Fate and migration of polybrominated diphenyl ethers in a workshop for waste printed circuit board de-soldering

20 years of polybrominated diphenyl ethers on toxicity assessments

Polybrominated diphenyl ethers (PBDEs) serve as brominated flame retardants which continue to receive considerable attention because of their persistence, bioaccumulation, and potential toxicity. Although PBDEs have been restricted and phased out, large amounts of commercial products containing PBDEs are still in use and discarded annually. Consequently, PBDEs added to products can be released into our surrounding environments, particularly in aquatic systems, thus posing great risks to human health. Many studies and reviews have described the possible toxic effects of PBDEs, while few studies have comprehensively summarized and analyzed the global trends of their toxicity assessment. Therefore, this study utilizes bibliometrics to evaluate the worldwide scientific output of PBDE toxicity and analyze the hotspots and future trends of this field. Firstly, the basic information including the most contributing countries/institutions, journals, co-citations, influential authors, and keywords involved in PBDE toxicity assessment will be visualized. Subsequently, the potential toxicity of PBDE exposure to diverse systems, such as endocrine, reproductive, neural, and gastrointestinal tract systems, and related toxic mechanisms will be discussed. Finally, we conclude this review by outlining the current challenges and future perspectives in environmentally relevant PBDE exposure, potential carriers for PBDE transport, the fate of PBDEs in the environment and human bodies, advanced stem cell-derived organoid models for toxicity assessment, and promising omics technologies for obtaining toxic mechanisms. This review is expected to offer systematical insights into PBDE toxicity assessments and facilitate the development of PBDE-based research.

Effect of Microwave Pretreatment on the Leaching and Enrichment Effect of Copper in Waste Printed Circuit Boards

The use of efficient and clean methods for the recycling of waste circuit boards is an ongoing challenge. In this research, the effect of microwave pretreatment on the leaching and enrichment of copper from waste print circuit board (WPCB) was studied. The morphology and chemical structure of WPCB particles before and after microwave pretreatment were analyzed by SEM/EDS and Fourier infrared spectroscopy. Leaching experiments and copper enrichment tests were designed to investigate the effect of different microwave irradiation powers and microwave irradiation times on the copper leaching rate and copper enrichment rate in WPCB. The leaching experiment results showed that microwave pretreatment can effectively improve the leaching rate of WPCB. When the microwave irradiation power was 700 W, the irradiation time was 120 s, and the leaching time was 15 min, the copper leaching rate in WPCB was 57.01%, which was 24.34% higher than that in the untreated condition. The results of copper enrichment experiment show that microwave pretreatment can effectively improve the copper enrichment of WPCB. After microwave pretreatment, copper was effectively enriched in the 4-2 and 2-1 mm particle sizes. When the microwave irradiation time was 120 s, the copper enrichment rates in the 4-2 and 2-1 mm particle sizes were 1.74 and 1.66, which increased by 0.63 and 0.32, respectively, compared to the untreated condition. Microwave pretreatment enables the effective separation of metallic copper from non-metallic components in WPCB, increasing the exposure area of copper and promoting the monomer separation of copper, thus improving the leaching and enrichment of copper.

Characteristics of microplastics and the role for complex pollution in e-waste recycling base of Shanghai, China

Plastics used in electric and electronic products cover a wide range, and contain many additives, such as brominated flame retardant and so on. These compounds and microplastics may be released into environment when the electric and electronic products are obsoleted and recycled. This study explores the characteristics of microplastics and the complex pollutions in a formal e-waste recycling base in Shanghai, China. The maximum abundance of microplastics is observed in dust samples of the recycling base and the average abundance is 44277 ± 69032p/50 g. 103 kinds of polymers are identified, including 4 kinds of packaging plastics, 32 kinds of engineering plastics, 18 kinds of rubber, and 49 kinds of other polymers. It is found that microplastics show weak adsorption effect for heavy metals. However, microplastics are important carrier of ∑₈PBDEs released during the whole recycling processes, and BDE-209 account for more than 50 % of PBDEs in microplastics. It is estimated that the microplastics load inside the e-waste recycling base was 4.01 tons based on the measured statistics. This study will provide theoretical basis for further understanding the potential pollution of microplastics and upgrading the corresponding control measures.

Exposure evaluation and risk assessment of polybrominated diphenyl ethers in dust from microenvironments in Nsukka, Nigeria

The health risks of polybrominated diphenyl ethers (PBDEs) to toddlers, children, and adults in creches, nursery schools, cars, and offices in Nsukka, Nigeria, via inhalation, ingestion, and dermal exposure pathways were evaluated. Eight PBDEs congeners (BDE-28, BDE-47, BDE-100, BDE-99, BDE-154, BDE-153, BDE-183, and BDE-209) were determined using gas chromatography-mass spectrometry. This is the first study on PBDEs in creches and nursery schools in Africa. The mean (median) ∑8PBDEs (ng/g) in creches, nursery schools, offices, and cars were 4355 (1850), 2095 (1130), and 37741 (2620) respectively. The concentrations of PBDEs between the three microenvironments were significantly different (p ˂ 0.05), and the highest concentration was found in cars. Ingestion of dust was the predominant pathway of exposure to PBDEs for toddlers and children, while dermal absorption was the dominant pathway for adults. Dermal absorption and ingestion in cars, creches, and nursery schools were of the same magnitude. Toddlers with the highest ingestion rate of PBDEs in creches, nursery schools, and cars are at risk especially from prolonged exposure.