Haipu Li

Mass loading and emission of thirty-seven pharmaceuticals in a typical municipal wastewater treatment plant in Hunan Province, Southern China

The occurrence, fate, mass loading and environmental emission of 37 pharmaceuticals were studied through an integrated approach involving both dissolved and adsorbed phase at a typical wastewater treatment plant in Hunan Province, Southern China. The results displayed the prevalence of 24 and 23 compounds in dissolved phase of influent and effluent, respectively. Fourteen compounds were found adsorbed onto sludge with a mean concentration ranging from 0.85 to 2900μg/kg dry weight. Twelve compounds exhibited high adsorption potential onto suspended particulate matter (SPM) with a mean fraction ranging from 8.8% (trimethoprim) to 97% (tetracycline). Furthermore, SPM showed a diverse absorbability in influent and effluent water circumstance. The overall elimination varied from -16% for lincomycin to 99% for paracetamol, while macrolides were able to withstand the whole treatment process. Mass balance analysis indicated that degradation was the predominant removal pathway for most compounds, and adsorption onto sludge combined with a minor portion of degradation explained for the reduction of tetracyclines and fluoroquinolones, whereas macrolides were recalcitrant to both two processes. The total mass loading was estimated to be up to 2800mg/d/1000 inhabitants and most compounds exhibited lower or comparable level comparing to the global published data. The total environmental emission was estimated up to be 1000mg/d/1000 inhabitants, and a value of 650mg/d/1000 inhabitants was obtained when considering merely the dissolved phase. This work would be helpful for the better understanding of ultimate fate and real pollution of pharmaceuticals in the water environment.

Occurrence of and human exposure to parabens, benzophenones, benzotriazoles, triclosan and triclocarban in outdoor swimming pool water in Changsha, China

The entry of personal care products (PCPs) into the environment has, in turn, caused negative influences to human health. Public swimming pools are places that have attracted increasing concerns. In this article, 35 outdoor swimming pools in Changsha City (China) were examined in view of the occurrence of 22 target PCPs contaminants, which fall into four categories: preservatives, UV filters, anticorrosion agents, and antimicrobials. Out of them, 16 compounds were detected in the collected samples. The preservatives was the most dominant category, with methyl paraben being the top compound (a.v. 0.85μg/L) followed by p-hydroxybenzoic acid (a.v. 0.13μg/L) and 1H-benzotriazole (a.v. 0.14μg/L). The correlations among 22 PCPs and their four categories were evaluated using the nonparametric Spearman correlations analysis. In the source tracing investigation, the level of PCPs in swimming pools was determined to be primarily associated with the consumption of these products while weakly related to the filling waters. The quantitative risk assessment revealed that the PCPs concentrations were at a safe level.

Analysis of metallic nanoparticles and their ionic counterparts in complex matrix by reversed-phase liquid chromatography coupled to ICP-MS

Developing quantification and characterization methodology for metallic nanoparticles (MNPs) and their ionic component in complex matrix are crucial for the evaluation of their environmental behavior and health risks to humans. In this study, reversed phase high performance liquid chromatography combined ICP-MS was established for the characterization of MNPs in complex matrix. The ionic component could be separated from NPs with the optimized parameters of aqueous mobile phase. Good linear relationship between average diameter and retention time of NPs was obtained using HPLC-ICP-MS and the size smaller than 40 nm could be determined with this method, the detected results were in accordance with TEM results. The low detection limit of AuNPs and Au(Ⅲ) (both in sub-μg/L level) showed that this method was promising for the characterization of AuNPs and Au(Ⅲ) in environmental water. The mass concentration of ionic Au(Ⅲ) in environmental water could be detected using the proposed HPLC-ICP-MS and the concentration of AuNPs was obtained by subtracting the Au(Ⅲ) concentration from the total Au (The concentration of total Au was detected by ICP-MS after microwave digestion). Furthermore this proposed HPLC-ICP-MS method and single particle-ICPMS (SP-ICP-MS) was used for the analysis of the Ag speciation in commercial antibacterial products.

Size characterization of silver nanoparticles after separation from silver ions in environmental water using magnetic reduced graphene oxide

This study involved the synthesis of magnetic reduced graphene oxide (M-rGO) using a co-precipitation method and examined its resultant adsorption properties for mixtures containing silver ions and silver nanoparticles (AgNPs). The results indicate that M-rGO preferentially adsorbs silver ions in mixtures containing AgNPs, enabling the size characterization of smaller AgNPs (<60nm) at ultra-trace concentration levels to be more attainable. The sorbents after adsorption could be easily recovered through an external magnet. The AgNPs retained in solution were characterized using single-particle ICPMS (SP-ICPMS). The adsorption behavior of silver ions on M-rGO was well fitted with the pseudo-second-order kinetic model and the Freundlich adsorption isotherm model, with the conclusion that the adsorption of silver ions occurred primarily through the chemical bond effect and the heterogeneous surface of the sorbent. Finally, the application of M-rGO with the approach developed herein to actual environmental water samples was successful.

