Insights into Full-congener Profiles of Chlorinated Benzenes in Fly and Bottom Ash: Case Study in Vietnamese Industrial and Municipal Waste Incinerators.

Chlorinated benzenes (CBzs) are a group of organic pollutants, which have been industrially or unintentionally produced through various chemical and thermal processes. Studies on full congener profiles of CBzs in waste and environmental samples are relatively limited and not updated. In the present study, concentrations of 12 CBzs were determined in fly ash (FA) and bottom ash (BA) samples collected from one municipal waste incinerator (MWI) and one industrial waste incinerator (IWI) in northern Vietnam. Levels of Σ12CBzs were higher in bottom ash (median 25.3; range 1.59-45.7 ng/g) than in fly ash (median 7.30; range 1.04-30.0 ng/g). The CBz profiles were dominated by di- and tri-chlorinated congeners with the major congeners as 1,2,4-TCB, 1,2,3-TCB, 1,2-DCB, and 1,3-DCB. However, CBz profiles varied greatly between sample types and incinerators, implying differences in input materials, formation pathways, and pollutant behaviors. Incomplete combustion is possibly responsible for high levels of CBzs in industrial bottom ash. The emission factors of Σ12CBzs ranged from 21 to 600 µg/ton for fly ash and from 190 to 4570 µg/ton for bottom ash, resulting in annual emissions of about 6 and 3 g/year for the IWI and MWI, respectively. Our results suggest additional investigations on industrial emission and environmental occurrence of all 12 CBzs rather than solely focusing on regulated congeners like hexachlorobenzene and pentachlorobenzene.

Bioaccessibility of halogenated flame retardants and organophosphate esters in settled dust: Influences of specific dust matrices from informal e-waste and end-of-life vehicle processing areas in Vietnam.

Bioaccessibility of halogenated flame retardants (HFRs) and organophosphorus esters (OPEs) is necessarily investigated to provide more accurate risk assessment and information about absorption behavior of these pollutants. In this study, total and bioaccessible concentrations of HFRs (including legacy and alternative substances) and OPEs were determined in settled dust samples collected from Vietnamese e-waste and end-of-life vehicle (ELV) processing areas. Concentrations of both HFRs and OPEs were significantly higher in the e-waste dust than ELV dust. Bioavailability of HFRs and OPEs in dust was determined by using an in vitro assay with human-simulated digestive fluids, dialysis membrane, and Tenax® TA sorptive sink. Bioaccessibility of HFRs was markedly lower than that of OPEs, which could be largely due to higher hydrophobicity of HFRs compared to OPEs. Bioaccessibility of almost hydrophobic compounds were markedly lower in the e-waste dust (containing micronized plastic debris) than in the ELV dust (containing oily materials), suggesting the influence of specific dust matrices on pollutant bioaccessibility. Although the daily uptake doses of selected HFRs and OPEs from dust were markedly higher in the e-waste sites compared to the ELV sites, the direct exposure risk was not significant. Our results suggest that bioaccessibility can partly explain the differences between dust and uptake profiles, which may relate to accumulation profiles of HFRs and OPEs in human samples.

THE RETROSPECTIVE ANALYSIS OF TRIGEN INTERTAN NAIL IN THE TREATMENT OF UNSTABLE INTERTROCHANTERIC FEMORAL FRACTURES AT HOSPITAL FOR TRAUMATOLOGY AND ORTHOPAEDICS.

