In this study, the concentrations of 10 organophosphorus flame retardants (PFRs) were determined ... more In this study, the concentrations of 10 organophosphorus flame retardants (PFRs) were determined in 89 human breast milk samples collected from Japan, the Philippines and Vietnam. Among the targeted PFRs, tris(2-chloroexyl) phosphate (TCEP) and triphenyl phosphate (TPHP) were the predominant compounds and were detected in more than 60% of samples in all three countries. The concentrations of PFRs in human breast milk were significantly higher (p < 0.05) in the Philippines (median 70 ng g À1 lipid wt.) than those in Japan (median 22 ng g À1 lipid wt.) and Vietnam (median 10 ng g À1 lipid wt.). The present results suggest that the usage of products containing PFRs in the Philippines is higher than those of Japan and Vietnam. Comparing with a previous literature survey in Sweden, the levels of PFRs in human breast milk from the Philippines were 1.5–2 times higher, whereas levels in Japan and Vietnam were 4–20 times lower, suggesting that these differences might be due to their variation in the usage of flame-retarded products utilized in each country. When daily intake of PFRs to infants via human breast milk was estimated , some individuals accumulated tris(2-butoxyethyl) phosphate (TBOEP) and TCEP were close to Chemosphere j o u r n a l h o m e p a g e : w w w. e l s e v i e r. c o m / l o c a t e / c h e m o s p h e r e Please cite this article in press as: Kim, J.-W., et al. Organophosphorus flame retardants (PFRs) in human breast milk from several Asian countries. Chemosphere (2014), http://dx.doi.org/10.1016/j.chemosphere.2014.02.033 reference dose (RfD). This is the first report to identify PFRs in human breast milk samples from Asian countries.
Industrialization, urbanization and high economic growth in recent years are accompanied by degra... more Industrialization, urbanization and high economic growth in recent years are accompanied by degradation of environmental quality in developing countries, where the pollution of the ambient air in large cities has become a major concern. It has been reported that the average concentrations of particulate matter (PM 2.5 and PM 10 ) in six Asian cities-Bandung (Indonesia), Bangkok (Thailand), Beijing (China), Chennai (India), Manila (Philippines), and Hanoi (Vietnam)-were in range of 18-168 and 33-262 µg m -3 and frequently exceeded the corresponding 24-h U.S. EPA standards (65 and 150 µg m -3 , respectively) 1 . The same study also found traffic as the most important contributor of PM emission. There is association between air particle pollution and polycyclic aromatic hydrocarbons (PAHs), a major source of which is vehicle exhaust, and high levels of PAHs have been found in road dust-a sink for traffic-related pollutants 2 -from Asian developing countries 3-5 .
In view of the development of miniaturized sensor arrays, a solid-contact ammonium ion selective ... more In view of the development of miniaturized sensor arrays, a solid-contact ammonium ion selective electrode has been investigated. A conductive polypyrrole film was electrochemically deposited on a glassy carbon surface and used as an internal solid contact layer between the sensing membrane and solid electrode surface. A systematic evaluation of the important parameters affecting the electromotive force (emf) response is presented. The performances of this solid-contact sensor were verified using a batch-mode measurement setup and a wall-jet flow cell system. The designed sensor exhibited excellent selectivity for the primary ion and a linear response over the pNH4+ range 1-5 with a slope of 56.3 mV decade(-1) . The sensor has a fast response and is relatively robustness, and was also used to determine ammonium concentrations in natural waters, with promising results.
Journal of Japan Society on Water Environment, 2002
Abstract;The quality of leachate collected from waste landfills which received industrial and mun... more Abstract;The quality of leachate collected from waste landfills which received industrial and municipal waste in Hanoi was analyzed in order to obtain information on the current situation of pollutants in these sites. The leachate collected from Tay Mo landfill and Nam Son landfill showed ...
