Rivers In Beijing Research Articles

Pollution Characteristics and Multilevel Risk Assessments of Antibiotics in the Urban Rivers of Beijing, China

To comprehensively assess the pollution characteristics and ecological risks of antibiotics in the rivers in Beijing, the concentrations of 35 common antibiotics belonging to four categories were quantified by using solid phase extraction combined with high-performance liquid chromatography-tandem mass spectrometry. The ecological risks of antibiotics were evaluated using the methods of risk quotient (RQ) and joint probability curves (JPCs). The results showed that a total of 33 antibiotics were detected in the surface water of ten rivers in Beijing, and the total concentrations of antibiotics ranged from N.D. to 1 573.57 ng·L-1. Sulfamethoxazole showed the highest concentration (N.D.-160.04 ng·L-1), followed by sulfadiazine (0.09-147.90 ng·L-1) and ofloxacin (0.28-94.72 ng·L-1). There were 16 antibiotics with a detection frequency greater than 50.0 %. The RQ method showed that there were 12 antibiotics with potential ecological risks. Tetracycline, clarithromycin, and trimethoprim showed the highest risks, with RQs of 3.99, 1.86, and 1.01, respectively. The risks of antibiotics at the outlets of wastewater treatment plants were higher than those in mainstream rivers. The PNEC exceedance rates of tetracycline, clarithromycin, and trimethoprim were above 2.3 %. Based on JPCs, the maximum risk product of clarithromycin was 1.66 %, and it showed low risks to 0.3 %-7.0 % of species. The risks of other antibiotics could be ignored. The detection frequency, distribution of concentrations, most sensitive species, and species sensitivity distribution of antibiotics had important impacts on the ecological risk assessment. Using the multilevel ecological risk assessment strategy can effectively avoid inadequate protection and overprotection and is also conducive to the hierarchical and zoning management of antibiotics throughout the region.

EDNA metabarcoding as a promising conservation tool to monitor fish diversity in Beijing water systems compared with ground cages

Fish diversity, an important indicator of the health of aquatic ecosystems, is declining sharply due to water pollution, overfishing, climate change, and species invasion. For protecting fish diversity, effective surveying and monitoring are prerequisites. In this study, eDNA (environmental DNA) metabarcoding and ground cages were used to survey the fish diversity of the Chaobai and Beiyun Rivers in Beijing. Based on the two methods, we identified 40 species, belonging to 35 genera, 18 families, and six orders. The richness of fish identified by eDNA metabarcoding was significantly higher than that captured by ground cages in both rivers. The fish captured by the ground cage method were all recognized by eDNA metabarcoding, except Squalidus wolterstorffi and Saurogobio dabryi, which were captured only in ground cages. The correlation of relative abundance between the two methods was affected by the properties of the rivers, such as the flow rate. Fish caught by ground cage in the Beiyun River were identified by eDNA, but not in the Chaobai River. Our results also suggest that the Chaobai River has higher fish diversity than the Beiyun River and different community assemblage. In addition to differences in the natural properties of the focal rivers, the development of urbanization is also an important contributor to different community structures overserved. eDNA metabarcoding as a new survey tool has great application prospects, it provides certain theoretical data and methodological references for the protection and management of river fish diversity.

Comparison and prioritization of antibiotics in a reservoir and its inflow rivers of Beijing, China.

The occurrence of antibiotics in drinking water resources, like reservoirs, is of considerable concern due to their potential risks to ecosystem, human health, and antimicrobial resistance development. Here, we quantified 83 antibiotics in water and sediments of wet and dry seasons from the Miyun reservoir and its inflow rivers in Beijing, China. Twenty-four antibiotics were detected in water with concentrations of ND-11.6 ng/L and 19 antibiotics were observed in sediments with concentrations of ND-6.50 ng/g. Sulfonamides (SAs) were the dominated antibiotics in water in two seasons. SAs and quinolones (QNs) in wet season and macrolides (MLs) and QNs in dry season predominated in sediments. The reservoir and inflow rivers showed significant differences in antibiotic concentrations and compositions in water and sediments. As an important input source of reservoir, the river water showed significantly higher total antibiotic concentrations than those in the reservoir. In contrast, the reservoir sediments are the sink of antibiotics, and had higher total antibiotic concentrations compared with rivers. A prioritization approach based on the overall risk scores and detection frequencies of antibiotics was developed, and 3 (sulfaguanidine, anhydroerythromycin, and sulfamethoxazole) and 5 (doxycycline, sulfadiazine, clarithromycin, roxithromycin, and flumequine) antibiotics with high and moderate priority, respectively, were screened. The study provides a comprehensive insight of antibiotics in the Miyun Reservoir and its inflow rivers, and is significant for future monitoring and pollution mitigation of antibiotics.