Background: Intertrochanteric fractures are highly prevalent among the elderly population, with approximately 90% occurring in individuals aged over 65. These geriatric fractures are associated with elevated mortality rates and significant functional impairment. Common treatment modalities for unstable intertrochanteric fractures include proximal femoral nail antirotation (PFNA) and the InterTan nail (IT). PFNA and IT are frequently employed due to their lower failure rates and favorable biomechanical properties, resulting in positive clinical outcomes for the management of unstable intertrochanteric fractures. The unique design of the IT nail, featuring two cephalocervical screws within an integrated mechanism, permits linear intraoperative compression and rotational stability of the neck and head fragment. In this study, we assess the clinical outcomes of IT nail utilization in the treatment of intertrochanteric fractures at the Hospital for Traumatology and Orthopedics. Methods: This study comprises a retrospective analysis and case series report. Between February 2021 and August 2021, we retrospectively evaluated 35 patients who underwent treatment with the IT nail for unstable intertrochanteric fractures. Epidemiological data, operative duration, intraoperative blood loss, intraoperative blood transfusion requirements, length of hospital stay, bone healing rates, and IT nail-related complications were recorded. Results: The mean age of the patients was 70.97 ± 16.97 years, with a mean operative time of 60 minutes, mean intraoperative blood loss of 160.86 ± 72.8 ml, mean intraoperative blood transfusion volume of 203.43 ± 189.29 ml, and a mean hospital stay of 7 days. Bone healing was observed in 97.14% of cases. Conclusions: The treatment of unstable intertrochanteric fractures using the IT nail in elderly patients was successful. Our findings indicate favorable clinical outcomes in terms of surgical duration, intraoperative blood loss, hospitalization duration, and union rates for elderly patients. Further investigations are warranted to validate these early results.

Quantification of parabens in marine fish samples by a rapid, simple, effective sample preparation method.

Parabens (p-hydroxybenzoic acid esters) commonly used preservatives (in cosmetics, pharmaceuticals, and foods) can pose potential effects on environmental health. In this study, seven parabens were quantified in marine fish samples using an ultra-high performance liquid chromatography triple quadrupole mass spectrometer (UHPLC-MS/MS) system. Parabens in the fish samples were extracted and purified by a rapid, simple, and effective procedure comprising sample homogenization with solvent, solid-phase extraction clean-up, and solvent evaporation. Results demonstrated that the recoveries of seven compounds (with relative standard deviation < 15%) were 88-103% in matrix-spike samples and 86-105% in surrogate standards. The method detection limits and method quantification limits of seven parabens were 0.015-0.030 and 0.045-0.090 ng/g-ww (wet weight), respectively. The optimized method was applied to measure the concentration of parabens in the 37 marine fish samples collected from Vietnam coastal waters. The concentration ranges of seven parabens found in round scad and greater lizardfish samples were 6.82-25.3 ng/g ww and 6.21-17.2 ng/g-ww, respectively. Among parabens, methylparaben accounted for the highest contribution in both fish species (43.2 and 44.9%, respectively). Based on the measured concentrations of parabens in marine fish samples, the estimated daily intake was calculated for children and adults with the corresponding values of 0.0477 µg/kg/day and 0.0119 µg/kg/day, respectively. However, the presence of parabens in Vietnamese marine fish may not pose a significant risk to human health.

Perfluoroalkyl substances in food contact materials: preliminary investigation in Vietnam and global comparison.

Per- and polyfluoroalkyl substances (PFASs) are a group of concerned persistent toxic substances, especially for their application or unintentional formation in food contact materials (FCMs). However, information about the occurrence, sources, and fate of these pollutants in food packaging materials from Vietnam as well as Southeast Asian countries is probably still obscured. In this study, levels of 13 perfluoroalkyl carboxylic acids (PFCAs) and 4 sulfonates (PFSs) were determined in various types of food packaging samples collected from Vietnamese markets. Generally low concentrations of total 17 PFASs (median 0.341; max 624 ng/g) suggested that these compounds were mainly inadvertently produced rather than intentionally added to the packaging materials. A few mochi paper tray samples had relatively high PFAS levels (372-624 ng/g), which were dominated by long-chain (C8-C12) PFCAs. A comprehensive and updated overview of PFASs in FCMs from different countries in the world was also provided. Current database could not provide conclusive trends of PFAS concentrations and profiles in FCMs between continents and countries. The highest levels up to ppm were reported for PFCAs (e.g., PFBA, PFHxA, PFOA, and PFDA) and several fluorotelomer alcohols and carboxylic acids, while PFSs were almost absent in FCMs. FPASs can emit from FCMs, migrate to food, and then contribute to dietary exposure in humans and animals. Additional investigations on the occurrence, sources, behavior and fate, and impacts of PFASs in FCMs are critically needed, especially in emerging and developing countries.

Polycyclic Aromatic Hydrocarbons in Air and Dust Samples from Vietnamese End-of-life Vehicle Processing Workshops: Contamination Status, Sources, and Exposure Risks.

