Publications by authors named "Le Huu Tuyen"

21 Publications

  • Page 1 of 1

Characterization of unsubstituted and methylated polycyclic aromatic hydrocarbons in settled dust: Combination of instrumental analysis and in vitro reporter gene assays and implications for cancer risk assessment.

Sci Total Environ 2021 Sep 18;788:147821. Epub 2021 May 18.

Center of Advanced Technology for the Environment (CATE), Graduate School of Agriculture, Ehime University, 3-5-7 Tarumi, Matsuyama 790-8566, Japan. Electronic address:

Concentrations of 34 unsubstituted and methylated polycyclic aromatic hydrocarbons (PAHs and Me-PAHs) and AhR-mediated activities in settled dust samples were determined by a combination of gas chromatography-mass spectrometry and an in vitro reporter gene assay (PAH-CALUX). The levels of Σ34PAHs and bioassay-derived benzo[a]pyrene equivalents (CALUX BaP-EQs) were significantly higher in workplace dust from informal end-of-life vehicle dismantling workshops than in common house dust and road dust. In all the samples, the theoretical BaP-EQs of PAHs (calculated using PAH-CALUX relative potencies) accounted for 28 ± 19% of the CALUX BaP-EQs, suggesting significant contribution of aryl hydrocarbon receptor (AhR) agonists and/or mixture effects. Interestingly, the bioassay-derived BaP-EQs in these samples were significantly correlated with not only unsubstituted PAHs with known carcinogenic potencies but also many Me-PAHs, which should be included in future monitoring and toxicity tests. The bioassay responses of many sample extracts were substantially reduced but not suppressed with sulfuric acid treatment, indicating contribution of persistent AhR agonists. Cancer risk assessment based on the CALUX BaP-EQs has revealed unacceptable level of risk in many cases. The application of bioassay-derived BaP-EQs may reduce underestimation in environmental management and risk evaluation regarding PAHs and their derivatives (notably Me-PAHs), suggesting a consideration of using in vitro toxic activity instead of conventional chemical-specific approach in such assessment practices.
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http://dx.doi.org/10.1016/j.scitotenv.2021.147821DOI Listing
September 2021

Polycyclic aromatic hydrocarbons in airborne particulate matter samples from Hanoi, Vietnam: Particle size distribution, aryl hydrocarbon ligand receptor activity, and implication for cancer risk assessment.

Chemosphere 2021 Apr 30;280:130720. Epub 2021 Apr 30.

Centre for Environmental Technology and Sustainable Development (CETASD), University of Science, Vietnam National University, Hanoi, 334 Nguyen Trai, Hanoi, 11400, Viet Nam. Electronic address:

Concentrations and profiles of unsubstituted and methylated polycyclic aromatic hydrocarbons (PAHs and Me-PAHs) were analyzed in airborne particulate matter (PM) samples collected from high-traffic roads in Hanoi urban area. Levels of PAHs and Me-PAHs ranged from 210 to 660 (average 420) ng/m in total PM, and these pollutants were mainly associated with fine particles (PM) rather than coarser ones (PM and PM). Proportions of high-molecular-weight compounds (i.e., 5- and 6-ring) increased with decreasing particle size. Benzo[b+k]fluoranthene, indeno[1,2,3-cd]pyrene, and benzo[ghi]perylene were the most predominant compounds in the PM samples. In all the samples, Me-PAHs were less abundant than unsubstituted PAHs. The PAH-CALUX assays were applied to evaluate aryl hydrocarbon receptor (AhR) ligand activities in crude extracts and different fractions from the PM samples. Benzo[a]pyrene equivalents (BaP-EQs) derived by the PAH-CALUX assays for low polar fractions (mainly PAHs and Me-PAHs) ranged from 300 to 840 ng/m, which were more consistent with theoretical values derived by using PAH-CALUX relative potencies (270-710 ng/m) rather than conventional toxic equivalency factor-based values (22-69 ng/m). Concentrations of PAHs and Me-PAHs highly correlated with bioassay-derived BaP-EQs. AhR-mediated activities of more polar compounds and interaction effects between PAH-related compounds were observed. By using PAH-CALUX BaP-EQs, the ILCR values ranged from 1.0 × 10 to 2.8 × 10 for adults and from 6.4 × 10 to 1.8 × 10 for children. Underestimation of cancer risk can be eliminated by using effect-directed method (e.g., PAH-CALUX) rather than chemical-specific approach.
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http://dx.doi.org/10.1016/j.chemosphere.2021.130720DOI Listing
April 2021

Unsubstituted and Methylated PAHs in Surface Sediment of Urban Rivers in the Red River Delta (Hanoi, Vietnam): Concentrations, Profiles, Sources, and Ecological Risk Assessment.

Bull Environ Contam Toxicol 2021 Mar 24. Epub 2021 Mar 24.

Laboratory of Environmental Chemistry, Institute of Natural Product Chemistry, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Hanoi, 10000, Vietnam.