Three oligomeric organophosphorus flame retardants (o-PFRs), eight monomeric PFRs (m-PFRs), tetra... more 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 6.6-14000ng/g-dry, &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;2-1500ng/g-dry, 11-3300ng/g-dry, &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;5-2900ng/g-dry, and 67-9200ng/g-dry in surface soils, and 4.4-78ng/g-dry, &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;2-20ng/g-dry, 7.3-38ng/g-dry, 6.0-44ng/g-dry and 100-350ng/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 &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;2-190ng/g-dry, &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;2-69ng/g-dry, &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;3-51ng/g-dry and 1.7-67ng/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.
Methylated polycyclic aromatic hydrocarbons (MePAHs), unsubstituted PAHs and AhR-mediated activit... more 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.
Although informal e-waste recycling sites (EWRSs) are hotspots of both polychlorinated and polybr... more 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 ¼ 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 o1.1 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.
An efficient method for the simultaneous determination of the degradation products of nonylphenol... more An efficient method for the simultaneous determination of the degradation products of nonylphenol polyethoxylates (NPnEOs, n = number of ethoxy units), i.e., nonylphenol (NP), NPnEOs (n = 1-3), nonylphenoxy carboxylic acids (NPnECs, n = 1-2, number of ethoxy units plus an acetate) and their halogenated derivatives (XNP, XNP1EO and XNP1EC; X = Br or Cl), in water samples were developed. After trimethylsilylation with N,O-bis(trimethysilyl)acetamide, all the analytes were determined by gas chromatography-tandem mass spectrometry (GC-MS-MS) with electron ionization (EI). The ion peaks of [M − 85] + of the derivatives were selected as precursor ions and their product ions showing the highest intensities were used for the quantitative analysis. The instrumental detection limits were in the range from 2.1 to 11 pg. The recoveries of the analytes from the water samples were optimized by using solid-phase extraction (SPE). The deuterated reagents of octylphenol, octylphenol monoethoxylate and octylphenoxyacetic acid were used as the surrogates. The method detection limits (500 ml water sample) using C 18 SPE were from 2.5 to 18 ng/l. The recoveries from spiked pure water and the environmental water samples were greater than 78%. The method was successfully applied to environmental samples. Remarkably, the concentrations of the halogenated compounds (ClNP, ClNP1EO and BrNP1EO) were detected at the hundreds of ng/l levels in the Neya river.
The possible use of an electrode modified with electroactive conductive poly(3-methylthiophene) (... more The possible use of an electrode modified with electroactive conductive poly(3-methylthiophene) (PMeT)/ Nafion as a chemical sensor was investigated for the voltammetric analysis of Dopamine (DA). The electrochemical behavior of dopamine was examined by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques. By using a PMeT-modified glassy carbon (GC/PMeT) electrode, DA and Ascorbic Acid (AA) signals could be separated but the AA at high concentrations still caused significant interference by overlapping the DA peak. In comparison to the GC/PMeT electrode, the glassy carbon (GC/Nafion/PMeT) electrode modified with hybrid film Nafion/PMeT was found to permit a superior separation by shifting the oxidation of AA peak toward the less positive potential. The DPV curves for a mixture of DA and AA at an GC/Nafion/PMeT electrode in a 0.1 M H 2 SO 4 solution showed peaks of DA and AA, at 0.45 and 0.21 V, respectively, indicating that the difference in the oxidation potential was 240 mV. In the 0.1 M H 2 SO 4 solution, the oxidation peak current on the differential pulse voltammograms for the GC/PMeT electrode increased linearly with the concentration of DA in the range 1 9 10 -6 to 1 9 10 -3 M, and the oxidation peak current on the differential pulse voltammograms for the GC/Nafion/PMeT electrode in the range 5 9 10 -7 to 2 9 10 -4 M. The DA detection sensitivity of the GC/Nafion/PMeT electrode (26.7 lA lM -1 cm -2 ) was 22 times higher than that of the GC/PMeT electrode (1.21 lA lM -1 cm -2 ).
The accumulation and inadequate management of obsolete pesticides and other hazardous chemicals c... more The accumulation and inadequate management of obsolete pesticides and other hazardous chemicals constitutes a threat for health and environment, locally, regionally and globally. Estimates indicate that more than 500,000 tonnes of obsolete pesticides are accumulated globally, ...