Concentrations of 18 unsubstituted polycyclic aromatic hydrocarbons (PAHs) and 11 methylated derivatives (Me-PAHs) were measured in polyurethane foam-based passive air (PUF-PAS) and settled dust samples collected from end-of-life vehicle (ELV) processing workshops in northern Vietnam. Concentrations of total 29 PAHs ranged from 42 to 95 (median 57) ng/m3 and from 860 to 18,000 (median 5700) ng/g in air and dust samples, respectively. PAH levels in ELV air and dust samples were 1.5 ± 0.4 and 9.4 ± 7.9 times higher than levels found in a control house, suggesting ELV processing as potential PAH emission sources. Concentrations and proportions of Me-PAHs in total PAHs of the ELV air (26% ± 7%) and dust (41% ± 14%) were higher than those found in control house (18% in both air and dust). The occurrence of PAHs and Me-PAHs in the ELV workshops are attributed to not only pyrogenic but also petrogenic sources (i.e., improper treatment and management of fuels, lubricants, and vehicle oils).

The first full-congener analysis of 209 polychlorinated biphenyls (PCBs) in the blubber of short-finned pilot whales (Globicephala macrorhynchus) stranded along the coast of Savu Island, Indonesia.

Short-finned pilot whales (SFPW) are a group of cetaceans found globally in tropical and temperate seas and are commonly stranded in the group, but the reason behind their stranding is still unknown. No detailed information on the contamination status and bioaccumulation of halogenated organic compounds, including polychlorinated biphenyls (PCBs), in the SFPW from Indonesian waters has been reported. Therefore, we analyzed all 209 PCB congeners in the blubber of 20 SFPW specimens stranded along the coast of Savu Island, East Nusa Tenggara, Indonesia, in October 2012 to explain the status of contamination, congener profiles, potential risk of PCBs to cetaceans, and the determination of unintentionally produced PCBs (u-PCBs) in the blubber of SFPW. Concentrations of Σ209PCBs, Σ7in-PCBs, Σ12dl-PCBs, and Σ21u-PCBs were between 48 and 490 (mean:240 ± 140), 22-230 (110 ± 60), 2.6-38 (17 ± 10), and 1.0-13 (6.3 ± 3.7) ng g-1 lipid weight (lw), respectively. Congener-specific profiles of PCBs among sex and estimated age groups were observed; relatively high proportions of tri-to penta-CBs in juveniles and highly chlorinated recalcitrant congeners in structure-activity groups (SAGs) in sub-adult females were noted. The estimated toxic equivalency (TEQs) value for dl-PCBs ranged from 2.2 to 60 TEQWHO pg/g lw, with juveniles containing high TEQ values than sub-adults and adults. Although the TEQs and concentrations of PCBs in SFPW stranded along Indonesian coasts were lower than those reported for similar whale species from other North Pacific regions, further research is needed to assess the long-term impact of halogenated organic pollutants on their survival and health.

Widespread distribution of phthalic acid esters in indoor and ambient air samples collected from Hanoi, Vietnam.

In the present study, distribution characteristics of ten typical phthalic acid esters (PAEs) were investigated in 90 air samples collected from the urban areas in Hanoi, Vietnam from May to August 2022. The total concentrations of PAEs in indoor and ambient air samples were in the range of 320-4770 ng/m3 and 35.9-133 ng/m3, respectively. Total concentrations of PAEs in indoor air were about one order of magnitude higher than those in ambient air. Among PAEs studied, di-(2-ethyl)hexyl phthalate (DEHP) was measured at the highest levels in all air samples, followed by di-n-octyl phthalate (DnOP) and di-n-butyl phthalate (DnBP). The PAEs concentrations in air samples collected from laboratories at nighttime were significantly higher than those during daytime (p < 0.05). Meanwhile, the distributions of PAEs in various micro-environments in the same house are no statistically significant difference. The median exposure doses of PAEs through inhalation for adults and children were 248 and 725 ng/kg-bw/d, respectively. These exposure levels were still lower than the respective reference doses (RfD) proposed by the US EPA for selected compounds such as diethyl phthalate (DEP), DnBP, and DEHP.

