Microbial community structure in the river sediments from upstream of Guanting Reservoir: Potential impacts of reclaimed water recharge.

This work systematically investigated the microbial community structure in the river sediments from upstream of Guanting Reservoir, Beijing, China. A total of 6 wastewater treatment plants (WWTPs) locate along the main rivers connected to the reservoir. Water and sediment samples were collected at sites near the effluents of WWTPs (regarded as W groups) or at the upstream/downstream rivers (R groups) to reveal the roles of the reclaimed water recharge. Multivariate techniques including typical statistical analysis, redundancy analysis (RDA), nonmetric multidimensional scaling analysis, and molecular ecological network analysis were used to evaluate the results and their relationships. The representative C/N/P water parameters and concentrations of target organic contaminants kept stable for W and R sites, while the microbial community parameters varied greatly for two groups. The microbial population at W sites were higher but with a lower biological diversity (with a lower Shannon index) than that at R sites, indicating WWTPs greatly altered the microbial community structure at the local reach. RDA results revealed that total organic carbon (TOC) and organophosphorus pesticides (OPPs) were two dominant factors affecting the function and composition of microbial communities at the phylum level. The network analysis revealed that the microbes with the most interactions mainly from R sites and they had closer relationships with each other.

Parental exposure to environmental concentrations of tris(1,3-dichloro-2-propyl)phosphate induces abnormal DNA methylation and behavioral changes in F1 zebrafish larvae.

Tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) has been demonstrated to be transferred from parental animals to their offspring. However, whether parental exposure to environmental concentrations of TDCIPP show neurodevelopmental toxicity in the F1 generation and the possible underlying mechanism remain unclear. Therefore, in this study, zebrafish embryos were exposed to environmental concentrations of TDCIPP (3, 30 and 300 ng L-1) for 120 days. The effects of exposure on motor behaviors, neurotransmitter levels, DNA methylation, and gene expression of F1 larvae were investigated. Parental exposure left TDCIPP residues in F1 eggs as well as reduced body length of F1 larvae. Moreover, parental exposure significantly reduced swimming activity in F1 5 dpf larvae, although it did not significantly alter serotonin, dopamine, 3,4-dihydroxyphenylacetic acid, γ-aminobutyrate, and acetylcholine levels. Genes encoding DNA methylation transferases (dnmt3aa and dnmt1) were downregulated in F1 larvae. Reduced representation bisulfite sequencing analysis revealed 446 differentially methylated regions and enriched neuronal cell body Gene Ontology term in F1 generation. Correlation analysis between the expression of genes related to neural cell body and swimming speed indicated that solute carrier family 1 member 2b (slc1a2b) downregulation might be responsible for the inhibition of motor behaviors. Furthermore, bisulfite amplicon sequencing analysis confirmed hypermethylation of the promoter region of slc1a2b in F1 larvae following parental exposure to 300 ng L-1 TDCIPP, which might have led to significant downregulation of gene expression and, in turn, influenced the motor behaviors. These results indicate that parental exposure to environmental concentrations of TDCIPP alters DNA methylation, downregulates gene expressions and, thus inducing developmental neurotoxicity, in F1 larvae.

Tracing the sources of nitrate in the rivers and lakes of the southern areas of the Tibetan Plateau using dual nitrate isotopes.

Based on a quantitative analysis of nitrate concentrations, the nitrate sources and temporal variability of the rivers, lakes, and wetlands of Tibet were assessed for the first time using dual isotope technology. Water samples were collected once in July 2017 for analysis of nitrate concentration and isotopic composition. The overall values of δ15N-NO3- and δ18O-NO3- ranged from +1.8‰ to +23.0‰, and from -6.3‰ to +22.2‰ respectively. Duel isotopic composition suggested that nitrification of soil organic nitrogen was the main source of nitrate in the Yalu Tsangpo River. Furthermore, anthropogenic nitrogen inputs become more important in downstream than upstream because of intensive agricultural activities and urban input. In the rivers of the Ngari District, nitrate is mainly derived from desert deposits, manure and sewage, and chemical fertilisers. Different rivers show different characteristics of nitrate sources depending on the location, topography, landform, and climate of the river basins. Animal manure, nitrification of soil organic matter, and desert deposits are mainly responsible for the shifting of nitrate isotopic signatures in lakes, which are minimally affected by human activities. In wetlands, biological nitrification and denitrification could be the main processes of nitrogen migration and transformation. These results provide useful information in revealing the fate of nitrate in different aquatic ecosystems and different areas of Tibet.