Pharmaceutically active compounds in the Xiangjiang River, China: Distribution pattern, source apportionment, and risk assessment

The occurrence of 36 pharmaceutically active compounds in surface water of the Xiangjiang River was investigated in two seasons (n = 38). Twenty-five of these compounds were detected, with cefotaxime (maximum concentration 830 ng L-1) the most abundant compound followed by amoxicillin (maximum concentration 710 ng L-1). The spatiotemporal distribution was observed; indicating that pollution hotspots were mostly located in economically developed and densely populated regions such as Changsha City. Lower concentrations were found in summer than winter, which may be attributed to the dilution effect of a flood event and higher water temperatures. The distribution of pharmaceuticals was significantly correlated with temperature and ammonia nitrogen content. A principal component analysis-multiple linear regression model estimated that domestic sewage was the main source of pharmaceuticals, although the source composition varied among different sampling sites. Risk assessment was conducted using both individual and mixture models for preliminary identification of potential hazards. Sulfamethoxazole, clarithromycin, and azithromycin posed a high risk to algae, while sulfamethoxazole, trimethoprim, and erythromycin-H2O showed a medium risk to invertebrates. Moreover, the mixture risk quotients calculated using a concentration addition model ranged from 0.31 to 9.60 in winter, and from 0.06 to 0.61 in summer, indicating a potential risk to the aquatic environment. This study provides scientific support to policy-makers to establish contaminant management priorities and enriches the global data on emerging contaminants.

Simultaneous determination of haloanisoles and halophenols in water using in situ acylation combined with solid-phase microextraction with gas chromatography and mass spectrometry

In this work, an in situ acylation combined with solid-phase microextraction coupled to gas chromatography and mass spectrometry method has been developed for simultaneously determining haloanisoles (2,4,6-trichloranisole, 2,4,6-tribromoanisole), and their direct precursors (2,4,6-trichlorophenol, 2,4,6-tribromophenol) and indirect precursors (2-chloropenol, 2,4-dichlorophenol, 2-bromophenol, 2,4-dibromophenol) in water. The key parameters for the solid-phase microextraction were determined by using Plackett-Burman screening and optimized by central composite optimization. Under optimal conditions, the eight compounds can be analyzed in a short time (33 min) with a strong linearity ranging from 2 to 200 ng/L (correlation coefficient greater than 0.996), showing good sensitivities with the limit of detection in a range of 0.23-0.91 ng/L and a limit of quantification of 0.77-3.03 ng/L, good repeatability (2.00-9.10%) and interday precision (1.67-11.3%). When environmental water samples were treated, the recoveries of target compounds were 75.5-127.3%, suggesting that the developed method could be applied in probing the origin of haloanisoles and monitoring halophenols and haloanisoles in natural waters at concentration levels of ng/L.

Influence of filtration during sample pretreatment on the detection of antibiotics and non-steroidal anti-inflammatory drugs in natural surface waters

Owing to the ease and effectiveness of removing suspended substances (SSs), filtration has become a universal pretreatment step during water sample preparation. However, it can lead to the underestimation of contaminants if the targets easily associate with the SSs or filters. For the first time, this study comprehensively assessed issues related to filtration for the accurate quantification of 35 typical pharmaceuticals, including 28 antibiotics and seven non-steroidal anti-inflammatory drugs (NSAIDs), in water samples by comparing the effects of different filter materials, preservatives, and water matrices on the recoveries. The results showed that some sulfonamides and NSAIDs had an affinity for nylon filters, whereas trimethoprim and macrolides were easily retained on mixed cellulose ester filters. The use of glass fiber filter (0.7 μm) resulted in improved recovery of all the targets. Acidification promoted the adsorption of fluoroquinolones, tylosin, and roxithromycin on SSs, whereas 5% methanol resulted in desorption of macrolides from the SSs and other pharmaceuticals (sulfadiazine, trimethoprim, etc.) from the solid-phase extraction cartridges. Without additional detection of targets adsorbed on the SSs and filters, the addition of appropriate surrogates prior to filtration can help correct the loss.