First insight into accumulation of characteristics and tissue distribution of PCBs, PBDEs, and other BFRs in the living Indonesian coelacanth (Latimeria menadoensis).

Persistent organic pollutants, including polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and other brominated flame retardants, were detected in the liver, muscle, and ovary tissues of the Indonesian coelacanth (Latimeria menadoensis) incidentally caught around Gangga Island, North Sulawesi Province, Indonesia, on November 5, 2014. Concentrations of total PCBs (209 congeners, 300-2600 ng g-1 lipid weight) in all tissues showed higher than those of PBDEs (41 congeners, 3.9-6.3 ng g-1 lw) and BTBPE (1.1-3.6 ng g-1 lw). The tissue-specific PCB and PBDE profiles were likely due to differences in the lipid composition. Toxic equivalent (TEQ) values of dioxin-like PCBs in coelacanth tissues were lower than the benchmark values for early-life fish. However, compared with the data reported for deep-sea fishes in the Pacific and Indian Oceans, the relatively high concentrations of PCBs detected in this study raise concerns regarding Indonesian coelacanth conservation and habitat conditions.

Green Analytical Method for Simultaneous Determination of Glucosamine and Calcium in Dietary Supplements by Capillary Electrophoresis with Capacitively Coupled Contactless Conductivity Detection.

The need for analytical methods that are fast, affordable, and ecologically friendly is expanding. Because of its low solvent consumption, minimal waste production, and speedy analysis, capillary electrophoresis is considered a "green" choice among analytical separation methods. With these "green" features, we have utilized the capillary electrophoresis method with capacitively coupled contactless conductivity detection (CE-C4D) to simultaneously determine glucosamine and Ca2+ in dietary supplements. The CE analysis was performed in fused silica capillaries (50 µm inner diameter, 40 cm total length, 30 cm effective length), and the analytical time was around 5 min. After optimization, the CE conditions for selective determination of glucosamine and Ca2+ were obtained, including a 10 mM tris (hydroxymethyl) aminomethane/acetic acid (Tris/Ace) buffer of pH 5.0 as the background electrolyte; separation voltage of 20 kV; and hydrodynamic injection (siphoning) at 25 cm height for 30 s. The method illustrated good linearity over the concentration range of 5.00 to 200 mg/L of for glucosamine (R 2 = 0.9994) and 1.00 to 100 mg/L for Ca2+ (R 2 = 0.9994). Under the optimum conditions, the detection limit of glucosamine was 1.00 mg/L, while that of Ca2+ was 0.05 mg/L. The validated method successfully analyzed glucosamine and Ca2+ in seven dietary supplement samples. The measured concentrations were generally in line with the values of label claims and with cross-checking data from reference methods (HPLC and ICP-OES).

Sediment contamination with polybrominated diphenyl ethers and alternative brominated flame retardants: case study in urban lakes of Hanoi, Vietnam.

Information regarding the contamination of brominated flame retardants (BFRs) in lake sediments from Vietnam and Southeast Asia is still very limited. To fill such knowledge gaps, surface sediment samples from five urban lakes in Hanoi, Vietnam, were analyzed for polybrominated diphenyl ethers (PBDEs) and some other BFRs. Concentrations of total PBDEs ranged from 1.1 to 26 (median 6.6) ng/g dry weight with the most predominant congeners as BDE-209 (62 ± 17%), BDE-99 (10 ± 8%), and BDE-47 (6 ± 5%). Concentrations of other BFRs decreased in the order: decabromodiphenyl ethane (DBDPE) > 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE) > hexabromobiphenyl (BB-153) > pentabromoethylbenzene (PBEB), which were about one to two orders of magnitude lower than PBDEs. BDE-209 and DBDPE were highly correlated (Pearson's r = 0.879; p < 0.01), suggesting their similar applications and/or environmental fate. Potential sources of BFRs in lake sediments are estimated to be wastewater discharge, riverine inflow, and atmospheric deposition.

Assessment of cyclic volatile methyl siloxanes (CVMSs) in indoor dust from different micro-environments in northern and central Vietnam.