Unsubstituted and methylated polycyclic aromatic hydrocarbons (22 PAHs and 17 Me-PAHs) were examined in surface sediments collected from the Red River and four inner-city rivers of Hanoi City, Vietnam. Concentrations of total PAHs and Me-PAHs ranged from 52 to 920 (median 710) and from 70 to 2600 (median 1000) ng/g dry weight in samples of dry and wet seasons, respectively. Significant correlation was observed between total PAHs and organic carbon contents (Spearman's ρ = 0.782; p < 0.05). PAHs were more abundant than Me-PAHs in all samples and dominated by 4-6 ring compounds. The most predominant PAHs were benzo[ghi]perylene, benzo[b/j]fluoranthene, chrysene, pyrene, fluoranthene, and phenanthrene. Methylated derivatives of naphthalene, phenanthrene, anthracene, and benz[a]anthracene were frequently detected. The patterns of PAHs indicated principal pyrogenic sources (notably gasoline exhaust) in this highly urbanized area. The occurrence of several PAHs were occasionally associated with adverse effects on benthic organisms of the inner-city rivers.
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http://dx.doi.org/10.1007/s00128-021-03174-yDOI Listing
March 2021

Inhalation bioaccessibility and health risk assessment of flame retardants in indoor dust from Vietnamese e-waste-dismantling workshops.

Sci Total Environ 2021 Mar 9;760:143862. Epub 2020 Dec 9.

Center for Material Cycles and Waste Management Research, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba 305-8506, Japan.

Although bioaccessibility testing is applied worldwide for appropriate chemical risk assessment, few studies have focused on the bioaccessibility of flame retardants (FRs), especially inhalation exposure. This study assessed inhalation exposure to FRs in indoor dust by workers at e-waste-dismantling workshops in northern Vietnam, by using modified simulated epithelial lung fluid (SELF) and artificial lysosomal fluid (ALF). The average mass concentrations of FRs were 130,000 ng/g for workplace dust (n = 3), 140,000 ng/g for floor dust (n = 3), and 74,000 ng/g for settled dust (n = 2), whereas the average bioaccessible concentrations of FRs were 1900, 1400, and 270 ng/g in the SELF condition and 2600, 770, and 490 ng/g in the ALF condition, respectively. Results clearly indicate that the bioaccessible concentrations of FRs are markedly lower than their mass concentrations. Tris(2-chloroethyl) phosphate (TCEP, ~19%), tris(2-chloroisopropyl) phosphate (TCIPP, ~35%), and tris(1,3-dichloroisopropyl) phosphate (TDCIPP, ~22%) showed comparably high bioaccessibility in both SELF and ALF conditions. In contrast, the bioaccessibility of tetrabromobisphenol A (TBBPA, ~20%) was high in the SELF condition, but not in the ALF condition. With regard to the test compounds' physicochemical properties, the inhalation bioaccessibility of FRs in both conditions increased as molecular weight or octanol-water partition coefficient decreased, and it decreased as water solubility decreased. Health risk assessment clearly indicated that the hazard quotient of FRs via inhalation exposure for workers in the e-waste-dismantling workshops was less than 1, suggesting that the inhalation exposure to FRs during indoor dismantling of e-waste at this site was negligible based on the current methodology of non-cancer health risk assessment used in this study.
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http://dx.doi.org/10.1016/j.scitotenv.2020.143862DOI Listing
March 2021

Antibiotic and antiparasitic residues in surface water of urban rivers in the Red River Delta (Hanoi, Vietnam): concentrations, profiles, source estimation, and risk assessment.

Environ Sci Pollut Res Int 2021 Mar 24;28(9):10622-10632. Epub 2020 Oct 24.

Laboratory of Environmental Chemistry, Institute of Natural Product Chemistry, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Cau Giay, Hanoi, 10000, Vietnam.

Antibiotic residues and antimicrobial resistance in surface water are issues of global concern, especially in developing countries. In this study, the occurrence of seven antibiotics and one antiparasitic agent was determined in surface water samples collected from four rivers running through Hanoi urban area in the Red River Delta, northern Vietnam. The pharmaceuticals in water samples were analyzed by solid-phase extraction combined with liquid chromatography-tandem mass spectrometry method. The concentrations of pharmaceuticals in our samples ranged from 3050 to 16,700 (median 7800) ng/L, which were generally higher than levels found in river water from many other locations in the world. Amoxicillin, oxfendazole, and lincomycin were the most dominant and frequently detected compounds (detection rate 100%), which together accounted for 76 ± 14% of total concentrations. Sulfacetamide and sulfamethoxazole were detected at moderate concentrations in more than two-thirds of the analyzed samples. The remaining antibiotics (i.e., azithromycin, ciprofloxacin, and ofloxacin) were found at lower detection frequency and concentrations. Antibiotic concentrations in the water samples were not significantly different between the investigated rivers. Meanwhile, levels of pharmaceuticals in the samples collected in February 2020 were higher than those found in the remaining samples, largely due to the sharp decrease in sulfamethoxazole and azithromycin concentrations of the samples collected in March and April. Considerable ecological risks of antibiotics in surface water were estimated for some compounds such as amoxicillin, ciprofloxacin, and ofloxacin.
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http://dx.doi.org/10.1007/s11356-020-11329-3DOI Listing
March 2021

Antibiotics in surface water of East and Southeast Asian countries: A focused review on contamination status, pollution sources, potential risks, and future perspectives.