Composition and Distribution of Microplastics in the Water and Sediments of Urban Rivers in Beijing

It has been confirmed that microplastics widely exist in the natural environment, causing potential harm to organisms and humans. An investigation into the occurrence of microplastics is helpful to understand the level of pollution of microplastics in urban rivers and sediments. In this study, eight sampling points of water samples and three of sediments samples were placed along the North Canal and Huaihe River in Beijing, to compare the composition and distribution characteristics of the abundance, particle size, color, shape, and species of microplastics. The results showed that the abundance of microplastics in the water and sediments of the North Canal were(1941±201)-(8155±1781) n·m-3(n refers to the number of microplastics) and (120±11)-(268±31) n·kg-1, respectively. The average abundance of microplastics in the water of the North Canal was 4160 n·m-3. Compared with the North Canal, the pollution degree of microplastics in the Huaihe River was lower with an average abundance of 2357 n·m-3. Furthermore, the abundance of microplastics in the water and sediments in the upper reaches of the North Canal was higher than that in the lower reaches. No significant difference of microplastics distribution was observed in the water of the Huaihe River on the whole; however, there was a marked difference in abundance between the two distant locations. The main particle size range of microplastics at all site points was<300 μm, and mostly white/transparent(50.75%-83.91%); the main shape were fragments(50.00%-95.08%) and fibers(3.86%-30.00%). Polyurethane(PU) and ethylene vinyl acetate(EVA) were two main plastic species found at all sites. Microplastics in the water and sediments of the North Canal might have originated from urban construction and development, while the surrounding villages might have only affected the abundance of microplastics in the Huaihe River.

Profiles and risk assessment of legacy and current use pesticides in urban rivers in Beijing, China.

Pesticides in the environment can pose serious risks to aquatic ecosystems. This study focused on the existence of 27 pesticides, including 13 pesticides regulated by the Stockholm Convention as persistent organic pollutants (POPs) and 14 commonly used pesticides in three urban rivers in Beijing that receive effluents from three municipal wastewater treatment plants (MWTPs). Among the 27 pesticides, 12 were detected at least once over a period of 4 seasons. Atrazine, aldrin and dieldrin were universally found in the three rivers, with the highest concentrations being 311, 163 and 23.3 ng/L, respectively. HCHs, DDTs, heptachlor and endosulfan, which are POPs, were detected at lower concentrations (ND-16.7 ng/L). Most of the insecticides and some of the herbicides in the rivers originated from MWTP effluents. The risk assessment results showed that aldrin posed medium risk (0.1 ≤ RQ < 1) to fish, and atrazine exhibited medium risk to both fish and algae. Despite the implementation of the Stockholm Convention and the upgrades of MWTPs emitting ozone, high loads of aldrin, atrazine and dieldrin were discharged to the rivers. Efforts should be devoted to identifying POP pesticide sources and upgrading MWTPs with other technologies to ensure the ecological safety of rivers.

Determination and occurrence of sulfonamide transformation products in surface waters.

