[Research Progress on Pollution Characteristics, Degradation, and Transformation of Typical PPCPs in the Process of Wastewater Treatment].

Pharmaceuticals and personal care products (PPCPs) have received extensive attention as a new type of pollutant inin the 21st century, and the ecological and health risks caused by PPCPs have gradually been recognized by government regulatory agencies. Daily use of PPCPs has led to their frequent detection and high concentrations in the influent, effluent, and sludge of wastewater treatment plants, but traditional wastewater treatment processes can't remove them effectively. Most research about enhancing the removal of PPCPs through microbial degradation, photodegradation, and ozonation is still in the laboratory research stage, and the removal effects are not satisfactory when applied to actual sewage treatment. Therefore, the effective removal of PPCPs from domestic wastewater is a critical technical problem that urgently needs to be studied and solved in the coming years. At present, many scholars do not have a comprehensive understanding about the degradation and transformation behaviors of microbes, ultraviolet, and ozone for typical PPCPs in the wastewater treatment process, so it is necessary to conduct a systematic analysis and discussion. In this study, 16 typical PPCPs frequently detected in sewage treatment plants were selected as research objects through a literature review. The occurrence, removal characteristics, and sludge adsorption properties of typical PPCPs in wastewater treatment plants were analyzed and summarized. The degradation and transformation behavior of typical PPCPs under microbial, ultraviolet, and ozone treatments in the wastewater treatment process were also discussed. Finally, based on current research gaps, some research directions for the removal and transformation of PPCPs in wastewater were proposed:① investigation into the removal characteristics of PPCPs by actual biochemical treatment; ② study on the mechanism of microbial degradation and transformation of typical PPCPs during biochemical treatment; ③ study on the degradation and transformation mechanism of typical PPCPs by UV/ozone in an actual sewage system; and ④ research on the application technology of removing PPCPs from sewage via microbial degradation, photodegradation, ozone oxidation, etc. The relevant results of this study can provide a reference for the pollution control of typical PPCPs in the sewage treatment process.

Effect comparisons of different conditioners and microbial agents on the degradation of estrogens during dairy manure composting.

To investigate the degradation efficiency of conditioners and commercial microbial agents on estrogens (E1, 17α-E2, 17ß-E2, E3, EE2, and DES) in the composting process of dairy manure, seven different treatments (RHB-BF, OSP-BF, SD-BF, MR-BF, MR-FS, MR-EM, and MR-CK) under forced ventilation conditions were composted and monitored regularly for 30 days. The results indicated that the removal rates of estrogens in seven treatments ranged from 95.35% to 99.63%, meanwhile the degradation effect of the composting process on 17ß-Estradiol equivalent (EEQ) was evaluated, and the removal rate of ΣEEQ ranged from 96.42% to 99.72%. With the combined addition of rice husk biochar (RHB) or oyster shell powder (OSP) and bio-bacterial fertilizer starter cultures (BF), namely RHB-BF and OSP-BF obviously promoted the rapid degradation of estrogens. 17ß-E2 was completely degraded on the fifth day of composting in OSP-BF. Microbial agents have some promotional effect and enhances the microbial degradation of synthetic estrogen (EE2, DES). According to the results of RDA, pH and EC were the main environmental factors affecting on the composition and succession of estrogen-related degrading bacteria in composting system. As predominant estrogens-degrading genera, Acinetobacter, Bacillus, and Pseudomonas effected obviously on the change of estrogens contents. The research results provide a practical reference for effective composting of dairy manure to enhancing estrogens removal and decreasing ecological risk.

[Sorption Characteristics and Site Energy Distribution Theory of Typical Estrogens on Microplastics].