Sci Total Environ 2021 Apr 9;764:142865. Epub 2020 Oct 9.

University of Science, Vietnam National University, 334 Nguyen Trai, Thanh Xuan, Hanoi 10000, Viet Nam.

This review provides focused insights into the contamination status, sources, and ecological risks associated with multiple classes of antibiotics in surface water from the East and Southeast Asia based on publications over the period 2007 to 2020. Antibiotics are ubiquitous in surface water of these countries with concentrations ranging from <1 ng/L to hundreds μg/L and median values from 10 to 100 ng/L. Wider ranges and higher maximum concentrations of certain antibiotics were found in surface water of the East Asian countries like China and South Korea than in the Southeast Asian nations. Environmental behavior and fate of antibiotics in surface water is discussed. The reviewed occurrence of antibiotics in their sources suggests that effluent from wastewater treatment plants, wastewater from aquaculture and livestock production activities, and untreated urban sewage are principal sources of antibiotics in surface water. Ecological risks associated with antibiotic residues were estimated for aquatic organisms and the prevalence of antibiotic resistance genes and antibiotic-resistant bacteria were reviewed. Such findings underline the need for synergistic efforts from scientists, engineers, policy makers, government managers, entrepreneurs, and communities to manage and reduce the burden of antibiotics and antibiotic resistance in water bodies of East and Southeast Asian countries.
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http://dx.doi.org/10.1016/j.scitotenv.2020.142865DOI Listing
April 2021

Assessment and source identification of As and Cd contamination in soil and plants in the vicinity of the Nui Phao Mine, Vietnam.

Environ Geochem Health 2020 Dec 1;42(12):4193-4201. Epub 2020 Jul 1.

Department of Energy and Resources Engineering, Kangwon National University, Chuncheon-si, 24341, Republic of Korea.

This study investigated the contamination levels and sources of As and Cd vicinity area from Nui Phao mine that is one of the largest tungsten (W) open pit mines in the world. Soil and plant samples were collected from the study area to identify the concentrations of As and Cd using aqua-regia or HNO digestion. According to the Vietnamese agricultural soil criteria, all soil samples were contaminated with As and Cd. The distribution of As concentration is related to the distance from the Nui Phao mine. The higher As concentrations were measured in the area close to the mine. However, the Cd distribution in the soil showed a different pattern from As. Enrichment factor and Geoaccumulation Index (Igeo) indicated that As in the soil is derived from the mining activities, while Cd could have other geogenic or anthropogenic sources. The ranges of As and Cd concentration in polished rice grains in the Nui Phao mine area exceeded the CODEX criteria (0.2 mg/kg), which indicated extreme contamination. The arsenic concentration between soil and plant samples was determined to be a positive correlation, while the Cd concentration showed a negative correlation, implying that As and Cd have different geochemical behavior based on their sources.
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http://dx.doi.org/10.1007/s10653-020-00631-1DOI Listing
December 2020

Polychlorinated biphenyls in settled dusts from an end-of-life vehicle processing area and normal house dusts in northern Vietnam: Occurrence, potential sources, and risk assessment.

Sci Total Environ 2020 Aug 21;728:138823. Epub 2020 Apr 21.

Center of Advanced Technology for the Environment (CATE), Graduate School of Agriculture, Ehime University, 3-5-7 Tarumi, Matsuyama 790-8566, Japan. Electronic address:

Concentrations and congener-specific profiles of total 209 polychlorinated biphenyls (PCBs) were investigated in settled dust samples collected from end-of-life vehicle (ELV) processing, urban, and rural areas in northern Vietnam. Concentrations of total 209 PCBs, seven indicator congeners, and twelve dioxin-like PCBs decreased in the order: ELV working > ELV living ≈ urban > rural dusts. Penta- and hexa-CBs dominated the homolog patterns in all the samples with higher proportions in the ELV dusts compared to the urban and rural house dusts. The abundance and pattern of PCBs in the ELV dusts suggest on-going emissions of these compounds related to processing of vehicular oils and lubricants containing PCBs, whereas the presence of PCBs in the urban and rural house dusts indicate long-time releases. However, levels of some PCBs identified as by-products of pigment manufacturing (e.g., PCB-11 and PCB-209) were higher in the urban house dusts than those from other locations, resulting from human activities utilizing paints and pigments. Daily intake doses (ID), non-carcinogenic hazard quotient (HQ), and lifetime cancer risk (CR) of PCBs through dust ingestion were estimated for ELV workers and residents in the studied areas. The workers and children in the ELV sites were estimated to be at higher risk of PCB exposure, however almost all of the HQ < 1 and CR < 10 indicate no serious risk related to dust-bound PCBs.
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http://dx.doi.org/10.1016/j.scitotenv.2020.138823DOI Listing
August 2020

Contamination of heavy metals in paddy soil in the vicinity of Nui Phao multi-metal mine, North Vietnam.

Environ Geochem Health 2020 Dec 6;42(12):4141-4158. Epub 2020 Jun 6.

School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju, 61005, Republic of Korea.