Soils and agricultural products from the Red River basin in Northern Vietnam were reported to be ... more Soils and agricultural products from the Red River basin in Northern Vietnam were reported to be contaminated by agrichemicals. To assess potential exposure of local farmers and consumers to these contaminants, pesticide use and management practices of local farmers were surveyed and residue concentrations were determined for recently used as well as for banned pesticides in water, soil, vegetables, and fish samples in two communes of Northern Vietnam. DDTs, HCHs, and Drin compounds still persist at relatively high concentrations in soil and occur in vegetable and fish samples. Recently used pesticides, such as fenobucarb, trichlorfon, cyfluthrin, and cypermethrin were detected in vegetable and fish samples. Thresholds for acceptable daily intake levels (ADI) were frequently reached in the analyzed food products pointing to the fact that current pesticide management practices do not only result in a pollution of the environment but also pose threats to human health.
A voltammetric method based on a combination of incorporated Nafion, single-walled carbon nanotub... more A voltammetric method based on a combination of incorporated Nafion, single-walled carbon nanotubes and poly(3-methylthiophene) film-modified glassy carbon electrode (NF/SWCNT/PMT/GCE) has been successfully developed for selective determination of dopamine (DA) in the ternary mixture of dopamine, ascorbic acid (AA) and uric acid (UA) in 0.1 M phosphate buffer solution (PBS) pH 4. It was shown that to detect DA from binary DA-AA mixture, the use of NF/PMT/GCE was sufficient, but to detect DA from ternary DA-AA-UA mixture NF/SWCNT/PMT/GCE was required. The later modified electrode exhibits superior electrocatalytic activity towards AA, DA and UA thanks to synergic effect of NF/SWCNT (combining unique properties of SWCNT such as high specific surface area, electrocatalytic and adsorptive properties, with the cation selectivity of NF). On the surface of NF/SWCNT/PMT/GCE AA, DA, UA were oxidized respectively at distinguishable potentials of 0.15, 0.37 and 0.53 V (vs. Ag/AgCl), to form welldefined and sharp peaks, making possible simultaneous determination of each compound. Also, it has several advantages, such as simple preparation method, high sensitivity, low detection limit and excellent reproducibility. Thus, the proposed NF/SWCNT/PMT/GCE could be advantageously employed for the determination of DA in real pharmaceutical formulations.
To assess the organochlorine contamination in the northeast coastal environment of Vietnam, a tot... more To assess the organochlorine contamination in the northeast coastal environment of Vietnam, a total of 41 surface sediments were collected from Ha Long Bay, Hai Phong Bay, and Ba Lat estuary, and analyzed for their organochlorine content. Organochlorine compounds (OCs) were widely distributed in the Vietnamese coastal environment. Among the OCs measured, DDT compounds predominated with concentrations ranging from 0.31 to 274 ng g À1 . The overall contamination level of DDTs in coastal sediments from northern Vietnam is comparable with those from other Asian countries. However, concentrations exceeding 100 ng g À1 are comparable with high concentrations reported from India and China, the largest DDT consumers in the world. The overall concentrations of PCBs, HCHs, and chlordanes in surface sediments were in the ranges of 0.04-18.71 ng g À1 , not detected (n.d.) -1.00 ng g À1 , and n.d. -0.75 ng g À1 , respectively. Ha Long Bay and Hai Phong Bay were relatively more contaminated with DDTs and PCBs than other regions, respectively. In contrast, the distribution of HCHs was relatively homogeneous. OCs contamination in the coastal environment of Vietnam is closely related to shipping and industrial activities. The levels of DDT compounds in harbors and industrial areas exceeded their sediment quality guideline values suggested