Microplastics (MPs) and estrogens are high-profile emerging contaminants at present, and MPs might become the carrier of estrogens in the environment and induce combined pollution. To study the adsorption behavior of polyethylene (PE) microplastics to typical estrogens, the adsorption isothermal properties of the six estrogens[estrone (E1), 17α-estradiol (17α-E2), 17ß-estradiol (17ß-E2), estriol (E3), diethylstilbestrol (DES), and ethinylestradiol (17α-EE2)] in single-solute and mixed-solute systems were studied through batch equilibrium adsorption experiments, in which the PE microplastics before and after adsorption were characterized by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). Then, the site energy distribution theory of the adsorption of six estrogens on PE microplastics was further analyzed based on the Freundlich model. The results showed that the adsorption process of selected estrogens with two concentrations (100 µg·L-1 and 1000 µg·L-1) on PE were more consistent with the pseudo-second order kinetic model. The increase in initial concentration reduced the equilibrium time of adsorption and increased the adsorbing capacity of estrogens on PE. In the single system (one estrogen) or mixed system (six estrogens) with different concentrations (10 µg·L-1-2000 µg·L-1), the Freundlich model showed the best fitting effect for the adsorption isotherm data (R2>0.94). The results of isothermal adsorption experiments and XPS and FTIR spectra showed that the adsorption of estrogens on PE in the two systems was heterogeneous adsorption, and hydrophobic distribution and van der Waals forces were the principal factors in the process of adsorption. The occurrence of C-O-C (in only the DES and 17α-EE2 systems) and O-C[FY=,1]O (in only the 17α-EE2 system) indicated that the adsorption of synthetic estrogens on PE was affected slightly by chemical bonding function, but no obvious effects were observed for natural estrogens. The results of site energy distribution analysis showed that, compared with the single system, the adsorption site energy of each estrogen shifted to the high-energy region in its entirety in the mixed system, and the site energy increased by 2.15%-40.98%. The energy change in DES was the most significant among all of the estrogens, indicating its competitive advantage in the mixed system. The above results of this study can provide some reference for the study of adsorption behavior, mechanism of action, and environmental risks under the coexisting condition of organic pollutants and MPs.

Emission of volatile organic compounds (VOCs) from application of commercial pesticides in China.

Applying pesticides can result in emissions of volatile organic compounds (VOCs), but little is known about VOC emission characteristics and the quantities in particular regions. We investigated the use of pesticides in China based on a large-scale survey of 330 counties in 31 provinces and evaluated the national pesticide VOC emission potentials based on thermogravimetric analysis of 1930 commercial pesticides. The results showed that herbicides were the most extensively used pesticide category in China, accounting for 43.47%; emulsifiable concentrate (EC), suspension concentrate, and wettable powder were the dominant pesticide formulations, with proportions of 26.75%, 17.68%, and 17.31%, respectively. The VOC emission potential coefficient (EP) of the liquid formulations was higher than the solid formulations, and the maximum mean EP was 45.59% for EC and the minimum was 0.76% for WP. Among 437 high-VOC pesticide products used in China, EC accounted for 83.52%, and 16.93% of those contained abamectin. The total VOC emissions derived from commercial pesticides in China were 280 kt (kilotons) in 2018, and 65.35% of the contribution was derived from EC. Shandong, Hunan, and Henan were the three provinces with the highest pesticide VOC emissions (>21 kt/y). The emission rate of VOCs from pesticides was 24.80 t/d in China, which was higher than in San Joaquin Valley, California. These findings suggest that some comprehensive measures (e.g., perfecting pesticide management policy, strict supervision for pesticide production and use, and strengthening pesticide reduction publicity) should be taken to reduce VOC emissions from pesticide applications.

Variations of antibiotic resistome in swine wastewater during full-scale anaerobic digestion treatment.