Microbial diversity and activity of an aged soil contaminated by polycyclic aromatic hydrocarbons.

In-depth understanding of indigenous microbial assemblages resulted from aged contamination by polycyclic aromatic hydrocarbons (PAHs) is of vital importance in successful in situ bioremediation treatments. Soil samples of three boreholes were collected at 12 different vertical depths. Overall, the dominating three-ring PAHs (76.2%) were closely related to distribution patterns of soil dehydrogenase activity, microbial cell numbers, and Shannon biodiversity index (H') of indigenous microorganisms. High-molecular-weight PAHs tend to yield more diverse communities. Results from 16S rRNA analysis indicated that possible functional groups of PAH degradation include three species in Bacillus cereus group, Bacillus sp. SA Ant14, Nocardioides sp., and Ralstonia pickettii. Principal component analysis indicates significant positive correlations between the content of high-molecular-weight PAHs and the distribution of Bacillus weihenstephanensis KBAB4 and Nocardioides sp. The species B. cereus 03BB102, Bacillus thuringiensis, B. weihenstephanensis KBAB4, and Nocardioides sp. were recognized as main PAH degraders and thus recommended to be utilized in further bioremediation applications. The vertical distribution characteristics of PAHs in soil profiles (1-12 m) and the internal relationship between the transport mechanisms of PAHs and the response of soil biological properties help further understand the microbial diversity and activity in an aged site.

Occurrence of pharmaceuticals and personal care products, and their associated environmental risks in a large shallow lake in north China.

Eighteen selected pharmaceuticals and personal care products (PPCPs), consisting of five non-antibiotic pharmaceuticals (N-APs), four sulfonamides (SAs), four tetracyclines (TCs), four macrolides (MCs), and one quinolone (QN) were detected in water, pore water, and sediment samples from Baiyangdian Lake, China. A total of 31 water samples and 29 sediment samples were collected in March 2017. Caffeine was detected with 100% frequency in surface water, pore water, and sediment samples. Carbamazepine was detected with 100% frequency in surface water and sediment samples. Five N-APs were prominent, with mean concentrations of 4.90-266.24 ng/l in surface water and 5.07-14.73 µg/kg in sediment samples. Four MCs were prominent, with mean concentrations of 0.97-29.92 ng/l in pore water samples. The total concentrations of the different classes of PPCPs followed the order: N-APs (53.26%) > MCs (25.39) > SAs (10.06%) > TCs (7.64%) > QNs (3.64%) in surface water; N-APs (42.70%) > MCs (25.43%) > TCs (14.69%) > SAs (13.90%) > QNs (3.24%) in sediment samples, and MCs (42.12%) > N-APs (34.80%) > SAs (11.71%) > TCs (7.48%) > QNs (3.88%) in pore water samples. The geographical differences of PPCP concentrations were largely due to anthropogenic activities. Sewage discharged from Baoding City and human activities around Baiyangdian Lake were the main sources of PPCPs in the lake. An environmental risk assessment for the upper quartile concentration was undertaken using calculated risk quotients and indicated a low or medium-high risk from 18 PPCPs in Baiyangdian Lake and its five upstream rivers.

Occurrence of pharmaceuticals and personal care products, and their associated environmental risks in Guanting Reservoir and its upstream rivers in north China.