The levels of polychlorinated dibenzo-p-dioxin and dibenzofuran (PCDD/PCDFs), and dioxin-like pol... more The levels of polychlorinated dibenzo-p-dioxin and dibenzofuran (PCDD/PCDFs), and dioxin-like polychlorinated biphenyls (DL-PCBs) were determined in sediment samples from Can Gio, South Vietnam, and Osaka, Japan. Can Gio is known for the defoliation of its mangrove forests by aerial spraying with Agent Orange during the Vietnam War, whereas Osaka is renowned for a PCDD/PCDF pollution accident at a municipal solid-waste incinerator. For comparison, we also analyzed PCDD/PCDFs and DL-PCBs in sediment samples from Hue and Hanoi, Vietnam. The toxic equivalent quantity (TEQ) values in Can Gio were as high as those in Hue, Hanoi, and suburban areas of Osaka, but much lower than those in urban areas of Osaka. The proportion of the World Health Organization (WHO)-TEQ value contributed by 2,3,7,8-tetrachlorinated dibenzo-p-dioxin (TCDD) in Can Gio was approximately 30%, higher than the values in the other sample areas. These data suggest that residual sedimentary TCDD that originated from aerial spraying of Agent Orange occur in only low concentrations in Can Gio. The main contributors to WHO-TEQ values in Can Gio are natural sources, as in Hue. In contrast, commercial PCBs are the dominant contributors to WHO-TEQ values in Hanoi. In Osaka, agrochemicals used in rice cultivation, the incineration of solid waste, and commercial PCBs equally contributed to WHO-TEQ values at suburban locations. The dumping of incinerator-related materials and/or the inadequate management of commercial PCBs have resulted in significantly elevated WHO-TEQ values of 240-370 ng kg -1 dw at urban locations in Osaka.
Bulletin of Environmental Contamination and Toxicology, 2008
We analyzed the concentrations of polycyclic aromatic hydrocarbons (PAHs) in both particulate mat... more We analyzed the concentrations of polycyclic aromatic hydrocarbons (PAHs) in both particulate matter (PM) and the gaseous phase at 10 roadside sites in Hanoi, Vietnam. The average concentrations of 47
The present study investigated the human exposure to PCBs, PBDEs and HBCDs in three Vietnamese e-... more The present study investigated the human exposure to PCBs, PBDEs and HBCDs in three Vietnamese e-waste recycling sites (EWRS) using breast milk as bioindicator. The general contamination patterns followed the order of PCBs > PBDEs > HBCDs except for some recycling workers with higher levels of PBDEs than PCBs. Compared with the urban site, human exposure to PBDEs in two EWRS was significantly higher, up to two orders of difference for a number of recyclers. These highly PBDE-exposed individuals also had significantly higher levels of HBCDs than the urban population. In EWRS, PBDE and HBCD positively correlated with each other but not with PCBs, suggesting different sources of PCBs and BFRs. Levels of penta-to deca-PCBs were found to be associated with consumption of lipid-rich food whereas levels of the lower PCB congeners and BFRs were related to recycling activities. Comparing the estimated daily intake of PBDEs with their reference doses, potential health risks associated with feeding mother milk were suggested for children of Bui Dau recycler mothers. To our knowledge, these preliminary results are the first to be reported on human exposure to BFRs related to e-waste recycling in Vietnam.