Anaerobic digesters have been widely used to treat wastewaters in livestock farms. With the increasing risk of antibiotic resistance originated from livestock husbandry, removal of antibiotics and antibiotic resistance genes (ARGs) via anaerobic digesters deserved more attention. Here we investigated the removal of antibiotics and ARGs in swine wastewater by three on-farm full-scale anaerobic digesters, including buried biogas digester (BBD), up-flow anaerobic sludge blanket (UASB) and high density polyethylene covered biogas digester (HDPE-BD). Variations of antibiotic resistome in swine wastewater were further revealed by metagenomic sequencing. Results showed the removal efficiencies for antibiotics, ARGs and mobile genetic elements (MGEs) varied in the three digesters, ranging from 65.1% to 98.1%, 3.5%-71.0% and 26.9%-77.2%, respectively. In general, UASB and HDPE-BD showed better removal efficiencies than BBD. However, enrichment of metal resistance genes (MRGs) was noted in UASB. Pathogens could not be effectively removed by all of the three digesters. What's more, accumulation of pathogens was found in UASB (removal efficiencies: -8.5%-13.6%). Bacterial community succession, horizontal genetic transfer and biocide and metal resistance genes (BMRGs) profiles jointly structured the variation of antibiotic resistome during anaerobic digestion. A total of 334 high-quality bins were identified from swine wastewater, 96 of which belonged to phylum of Firmicutes, Bacteroidetes and Proteobacteria carried ARGs. Proteobacteria was the dominant multi-drug resistant flora. Meanwhile, ARG-carrying pathogens (Bacteroides and Mycolicibacter) were found in the swine wastewater, suggesting a potential threat to human and animal health. The findings from this study showed that HDPE-BD is the most eco-friendly and effective anaerobic digester in controlling risks from antibiotic resistance determinants in swine wastewater.

Comparisons of pollution characteristics, emission situations, and mass loads for heavy metals in the manures of different livestock and poultry in China.

The application of livestock and poultry manures was the predominant source of heavy metals in agricultural soils, particularly in China. It is important to systematically compare the pollution characteristics, emission situations and mass loads for heavy metals in the manures of different livestock and poultry in China. According to analysis and estimation based on the reported concentration levels of eight heavy metals (Zn, Cu, Pb, Cd, Cr, Hg, As, and Ni) and the feed quantities of livestock (pig, cattle, and sheep) and poultry in 2017, the concentrations of Zn and Cu and the over-standard frequencies of Zn, Cu, Cd, and As were much higher than those of other heavy metals, especially in pig manure. In 2017, the total emission of livestock and poultry manure in China was 1.64 × 109 t (FW), which was mainly excreted from cattle (45.77%); while the total emission of heavy metals sourced from manures was 2.86 × 105 t (DW), with the predominant contribution originating from pig manure (71.52%). The highest mass loads of manures and heavy metals were observed in Shandong, Tianjin, Henan, and Shanghai, where heavy metal contamination may be occurring (especially for Zn and Cu). The heavy metal concentrations in livestock and poultry manures of China were similar to other countries; however, more heavy metals were discharged into agricultural land through manure (especially for Zn and Cu). For many countries, abundant Zn and Cu exist in agricultural soils, principally contributed by livestock and poultry manures. These heavy metals originate from their addition to livestock and poultry feeds. Therefore, reducing the addition of Zn and Cu in feeds is an effective measure to lower their input into agricultural soils.

[Occurrence and Removal of N-nitrosamines in the Wastewater Treatment Plants Using Different Treatment Processes].

This study measured the concentrations of six N-nitrosamines (NAs) in water samples from each process stage of three wastewater treatment plants (WWTPs) and their corresponding receiving rivers. The occurrence and removal of NAs was then systematically studied in three WWTPs using different treatment processes, and their pollution profiles and sources in the receiving rivers were analyzed. The results showed that the six NAs occurred widely in the wastewater from every process stage of three WWTPs. NPIP, NDMA, and NPYR were the dominant pollutants with concentrations in the tens to hundreds ng·L-1. The three WWTPs using different treatment processes removed a certain amount of NAs, and the modified A2/O and A2/O+MBR showed good NAs removal effects, with total removal rates of 95% and 63%, respectively. The removal of NAs mainly relied on microbial degradation and transformation during the biochemical stage. During the filtration, disinfection, and MBR stages, NAs precursors in the wastewater treatment system could form some added NAs after a series of reactions. The six NAs were also frequently detected in the surface waters of receiving rivers, where the main pollutants were also MDMA, NPIP, and NPYR, which was consistent with the influent of the WTTPs. The sources of NAs in the receiving rivers were wide ranging and complicated, including emission from the effluent of the WTTPs, the release of untreated sanitary sewage, industrial wastewater, and surface runoff from industrial districts. Therefore, effective measures should be taken to reduce the input of NAs into receiving rivers, such as enhancing the capacity of sewage collection and treatment and optimizing sewage treatment processes.

