of perfluorooctanoic acid and its salts (PFOA/PFO). However, the flows of PFOA/PFO from manufacture and application to the environment are indistinct, especially flows from waste treatment sites to the environment. Here, a life cycle analysis of PFOA/PFO is conducted in which all major flows of PFOA/PFO have been characterized for 2012. Processes related to uses and possible releases of PFOA/PFO include manufacture and use, waste management, and environmental storage. During manufacture and use, emission from application was the most important (117.0 t), regardless of whether it flowed first to waste treatment facilities or was directly released to the environment, followed by manufacture of PFOA/PFO (3.9 t), while flows from the service life and end of life of consumer products were the lowest (1.2 t). Among five waste treatment routes, flows through wastewater treatment plants (WWTPs) were the highest (10.6 t), which resulted in 12.8 t of PFOA/PFO being emitted into the environment. Masses of PFOA/PFO emission were estimated to be 96.3 t to the hydrosphere, 25.6 t to the atmosphere, and 3.2 t to soils. Therefore, control over reduction of PFOA/PFO should focus on application of reliable alternatives and emission reduction from WWTPs using effective treatment techniques.

Human Excretion of Polybrominated Diphenyl Ether Flame Retardants: Blood, Urine, and Sweat Study

Commonly used as flame retardants, polybrominated diphenyl ethers (PBDEs) are routinely detected in the environment, animals, and humans. Although these persistent organic pollutants are increasingly recognized as having serious health implications, particularly for children, this is the first study, to our knowledge, to investigate an intervention for human elimination of bioaccumulated PBDEs. Objectives. To determine the efficacy of blood, urine, and perspiration as PBDE biomonitoring mediums; assess excretion of five common PBDE congeners (28, 47, 99, 100, and 153) in urine and perspiration; and explore the potential of induced sweating for decreasing bioaccumulated PBDEs. Results. PBDE congeners were not found in urine samples; findings focus on blood and perspiration. 80% of participants tested positive in one or more body fluids for PBDE 28, 100% for PBDE 47, 95% for PBDE 99, and 90% for PBDE 100 and PBDE 153. Induced perspiration facilitated excretion of the five congeners, with different rates of excretion for different congeners. Conclusion. Blood testing provides only a partial understanding of human PBDE bioaccumulation; testing of both blood and perspiration provides a better understanding. This study provides important baseline evidence for regular induced perspiration as a potential means for therapeutic PBDE elimination. Fetotoxic and reproductive effects of PBDE exposure highlight the importance of further detoxification research.

Substance flow analysis and environmental releases of PBDEs in life cycle of automobiles

Polybrominated diphenyl ethers (PBDEs), a class of brominated flame retardants, have been widely used in many applications in industry such as automobiles, textiles, and electronics. This study focused on a quantitative substance flow analysis (SFA) of PBDEs in automobiles in order to identify their flow by life cycle and treatment pathways of PBDEs-containing materials in end-of-life vehicles (ELVs) in Korea. In addition, this study has estimated environmental releases of PBDEs in automobiles by life cycle in Korea. During this study, PBDEs were analyzed for the samples collected from several ELVs treatment facilities using X-ray fluorescence and gas chromatography/mass spectrometry (GC/MS) methods. The system boundary for SFA of PBDEs ranged from manufacturing/trade to disposal stage of automobiles by life cycle. Based on the result of the SFA, it was found that the amount of PBDEs in automobiles were the highest in use stage (7748ton/year), followed by production stage (1743ton/year) in 2014. In disposal stage, automobile shredded residues (ASR) and seat fabrics were the main components with relatively high levels of PBDEs in ELVs. The major treatment methods of such components included incineration (84%), energy recovery (9%), and landfilling (6%). This research indicates that PBDEs were emitted the highest amount from interior components during the use stage of automobiles, followed by recycling processes such as dismantling and shredding. This study suggests that PBDEs in ASR and seat fabrics should be properly managed to prevent the widespread dispersion in the environment.

Overview on relative importance of house dust ingestion in human exposure to polybrominated diphenyl ethers (PBDEs): International comparison and Korea as a case

Human exposure studies to polybrominated diphenyl ethers (PBDEs) have reached different results about the relative importance of diet intake and house dust ingestion. In the present study, concentrations of PBDEs in Korean house dust (n=15) from geographically different cities were measured, which were in agreement with a previous result, and compared with those for 22 countries of five continents collected from the most recent scientific literature. Compared with other exposure pathways, diet intake was the most important contributor to total PBDEs exposure of Korean adults (i.e., 71% of overall intake). On global comparison, total PBDE levels in house dust differed by two to three orders of magnitude among the countries investigated, with a significant relationship with gross domestic product (GDP). Whereas, dietary daily intakes exhibited a narrow difference within one order of magnitude worldwide and no relationship with GDP. Consequently, the relative importance of major two pathways depended on the contamination extent of PBDEs in house dust, which may be associated with the amount of PBDE products in use. In most countries except for UK and USA, the contribution of house dust ingestion was less important than diet intake in the current and are expected to much more mitigate in the future. However, how fast the effect of regulation will be reflected to house dust and human exposure is necessary to be monitored steadily.

Levels, distributions and correlations of polybrominated diphenyl ethers in air and dust of household and workplace in Shanghai, China: implication for daily human exposure

Polybrominated diphenyl ethers (PBDEs) were measured in air (TSP and PM2.5) and dust samples collected from 16 households and the corresponding workplaces of eight volunteer citizens in Shanghai, China. The PBDEs concentrations in the workplace air (mean: 281 ± 126 pg m(-3)) were over two times higher than those in the household (121 ± 44.0 pg m(-3)), while the mean levels of PBDEs in dust were 995 ± 547 and 544 ± 188 ng g(-1) for workplace and household, respectively. BDE209 was the most abundant congener in all samples. PBDEs appeared to be composed of mostly small particles. The C particle/C dust ratios of less brominated PBDEs in PM2.5 were higher than those in TSP, while the values were approximately constant for the more brominated PBDEs. A correlation analysis by network indicated different sources and behavior of the PBDE congeners. The results of a cluster analysis were displayed on a heat map that specified the source and abundance of each PBDE congener. The daily PBDE exposure via dust ingestion was the predominant part of the total intake and was more than 10 times higher than the intake via inhalation.

"Control-alt-delete": rebooting solutions for the E-waste problem

A number of efforts have been launched to solve the global electronic waste (e-waste) problem. The efficiency of e-waste recycling is subject to variable national legislation, technical capacity, consumer participation, and even detoxification. E-waste management activities result in procedural irregularities and risk disparities across national boundaries. We review these variables to reveal opportunities for research and policy to reduce the risks from accumulating e-waste and ineffective recycling. Full regulation and consumer participation should be controlled and reinforced to improve local e-waste system. Aiming at standardizing best practice, we alter and identify modular recycling process and infrastructure in eco-industrial parks that will be expectantly effective in countries and regions to handle the similar e-waste stream. Toxicity can be deleted through material substitution and detoxification during the life cycle of electronics. Based on the idea of "Control-Alt-Delete", four patterns of the way forward for global e-waste recycling are proposed to meet a variety of local situations.