Comprehensive studies on emerging contaminants like volatile methyl siloxanes in settled dust from different micro-environments are still limited. In this study, concentrations and distribution of cyclic volatile methyl siloxanes (CVMSs) including D3, D4, D5, and D6 were examined in indoor dust samples collected from various micro-environments in northern and central Vietnam. Concentrations of total CVMSs in the dust samples ranged from 86.0 to 5890 (median 755) ng/g and decreased in the order: waste processing workshops (median 1560; range 329-5890) > common houses (650; 115-1680) > university classrooms (480; 86.0-1540) > vehicle repair shops (295; 126-1950) ng/g. This observation suggests that informal waste processing activities are sources of CVMSs. Among the studied CVMSs, D5 was the most predominant compound (41 ± 14%), followed by D6 (26 ± 13%), D4 (23 ± 12%), and D3 (11 ± 11%). Moderate positive correlations between D3/D4, D4/D5, and D5/D6 were found. Median daily intake doses of D3, D4, D5, and D6 through dust ingestion were 0.016, 0.051, 0.11, and 0.054 ng/kg/d, respectively, which were comparable to water consumption and markedly lower than the air inhalation pathway.

Occurrence, emission sources, and risk assessment of polybrominated diphenyl ethers and current-use brominated flame retardants in settled dust from end-of-life vehicle processing, urban, and rural areas, northern Vietnam.

Settled dust samples from Vietnamese end-of-life vehicle (ELV) processing, urban, and rural areas were analyzed for polybrominated diphenyl ethers (PBDEs) and other current-use brominated flame retardants (BFRs). PBDE levels found in dust samples collected from ELV workshops (median 390; range 120-520 ng/g) and nearby living areas (110; 36-650 ng/g) were generally higher than those in common house dust (25-170 ng/g). BDE-209 was the most predominant congener detected in almost all the samples, indicating extensive application of products containing deca-BDE mixtures. The dust samples from ELV workplaces showed a more abundance of lower brominated congeners (e.g., tetra- to hexa-BDEs) that may originate from car interior materials treated by penta-BDE formulations. Concentrations of other BFRs decreased in the order urban > rural > ELV dust, reflecting the current use of these compounds in new consumer products. Decabromodiphenyl ethane (DBDPE) and 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE) were the major alternative BFRs. Daily intake doses and hazard indexes of PBDEs and some other BFRs through dust ingestion were estimated and showed acceptable levels of risk. However, more comprehensive risk assessment considering multiple exposure pathways should be performed, especially for ELV workers and children in the ELV processing and urban areas.

A review on management practices, environmental impacts, and human exposure risks related to electrical and electronic waste in Vietnam: findings from case studies in informal e-waste recycling areas.

Electrical and electronic waste (e-waste) has become a global concern, especially in developing countries. In this review, we conducted a literature survey of e-waste management practices, processing activities, and adverse effects in Vietnam, an emerging country in Southeast Asia, by gathering data from peer-reviewed articles published between 2009 and 2021. This is the first review paper to comprehensively discuss management and research aspects regarding e-waste in an Asian developing country. Due to the lack of an effective management and recycling system, a certain portion of Vietnamese e-waste has been processed by informal sectors without appropriate recycling and pollution control technology, resulting in localized contamination and human exposure to toxic chemicals. Primitive processing activities, such as manual dismantling, open burning, and plastic recycling, have been identified as important contributors to the environmental emission and human exposure to toxic elements (notably As, Mn, Ni, Pb, Zn) and organic pollutants like flame retardants, PAHs, PCBs, and dioxin-related compounds. Informal e-waste processing from these small-scale workshops can release pollutants at similar levels compared to large-scale facilities in developed countries. This fact suggests an urgent need to develop management best practices for e-waste in Vietnam as well as other emerging and developing countries, in order to increase recycling efficiency and minimize their adverse impacts on environmental and human health.

Silicone wristband- and handwipe-based assessment of exposure to flame retardants for informal electronic-waste and end-of-life-vehicle recycling workers and their children in Vietnam.