Nui Phao mine in Thai Nguyen Province, Vietnam, is the second-largest tungsten (W) open-pit mine in the world, but the level of environmental impacts is not well known. In order to examine the heavy metal contamination in the ecosystem of this mining area, we analyzed six trace elements (As, Cd, Cr, Cu, Pb and Zn) in the collected soil samples. The analytical results showed that all the soil samples were contaminated by Cd and As. Most of the soil samples were contaminated by As (mean value 50.93 ± 55.44 mg/kg) and Cd (mean value 15.22 ± 9.51 mg/kg), which figures are up to 16 and 23 times higher, respectively, compared with the Vietnamese soil quality standard for agriculture (QCVN 03-MT:2015/BTNMT) of 15 mg/kg for As and 1.5 mg/kg for Cd. Contamination factor (CF), enrichment factor (EF), geo-accumulation index (Igeo), principal component analysis (PCA) and hierarchical clustering analysis (HCA) were used to identify the influence of mining activity in the contamination. The CF, EF, pollution index (PI) and Igeo indicated that this area was extremely polluted by Cd, severely to moderately-heavily polluted by As and slightly to moderately polluted by other elements such as Cr, Cu, Pb and Zn. The PCA and HCA results also attribute the source of As, Pb and Zn contamination and enrichment of Cd, Cr and Cu in the study area to Nui Phao mining activities. The PI and contamination degree (C) values of soil quality indicate that the study area was contaminated with particular reference to Cd and As and the level of contamination was decreased in the order of Pb > Cr > Cu > Zn. The study area had high potential ecological risk, and the carcinogenic risk value was higher than the acceptable value (1 × 10 to 1 × 10). This means that the local resident health is strongly affected by Nui Phao mining activities both directly and indirectly via food consumption, when rice plant grown in the paddy field is the dominant crop in the study area.
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http://dx.doi.org/10.1007/s10653-020-00611-5DOI Listing
December 2020

Bioaccessibility and exposure assessment of flame retardants via dust ingestion for workers in e-waste processing workshops in northern Vietnam.

Chemosphere 2020 Jul 29;251:126632. Epub 2020 Mar 29.

Center for Material Cycles and Waste Management Research, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, 305-8506, Japan.

Flame retardants (FRs) from electronic waste (e-waste) are a widespread environmental concern. In our study, in vitro physiologically based extraction tests (PBETs) for FRs were conducted in three different areas where dust remained after processing of e-waste to identify the bioaccessible FRs and quantify their bioaccessibilities of gastrointestinal tract for human as well as to assess the exposure via ingestion of workers in e-waste processing workshops. All 36 FRs were measured and detected in indoor dusts. Among the FRs, the mean concentrations of polybrominated diphenyl ethers (PBDEs) in the floor dust and settled dust were highest, 65,000 ng/g, and 31,000 ng/g, respectively. In contrast, phosphorus-containing flame retardants (PFRs) presented the highest mean concentration in the workplace dust samples, 64,000 ng/g. However, the highest bioaccessible concentrations in workplace dust, floor dust, and settled dust were observed for PFRs: 5900, 1600, and 680 ng/g, respectively. This study revealed that the higher bioaccessibility of PFRs versus other compounds was related to the negative correlation between FR concentrations and log K (hydrophobicity) values. The fact that hazard indices calculated using measured bioaccessibilities were less than 1 suggested that the non-cancer risk to human health by the FRs exposure via dust ingestion might be low.
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http://dx.doi.org/10.1016/j.chemosphere.2020.126632DOI Listing
July 2020

Polyurethane foam-based passive air sampling for simultaneous determination of POP- and PAH-related compounds: A case study in informal waste processing and urban areas, northern Vietnam.

Chemosphere 2020 May 21;247:125991. Epub 2020 Jan 21.

Center of Advanced Technology for the Environment (CATE), Graduate School of Agriculture, Ehime University, 3-5-7 Tarumi, Matsuyama, 790-8566, Japan. Electronic address:

Polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), hexabromobiphenyl (BB-153), novel brominated flame retardants (NBFRs), and unsubstituted/methylated polycyclic aromatic hydrocarbons (PAHs/Me-PAHs) were simultaneously monitored in the air samples collected from Vietnamese urban and vehicular waste processing areas by using polyurethane foam-based passive air sampling (PUF-PAS) method. Concentrations (pg m) of organic pollutants decreased in the order: PAHs (median 29,000; range 5100-100,000) > Me-PAHs (6000; 1000-33,000) > PCBs (480; 170-1100) > PBDEs (11; 5.3-86) > NBFRs (0.20; n. d. - 51) > BB-153 (n.d.). The difference in total PCB and PBDE concentrations between the urban and waste processing air samples was not statistically significant. Meanwhile, levels of PAHs, Me-PAHs, benzo [a]pyrene equivalents (BaP-EQs), and toxic equivalents of dioxin-like PCBs (WHO-TEQs) were much higher in the waste processing sites. This is the first report on the abundance of mono- and di-CBs (notably CB-11) in the air from a developing country, suggesting their roles as emerging and ubiquitous air pollutants. Our results have indicated potential sources of specific organic pollutants such as dioxin-like PCBs, PAHs, and Me-PAHs from improper treatment of end-of-life vehicles and other vehicle related materials (e.g., waste oils and rubber tires), as well as current emission of PCBs and PBDEs in the urban area in Vietnam. Further atmospheric monitoring studies should be conducted in this developing country that cover both legacy and emerging contaminants with a focus on areas affected by rapid urbanization and informal waste processing activities.
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http://dx.doi.org/10.1016/j.chemosphere.2020.125991DOI Listing
May 2020

Soil and sediment contamination by unsubstituted and methylated polycyclic aromatic hydrocarbons in an informal e-waste recycling area, northern Vietnam: Occurrence, source apportionment, and risk assessment.