The transformation products of sulfonamides (SAs) have raised increasing environmental and health concerns in recent years, but information on their analysis and environmental fates remains limited. In this study, an analytical method using liquid chromatography with tandem mass spectrometry (LC-MSMS) was optimized to simultaneously analyze 9 SA transformation products and 14 SAs in water samples. This method was applied to investigate the occurrence of antibiotics in three urban rivers in Beijing, and all of the target compounds were detected. N-acetylsulfamethoxazole, N-acetylsulfapyridine, and N-acetylsulfamethazine were found to be the predominant acetyl SAs in the aquatic environment, and high frequencies of hydroxylated SA (5-hydroxysulfapyridine) and glucuronide-conjugated SA (sulfamethoxazole β-D-glucuronide) were also detected. The SA transformation products accounted for 22-32% of the total concentrations of SAs and their transformation products in the water samples. The pollution levels of the compounds exerted only minor effects on the proportions of the SA transformation products. The compound-specific transformation of sulfamethoxazole, sulfapyridine, and sulfadiazine in the water samples was consistent with their acetylation efficiencies in metabolic processes in organisms, which suggests that the SA-acetylated products were derived mainly from biological metabolism in humans or animals. This finding was supported by the fact that environmental degradation exerts a weak effect on SA profiles in the water samples.

Identifying unknown antibiotics with persistent and bioaccumulative properties and ecological risk in river water in Beijing, China.

The goal of this study was to identify antibiotics with potential risk in river water of the megacity Beijing, China. This was accomplished by using a tiered approach that combined hazard (phase I) and monitoring-based risk (phase II) assessment. Ninety-five candidate antibiotics were screened and 31 was identified as hazardous during phase I assessment. Of these hazardous antibiotics, 29 were identified as persistent and 7 were identified as bioaccumulative antibiotics. Fluoroquinolones, macrolides, sulfonamides, and aminoglycosides account for over 80% of these hazardous antibiotics. During phase II, four antibiotics (erythromycylamine, cefotaxime, ampicillin, and fusidic acid) that were not previously reported were detected in the surface water sampled from four major rivers in Beijing, with concentrations ranging from not detected to approximately 300ng/L. The ecological risk assessment showed that erythromycylamine, cefotaxime, and ampicillin posed low to high levels of risk to the aquatic organisms. To summarize, erythromycylamine, cefotaxime, and ampicillin were identified as priority antibiotics in rivers in Beijing, China. Our results demonstrated the necessity of conducting monitoring-based verification process in identification of priority antibiotics in a specific region.

Impacts of wastewater treatment plant upgrades on the distribution and risks of pharmaceuticals in receiving rivers

Upgrades of wastewater treatment plant (WWTP) and full-scale application of additional advanced oxidation processes have been proven to be effective in reducing the nutrient emissions to the environment; however, the impacts of WWTP upgrades on the receiving waters with regard to the occurrence and ecological risks of pharmaceuticals are still unclear. In this study, 27 pharmaceuticals with diverse physicochemical properties were monitored in four rivers in Beijing, each of which was heavily impacted by a large-scale WWTP. Three-year sampling campaigns were conducted, covering the periods before and after the WWTP upgrades. The results show that the newly added combined treatment processes (e.g., biological filter, ultrafiltration, ozonation, and NaClO disinfection) reduced the total pharmaceutical concentrations in the effluents by 45–74%. The composition profiles reveal that the upgrades of two studied WWTPs resulted in a significant reduction of pharmaceutical concentrations in the receiving rivers, while little impacts were observed for the other rivers. The risk assessment shows that the acute toxic pressures in the studied rivers were generally low and the WWTP upgrades were conducive to reduce the risks for most of pharmaceuticals. However, erythromycin and ofloxacin still posed high risk, indicating the potential adverse effect of pharmaceuticals on aquatic environment.