Endocrine disrupting chemicals in wild freshwater fishes: Species, tissues, sizes and human health risks

Increasing attention has been devoted to the adverse effects of endocrine disrupting chemicals (EDCs) on aquatic environments, such as water, sediment and sludge. To date, few studies have investigated the bio-accumulative characteristics of EDCs in different tissues of diverse wild freshwater fish species and their combined impacts on human health. Five EDCs were investigated in the muscle, liver, gill and, especially, gonad of three fish species collected from the Xiangjiang River, southern China. Carnivorous Siniperca Chuatsi or omnivorous Cyprinus Carpio accumulated higher contents of bisphenol A (BPA) and estrone than herbivorous Parabramis Pekinensis in muscle. Furthermore, 4-n-nonylphenol and estrone were found at higher levels and more frequently in the liver, implying that the liver played an important role in basic metabolism for accumulation, biotransformation and excretion of EDCs. Highest concentrations of BPA found in the gonad revealed that the BPA may pose a serious threat to the reproductive system of aquatic organisms. The mean liver/muscle concentration ratios of 4-n-nonylphenol, BPA, estrone and 17α-ethynyl estradiol confirmed the prolonged exposure of the fish to these EDCs. In addition, the relationships between the fish sizes and the EDC concentrations analyzed by Pearson correlation analysis implied that the bioaccumulation of diethylstilbestrol and BPA increased with the growth of Parabramis Pekinensis, and there was a balance between the uptake rate and elimination rate of EDCs in Siniperca Chuatsi and Cyprinus Carpio. Most importantly, the cumulative impacts of combined EDCs on human health by fish consumption were evaluated. The total estradiol equivalent quantity of estrogens was higher than that of phenols. Also, based on the results of the Monte-Carlo simulation, the 95th percentile values of the total estimated daily intakes from consuming the three freshwater fish species from the Xiangjiang River were higher than the acceptable daily intake.

Endocrine-disrupting compounds in the Xiangjiang River of China: Spatio-temporal distribution, source apportionment, and risk assessment

Endocrine-disrupting compounds (EDCs) were seasonally investigated in the surface water of the Xiangjiang River (south China) in order to understand their spatio-temporal distribution, source apportionment, and ecological risks. The occurrence of 21 EDCs were determined with liquid chromatography-tandem mass spectrometry in the water samples collected along the river over four seasons, and the results were statistically analyzed. The concentrations of progestagens, androgens, estrogens ranged from not detected (ND) to 98.3 ng L-1; while the concentrations of alkylphenols ranged from 0.8 to 3.1 × 103 ng L-1; and that of caffeine ranged from 0.1 to 49.8 ng L-1. The detection frequencies of bisphenol A, 4-tert-octylphenol, 4-n-nonylphenol, estrone, and 17β-estradiol were 95-100% during the four sampling campaigns. The seasonal and spatial variation trend of EDCs in the Xiangjiang River was noticeable. The concentration of EDCs in Yueyang section (downstream) was the highest in winter, while the concentration in Yongzhou (upstream) section was the lowest in spring. The concentration of EDCs in the Xiangjiang River was significantly correlated with the levels of the total organic carbon, water temperature, and dissolved oxygen. Source analysis indicated that untreated sewage was the major source of EDCs. Furthermore, the potential risks of EDCs in the surface water to aquatic organisms were assessed with the risk quotient method (European Commission, 2003), and the results indicated the highest ecological risk of 17β-estradiol in the Xiangjiang River.

Assessment of heavy metal contamination, distribution and source identification in the sediments from the Zijiang River, China

In this study, the contents of 10 heavy metals (Sb, Cd, Cr, Mn, Co, Ni, Cu, Zn, As, and Pb) in 49 sediment samples from the Zijiang River were determined by using inductively coupled plasma-optical emission spectrometry. Contamination indexes including geoaccumulation index, modified degree of contamination, sediment quality guidelines, potential ecological risk index, together with potential ecological risk factor were used to assess heavy metal contamination in the sediments of the Zijiang River. Pearsons correlation analysis and principal component analysis were used to identify the sources of heavy metals. The results indicated that the mean values of heavy metals in the Zijiang Rivers sediments were found to be significantly higher than the corresponding background values. But when comparing with that in other rivers in the world, they were at medium levels except for Sb. Furthermore, a comparison of the heavy metal concentrations and the consensus-based sediment quality guidelines showed that the heavy metal pollutions (Cd, Cr, Ni, Cu, Zn, As, and Pb) tended to occasionally pose harmful impacts on the ecosystem. The values of contamination indexes revealed that serious heavy metal contamination and relatively high potential ecological risks were mainly existed in the downstream of antimony mining and smelting factories (S23-S49). In addition, high potential ecological risks of Sb were observed in sampling sites that were close to those factories (S23, S24, S25, and S27), and high potential ecological risks of Cd were observed in the downstream (S37-S49). Basing on the Pearsons correlation analysis and principal component analysis, three main sources were identified. Co, Zn, Cd, and Cu contaminants were mainly derived from agricultural activities; As, Sb, Mn, and Pb mainly came from mining and smelting activities; Cr and Ni were mainly from natural sources.