Sci Total Environ 2020 Mar 5;709:135852. Epub 2019 Dec 5.

Centre for Environmental Technology and Sustainable Development (CETASD), VNU University of Science, Vietnam National University, Hanoi, 334 Nguyen Trai, Hanoi, Viet Nam. Electronic address:

Improper processing activities of e-waste are potential sources of polycylic aromatic hydrocarbons (PAHs) and their derivatives, however, information about the environmental occurrence and adverse impacts of these toxic substances is still limited for informal e-waste recycling areas in Vietnam and Southeast Asia. In this study, unsubstituted and methylated PAHs were determined in surface soil and river sediment samples collected from a rural village with informal e-waste recycling activities in northern Vietnam. Total levels of PAHs and MePAHs decreased in the order: workshop soil (median 2900; range 870-42,000 ng g) > open burning soil (2400; 840-4200 ng g) > paddy field soil (1200; range 530-6700 ng g) > river sediment samples (750; 370-2500 ng g). About 60% of the soil samples examined in this study were heavily contaminated with PAHs. Fingerprint profiles of PAHs and MePAHs in the soil and sediment samples indicated that these pollutants were mainly released from pyrogenic sources rather than petrogenic sources. The emissions of PAHs and MePAHs in this area were probably attributed to uncontrolled burning of e-waste and agricultural by-products, domestic coal and biomass combustion, and traffic activities. Carcinogenicity and mutagenicity of PAHs in the e-waste workshop soils were significantly higher than those of the field soils; however, the incremental lifetime cancer risk of PAH-contaminated soils in this study ranged from 5.5 × 10 to 4.6 × 10, implying acceptable levels of human health risk. Meanwhile, concentrations of some compounds such as phenanthrene, anthracene, fluoranthene, benz[a]anthracene, and benzo[a]pyrene in several soil samples exceeded the maximum permissible concentrations, indicating the risk of ecotoxicological effects.
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http://dx.doi.org/10.1016/j.scitotenv.2019.135852DOI Listing
March 2020

Emission Characteristics of Polycyclic Aromatic Hydrocarbons and Nitro-Polycyclic Aromatic Hydrocarbons from Open Burning of Rice Straw in the North of Vietnam.

Int J Environ Res Public Health 2019 07 2;16(13). Epub 2019 Jul 2.

Institute of Nature and Environmental Technology, Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa 920-1192, Japan.

This research investigated the distribution and contribution of polycyclic aromatic hydrocarbons (PAHs) and nitro-polycyclic aromatic hydrocarbons (NPAHs) bound to particulate matter (PM) emitted from open burning of rice straw (RS) into the atmosphere in the north of Vietnam. The experiments were conducted to collect PM and total suspended particulates (TSP) prior to and during burning in the period of 2016-2018 in suburban areas of Hanoi. Nine PAHs and 18 NPAHs were determined using the HPLC-FL system. The results showed that the proportion of RS burning seasonally affects the variation of PAHs emission in atmospheric environment. The levels of nine PAHs from RS burning were 254.4 ± 87.8 µg g for PM and 209.7 ± 89.5 µg g for TSP. We observed the fact that, although fluoranthene (Flu) was the most abundant PAH among detected PAHs both in PM and TSP, the enrichment of Flu in TSP from burning smoke was higher than that in PM while the contribution of benzo[]pyrene (BP) and indeno[]pyrene (IDP) in PM from burning smoke were much higher than those in TSP. This research found that 1-nitropyrene (1-NP) and 6-nitrochrysene (6-NC) emit from RS burning with the same range with those from wood burning. The 2-nitrofluorene (2-NF) and 2-nitropyrene (2-NP) released from RS burning as the secondary NPAHs. This research provides a comprehensive contribution characterization of PAHs and NPAHs in PM with different size emitted from traditional local rice straw burning in the north of Vietnam. The results help to clarify the environmental behavior of toxic organic compounds from RS burning in Southeast Asia.
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http://dx.doi.org/10.3390/ijerph16132343DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6651601PMC
July 2019

Polycyclic aromatic hydrocarbons and their methylated derivatives in settled dusts from end-of-life vehicle processing, urban, and rural areas, northern Vietnam: Occurrence, source apportionment, and risk assessment.

Sci Total Environ 2019 Jul 3;672:468-478. Epub 2019 Apr 3.