Measurements of gaseous SO 2 , NH 3 , and O 3 using IVL passive sampler technology were obtained ... more Measurements of gaseous SO 2 , NH 3 , and O 3 using IVL passive sampler technology were obtained during a pilot measurement program initiated as a key component of the newly established WMO/GAW Urban Research Meteorology and Environment (GURME) project. Monthly measurements were obtained at 50 stations in Asia, Africa, South America, and Europe. The median SO 2 concentrations vary from a high of 13 ppb at Linan, China, to o0.03 ppb at four stations. At 30 of 50 regional stations, the observed median concentrations are o1 ppb. Median ammonia concentrations range from 20 ppb at Dhangadi, India, to o1 ppb at nine stations. At 27 of regional stations, the ambient ammonia levels exceed 1 ppb. The median ozone concentrations vary from a maximum of 45 ppb at Waliguan Mountain, China, to 8 ppb in Petit Saut, French Guiana. In general, the highest ozone values are found in the midlatitudes, with the Northern hemisphere mid-latitude values exceeding the Southern hemisphere mid-latitude levels, and the lowest values are typically found in the tropical regions. r
In this study, the concentrations of 10 organophosphorus flame retardants (PFRs) were determined ... more In this study, the concentrations of 10 organophosphorus flame retardants (PFRs) were determined in 89 human breast milk samples collected from Japan, the Philippines and Vietnam. Among the targeted PFRs, tris(2-chloroexyl) phosphate (TCEP) and triphenyl phosphate (TPHP) were the predominant compounds and were detected in more than 60% of samples in all three countries. The concentrations of PFRs in human breast milk were significantly higher (p < 0.05) in the Philippines (median 70 ng g À1 lipid wt.) than those in Japan (median 22 ng g À1 lipid wt.) and Vietnam (median 10 ng g À1 lipid wt.). The present results suggest that the usage of products containing PFRs in the Philippines is higher than those of Japan and Vietnam. Comparing with a previous literature survey in Sweden, the levels of PFRs in human breast milk from the Philippines were 1.5–2 times higher, whereas levels in Japan and Vietnam were 4–20 times lower, suggesting that these differences might be due to their variation in the usage of flame-retarded products utilized in each country. When daily intake of PFRs to infants via human breast milk was estimated , some individuals accumulated tris(2-butoxyethyl) phosphate (TBOEP) and TCEP were close to Chemosphere j o u r n a l h o m e p a g e : w w w. e l s e v i e r. c o m / l o c a t e / c h e m o s p h e r e Please cite this article in press as: Kim, J.-W., et al. Organophosphorus flame retardants (PFRs) in human breast milk from several Asian countries. Chemosphere (2014), http://dx.doi.org/10.1016/j.chemosphere.2014.02.033 reference dose (RfD). This is the first report to identify PFRs in human breast milk samples from Asian countries.
Industrialization, urbanization and high economic growth in recent years are accompanied by degra... more Industrialization, urbanization and high economic growth in recent years are accompanied by degradation of environmental quality in developing countries, where the pollution of the ambient air in large cities has become a major concern. It has been reported that the average concentrations of particulate matter (PM 2.5 and PM 10 ) in six Asian cities-Bandung (Indonesia), Bangkok (Thailand), Beijing (China), Chennai (India), Manila (Philippines), and Hanoi (Vietnam)-were in range of 18-168 and 33-262 µg m -3 and frequently exceeded the corresponding 24-h U.S. EPA standards (65 and 150 µg m -3 , respectively) 1 . The same study also found traffic as the most important contributor of PM emission. There is association between air particle pollution and polycyclic aromatic hydrocarbons (PAHs), a major source of which is vehicle exhaust, and high levels of PAHs have been found in road dust-a sink for traffic-related pollutants 2 -from Asian developing countries 3-5 .
In view of the development of miniaturized sensor arrays, a solid-contact ammonium ion selective ... more In view of the development of miniaturized sensor arrays, a solid-contact ammonium ion selective electrode has been investigated. A conductive polypyrrole film was electrochemically deposited on a glassy carbon surface and used as an internal solid contact layer between the sensing membrane and solid electrode surface. A systematic evaluation of the important parameters affecting the electromotive force (emf) response is presented. The performances of this solid-contact sensor were verified using a batch-mode measurement setup and a wall-jet flow cell system. The designed sensor exhibited excellent selectivity for the primary ion and a linear response over the pNH4+ range 1-5 with a slope of 56.3 mV decade(-1) . The sensor has a fast response and is relatively robustness, and was also used to determine ammonium concentrations in natural waters, with promising results.
Journal of Japan Society on Water Environment, 2002
Abstract;The quality of leachate collected from waste landfills which received industrial and mun... more Abstract;The quality of leachate collected from waste landfills which received industrial and municipal waste in Hanoi was analyzed in order to obtain information on the current situation of pollutants in these sites. The leachate collected from Tay Mo landfill and Nam Son landfill showed ...