Measuring personal exposure to flame retardants (FRs) is crucial for assessing and controlling human health risks posed by FRs during the recycling of electronic waste (e-waste) and end-of-life vehicles (ELVs). Here, we examined the use of handwipes and silicone wristbands to measure personal FR exposure for e-waste and ELV recycling workers and their children in Vietnam. On the handwipes from the e-waste recycling workers, the predominant five FRs detected were TBBPA (median concentration: 3700 ng/wipe), BDE-209 (1700 ng/wipe), TPHP (500 ng/wipe), DBDPE (410 ng/wipe), and BPA-BDPP (360 ng/wipe). On the handwipes from ELV recycling workers, TPHP (60 ng/wipe), IPPDPP (47 ng/wipe), BIPPPP/DIPPDPP (33 ng/wipe), BDE-209 (26 ng/wipe), and TCIPP (23 ng/wipe) were detected as the five predominant FRs. On the wristbands from the e-waste recycling workers, the five predominant FRs detected were TBBPA (median concentration: 340 ng/g), BDE-209 (330 ng/g), DBDPE (65 ng/g), TPHP (50 ng/g), and TMPP (34 ng/g). On the wristbands from the ELV recycling workers, TPHP (34 ng/g), IPPDPP (18 ng/g), TCIPP (14 ng/g), TDMPP (13 ng/g), BIPPPP/DIPPDPP (9.3 ng/g) and TMPP (9.3 ng/g) were detected as the predominant FRs. The data obtained with the wristbands were comparable to those obtained with the handwipes. Similar FR profiles were found in between the workers and their children. The profiles indicate that the informal e-waste and ELV recycling caused FR exposure not only for workers but also for their children who live in the workshops. By using the handwipe and wristband sampling approaches, we determined types and concentrations of FRs to which the workers and their children were dominantly exposed. Silicone wristband- and handwipe-based assessment is expected to be effective means of measuring personal FR exposure for the informal e-waste and ELV recycling workers and their children.

Comprehensive characterization of halogenated flame retardants and organophosphate esters in settled dust from informal e-waste and end-of-life vehicle processing sites in Vietnam: Occurrence, source estimation, and risk assessment.

Information about the co-occurrence of halogenated flame retardants (HFRs) and organophosphate esters (OPEs) in the environment of informal waste processing areas is still limited, especially in emerging and developing countries. In this study, OPEs and HFRs including polybrominated diphenyl ethers (PBDEs), novel brominated flame retardants (NBFRs), and chlorinated flame retardants (CFRs) were determined in settled dust from Vietnamese e-waste recycling (WR) and vehicle processing (VP) workshops. Pollutant concentrations decreased in the order: OPEs (median 1500; range 230-410,000 ng/g) ≈ PBDEs (1200; 58-250,000) > NBFRs (140; not detected - 250,000) > CFRs (13; 0.39-2200). HFR and OPE levels in the WR workshops for e-waste and obsolete plastic were significantly higher than in the VP workshops. Decabromodiphenyl ether and decabromodiphenyl ethane are major HFRs, accounting for 60 ± 26% and 25 ± 29% of total HFRs, respectively. Triphenyl phosphate, tris(2-chloroisopropyl) phosphate, and tris(1,3-dichloroisopropyl) phosphate dominated the OPE profiles, accounting for 30 ± 25%, 25 ± 16%, and 24 ± 18% of total OPEs, respectively. The OPE profiles differed between WR and VP dust samples, implying different usage patterns of these substances in polymer materials for electric/electronic appliance and automotive industries. Human health risk related to dust-bound HFRs and OPEs in the study areas was low.

PCDD/Fs and Dioxin-like PCBs in Chicken Eggs and Soils in Dong Nai Province, Southern Vietnam: Impacts of Raising Methods and Nearby Pollution Sources.

Polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs) and dioxin-like PCBs (DL-PCBs) were examined in chicken egg and soil samples collected from Dong Nai Province, southern Vietnam. PCDD/F and DL-PCB levels in egg samples ranged from 5.74 to 1320 (median 350) and from 120 to 51,200 (median 1470) pg/g lipid weight (lw), respectively. Toxic equivalents to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TEQ) in egg samples ranged from 0.817 to 245 (median 10.8) pg TEQ/g lw. Higher dioxin levels were found in free-range eggs than non-free-range ones. We found significant correlation between TEQ levels in paired egg and soil samples collected from the Bien Hoa Airbase and some communities adjacent to industrial areas (Spearman's ρ = 0.671; p < 0.05), suggesting the co-occurrence of legacy and current dioxin emission sources in these areas.