Wastewater treatment plant upgrade induces the receiving river retaining bioavailable nitrogen sources

Currently, wastewater treatment plant (WWTP) upgrades have been implemented in various countries to improve the water quality of the receiving ecosystems and protect aquatic species from potential deleterious effects. The impact of WWTP upgrades on biological communities and functions in receiving waters is a fundamental issue that remains largely unaddressed, especially for microbial communities. Here, we selected two wastewater-dominant rivers in Beijing (China) as study sites, i.e., one river receiving water from an upgraded WWTP to explore the impacts of upgrade on aquatic ecosystems and another river receiving water from a previously upgraded WWTP as a reference. After a five-year investigation, we found that WWTP upgrade significantly decreased total organic nitrogen (N) in the receiving river. As a biological response, N-metabolism-related bacterioplankton are accordingly altered in composition and tend to intensively interact according to the network analysis. Metagenomic analysis based on the N-cycling genes and metagenomic-assembled genomes revealed that WWTP upgrade decreased the abundance of nitrifying bacteria but increased that of denitrifying and dissimilatory nitrate reduction to ammonium (DNRA) bacteria in the receiving river, according to their marker gene abundances. After calculation of the ratios between DNRA and denitrifying bacteria and quantification of genes/bacteria related to ammonium cycling, we deduced the changes in N-metabolism-related bacteria are likely an attempt to provide enough bioavailable N for plankton growth as conservation of ammonium was enhanced in receiving river after WWTP upgrade.

Development and application of the analytical method for illicit drugs and metabolites in fish tissues

In this study, we developed a screening method for highly accurate and sensitive analysis of 12 illicit drugs and metabolites in fish tissues. The approach was based on ultrasonic-assisted extraction and solid phase extraction, followed by ultra-performance liquid chromatography-tandem mass spectrometry analysis. The homogenized samples were ultrasonic-assisted extracted with 1% acetic acid in methanol followed by SPE cleanup with Oasis MCX cartridge. The method was validated in accordance with the European Medicines Agency guidelines by evaluating the following required parameters: the limits of detection and limits of quantification, linearity, accuracy, repeatability, recovery of extraction, and matrix effect. For the tissues involved in this study, the recoveries ranged from 60% to 127%, and the matrix effect ranged from −19% to 83% with the inter- and intra-day variability below 12%. The method has been successfully applied to wild fish caught from six sampling sites of four urban rivers in Beijing, China. The analysis showed that the target compounds, including amphetamine, 3,4-methylenedioxyamphetamine, codeine and heroin were detected with high detection frequencies. Codeine exhibited the highest bioaccumulation factor (up to 73,986) in the muscle of Crucian carp, while ketamine tended to accumulate in the skin, 3,4-methylenedioxyamphetamine and heroin tended to accumulate in gastrointestinal tract, respectively.

Distribution and Risk Assessment of Polycyclic Aromatic Hydrocarbons and Their Derivatives in Wastewater-Receiving Rivers in Beijing

To analyze the pollution levels and health risk assessment of Polycyclic Aromatic Hydrocarbons (PAHs) and their derivatives (SPAHs) in five typical effluents from sewage treatment plants and receiving rivers in Beijing, the concentrations of PAHs and SPAHs in samples were measured by the combined method of solid extraction and gas chromatography-mass spectrometry. The distribution characteristics were also analyzed. At the same time, the probabilistic health risk was assessed using toxic equivalent factors. The results show that the contamination of PAHs and SPAHs in five typical effluents from sewage treatment plants and receiving rivers in Beijing is 75-584 ng·L-1 and 91-1822 ng·L-1, respectively. These PAHs are dominated by 2-and 3-ring PAHs, which account for 23%-48% of the total PAHs. The SPAHs in this study include three substances:methyl polycyclic aromatic hydrocarbons (MPAHs), oxygenated polycyclic aromatic hydrocarbons (OPAHs), and chlorinated polycyclic aromatic hydrocarbons (ClPAHs). The proportion of OPAHs in total SPAHs is 75%, while the total proportion of MPAHs and ClPAHs is overall low (12% and 13%, respectively). Calculations of the toxicity equivalents of PAHs in five rivers indicate that attention should be paid to high-PAHs pollution during the heating season (December).

Investigation and Application of a New Passive Sampling Technique for in Situ Monitoring of Illicit Drugs in Waste Waters and Rivers.