Three oligomeric organophosphorus flame retardants (o-PFRs), eight monomeric PFRs (m-PFRs), tetra... more 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 6.6-14000ng/g-dry, &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;2-1500ng/g-dry, 11-3300ng/g-dry, &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;5-2900ng/g-dry, and 67-9200ng/g-dry in surface soils, and 4.4-78ng/g-dry, &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;2-20ng/g-dry, 7.3-38ng/g-dry, 6.0-44ng/g-dry and 100-350ng/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 &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;2-190ng/g-dry, &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;2-69ng/g-dry, &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;3-51ng/g-dry and 1.7-67ng/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.
Methylated polycyclic aromatic hydrocarbons (MePAHs), unsubstituted PAHs and AhR-mediated activit... more 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.
Although informal e-waste recycling sites (EWRSs) are hotspots of both polychlorinated and polybr... more 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 ¼ 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 o1.1 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.
An efficient method for the simultaneous determination of the degradation products of nonylphenol... more An efficient method for the simultaneous determination of the degradation products of nonylphenol polyethoxylates (NPnEOs, n = number of ethoxy units), i.e., nonylphenol (NP), NPnEOs (n = 1-3), nonylphenoxy carboxylic acids (NPnECs, n = 1-2, number of ethoxy units plus an acetate) and their halogenated derivatives (XNP, XNP1EO and XNP1EC; X = Br or Cl), in water samples were developed. After trimethylsilylation with N,O-bis(trimethysilyl)acetamide, all the analytes were determined by gas chromatography-tandem mass spectrometry (GC-MS-MS) with electron ionization (EI). The ion peaks of [M − 85] + of the derivatives were selected as precursor ions and their product ions showing the highest intensities were used for the quantitative analysis. The instrumental detection limits were in the range from 2.1 to 11 pg. The recoveries of the analytes from the water samples were optimized by using solid-phase extraction (SPE). The deuterated reagents of octylphenol, octylphenol monoethoxylate and octylphenoxyacetic acid were used as the surrogates. The method detection limits (500 ml water sample) using C 18 SPE were from 2.5 to 18 ng/l. The recoveries from spiked pure water and the environmental water samples were greater than 78%. The method was successfully applied to environmental samples. Remarkably, the concentrations of the halogenated compounds (ClNP, ClNP1EO and BrNP1EO) were detected at the hundreds of ng/l levels in the Neya river.
The possible use of an electrode modified with electroactive conductive poly(3-methylthiophene) (... more The possible use of an electrode modified with electroactive conductive poly(3-methylthiophene) (PMeT)/ Nafion as a chemical sensor was investigated for the voltammetric analysis of Dopamine (DA). The electrochemical behavior of dopamine was examined by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques. By using a PMeT-modified glassy carbon (GC/PMeT) electrode, DA and Ascorbic Acid (AA) signals could be separated but the AA at high concentrations still caused significant interference by overlapping the DA peak. In comparison to the GC/PMeT electrode, the glassy carbon (GC/Nafion/PMeT) electrode modified with hybrid film Nafion/PMeT was found to permit a superior separation by shifting the oxidation of AA peak toward the less positive potential. The DPV curves for a mixture of DA and AA at an GC/Nafion/PMeT electrode in a 0.1 M H 2 SO 4 solution showed peaks of DA and AA, at 0.45 and 0.21 V, respectively, indicating that the difference in the oxidation potential was 240 mV. In the 0.1 M H 2 SO 4 solution, the oxidation peak current on the differential pulse voltammograms for the GC/PMeT electrode increased linearly with the concentration of DA in the range 1 9 10 -6 to 1 9 10 -3 M, and the oxidation peak current on the differential pulse voltammograms for the GC/Nafion/PMeT electrode in the range 5 9 10 -7 to 2 9 10 -4 M. The DA detection sensitivity of the GC/Nafion/PMeT electrode (26.7 lA lM -1 cm -2 ) was 22 times higher than that of the GC/PMeT electrode (1.21 lA lM -1 cm -2 ).
The accumulation and inadequate management of obsolete pesticides and other hazardous chemicals c... more The accumulation and inadequate management of obsolete pesticides and other hazardous chemicals constitutes a threat for health and environment, locally, regionally and globally. Estimates indicate that more than 500,000 tonnes of obsolete pesticides are accumulated globally, ...
