Co-occurrence of phthalic acid esters (PAEs) and cyclic volatile methylsiloxanes (cVMSs) in fine particulate matter (PM0.5 and PM0.1) collected from an industrial area in Vietnam.

Distribution patterns of 10 phthalic acid diesters (PAEs) and four cyclic volatile methylsiloxanes (cVMSs) were investigated in fine particulate matter (PM0.1 and PM0.5) collected from Bac Ninh, an industrial province in Vietnam during September-October in 2021. Total concentrations of PAEs found in PM0.1 and PM0.5 were in the ranges of 1.76-372 (median: 34.0 ng/m3) and 2.23-895 ng/m3 (median: 15.4 ng/m3), respectively. Among PAEs, di-n-butyl phthalate (DBP) was the most abundant compound found in PM0.1, whereas, di-2-(ethyl)hexyl phthalate (DEHP) was measured at the highest concentration in PM0.5. Total concentrations of cVMSs measured in PM0.1 and PM0.5 were in the ranges of method quantification limit (MQL)-203 (median: 2.10 ng/m3) and MQL-537 ng/m3 (median: 0.389 ng/m3), respectively. Among cVMSs, decamethylcyclopentasiloxane (D5) was found at the highest concentration in both PM0.1 and PM0.5 fractions of particulate matter. The concentration ratios between PAEs and cVMSs in PM0.1/PM0.5 were greater than 1 (except di-n-octyl phthalate: DnOP), suggesting that these chemicals tend to sorb to PM0.1 more preferentially than PM0.5. Among sampling locations, high concentrations of PAEs and cVMSs were found at traffic intersections (Que Vo district) and a craft village (Tu Son city). Relatively stronger correlations existed between cVMSs pairs in PM0.1 and PM0.5 (correlation coefficient: 0.73-1) than those of PAEs (-0.83-0.90). The human exposure doses to PAEs and cVMSs through inhalation of particulate matter were estimated based on the measured concentrations in PM0.1 and PM0.5 fractions. The estimated exposure doses of PAEs and cVMSs for infants (7.1 ng/kg-bw/d and 2.5 ng/kg-bw/d) were higher than those for adults (2.6 ng/kg-bw/d and 0.9 ng/kg-bw/d).

Distribution and ecological risk assessment of phthalic acid esters in surface sediments of three rivers in Northern Vietnam.

Pollution status and distribution characteristics of ten typical phthalic acid esters (PAEs) were investigated in 36 sediment samples collected from three rivers in Northern Vietnam from June to October 2020. The total concentrations of PAEs in sediment samples collected from the To Lich River (n = 9), the Nhue River (n = 12), and the Day River (n = 15) were in ranges of 11,000-125,000 ng/g-dwt (mean/median: 50,000/42,200 ng/g-dwt), 2140-89,900 ng/g-dwt (mean/median: 29,300/20,700 ng/g-dwt), and 1140-43,100 ng/g-dwt (mean/median: 13,800/10,400 ng/g-dwt), respectively. Among ten PAEs studied, di-(2-ethylhexyl) phthalate (DEHP) was found at the highest levels in all samples meanwhile dimethyl phthalate (DMP), diethyl phthalate (DEP), and dipropyl phthalate (DPP) were detected at low frequency and concentration. Significant correlations have existed between the median-chain (C4-C7) PAE pairs in sediment samples. Due to the high accumulation in the sediments, the median-chain PAEs had a higher ecological risk than the short-chain (C1-C3) PAEs. These contaminants may present a longstanding influence on organisms and ecosystems.

A survey of parabens in aquatic environments in Hanoi, Vietnam and its implications for human exposure and ecological risk.

Seven parabens including methylparaben (MeP), ethylparaben (EtP), propylparaben (PrP), iso-propylparaben (iPrP), butylparaben (BuP), benzylparaben (BzP), and heptylparaben (HepP) were determined in bottled water, tap water, river water, lake water, and wastewater samples collected from Hanoi, Vietnam, using solid phase extraction (SPE) followed by ultrahigh performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The highest total concentration of parabens were measured in wastewater (range, 27.3-1050 ng/L; mean/median, 268/175 ng/L), followed by lake water (range, 18.0-254 ng/L; mean/median, 51.7/58.5 ng/L), river water (range, 16.5-52.1 ng/L; mean/median, 32.1/42.6 ng/L), tap water (range, 5.01-54.3 ng/L; mean/median, 28.6/41.1 ng/L), and bottled water (range, 1.56-39.9 ng/L; mean/median, 6.92/9.19 ng/L). Methylparaben and propylparaben were the predominant compounds found in all samples. The mean estimated human exposure dose of parabens through drinking bottled water was 0.27 ng/kg-bw/day, which is 6 orders of magnitude below the safety threshold recommended by the Joint FAO/WHO Expert Committee on Food Additive in 1974 (10 mg/kg-bw/day). Concentrations of parabens measured in river water, lake water, and wastewater samples were assessed to pose low to moderate ecological risks to aquatic organisms (0.1 < RQ < 1). Methyl, ethyl, and propyl parabens exhibited significant correlations in water samples.

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

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

Profiles of phthalic acid esters (PAEs) in bottled water, tap water, lake water, and wastewater samples collected from Hanoi, Vietnam.

Contamination levels and distribution patterns of ten typical phthalic acid esters (PAEs) were investigated in various types of water samples collected from Hanoi metropolitan area in Vietnam. Concentrations of 10 PAEs in bottled water, tap water, lake water, and wastewater samples were measured in the ranges of 1640-15,700 ng/L (mean/median: 6400/5820 ng/L), 2100-18,000 ng/L (mean/median: 11,200/9270 ng/L), 19,600-127,000 ng/L (mean/median: 51,800/49,300 ng/L), and 20,700-405,000 ng/L (mean/median: 121,000/115,000 ng/L), respectively. Among PAEs, di-(2-ethylhexyl) phthalate (DEHP) accounted for a major proportion of total concentrations (45%) in wastewater, followed by diisobutyl phthalate (DiBP, 10.3%), and dibutyl phthalate (DBP, 9.53%). Concentrations of PAEs in wastewater decreased significantly with distance from the wastewater treatment plants (WWTPs). Concentrations of PAEs in surface water samples did not vary greatly between locations. PAEs were found in bottled water in the following order: DBP (22.4%), DiBP (22.3%), benzylbutyl phthalate (BzBP, 20.1%), and DEHP (15.5%). The estimated mean exposure doses of 10 PAEs through consumption of drinking water for adults and children in Vietnam were 254 and 256 ng/kg-bw/day, respectively. Capsule: Highest concentrations of PAEs were measured in wastewater, followed by lake water, tap water, and bottled water.