Bioaccumulation, metabolism, and risk assessment of phenolic endocrine disrupting chemicals in specific tissues of wild fish.

Phenolic endocrine disrupting chemicals (EDCs) may pose a great hazard to wildlife and humans, owing to their ubiquitous presence in the environment and potential bioaccumulation ability. We investigated the bioaccumulation, metabolism, and human health risks of six phenolic EDCs, including bisphenol A (BPA), 4-tert-octylphenol (4-t-OP), 4-nonylphenol (4-NP), estrone (E1), 17ß-estradiol (E2), and 17α-ethinylestradiol (EE2), in wild fish from the Pearl River system, South China. Except EE2, the other five EDCs were detected in at least one of the four fish tissues (bile, liver, plasma, and muscle). The concentrations of BPA and 4-NP were greater than those of 4-t-OP, E1, and E2 in all tissues. The median values of log bioaccumulation factors for EDCs at the range of 3.86-4.52 in bile, 2.06-3.16 in liver, 2.69-3.87 in plasma, and 1.34-2.30 in muscle, indicating a higher bioaccumulation potential in fish bile than in other tissues. Greater levels of glucuronide/sulfate conjugated EDCs were found in fish bile and liver than in the plasma and muscle, suggesting that the liver and bile played an important role in the metabolism and excretion of phenolic EDCs in fish. The calculated hazard quotient values were below 1 for each compound, implying low risk to human health by intake of edible fish.

Bioaccumulation and risks of 24 personal care products in plasma of wild fish from the Yangtze River, China.

We used a hybrid precipitation method to simultaneously extract and analyze 24 personal care products (PCPs), including 16 biocides, 4 synthetic musks, and 4 benzotriazoles, in the plasma of fish. The method's performance was validated for plasma samples with and without ß-glucuronidase/aryl-sulfatase hydrolysis. The recoveries were in the range of 70-120% for most of the PCPs, except N,N-diethyl-3-methylbenzamide (DEET), clotrimazole (CTZ), miconazole and itraconazole at spiking concentration of 20 and 5 ng/mL. The quantification limits ranged between 0.89 and 17.9 ng/mL (hydrolyzed plasma) and 0.85-18.5 ng/mL (non-hydrolyzed plasma), except CTZ at 77.5 ng/mL and 76.3 ng/mL. Totally, 13 PCPs were detected in plasma samples of fish collected from the Yangtze River, with a maximum concentration of 58.4 ng/mL (galaxolide). Compounds with the phenol hydroxyl groups of parabens or triclosan in hydrolyzed plasma showed higher concentrations than those in unhydrolyzed plasma with the ratio of conjugation (glucuronides + sulfates) forms up to 86%. The median values for the logarithm of bioaccumulation factors were between 1.39 and 4.15, which were 2-3 orders of magnitude higher than the theoretical logarithm of bioconcentration factors. Using the fish plasma model, the effect ratios (effect concentration/measured plasma concentration ratios) of tonalide, galaxolide, benzotriazole, triclosan, and DEET reached 0.35, 4.15, 3.78, 7.52, and 9.24, respectively. These are recognized as priority chemicals for further risk assessment.

Fate of veterinary antibiotics during animal manure composting.

Antibiotics are widely used in animals for disease treatment and prevention. After use, these antibiotics end up in manure. Here we investigated the fate of veterinary antibiotics in animal manure during composting and their residues in manure-applied soils. The results showed that 64.7% of the detected veterinary antibiotics were removed after composting for 171 days, which mainly occurred at the thermophilic phase in the second week, followed by a long stable stage with limited variations. The removal rates for lincomycin, trimethoprim and the macrolides during the composting were >89.7%, while those for the sulfonamides, tetracyclines and fluoroquinolones were less than <63.7%. The dissipation of antibiotics during the composting was related to the change of compost physicochemical properties, especially moisture and C/N ratio. The application of compost products with antibiotic residues could still lead to soil contamination, which may pose risks of resistance selection to the soil ecosystem.

