Contamination of perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) in sediment of the Cau River, Vietnam.

Perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) are recognized as emerging environmental pollutants because of their high persistence in various environmental matrices and toxic effects on humans and animals. In Vietnam, PFOA and PFOS have been detected in surface water and sediment in recent studies. The objectives of this study were to evaluate the spatial and vertical distribution, determine the factors affecting the sorption onto sediment, and assess the environmental risk of PFOS and PFOA in the sediment of the Cau River. The average concentrations of PFOS and PFOA in the surface sediment were 2.66 ng/g and 0.84 ng/g, respectively. The highest concentrations were recorded in the areas receiving wastewater from domestic and industrial activities. According to the depth, the contents of target chemicals in the surface sediments (0-5 cm) were lower than those in the second layer (5-10 cm). The remaining layers have decreasing concentration as the depth of the sediment increases. The water-sediment distribution coefficient was relatively different for PFOS and PFOA with log Kd values ranging from 1.31 to 1.86 and from 0.08 to 1.31, respectively. This study also demonstrated that the level of PFOS and PFOA in sediment is significantly correlated with total organic carbon content of sediment. No apparent relation was found between PFOS, PFOA concentration in sediment, and particle size distribution. Risk quotients of the two compounds were below 0.01, indicating that the environmental risk in the sediment is negligible at present. The results of this study provide an overview of PFOS and PFOA contamination in sediment in the Cau River, Vietnam.

Distribution of pharmaceutical and personal care products (PPCPs) in aquatic environment in Hanoi and Metro Manila.

Pharmaceutical and personal care products (PPCPs) recently defined as emerging pollutants that widespread in surface water all around the world. This study investigated the distribution, and ecological risk of PPCPs in urban rivers of Hanoi, Vietnam, and Metro Manila, the Philippines. Of the 56 investigated PPCPs, 48 and 33 compounds were detected in the river water in Hanoi and in Metro Manila, respectively. The individual PPCP concentrations ranged from a few ng L-1 to thousands of ng L-1. The total concentration of PPCPs detected in water samples ranged from 7.5 to 20,789 ng L-1 in Hanoi and 118 to 3,394 ng L-1 in Manila. The predominant antibiotics was sulfamethoxazole detected in 27/28 samples with a maximum concentration up to 2,778 ng L-1 in Hanoi and presented in all samples with a maximum concentration up to 261 ng L-1 in Metro Manila. In Hanoi, the level of PPCPs in urban canals of Kim Nguu and To Lich Rivers was as high as that detected in domestic wastewater. The PPCP concentrations in tributaries and mainstream were lower than those found in urban canals. In rivers of both sites, PPCPs tended to increase along the stream. The concentration ratio of the labile marker caffeine to recalcitrant marker carbamazepine indicated that untreated domestic wastewater is the significant source of PPCPs in river water in Hanoi and Metro Manila. The ecological risk estimated by the risk quotient of the obtained maximum residue of PPCPs in investigated river water predicted a high risk of PPCPs to the aquatic organism in both Hanoi and Manila.

Occurrence of pharmaceutical and personal care products in Cau River, Vietnam.

This study evaluated the occurrence of PPCPs in Cau River (Vietnam). Surface water and sediment samples were collected to determine PPCP concentrations. The analysis results showed the presence of 36 out of 56 investigated PPCPs in samples. The total concentration of PPCPs in water samples ranged from 8.21 to 529 ng/L and the value observed in sediment was from 17.4 to 172.8 µg/kg. Along the Cau River, there was a trend of accumulation of PPCPs at the downstream. The highest level of PPCP was observed after the river flows through Thai Nguyen and Bac Ninh provinces. Among detected PPCPs, the ones detected with high frequency (over 70%) and high concentration were caffeine, sulfamethoxazole, and lincomycin in water and triclocarban, levofloxacin, and griseofulvin in sediment. The water-sediment partition coefficient (Kd) was estimated to explore the fate of PPCP in the river, and the observed Kd mean values for lincomycin, sulfamethoxazole, and griseofulvin were 223.0, 7.6, and 997.0 kg/L, respectively. Risk assessment was initially conducted by applying a semi-quantitative assessment risk quotient (RQ); the potential ecological risk to the aquatic organism of PPCPs posed a moderate risk.

Characteristics of roadside volatile organic compounds in an urban area dominated by gasoline vehicles, a case study in Hanoi.

Volatile organic compounds (VOCs) are important air pollution issues because of their potential health effects, and the contribution to ground ozone and secondary particulate matter. In this study, 53 VOC species near nine roads in Hanoi were monitored by sampling and analyzed by GC-FID four times per day on weekdays and in the morning on the weekend, from December 2014 to January 2015. In parallel with VOC sampling, vehicle number was counted, and meteorological conditions were recorded. A large share of motorbikes was found, accounted for 82% of overall for all period, and 88% in rush hours. The average TVOC concentration was 305.1 ppb; while those of BTEX were 12.8/27.4/4.8/15.9/6.0 ppb for benzene/toluene/ethylbenzene/m,p-xylenes/o-xylene, respectively. Isopentane was the most abundant species of VOCs. A significant carcinogenic risk of benzene species was found. Ozone formation potential (OFP) of VOCs was of 1752.7 ppb. Levels of VOC species reflected well the transportation volume. Strong correlations between motorbike number related parameters and ethylbenzene were found. High correlations were also found among ethylbenzene and almost all other VOC species. It implied that the majority of VOCs near road emitted from the same source, which is motorbikes. The calculation using emission factors from COPERT 5 model with conditions of fleets in Hanoi showed that VOCs from motorbikes contributed to more than 90% of the VOC level.