Center of Advanced Technology for the Environment (CATE), Graduate School of Agriculture, Ehime University, 3-5-7 Tarumi, Matsuyama 790-8566, Japan. Electronic address:

The occurrence and profiles of 19 polycyclic aromatic hydrocarbons (PAHs) and 15 methylated derivatives (Me-PAHs) were examined in settled dust samples collected from workplaces and living areas of an informal end-of-life vehicle (ELV) processing village, and house dusts from urban and rural areas in northern Vietnam. Concentrations of total PAHs and Me-PAHs decreased in the order: ELV workplace (median 5700, range 900-18,000 ng g) > rural house (3700, 1800-6200 ng g) > urban house (1800, 620-3100 ng g) ≈ ELV living dusts (1000, 600-3900 ng g). PAHs with 4 rings or more dominated in almost all the samples, indicating the abundance of pyrogenic sources (e.g., vehicular emissions and domestic thermal processes). Levels of Me-PAHs were exceeded those of PAHs in several ELV samples, revealing specific petrogenic sources derived from vehicle processing activities. Results from source apportionment analysis have partially identified traffic emission, biomass and coal combustion, and mixed petrogenic-pyrogenic sources related to ELV waste as the major sources of PAHs and Me-PAHs in the urban, rural, and ELV areas, respectively. Daily intake doses and health risk related to PAHs and Me-PAHs in settled dusts were estimated for ELV workers and residents living in the study areas. The worst exposure scenario of dust-bound PAHs showed a potential cancer risk for the ELV workers, meanwhile, no significant non-cancer and cancer risk was expected for other exposed groups. A more comprehensive and accurate risk assessment of PAHs and related compounds should be conducted in Vietnam.
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http://dx.doi.org/10.1016/j.scitotenv.2019.04.018DOI Listing
July 2019

A preliminary investigation of 942 organic micro-pollutants in the atmosphere in waste processing and urban areas, northern Vietnam: Levels, potential sources, and risk assessment.

Ecotoxicol Environ Saf 2019 Jan 22;167:354-364. Epub 2018 Oct 22.

Center of Advanced Technology for the Environment (CATE), Graduate School of Agriculture, Ehime University, 3-5-7 Tarumi, Matsuyama 790-8566, Japan. Electronic address:

Of 942 organic micro-pollutants screened, 167 compounds were detected at least once in the atmosphere in some primitive waste processing sites and an urban area in northern Vietnam by using a polyurethane foam-based passive air sampling (PUF-PAS) method and an Automated Identification and Quantification System with a Database (AIQS-DB) for GC-MS. Total concentrations of organic pollutants were higher in samples collected from an urban area of Hanoi city (2300-2600 ng m) as compared with those from an end-of-life vehicle (ELV) dismantling area in Bac Giang (900-1700 ng m) and a waste recycling cooperative in Thai Nguyen (870-1300 ng m). Domestic chemicals (e.g., n-alkanes, phthalate ester plasticizers, and synthetic phenolic antioxidants) dominated the organic pollutant patterns in all the samples, especially in the urban area. Pesticides (e.g., permethrins, chlorpyrifos, and propiconazole) were found in the atmosphere around the ELV sites at more elevated concentrations than the other areas. Levels of polycyclic aromatic hydrocarbons and their derivatives in the Bac Giang and Thai Nguyen facilities were significantly higher than those measured in Hanoi urban houses, probably due to the waste processing activities. Daily intake doses of organic pollutants via inhalation were estimated for waste processing workers and urban residents. This study shall provide preliminary data on the environmental occurrence, potential emission sources, and effects of multiple classes of organic pollutants in urban and waste processing areas in northern Vietnam.
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http://dx.doi.org/10.1016/j.ecoenv.2018.10.026DOI Listing
January 2019

Exposure assessment of heavy metals in an e-waste processing area in northern Vietnam.

Sci Total Environ 2018 Apr 2;621:1115-1123. Epub 2017 Nov 2.

Center for Material Cycles and Waste Management Research, National Institute for Environmental Studies, Japan.

In developing countries, inappropriate recycling of e-waste has resulted in the environmental release of toxicants, including heavy metals, that may have deleterious health effects. In this study, we estimated daily metal intakes in five households in a Vietnamese village located in an e-waste processing area and assessed the health risk posed by exposure to the metals. Garden soil, floor dust, 24-h duplicate diet, and ambient air samples were collected from five households in northern Vietnam in January 2014. All samples were acid-digested, and contents of Cd, Cu, Mn, Pb, Sb, and Zn were measured by using ICP mass spectrometry and ICP atomic emission spectroscopy. In addition, the soil, dust, and diet samples were subjected to an bioaccessibility extraction test to determine bioaccessible metal concentrations. Hazard quotients were estimated from bioaccessible metal concentrations, provisional tolerable weekly intakes, and reference doses. Garden soil and floor dust were estimated to be mainly contributors to daily Pb intake, as indicated by calculations using bioaccessible metal concentrations and the U.S. Environmental Protection Agency soil plus dust ingestion rate. Diet was suggested to contribute significantly to daily Cd, Cu, Mn, Sb, and Zn intake. Estimated metal exposures via inhalation were negligible, as indicated by calculations using International Atomic Energy Agency reference inhalation rates. The maximum hazard quotients were calculated as 0.2 (Cd), 0.09 (Cu), 0.3 (Mn), 0.6 (Pb), 0.2 (Sb), and 0.5 (Zn), on the basis of bioaccessible metal concentrations. The contributions of Cd, Cu, Mn, Sb, and Zn except Pb to potential noncancer risk for adult residents of the five households in the e-waste processing area may be low.
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http://dx.doi.org/10.1016/j.scitotenv.2017.10.115DOI Listing
April 2018

Concentrations of polybrominated diphenyl ethers and alternative flame retardants in surface soils and river sediments from an electronic waste-processing area in northern Vietnam, 2012-2014.