Biocides in the river system of a highly urbanized region: A systematic investigation involving runoff input.

This study aimed to investigate the occurrence of 19 biocides in the aquatic environments (including runoffs) of a highly urbanized region, and then analyze the sources and ecological risks of target biocides in the river system. The investigated results showed that 19 target biocides were universally detected in surface water (17), sediment (19) and rainfall runoff (18). The tributaries of the river system were seriously contaminated by the biocides compared to the main stream. The prominent biocides in the riverine environment were methylparaben, climbazole and N,N-diethyl-3-methylbenzamide (DEET) for surface water, climbazole, triclosan and triclocarban for sediment, and DEET and carbendazim for rainfall runoff. The biocides source analysis based on the mass contribution suggested that domestic wastewater was a dominant input source for most biocides in the riverine environment, while rainfall runoff was another crucial input source for some biocides, especially for DEET and carbendazim. The ecological risk assessment revealed that some high levels biocides (e.g. clotrimazole, carbendazim, and triclosan) could pose potential ecological risks to aquatic organisms. Therefore, it is essential that some efficient measures should be taken to reduce the input of biocides to river system from different sources.

Occurrence, fate and mass loadings of antibiotics in two swine wastewater treatment systems.

Antibiotics are widely applied in livestock industry to prevent or treat animal diseases. However, those antibiotics are poorly metabolized in livestock animals, most of them being excreted via feces or urine. Hence we need to understand the removal of antibiotics in swine farm wastewater treatment systems. This study investigated occurrence and fate of various antibiotics in two full-scale swine farm wastewater treatment systems (Farm A: anaerobic digester-A2/O-lagoon; Farm B: upflow anaerobic sludge blanket (UASB)-(A/O)2-lagoon). The results showed the presence of 25 antibiotics out of 40 target antibiotics in the wastewater and sludge samples from the two farms. In Farm A, sulfamonomethoxine, sulfachlorpyridazine, oxytetracycline and lincomycin were predominant in the influent with concentrations up to 166 ±â€¯3.64 µg/L, while in the dewatered sludge chlortetracycline, oxytetracycline, tetracycline and norfloxacin were the predominant target compounds with concentrations up to 29.2 ±â€¯3.74 µg/g. In Farm B, high concentrations (up to 3630 ±â€¯1040 µg/L) of sulfachlorpyridazine, sulfamonomethoxine and lincomycin were detected in the influent, and the predominant target antibiotics detected in the dewater sludge were similar to those in Farm A, with concentrations up to 28.6 ±â€¯0.592 µg/g. The aqueous removal rates for the total antibiotics were >99.0% in the wastewater treatment plants of both farms. Among a series of treatment units, the anaerobic digester in Farm A and UASB in Farm B made a significant contribution to the elimination of the target antibiotics from the animal wastewater. The daily mass loadings of total antibiotics in the manure, influent, dewatered sludge and effluent were 17.1, 28.0, 2.53, and 0.0730 g/d for Farm A and 24.5, 354, 3.17, and 0.293 g/d for Farm B. The full-scale swine wastewater treatment facilities could effectively remove antibiotics from swine wastewater, but the dewatered sludge needs to be further treated before disposal on land.

Determination of 24 personal care products in fish bile using hybrid solvent precipitation and dispersive solid phase extraction cleanup with ultrahigh performance liquid chromatography-tandem mass spectrometry and gas chromatography-mass spectrometry.