Soils and agricultural products from the Red River basin in Northern Vietnam were reported to be ... more Soils and agricultural products from the Red River basin in Northern Vietnam were reported to be contaminated by agrichemicals. To assess potential exposure of local farmers and consumers to these contaminants, pesticide use and management practices of local farmers were surveyed and residue concentrations were determined for recently used as well as for banned pesticides in water, soil, vegetables, and fish samples in two communes of Northern Vietnam. DDTs, HCHs, and Drin compounds still persist at relatively high concentrations in soil and occur in vegetable and fish samples. Recently used pesticides, such as fenobucarb, trichlorfon, cyfluthrin, and cypermethrin were detected in vegetable and fish samples. Thresholds for acceptable daily intake levels (ADI) were frequently reached in the analyzed food products pointing to the fact that current pesticide management practices do not only result in a pollution of the environment but also pose threats to human health.
A voltammetric method based on a combination of incorporated Nafion, single-walled carbon nanotub... more A voltammetric method based on a combination of incorporated Nafion, single-walled carbon nanotubes and poly(3-methylthiophene) film-modified glassy carbon electrode (NF/SWCNT/PMT/GCE) has been successfully developed for selective determination of dopamine (DA) in the ternary mixture of dopamine, ascorbic acid (AA) and uric acid (UA) in 0.1 M phosphate buffer solution (PBS) pH 4. It was shown that to detect DA from binary DA-AA mixture, the use of NF/PMT/GCE was sufficient, but to detect DA from ternary DA-AA-UA mixture NF/SWCNT/PMT/GCE was required. The later modified electrode exhibits superior electrocatalytic activity towards AA, DA and UA thanks to synergic effect of NF/SWCNT (combining unique properties of SWCNT such as high specific surface area, electrocatalytic and adsorptive properties, with the cation selectivity of NF). On the surface of NF/SWCNT/PMT/GCE AA, DA, UA were oxidized respectively at distinguishable potentials of 0.15, 0.37 and 0.53 V (vs. Ag/AgCl), to form welldefined and sharp peaks, making possible simultaneous determination of each compound. Also, it has several advantages, such as simple preparation method, high sensitivity, low detection limit and excellent reproducibility. Thus, the proposed NF/SWCNT/PMT/GCE could be advantageously employed for the determination of DA in real pharmaceutical formulations.
To assess the organochlorine contamination in the northeast coastal environment of Vietnam, a tot... more To assess the organochlorine contamination in the northeast coastal environment of Vietnam, a total of 41 surface sediments were collected from Ha Long Bay, Hai Phong Bay, and Ba Lat estuary, and analyzed for their organochlorine content. Organochlorine compounds (OCs) were widely distributed in the Vietnamese coastal environment. Among the OCs measured, DDT compounds predominated with concentrations ranging from 0.31 to 274 ng g À1 . The overall contamination level of DDTs in coastal sediments from northern Vietnam is comparable with those from other Asian countries. However, concentrations exceeding 100 ng g À1 are comparable with high concentrations reported from India and China, the largest DDT consumers in the world. The overall concentrations of PCBs, HCHs, and chlordanes in surface sediments were in the ranges of 0.04-18.71 ng g À1 , not detected (n.d.) -1.00 ng g À1 , and n.d. -0.75 ng g À1 , respectively. Ha Long Bay and Hai Phong Bay were relatively more contaminated with DDTs and PCBs than other regions, respectively. In contrast, the distribution of HCHs was relatively homogeneous. OCs contamination in the coastal environment of Vietnam is closely related to shipping and industrial activities. The levels of DDT compounds in harbors and industrial areas exceeded their sediment quality guideline values suggested