Chemosphere 2017 Jan 11;167:291-299. Epub 2016 Oct 11.

Center for Material Cycles and Waste Management Research, National Institute for Environmental Studies (NIES), 16-2 Onogawa, Tsukuba 305-8506, Japan.

We investigated the concentrations of polybrominated diphenyl ethers (PBDEs) and alternative flame retardants (FRs) in environmental samples collected in January 2012, 2013, and 2014 from an electronic waste-processing area in northern Vietnam. During the study period, PBDE and alternative FR concentrations in soils around the electronic waste-processing workshops ranged from 37 to 9200 ng g dry weight (dw) and from 35 to 24,000 ng g dw; the concentrations in soils around the open-burning sites ranged from 1.6 to 62 ng g dw and from <4 to 1900 ng g dw; and the concentrations in river sediments around the workshops ranged from 100 to 3800 ng g dw and from 23 to 6800 ng g dw, respectively. Over the course of study period, we observed significant decreases in concentrations of PBDEs and significant increases in concentrations of alternative FRs, particularly Dechlorane Plus isomers and oligomeric organophosphorus FRs (o-PFRs) in both soils and sediments around the workshops. We also report information on concentrations and environmental emissions of o-PFRs and their low-molecular-weight impurities in the same soils and sediments. The detection of o-PFR impurities around the workshops and the open-burning sites highlights an enhanced breakdown of o-PFRs probably due to weathering during open storage and high temperature attained during the burning of electronic wastes.
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http://dx.doi.org/10.1016/j.chemosphere.2016.09.147DOI Listing
January 2017

Flame retardant emission from e-waste recycling operation in northern Vietnam: environmental occurrence of emerging organophosphorus esters used as alternatives for PBDEs.

Sci Total Environ 2015 May 17;514:492-9. Epub 2015 Feb 17.

Center for Material Cycles and Waste Management Research, National Institute for Environmental Studies (NIES), 16-2 Onogawa, Tsukuba 305-8506, Japan; Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa 277-8563, Japan.

Three oligomeric organophosphorus flame retardants (o-PFRs), eight monomeric PFRs (m-PFRs), tetrabromobisphenol A (TBBPA), and polybrominated diphenyl ethers (PBDEs) were identified and quantified in surface soils and river sediments around the e-waste recycling area in Bui Dau, northern Vietnam. Around the e-waste recycling workshops, 1,3-phenylene bis(diphenyl phosphate) (PBDPP), bisphenol A bis(diphenyl phosphate) (BPA-BDPP), triphenyl phosphate (TPHP), TBBPA, and PBDEs were dominant among the investigated flame retardants (FRs). The respective concentrations of PBDPP, BPA-BDPP, TPHP, TBBPA and the total PBDEs were 6.6-14000 ng/g-dry, <2-1500 ng/g-dry, 11-3300 ng/g-dry, <5-2900 ng/g-dry, and 67-9200 ng/g-dry in surface soils, and 4.4-78 ng/g-dry, <2-20 ng/g-dry, 7.3-38 ng/g-dry, 6.0-44 ng/g-dry and 100-350 ng/g-dry in river sediments. Near the open burning site of e-waste, tris(methylphenyl) phosphate (TMPP), (2-ethylhexyl)diphenyl phosphate (EHDPP), TPHP, and the total PBDEs were abundantly with respective concentrations of <2-190 ng/g-dry, <2-69 ng/g-dry, <3-51 ng/g-dry and 1.7-67 ng/g-dry in surface soils. Open storage and burning of e-waste have been determined to be important factors contributing to the emissions of FRs. The environmental occurrence of emerging FRs, especially o-PFRs, indicates that the alternation of FRs addition in electronic products is shifting in response to domestic and international regulations of PBDEs. The emissions of alternatives from open storage and burning of e-waste might become greater than those of PBDEs in the following years. The presence and environmental effects of alternatives should be regarded as a risk factor along with e-waste recycling.
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http://dx.doi.org/10.1016/j.scitotenv.2015.02.008DOI Listing
May 2015

Methylated and unsubstituted polycyclic aromatic hydrocarbons in street dust from Vietnam and India: occurrence, distribution and in vitro toxicity evaluation.

Environ Pollut 2014 Nov;194:272-280

Center for Marine Environmental Studies (CMES), Ehime University, 2-5 Bunkyo-cho, Matsuyama 790-8577, Japan.

