Polycyclic Aromatic Hydrocarbons from Domestic Solid Waste Incinerators in Nam Dinh Province, Northern Area of Vietnam: A Comprehensive Assessment of Emission, Source Markers and Human Health Risk.

A comprehensive research of the polycyclic aromatic hydrocarbons (PAHs) emission from domestic waste incinerators in northern areas of Vietnam, were investigated. Sixty-four samples from two domestic waste incinerators were collected and analyzed for PAHs. The PAHs concentrations in the samples were determined using gas chromatography coupled with mass spectrometry. In April, June, September, and November 2021, Σ16PAHs mean concentrations in chimney air samples were 970.9 ± 57.4, 1061.9 ± 49.8, 1070.7 ± 41.3 and 1136.1 ± 136.5 µg m-3, respectively. The mean emission factors of Σ16PAHs were 7.5 mg/kg. The mean percentages of low molecular weight PAHs were predominant in the analyzed air samples. The toxic equivalent quotient of samples ranged from 30.7 to 41.7 mg/kg, whereas the incremental lifetime cancer risk exceeded 10- 3. This results implied a high level of concern with potentially negative health consequences. The four diagnostic ratios of PAHs were found and can be used for identification of sources markers from domestic waste incinerators.

Level of BTEX in the Areas of Domestic Waste Incinerators in Northern Vietnam: A Comprehensive Assessment of Contamination, Composition and Human Health Risk.

The trend of the treatment of solid domestic waste by the domestic waste incinerator system is an option to improve waste management and to reduce the negative impacts on the environment and human health. Benzene, toluene, ethylbenzene, and xylenes (o-, m- and p-) (BTEX) are toxic chemical environmental contaminants that are released from different sources such as the domestic waste incinerator system. To determine the concentration of BTEX in the ambient air from these incinerator areas, the research team conducted four sampling campaigns in April, June, September, and November 2021, with a total of 80 samples collected. Concentrations of benzene, toluene, (m,p)-xylenes, o- xylenes and ethylbenzene ranged from 4.53 to 36.75 µg/m3, from 16.29 µg/m3 to 125.36 µg/m3, from 2.82 µg/m3 to 31.45 µg/m3, from 1.42 µg/m3 to 25.61 µg/m3, from 1.32 µg/m3 to 10.79 µg/m3, respectively. As a result of the risk assessment, it was determined that the incinerator's exhaust gas caused secondary environmental damage, impacting the health of not only workers but also people living in nearby communities. On that basis, the article recommends applying a number of management measures to minimize the negative impacts of the operation of the solid waste incinerator on the environment and the health of the workers operating the incinerator.

Endocrine disrupting compounds in sediment from KimNguu river, Northern area of Vietnam: a comprehensive assessment of seasonal variation, accumulation pattern and ecological risk.

This research presents the assessment of seasonal variation, accumulation pattern and ecological risk of selected endocrine disrupting compounds (S-EDCs) in sediment samples covering six sites in KimNguu river, Hanoi, Northern area of Vietnam. Selected EDCs compose polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs) and polybrominated diphenyl ethers (PBDEs). Sediment sampling was carried out in dry season (April) and wet season (October) in 2018. Results pointed out a significant contamination with ∑6PCBs, ∑16PAHs and ∑7PBDE concentrations ranging from 4.73 to 36.34 ng g-1 dw, from 3.57 to 84.39 ng g-1 dw and from 4.49 to 12.49 ng g-1 dw, respectively. Composition analyses indicated the predominance of PCB 138, PCB 153, M-PAHs (Middle molecular weight PAHs: BaA, Chr, Pyr, Flt), BDE-47, BDE-99 and BDE-209. The values of TEQDL-PCBs, TEQ∑8PAHs and TEQ∑16PAHs range from 4.6 to 10.4 ng kg-1 dw, from 0.28 to 1.28 ng g-1 dw and from 0.29 to 1.38 ng g-1 dw, respectively. Ecological risks of S-EDCs range from very low to medium levels in the sediment of KimNguu river.

Endocrine Disrupting Compounds (EDCs) in Surface Waters of the KimNguu River, Vietnam.