Personal care products (PCPs) are ubiquitous in aquatic environments owing to the continuous discharge of domestic wastewater from highly urbanized regions. These PCPs can be adsorbed by fish and thereafter usually enter the bile of the fish through biliary excretion. In this study, a sensitive method based on a combination of hybrid solvent precipitation and dispersive solid phase extraction (d-SPE) purification was developed to simultaneously extract and detect 24 PCPs, namely, 16 biocides, 4 synthetic musks, and 4 benzotriazoles, from fish bile. Hybrid precipitation on solid phase extraction (SPE) tubes was applied to remove phospholipids and proteins, and a d-SPE procedure was used for further purification. The extraction solvents for the hybrid precipitation/SPE tubes and d-SPE materials were optimized. The method performance for bile samples both with and without enzyme hydrolysis using ß-glucuronidase/aryl-sulfatase were validated. The 24 PCPs in fish bile were spiked with standard concentrations of 10 ng/mL, 20 ng/mL, 100 ng/mL, and 200 ng/mL to evaluate recoveries, which ranged from 70 to 120% for 16, 16, 22, and 21 analytes with hydrolysis, respectively, and 70-120% for 14, 15, 23, and 23 analytes without hydrolysis, respectively. The quantification limits for target PCPs were in the range 0.26-7.38 ng/mL [excluding musk xylene (MX) and musk ketone (MK)] and 0.20-9.48 ng/mL (excluding MX and MK) for bile samples with and without enzyme hydrolysis, respectively. After enzyme hydrolysis, 12 PCPs were detected in bile from fish collected from the Yangtze River, with a maximum detected concentration of 460 ng/mL, for triclosan (TCS). The hydrolysis reaction indicated that high percentages of glucuronide and sulfate metabolites for some PCPs, i.e. four parabens and TCS, existed in the bile.

Occurrence, fate and risk assessment of androgens in ten wastewater treatment plants and receiving rivers of South China.

Androgens are one class of steroids that could cause endocrine disrupting effects in aquatic organisms. However, little information is available about androgens in wastewater treatment plants (WWTPs) with different treatment technologies. Here we investigated the occurrence, removal, and fate of fourteen natural and synthetic androgens in ten WWTPs of Guangdong province, south China. The results showed detection of ten androgens in the influents of the ten WWTPs, with concentrations up to 4650 ng/L (androsta-1,4-diene-3,17-dione). But only three androgens androsta-1,4-diene-3,17-dione, 4-androstene-3,17-dione and 17ß-boldenone were detected in the final effluents of the ten WWTPs, while six androgens androsta-1,4-diene-3,17-dione (N.D. to 43.0 ng/g), 4-androstene-3,17-dione (2.06-42.7 ng/g), epi-androsterone (N.D. to 506 ng/g), testosterone (0.29-4.24 ng/g), 17ß-boldenone (N.D. to 2.05 ng/g) and methyl testosterone (N.D. to 0.70 ng/g) were found in activated sludge. The aqueous phase removal rates for most androgens in the WWTPs exceeded 95% except for 4-androstene-3,17-dione with its removal rates varying between 79.5% and 100%. The removal of androgens in the WWTPs could be attributed mainly to biodegradation while removal by precipitation, volatilization, sludge absorption and oxidation was very limited. Eight androgens were also found in five receiving rivers. The risk quotients of some androgens (androsta-1,4-diene-3,17-dione, 4-androstene-3,17-dione, methyl testosterone, 17α-trenbolone) exceeded 1 in the receiving rivers, showing high risks to aquatic organisms. Further studies are needed to understand the origin of these high risk androgens and ecological effects.

Personal care products in wild fish in two main Chinese rivers: Bioaccumulation potential and human health risks.

Personal care products (PCPs) are widely applied in our daily life, however, little is known about their occurrence in wild fish. We investigated the bioaccumulation and potential risks of 24 PCPs in muscle and liver tissues of wild fish collected from two large rivers of Pearl and Yangtze Rivers in China. The results showed the detection of a total of 13 PCPs including 9 biocides, 2 synthetic musks and 2 benzotriazoles in at least one type of fish tissue from 12 fish species. The compounds with high detection frequencies (>50%) in fish muscle or liver tissues were N,N-diethyl-3-methylbenzamide, carbendazim, climbazole, miconazole (MCZ), methylparaben, propylparaben, triclosan (TCS), tonalide, galaxolide (HHCB) and 5-methyl-1H-benzotriazole (5-TT). Among biocides, synthetic musks and benzotriazoles, TCS, HHCB and benzotriazole showed the maximum concentrations of 79.5ng/g wet weight (ww), 299ng/g ww and 3.14ng/g ww, respectively, in muscle tissue, while MCZ, HHCB and 5-TT showed the maximum concentrations of 432ng/g ww, 2619ng/g ww and 54.5ng/g ww, respectively, in liver tissue. The median values of logarithm of bioaccumulation factors (BAF) for the detected 13 PCPs were ranged 0.8-3.35 in muscle and 0.85-4.58 in liver. The log BAF values of the PCPs displayed good linear relationships with log Kow and log Dow (pH-dependent Kow). The health hazard assessment of 10 detected PCPs in the muscle indicated no appreciable risk to human via consumption of the wild fish.