The levels of polychlorinated dibenzo-p-dioxin and dibenzofuran (PCDD/PCDFs), and dioxin-like pol... more The levels of polychlorinated dibenzo-p-dioxin and dibenzofuran (PCDD/PCDFs), and dioxin-like polychlorinated biphenyls (DL-PCBs) were determined in sediment samples from Can Gio, South Vietnam, and Osaka, Japan. Can Gio is known for the defoliation of its mangrove forests by aerial spraying with Agent Orange during the Vietnam War, whereas Osaka is renowned for a PCDD/PCDF pollution accident at a municipal solid-waste incinerator. For comparison, we also analyzed PCDD/PCDFs and DL-PCBs in sediment samples from Hue and Hanoi, Vietnam. The toxic equivalent quantity (TEQ) values in Can Gio were as high as those in Hue, Hanoi, and suburban areas of Osaka, but much lower than those in urban areas of Osaka. The proportion of the World Health Organization (WHO)-TEQ value contributed by 2,3,7,8-tetrachlorinated dibenzo-p-dioxin (TCDD) in Can Gio was approximately 30%, higher than the values in the other sample areas. These data suggest that residual sedimentary TCDD that originated from aerial spraying of Agent Orange occur in only low concentrations in Can Gio. The main contributors to WHO-TEQ values in Can Gio are natural sources, as in Hue. In contrast, commercial PCBs are the dominant contributors to WHO-TEQ values in Hanoi. In Osaka, agrochemicals used in rice cultivation, the incineration of solid waste, and commercial PCBs equally contributed to WHO-TEQ values at suburban locations. The dumping of incinerator-related materials and/or the inadequate management of commercial PCBs have resulted in significantly elevated WHO-TEQ values of 240-370 ng kg -1 dw at urban locations in Osaka.
Bulletin of Environmental Contamination and Toxicology, 2008
We analyzed the concentrations of polycyclic aromatic hydrocarbons (PAHs) in both particulate mat... more We analyzed the concentrations of polycyclic aromatic hydrocarbons (PAHs) in both particulate matter (PM) and the gaseous phase at 10 roadside sites in Hanoi, Vietnam. The average concentrations of 47
The present study investigated the human exposure to PCBs, PBDEs and HBCDs in three Vietnamese e-... more The present study investigated the human exposure to PCBs, PBDEs and HBCDs in three Vietnamese e-waste recycling sites (EWRS) using breast milk as bioindicator. The general contamination patterns followed the order of PCBs > PBDEs > HBCDs except for some recycling workers with higher levels of PBDEs than PCBs. Compared with the urban site, human exposure to PBDEs in two EWRS was significantly higher, up to two orders of difference for a number of recyclers. These highly PBDE-exposed individuals also had significantly higher levels of HBCDs than the urban population. In EWRS, PBDE and HBCD positively correlated with each other but not with PCBs, suggesting different sources of PCBs and BFRs. Levels of penta-to deca-PCBs were found to be associated with consumption of lipid-rich food whereas levels of the lower PCB congeners and BFRs were related to recycling activities. Comparing the estimated daily intake of PBDEs with their reference doses, potential health risks associated with feeding mother milk were suggested for children of Bui Dau recycler mothers. To our knowledge, these preliminary results are the first to be reported on human exposure to BFRs related to e-waste recycling in Vietnam.
Measurements of gaseous SO 2 , NH 3 , and O 3 using IVL passive sampler technology were obtained ... more Measurements of gaseous SO 2 , NH 3 , and O 3 using IVL passive sampler technology were obtained during a pilot measurement program initiated as a key component of the newly established WMO/GAW Urban Research Meteorology and Environment (GURME) project. Monthly measurements were obtained at 50 stations in Asia, Africa, South America, and Europe. The median SO 2 concentrations vary from a high of 13 ppb at Linan, China, to o0.03 ppb at four stations. At 30 of 50 regional stations, the observed median concentrations are o1 ppb. Median ammonia concentrations range from 20 ppb at Dhangadi, India, to o1 ppb at nine stations. At 27 of regional stations, the ambient ammonia levels exceed 1 ppb. The median ozone concentrations vary from a maximum of 45 ppb at Waliguan Mountain, China, to 8 ppb in Petit Saut, French Guiana. In general, the highest ozone values are found in the midlatitudes, with the Northern hemisphere mid-latitude values exceeding the Southern hemisphere mid-latitude levels, and the lowest values are typically found in the tropical regions. r
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