Eighteen selected pharmaceuticals and personal care products (PPCPs), consisting of five non-antibiotic pharmaceuticals (N-APs), four sulfonamides (SAs), four tetracyclines (TCs), four macrolides (MCs), and one quinolone (QN) were detected in surface water and sediments from Guanting Reservoir (GTR) and its upstream rivers in north China. Acetaminophen, caffeine, chlorotetracycline, and ofloxacin were detected with 100% frequency in the surface water of GTR and its upstream rivers, while diltiazem was also detected with 100% frequency in surface water from the reservoir's upstream rivers. Acetaminophen and caffeine were detected with 100% frequency in sediments from GTR and its upstream rivers, while high concentrations of ofloxacin in GTR, and carbamazepine, tetracycline, and chlortetracycline in upstream rivers were also detected in 100% of samples. Five N-APs, especially acetaminophen and caffeine, were prominent pollutants. The mean concentrations of acetaminophen were 155 and 302 ng L-1 in surface water and 529 and 202 ng g-1 in sediments from GTR and upstream rivers, respectively. The mean concentrations of caffeine were 208 and 338 ng L-1 in surface water samples and 1430 and 1020 ng g-1 in sediments from GTR and upstream rivers, respectively. The geographical differences in PPCP concentrations were largely due to anthropogenic activities. Sewage discharged from Zhangjiakou City and human activities around the GTR basin were the main sources of PPCPs in this area. An environmental risk assessment for the worst-case scenario was undertaken using calculated risk quotients, which indicated a medium risk from erythromycin in GTR and a high risk in its upstream rivers.

[Potential Risk and Distribution Characteristics of PPCPs in Surface Water and Sediment from Rivers and Lakes in Beijing, China].

Thirty-four water samples and twenty-three sediment samples from the urban rivers, ten water samples and five sediment samples from urban lakes were collected in Beijing. Ten PPCPs (acetaminophen, lincomycin, caffeine, trimethoprim, azithromycin, sulfamethoxazole, diltiazem, tylosin, carbamazepine, fluoxetine) were extracted from water samples by solid-phase extraction (SPE) and from sediment samples by ultrasonic extraction, and then analyzed by high-performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS). The ranges of geometric mean values were 0-655 ng·L-1 and 0-252 ng·L-1 in water samples from urban rivers and lakes,respectively. The range of detection ratio was 0-100% for 10 PPCPs in river water samples, caffeine was the dominant pollutant in water samples and the detection ratio was 100%, whereas sulfamethoxazole, diltiazem and tylosin were not detected in river samples. The range of detection ratio was 0-100% for 10 PPCPs in lake water samples. The detection ratios of acetaminophen, lincomycin, caffeine and azithromycin were 100%, whereas sulfamethoxazole, diltiazem, tylosin, carbamazepine were not detected in lake water samples. The ranges of geometric mean values were N.D.-1709 ng·g-1and N.D.-35.9 ng·g-1in sediment samples from urban rivers and lakes, respectively. The ranges of detection ratio were 4%-96% and 0-100% for 10 PPCPs in river and lake sediment samples, respectively. The detection ratio of trimethoprim was 96% and that of tylosin was 4% in river sediment, the detection ratio of diltiazem was 100% and caffeine, tylosin,carbamazepine were not detected. The concentrations of PPCPs in water and sediment samples from Yongyin River, Liangshui River, Tonghui River, Bahe River were higher than those in other rivers. The concentrations of PPCPs in water and sediment samples from Yongding River,Kunyu River were lower than those in other rivers. Further risk assessment results showed that the overall risk was not high in water of rivers and lakes and the RQ values were below 0.1, which showed low risk to microorganisms. But the condition was not the same in sediment from rivers and lakes. The RQ values of acetaminophen were between 0.1 and 1 in sediments from Yongyin River, Tonghui River, Bahe River. The RQ values of lincomycin were between 0.1 and 1 in sediments from Yongyin River, Wenyu River,Tonghui River, Hucheng River, Bahe River, Liangshui River, Houhai Lake. The RQ values of trimethoprim were between 0.1 and 1 in sediments from Yongyin River, Qinghe River, Wenyu River, Tonghui River Hucheng River, Bahe River, Liangma River, Liangshui River and Houhai Lake. The RQ values of azithromycin were between 0.1 and 1 in sediments from Liangma River, Liangshui River, which all showed medium risk to microorganisms in sediments. The RQ values of azithromycin exceeded 1 from Yongyin River, Qinghe River, Wenyu River, Tonghui River, Bahe River and Houhai Lake, which showed high risk to microorganisms in sediments.

[Pollution Characteristics of Chlorobenzenes in Organs of Fish from Typical Epidemic Areas of Schistosomiasis Prevalence].