Pharmaceuticals and personal care products (PPCPs) and artificial sweeteners (ASs) in surface and ground waters and their application as indication of wastewater contamination.

We systematically investigated the occurrence and distribution of 93 pharmaceuticals and personal care products (PPCPs) and 5 artificial sweeteners (ASs) in surface water and groundwater of Dongjiang River basin in south China. In surface water, 52 compounds were detected with median concentrations ranging from 0.06ng/L to 504ng/L, while in groundwater, 33 compounds were detected with concentrations up to 4580ng/L for acesulfame. PPCPs and ASs were widely detected in the surface water and groundwater samples, which indicated contamination by domestic wastewater in the surface water and groundwater of Dongjiang River basin. Temporal and spatial variations of the detected chemicals were observed in surface water. Acesulfame, sucralose and cyclamate can be used as wastewater indicators to imply contamination in groundwater caused by domestic wastewater due to their hydrophilicity, anthropogenic sources and ubiquity in groundwater. Moreover, the detection of the readily degradable ASs, cyclamate, was a strong indication of untreated wastewater in groundwater. Sucralose was found to be a suitable wastewater indicator to reflect domestic wastewater contamination in surface water and groundwater qualitatively and quantitatively, and it can be used to evaluate wastewater burden in surface water and groundwater of Dongjiang River basin. The wastewater burden data from this survey implied serious contamination in surface water and groundwater by domestic wastewater at Shima River, a tributary of the Dongjiang River. The findings from this study suggest that the selected labile and conservative chemicals can be used as indication of wastewater contamination for aquatic environments qualitatively and quantitatively.

Suitability of pharmaceuticals and personal care products (PPCPs) and artificial sweeteners (ASs) as wastewater indicators in the Pearl River Delta, South China.

Wastewater indicator is a useful tool for evaluating the wastewater impact on natural water, but there is little information about the suitability of wastewater indicators for different regions. This study aimed to select suitable wastewater indicators in the Pearl River Delta region, south China by screening a range of wastewater related organic compounds. The screening campaign was carried out by investigating the occurrence and removal efficiencies of 93 pharmaceuticals and personal care products (PPCPs) and 5 artificial sweeteners (ASs) in nine wastewater treatment plants (WWTPs) located in the region, and the occurrence of these target compounds in the contaminated and clean surface water of the Pearl River. An ideal wastewater indicator should be hydrophilic, source-specific for domestic wastewater, ubiquitous in contaminated surface water with detection frequency (DF) >80% and absent in background water samples. For liable indicators, high removal rates (>90%) should be observed in WWTPs and they should be detected in all the influent samples at concentrations fifty times higher than their limits of quantification. For conservative indicators, low removal rates (<50%) should be observed in WWTPs and they should be detected in all the effluent samples at concentrations fifty times higher than their limits of quantification. Based on the above criteria, sucralose and fluconazole were selected as conservative indicators in the region, while cyclamate, saccharin, methyl paraben, ethyl paraben, propyl paraben, paracetamol, salicylic acid and caffeine were selected as liable indicators.

Biocides in wastewater treatment plants: Mass balance analysis and pollution load estimation.