Methylated polycyclic aromatic hydrocarbons (MePAHs), unsubstituted PAHs and AhR-mediated activities were determined in street dust collected from Vietnam and India using a combined approach of chemical analysis and in vitro reporter gene assay. MePAHs and PAHs diagnostic ratios indicated that the main sources of MePAHs in Vietnam were pyrogenic emissions, whereas in India there were mixed sources of pyrogenic and petrogenic emissions. AhR-mediated activities determined by using DR-CALUX assay were observed in urban street dust at mean 40, 29 and 20 ng CALUX-TEQ/g dw for Hanoi, Bangalore and New Delhi, respectively. MePAHs and PAHs contributed only 5% or less to AhR-mediated activity in street dust, indicating the occurrence of unknown AhR agonists. The principal contributors to Theoretical-TEQs among target compounds were methyl benz[a]anthracene, benzo[b]- and benzo[k]fluoranthene. The present study indicates importance of MePAHs in evaluation of toxic risk related to AhR-mediated activity in urban polluted areas.
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http://dx.doi.org/10.1016/j.envpol.2014.07.029DOI Listing
November 2014

Dioxin-related compounds in breast milk of women from Vietnamese e-waste recycling sites: levels, toxic equivalents and relevance of non-dietary exposure.

Ecotoxicol Environ Saf 2014 Aug 21;106:220-5. Epub 2014 May 21.

Center for Marine Environmental Studies (CMES), Ehime University, 2-5 Bunkyo-cho, Matsuyama 790-8577, Japan.

Although informal e-waste recycling sites (EWRSs) are hotspots of both polychlorinated and polybrominated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs and PBDD/Fs), human exposure to the latter has not been studied in details. This study investigated the accumulation levels and profiles of dioxin-related compounds (DRCs) in breast milk samples from women living in two Vietnamese EWRSs and estimated the intake contribution from e-waste-related exposure. Screening results using Dioxin-Responsive Chemically Activated LUciferase gene eXpression assay (DR-CALUX) showed higher dioxin-like (DL) activities in samples from the EWRS Bui Dau than in those from the EWRS Trang Minh and a reference site (2.3-10 vs 1.7-4.8 and 0.60-5.7 pg CALUX-TEQ/g lipid, n=10, 6 and 9, respectively). Chemical analysis results of selected samples show that the WHO-TEQ levels of PCDD/Fs, DL-PCBs and PBDD/Fs in EWRS samples were not significantly higher than in those from the reference site (0.22-7.4 vs 1.1-3.0 pg/g lipid) and within the Vietnamese background range, but women involved in recycling accumulated higher concentrations of PCDFs (13-15 vs 2.3-8.8 pg/g lipid) and PBDFs (1.1-1.5 vs <1.1 pg/g lipid). By comparing the DRC profile in milk of these women with the reported profile in house dust from the same site, dust ingestion was estimated to contribute most of the intake for tetraBDF, 37 per cent to 55 per cent for penta-octaCDFs, but less than twenty per cent for PCDDs and DL-PCBs, and 26 per cent for total WHO-TEQs. The DL activities in some EWRS milk samples were not fully explained by chemical data, suggesting contribution from unidentified compounds. The estimated WHO-TEQ intake doses for breastfed infants (1.3-33 pg/kg/d) mostly exceeded the tolerable value, especially for those living in the EWRSs; and unidentified DRCs might increase further the dioxin-related health risk.
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http://dx.doi.org/10.1016/j.ecoenv.2014.04.046DOI Listing
August 2014

Aryl hydrocarbon receptor mediated activities in road dust from a metropolitan area, Hanoi-Vietnam: contribution of polycyclic aromatic hydrocarbons (PAHs) and human risk assessment.

Sci Total Environ 2014 Sep 9;491-492:246-54. Epub 2014 Feb 9.

Center for Marine Environmental Studies (CMES), Ehime University, 2-5 Bunkyo-cho, Matsuyama, Japan.

Dioxin-Responsive Chemical-Activated LUciferase gene eXpression assay (DR-CALUX) was applied to assess the total toxic activity of the mixture of PAHs and related compounds as well as dioxin-related compounds in road dust from urban areas of Hanoi, Vietnam. Road dust from Hanoi contained significantly higher DR-CALUX activities (3 to 39, mean 20 ng CALUX-TEQ/g dw) than those from a rural site (2 to 13, mean 5 ng CALUX-TEQ/g dw). The total concentrations of 24 major PAHs (Σ24PAHs) in urban road dust (0.1 to 5.5, mean 2.5 μg/g dw) were also 6 times higher than those in rural road dust (0.08 to 1.5, mean 0.4 μg/g dw). Diagnostic ratios of PAHs indicated vehicular engine combustion as the major PAH emission source in both sites. PAHs accounted for 0.8 to 60% (mean 10%) and 2 to 76% (mean 20%) of the measured CALUX-TEQs in road dust for Hanoi the rural site, respectively. Benzo[b]-/benzo[k]fluoranthenes were the major TEQ contributors among PAHs, whereas DRCs contributed <0.1% to CALUX-TEQs for both rural and urban sites. These results suggest TEQ contribution of other aryl hydrocarbon receptor agonists in road dust. Significant PAH concentrations in urban dust indicated high mutagenic and carcinogenic potencies. Estimated results of incremental life time cancer risk (ILCR) indicated that Vietnamese populations, especially those in urban areas such as Hanoi, are potentially exposed to high cancer risk via both dust ingestion and dermal contact. This is the first study on the exposure risk of AhR agonists, including PAHs and DRCs, in urban road dust from a developing country using a combined bio-chemical analytical approach.
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http://dx.doi.org/10.1016/j.scitotenv.2014.01.086DOI Listing
September 2014