Sixty-eight fish samples were collected from typical epidemic areas of schistosomiasis prevalence. The contents of 12 CB congeners in fish samples were measured using GC/MS technique. The results indicated that 1,3-DIC, 1,4-DIC, 1,2-DIC and HCB were the most predominant CB congeners in the samples from the studying area. The source of HCB was PCP (pentachlorophenol), which was used to control the schistosomiasis prevalence, used in study area. And DIC came from the degradation of HCB and the articles of daily use. The geometric average of CBs in muscle ranged from 2731.50 to 7811.23 ng·g-1 lipid weight, while the summarized concentration of CBs in fish gonads, brains, kidneys, livers ranged from 2557.89 to 4640.05 ng·g-1 lipid weight, 2423.18 to 3329.61 ng·g-1 lipid weight, 1628.05 to 4667.76 ng·g-1 lipid weight and 704.92 to 1086.96 ng·g-1 lipid weight, respectively. When compared to other studies in China and other countries, the concentrations of CBs in these fish samples were at a relatively high level.

[Spatial, Temporal Distribution Characteristics and Potential Risk of PPCPs in Surface Sediments from Taihu Lake].

Fourteen sediment samples from 15 river estuaries and six sediments from 6 drinking water resource were collected from Taihu Lake. Nine pharmaceutical and personal care products(PPCPs) in the sediments samples were measured by using the HPLC-MS/MS technique. The ranges of geometric mean values were 1.60-129 ng·g-1 and 1.36-22.0 ng·g-1, respectively. Caffeine was the dominant pollutant in fourteen sediments near the river estuary, the content of which covered 52% of amounts of 9 PPCPs. Lincomycin, trimethoprime, azithromycin, sulfamethoxazole and tylosin were the dominant pollutants in six sediments near the drinking water resource, the contents of which covered 79% of amounts 9 PPCPs. From the point of spatial distribution, the results of PPCPs in Zhushan bay and East of Yixing in the northwest and west of Taihu Lake showed higher concentration than those in other sample sites. From the composition, the origin of PPCPs was different. Municipal sewage, stock farming and aquaculture were the main sources of PPCPs in Taihu Lake. Pharmaceuticals of human use showed the dominant pollution in fourteen sediments near the river estuary and drugs of veterinary use showed the dominant pollution in six sediments near the water resource. The concentrations of PPCPs in fourteen sediments of river mouth showed high level. It suggested that PPCPs pollutants were discharged to Taihu Lake continuously. Further risk assessment results showed that the overall risk was not high except for some PPCPs compounds. The RQ exceeded 1 for acetaminophen, azithromycin and sulfamethoxazole in the surface sediments of 15 river estuaries and 6 water resources, which showed high risk. The RQ was between 0.01 to 0.1 for carbazepine in the surface sediments of 15 river estuaries and 6 water resources, which showed medium risk. The RQ was below 0.01 for caffeine, lincomycin, trimethoprim, diltiazem and tylosin in the sediments of 15 river estuaries and 6 water resources, which showed low risk.

[Distribution Characteristics and Potential Risk of CBs in Aquatic Organisms from Typical Epidemic Areas of Schistosomiasis Prevalence].

Eleven mollusca samples and 32 fish samples were collected from typical epidemic areas of schistosomiasis prevalence. The contents of 12 CB congeners in aquatic organism samples were measured using the GC/MS technique. The results indicated that 1,3-DIC, 1,4-DIC, 1,2-DIC and HCB were the most predominant CB congeners in the samples from the studying area. The geometric average of CBs in muscle of mollusca was 11 947 ng x g(-1) lipid weight. The summarized concentration of CBs in fish muscle ranged from 1 851 to 8 159 ng x g(-1) lipid weight. The highest concentration of CBs sum was detected in the catfish, while the lowest one was found in the crucian carp. The concentrations of CBs in fish samples were much higher than those reported in other countries, while in mollusca samples were at the same level. The estimated cumulative cancerigenic risks for the local residents consumed the aquatic organisms from the studying area were 1.49 x 10(-7) and 3.73-21.1 x 10(-7), respectively for mollusca and fish, both of which were acceptable.

Chronic exposure to pentachlorophenol alters thyroid hormones and thyroid hormone pathway mRNAs in zebrafish.