This study aimed to investigate the occurrence and removal of 19 biocides in ten different wastewater treatment plants (WWTPs), then estimate the usages and emissions per capita of 19 biocides based on mass balance analysis approach. The results showed that target biocides were universally detected in the WWTPs and their receiving rivers, and 19 for liquid samples and 18 for solid samples. The prominent compound for liquid was DEET (N,N-diethyl-3-methylbenzamide), with its maximum concentration of 393ng/L in influent; while that for solid was triclocarban with its maximum concentration of 2.11×103ng/g in anaerobic sludge. Most biocides were readily removed from the liquid phase of ten WWTPs, and the mean removal rate to ∑19 biocides was up to 75%. The removals of target biocides were attributed to biodegradation and adsorption onto activated sludge. The mean input per capita for ∑19 biocides based on influent was 907µg/d/person, while the emissions per capita were 187µg/d/person for effluent, and 121µg/d/person for excess sludge. As demonstrated, the biocides contamination of the receiving rivers could pose potential ecological risks for aquatic organisms. Therefore, advanced wastewater treatment technologies should be developed to reduce the emission of biocides into the receiving environment.

Simultaneous determination of 24 personal care products in fish muscle and liver tissues using QuEChERS extraction coupled with ultra pressure liquid chromatography-tandem mass spectrometry and gas chromatography-mass spectrometer analyses.

A sensitive and selective quick, easy, cheap, effective, rugged, and safe (QuEChERS) extraction combined with dispersive solid-phase extraction (d-SPE) cleanup method was developed to simultaneously extract a wide range of personal care products (16 biocides, 4 synthetic musks, and 4 benzotriazoles) in fish muscle and liver tissues. In order to get satisfactory recoveries, different extraction parameters were optimized, including extraction salts and d-SPE materials, extraction solvents and acetic acid contents in organic phase, and the ratios of solvent and water. Ultra pressure liquid chromatography-tandem mass spectrometry and gas chromatography-mass spectrometry were used to analyze the target compounds in the extracts. Among the 24 personal care products, the recoveries in the range of 70-120 % were obtained for 20, 19, and 12 analytes in fish muscle at the spiking concentrations of 10, 5, and 1 ng/g ww, respectively, and for 13, 12, and 11 analytes in liver at the spiking concentrations of 40, 20, and 4 ng/g ww, respectively. Method quantification limits (MQLs) of all analytes were 0.02-2.12 ng/g ww for fish muscle and 0.22-12.2 ng/g ww for fish liver tissues. The method was successfully applied to wild fish samples collected from Dongjiang River, south China. Twenty-one and 17 of the analytes were found in fish muscle and liver samples, respectively, in at least one site of the river with the concentrations between below MQLs and 119 ng/g ww, respectively. Graphical abstract Achieved satisfactory recoveries, high precision, and low method quantification limits (MQLs) for PCPs in wild fish tissues by QuEChERS procedure optimization combined with UPLC-MS/MS and GC-MS analyses.

Photodegradation of the azole fungicide climbazole by ultraviolet irradiation under different conditions: Kinetics, mechanism and toxicity evaluation.

Climbazole (CZ) has been known to persist in various environmental media, and may cause potential risks to aquatic organisms. This study investigated the photodegradation of CZ by ultraviolet (UV, 254nm) under different conditions. The results revealed that CZ could be effectively degraded in aqueous solutions under UV-254 irradiation with a half-life of 9.78min (pH=7.5), and the photodegradation followed pseudo-first-order kinetics. pH had almost no effect on its rate constants and quantum yields; but the water quality of natural waters could affect the photolysis of CZ, and the coexisting constituents such as Fe(3+), NO3(-), and HA obviously inhibited its photolysis. The addition of different radical scavengers also inhibited the photodegradation of CZ due to the reduction of reactive oxygen species (ROS). CZ underwent direct and self-sensitized photolysis involving ROS. Based on the identified photodegradation by-products, the proposed pathways included hydroxylative dechlorination, dechlorination and de-pinacolone. Moreover, toxicity evaluation using duckweed found significant toxicity reduction in the photodegradation system of CZ after the irradiation of UV-254, and the remaining by-products did not pose extra toxicity compared with CZ itself. These findings from present study suggest that CZ in effluent could be further reduced by applying UV photolysis treatment.