Phthalic acid esters (PAEs) in workplace and house dust from Vietnam: concentrations, profiles, emission sources, and exposure risk.

The occurrence of nine phthalic acid esters (PAEs) were determined in indoor dust samples collected from vehicle repair shops, waste processing workshops, and homes in Vietnam. Concentrations of total PAEs ranged from 585 to 153,000 (median 33,400 ng/g), which fall in the lower end of global range. The PAE levels in workplace dust (median 49,100; range 9210-153,000 ng/g) were significantly higher than those in house dust (median 23,700; range 585-83,700 ng/g), indicating waste processing activities as potential PAE sources. The most predominant compound was di-(2-ethyl)hexyl phthalate (DEHP), accounting for 62 ± 18% of total PAEs. Other major compounds were benzyl butyl phthalate (BzBP) (10 ± 12%), di-n-butyl phthalate (DnBP) (9.7 ± 7.7%), di-n-octyl phthalate (DnOP) (7.9 ± 8.1%), and diisobutyl phthalate (DiBP) (6.9 ± 5.0%). Proportions of BzBP and DnBP in some workplace dust samples were markedly greater than in common house dust, suggesting specific emission sources. Daily intake doses of selected PAEs (e.g., DnBP, DiBP, BzBP, and DEHP) through dust ingestion were much lower than reference doses, implying acceptable levels of risk.

Polybrominated diphenyl ethers in indoor dusts from industrial factories, offices, and houses in northern Vietnam: Contamination characteristics and human exposure.

Information about the occurrence of polybrominated diphenyl ethers (PBDEs) in indoor dusts from various industrial sectors in Southeast Asia is still scarce. In this study, concentrations and congener-specific profiles of PBDEs were determined in indoor dusts from industrial factories, offices, and houses in northern Vietnam. Levels of Σ8PBDEs were higher in the office dusts (median 270; range 230-300 ng/g) and factory dusts (170; 89-510 ng/g) than in the house dusts (61; 25-140 ng/g). BDE-209 was the most dominant congener, accounting for 27-98% (average 62%) of Σ8PBDEs, suggesting the abundance of products treated with deca-BDE mixtures. Residential, commercial, and industrial activities in the studied locations of this survey were not significant sources of PBDEs as compared to those of informal waste processing activities in Vietnam. Relatively low PBDE concentrations detected in our dust samples partially reflect effectiveness of the global PBDE phase-out. Human exposure and health risk associated with dust-bound PBDEs were estimated, indicating acceptable levels of risk (i.e., neurobehavioral effects). The contributions of workplace dusts in total daily intake doses of PBDEs via dust ingestion were more important for local workers in informal recycling areas than factory workers and general population, raising the need of appropriate labor protection measures.

Historical record of polychlorinated biphenyls in a sediment core from Lake Biwa, Japan: Significance of unintentional emission and weathering signals revealed by full congener-specific analysis.

The occurrence of 209 PCB congeners was determined in a sediment core dated between 1930 and 2019 from Lake Biwa, a typical temperate monomictic lake in Japan. Concentrations of total PCBs ranged from 5.3 to 48 ng/g dry weight (dw), showing a highest peak at the 1960s to 1970s. The temporal trend of total PCBs in this sediment core generally matched with Japanese PCB production and emission pattern (i.e., increasing from the 1950s, peaking at 1970, and gradually decreasing since 1972). The vertical PCB profiles in our core were affected by physical mixing and bioturbation. By using a detailed and comprehensive analytical method, we have found elevated concentrations and special historical profiles of several congeners such as CB-7, -11, -47/48/75, -51, -68, and -209, which are still rarely included in routine PCB analysis. Some tetra-CB congeners like CB-47/48/75, -51, and -68 showed their concentration peaks at the early 2010s, which may be unintentionally produced during polymer manufacturing processes. PCB homolog- and congener-specific profiles in our sediment core samples have experienced weathering with higher proportions of penta- and hexa-CBs as compared to the Kanechlor usage pattern (i.e., dominated by tri- and tetra-CBs). Both intentional (i.e., technical mixtures) and unintentional (e.g., PCB-containing polymers and pigments) sources of PCBs were suggested from congener-specific analysis.