Pentachlorophenol (PCP) is frequently detected in the aquatic environment and has been implicated as an endocrine disruptor in fish. In the present study, 4-month-old zebrafish (Danio rerio) were exposed to 1 of 4 concentrations of PCP (0.1, 1, 9, and 27 µg/L) for 70 d. The effects of PCP exposure on plasma thyroid hormone levels, and the expression levels of selected genes, were measured in the brain and liver. The PCP exposure at 27 µg/L resulted in elevated plasma thyroxine concentrations in male and female zebrafish and depressed 3, 5, 3'-triiodothyronine concentrations in males only. In both sexes, PCP exposure resulted in decreased messenger RNA (mRNA) expression levels of thyroid-stimulating hormone ß-subunit (tshß) and thyroid hormone receptor ß (trß) in the brain, as well as increased liver levels of uridine diphosphoglucuronosyl transferase (ugt1ab) and decreased deiodinase 1 (dio1). The authors also identified several sex-specific effects of PCP exposure, including changes in mRNA levels for deiodinase 2 (dio2), cytosolic sulfotransferase (sult1 st5), and transthyretin (ttr) genes in the liver. Environmental PCP exposure also caused an increased malformation rate in offspring that received maternal exposure to PCP. The present study demonstrates that chronic exposure to environmental levels of PCP alters plasma thyroid hormone levels, as well as the expression of genes associated with thyroid hormone signaling and metabolism in the hypothalamic-pituitary-thyroid (HPT) axis and liver, resulting in abnormal zebrafish development.

[Distribution characteristics of PBDEs in surface sediment from the Three Gorges Reservoir of Yangtze River].

A total of 28 surface sediment samples (at the top 0-5 cm layer) were collected from the Three Gorges Reservoir of Yangtze River. The content of polybrominated diphenyl ethers (PBDEs) in sediments was measured with Varian GC-MS (NCI). The results showed that sigma26 PBDEs and BDE209 both had a low concentration in sediments, with a mass concentration of 35.24 pg x g(-1) and 11.92 pg x g(-1), respectively. Among the 26 PBDEs, BDE28, 47, 77 and 99 were the most predominant sigma26 PBDEs congeners. The highest concentrations of sigma26 PBDEs and BDE209 were detected in the sediment samples collected from Long River, with geometric mean of 146.07 and 502.63 pg x g(-1), respectively. A significant correlation was found between sigma26 PBDEs and BDE209, indicating that they might have the same pollution source. The concentrations of sigma26 PBDEs and BDE209 in the sediment were in the same order of magnitude with those reported on background levels in sediments of remote lakes in other countries, which shows the toxic biological effects on aquatic biota and potential risk due to sigma26 PBDEs and BDE209 contamination in sediments are negligible.

Polyhalogenated aromatic hydrocarbons in surface sediments from Three Gorges Reservoir.

This study was conducted to investigate the current contamination status of polyhalogenated aromatic hydrocarbons (PHAHs) in sediments from the mainstream and 22 primary tributaries of the Yangtze River in the Three Gorges Reservoir region. To accomplish this, the concentrations of 22 polybrominated biphenyl (PBB) congeners, 27 polybrominated diphenyl ether (PBDE) congeners, and 27 polychlorinated biphenyl (PCB) congeners in sediment samples were measured by GC-MS/MS. The result showed that the observed values of PBBs and PBDEs were 22.41 and 35.24 pg g(-1) dw, respectively. PBB1, 31 and 103 were the predominant PBB congeners, while PBDE28, 47, 77 and 99 were the predominant PBDE congeners. PBB209 and BDE209 were detected in >39% of the samples, with geometric means 2.43 and 11.92 pg g(-1) dw, respectively. PCBs were found to be the predominant compounds in sediment samples among the three PHAH subfamilies, with a geometric mean of 1,231.11 pg g(-1) dw, and PCB8, 18, 28, 52 and 66 were the primary PCB congeners. The measured levels of PHAHs were compared with results recently reported in the literature and their respective sediment quality guidelines recommended by the USEPA. The levels of PHAHs in the present study were generally lower than their respective threshold-effect levels, or were comparable to those reported in relatively uncontaminated freshwater samples from other regions. Taken together, these results suggest that, in the reservoir, toxic biological effects on aquatic biota in response to PHAHs contamination of sediments can be expected to be negligible.