This research presents the assessment of contamination status, congener profiles and ecological risk of selected endocrine disrupting compounds (S-EDCs) in surface water from KimNguu River, Hanoi. Selected EDCs compose polychlorinated biphenyls (PCBs), phthalate esters (PAEs) and polybrominated diphenyl ethers (PBDEs). Water sampling and chemical analyses were carried out in collected water samples in dry season (April) and wet season (October) in 2018. Results pointed out a significant contamination with ∑6PCBs, ∑6PAEs and ∑7PBDE concentrations ranging from 1.89 to 8.93 ng/L, from 2.78 to 412.27 ng/L and from 1.92 to 7.08 ng/L, respectively. Composition analyses indicated the predominance of PCB52, PCB118, DEP, DEHP, DBP, BDE-47 and BDE-99. Ecological risks of S-EDCs range from very low to medium levels in the surface water of KimNguu River.

Residues of Polychlorinated Biphenyls (PCBs) in Sediment from CauBay River and Their Impacts on Agricultural Soil, Human Health Risk in KieuKy Area, Vietnam.

An evaluation of the PCB residues from CauBay River and KieuKy area, Vietnam was carried out. CauBay River has been playing an important role in irrigated water supply for agriculture activities at KieuKy area in the downstream. The PCBs concentrations of sediment, soil samples were analyzed and obtained results indicated the wide extent of contamination of PCBs in CauBay River (from 30.74 to 167.35 ng g(-1) dry weight) and KieuKy area (from 21.62 to 60.22 ng g(-1) dry weight). This clearly reflected the effect of PCB residues from CauBay River to the quality of agricultural soil of the KieuKy area. The PCBs composition analyses in the samples reflect their long-time release. The total cancer risk of PCBs in the soil of KieuKy fell into the very low range suggesting low risk. However, since PCBs were the species of POPs with more concern in this area, ecological risk assessment should be further investigated.

Contamination of selected organochlorine pesticides (OCPs) in sediment from CauBay River, Hanoi.

This work investigated the contamination status of selected organochlorine pesticides (OCPs: p,p'-DDT, p,p'-DDE, p,p'-DDD, α, ß, γ, δ-HCH) in sediment of the CauBay river. Wide occurrence and remarkable residue levels of these two OCPs have been found in the study areas. ΣDDT concentrations ranged from 51.84 to 92.76 ng.g(-1) dry weight, whereas ΣHCH concentrations ranged from 4.56 to 11.39 ng g(-1) dry weight. All of the sampling sites exceeded the effects range median levels for DDT (>46.1 ng g(-1)). The analyzed results show that ΣDDT and ΣHCH displayed uniform high and low distribution, respectively. There is no recent input of DDT and HCH in the study area.

Residue, temporal trend and half-life time of selected organochlorine pesticides (OCPs) in surface soils from Bacninh, Vietnam.

Selected organochlorine pesticides (p,p'-DDT, p,p'-DDE, p,p'-DDD, alpha,beta,gamma,delta-HCH) were analyzed in the surface soils of Bacninh, Viet Nam. Forty representative soil samples were collected from Bacninh town and three surrounding districts. SigmaDDT concentrations ranged from <0.02 to 160.86 ng g(-1) dry weight, whereas SigmaHCH concentrations ranged from <0.05 to 9.54 ng g(-1) dry weight. The half-life times of SigmaDDT and SigmaHCH are 6.7 and 4.9 years, respectively. The decreasing trends of SigmaDDT and SigmaHCH levels during the period from 1992 to 2006 are observed. There is no recent input of DDT and HCH in the study area.

Contamination by selected organochlorine pesticides (OCPs) in surface soils in Hanoi, Vietnam.

An evaluation of selected organochlorine pesticide residues [p,p'- dichlorodiphenyltrichloroethane (DDT), p,p'- dichlorodiphenyldichloroethylene (DDE), p,p'- dichlorodiphenyldichloroethane (DDD), alpha, beta, gamma and delta- hexachlorocyclohexane (HCH)] in the surface soils of Hanoi, Vietnam was carried out. Sixty representative soil samples were collected from the centre of Hanoi and five surrounding districts. In agricultural areas, SigmaDDT concentrations ranged from < 0.02 to 171.83 ng g(-1) (mean 89.86 ng g(-1)) dry weight, whereas SigmaHCH concentrations ranged from < 0.05 to 20.57 ng g(-1) (mean 8.03 ng g(-1)) dry weight. Investigation of the ratio of different isomers in the soil samples indicates that there has been no recent input of DDT and HCH in the study area.