[Distribution characteristics and potential risk of PCBs in surface water from three tributaries of Yangtze River in different periods].

Eighty-one surface water samples were collected from 3 tributaries of the Yangtze River in different periods. Contents of 28 PCB congeners in surface water samples were measured using Varian CP3800/300 GC-MS/MS technique. PCB8, 18, and 28 are the most predominant PCB congeners in the samples from tributaries. The measured level of PCBs in the samples from the Tuo river, downstream of Ouchi River and Songlihongdao tributary were 1.96-2.59 ng x L(-1), 1.84-2.54 ng x L(-1) and 1.52-2.38 ng x L(-1). The average concentrations of PCBs in the samples were lower than USEPA criterion continuous concentration (14 ng x L(-1)), which were also in the same order of magnitude of those reported with lower levels in European and American countries. The estimated cumulative cancer risk for the local residents who drink water from tributaries were 0.15 x 10(-7)-0.26 x 10(-7), which shows that cancer risk are negligible due to PCBs contamination in these samples.

[Distribution characteristics and potential risks of phenols in the rainy season surface water from Three Gorges Reservoir].

Forty-seven surface water samples were collected from the main stream and 22 tributaries in area of the Three Gorges Reservoir, 15 phenolic compounds in these samples were analyzed using GC/MS. The results showed that the concentrations of phenolic compounds in the samples from the main stream and tributaries were 52.47 ng x L(-1) and 87.99 ng x L(-1), respectively. The concentrations of non-chlorinated phenols were higher than those of chlorinated phenols in the main stream and tributaries, and so the non-chlorinated phenols were the predominant compounds in these surface water samples. Phenol, o-cresol and 2-nitrophenol were the predominant compounds accounted for 79.1%, 3.7% and 3.6% in the samples from the main stream, respectively. Phenol, o-cresol, 2,6-dichlorophenol and 2-nitrophenol were the main compounds accounted for 77.5%, 5.4%, 3.8% and 2.2% in the samples from the tributaries, respectively. As compared the concentrations of phenol and 2-nitrophenol with the standard limits in The National Environmental Health Risk List, the levels of phenol and 2-nitrophenol were much lower than the standard limits, suggesting negligible risk of phenol and 2-nitrophenol in these samples.

PHAHs in 14 principal river sediments from Hai River basin, China.

This study was undertaken to investigate the current contamination status of polyhalogenated aromatic hydrocarbons (PHAHs) in sediments from 14 principal rivers of the Hai River basin. The concentrations of 22 polybrominated biphenyl (PBB) congeners, 27 polybrominated diphenyl ether (PBDE) congeners, and 27 polychlorinated biphenyl (PCB) congeners in sediments were measured using GC-MS/MS technique. The highest PBB levels were detected in sediments from River Daqing: PBB3, 10, 4, 15, 26, 31, and 49 were observed in the sediments. The highest concentrations of PBDEs were in River Tuhe (G.M.=2.10 ng g(-1) dw), and PBDE15 was the most predominant congener in the sediments from all of the rivers of this study, except for River Tuhe, which accounted for >13.5% of the total PBDEs in sediments. PBDE209 was detected in sediments from the Beijingpaiwu, Nanyun, Majia and Tuhe rivers, with observed values ranging from 0.06 to 0.13 ng g(-1) dw. PCBs had the highest concentrations in sediment samples collected from River Luan and River Daqing, with levels of 18.13 and 25.62 ng g(-1) dw, respectively. The most predominant PCB congener in these samples was PCB138, which accounted for about 24% of the sum of the seven indicator PCB congeners (PCB28, 52, 101, 118, 138, 153, and 180) measured in the two rivers. The measured levels of PHAHs were compared with recent results, reported in the literature, and the respective sediment quality guidelines recommended by USEPA. The levels of PHAHs in the present study were generally lower than respective threshold-effect levels, or were comparable to those reported in relatively uncontaminated freshwaters from other regions. This suggests that, in these rivers, toxic biological effects on aquatic biota-due to PHAH contamination of sediments-can be expected to be negligible. Thus, in terms of PHAHs, the sediments can be regarded as relatively uncontaminated.