Illicit drugs constitute a class of emerging contaminants that has been drawing significant concern due to its potent pharmacological and biological activities. In this study, an in situ passive sampling approach that uses diffusive gradients in thin films (DGT) was successfully tested for measuring ketamine (KET), methamphetamine (METH), and amphetamine (AMP) in water. The diffusion coefficients of KET, METH, and AMP in diffusive gel were (8.13 ± 0.12) × 10-6, (8.55 ± 0.14) × 10-6, and (7.72 ± 0.18) × 10-6 cm2 s-1 at 22 °C, respectively. The capacities of an XAD binding gel for KET, METH, and AMP were 92, 57, and 45 μg per binding gel disc, which were suitable for long-term environmental monitoring. The DGT measurement of these drugs was not influenced by the pH (4 to 9) and the ionic strength (0.001 M - 0.1 M) and unaffected by the water flow, demonstrating the effectiveness of the XAD-based DGT for the in situ monitoring of illicit drugs. DGT samplers were deployed in a WWTP influent and natural rivers in Beijing, China. The ng L-1 levels of the drugs were high in the wastewater influent and low in river waters, with an insignificant fluctuation during the seven-day monitoring. The DGT-measured concentrations were comparable to the average concentrations determined by SPE method, which suggested that the average data measured by DGT could be substituted for high-frequency grab sampling. This study has demonstrated systematically for the first time that DGT is effective and accurate for monitoring illicit drugs in wastewater and surface waters, and provides a powerful tool to investigating the presence, transport, and environmental behaviors of these drugs in the aquatic ecosystem.

Impact of upgrading wastewater treatment plant on the removal of typical methyl, oxygenated, chlorinated and parent polycyclic aromatic hydrocarbons

Wastewater treatment plant (WWTP) secondary effluent is a main source for polycyclic aromatic hydrocarbons (PAHs) and their derivatives (SPAHs) to wastewater receiving rivers in Beijing. The treatment technologies are being upgraded in the WWTPs as the tertiary treatment. To assess the improvement of the removal efficiencies of PAHs and SPAHs after the treatment upgrading, we investigated 16 PAHs and 4 types of SPAHs in the secondary and tertiary treatment process in 5 major WWTPs. Most of the parent PAHs, methyl PAHs, oxygenated PAHs and chlorinated PAHs were detected in the influent, secondary and tertiary effluent. The concentrations of ΣSPAHs (61ng/L–529ng/L) were similar to ΣPAHs (89ng/L–474ng/L), indicating that SPAHs should not be ignored when studying the PAH contamination. ΣPAHs and ΣSPAHs were largely removed by the secondary treatment (45%–82%) and less by the tertiary treatment (0%–24%). The removal efficiencies were lower in the secondary and tertiary treatment in WWTPs than in the lab-scale experiment conducted previously, probably a result of the association of PAHs and SPAHs with dissolved organic matters (DOMs) in wastewater. DOMs might be a limiting factor for the removal of PAHs and SPAHs in WWTPs. The estimated yearly loadings of the total PAHs and SPAHs decreased only 21% in the tertiary effluent compared with the secondary effluent in WWTP1 and 9% in WWTP3. Therefore, the upgrading of WWTPs did not efficiently improve the removal of PAHs and SPAHs. DOMs should be further considered for improving the removal of PAHs, SPAHs and similar contaminants in WWTPs.

Drugs of abuse and their metabolites in the urban rivers of Beijing, China: Occurrence, distribution, and potential environmental risk.

The occurrence and distribution of five drugs of abuse and their metabolites, namely, methamphetamine (METH), amphetamine (AMP), ketamine (KET), ephedrine (EPH), and hydroxylimine (HY), were investigated in the surface water in urban rivers in Beijing, China. A total of 117 surface water samples were collected from the seven rivers in the Beijing urban areas during four different seasons. Laboratory analyses revealed that EPH and METH were the most predominant drugs, with detection frequency ranging from 94% to 100% and from 65% to 100%, respectively. High levels of METH and KET were observed in the center part of the urban areas, which was likely associated with the drug abuse and the entertainment activities. Seasonal variation of the drug occurrence showed that the highest concentration of drugs of abuse was found during winter, which was likely due to the high consumption, low temperature, and low water flows during the cold weather. By contrast, the concentration and detection frequency of AMP and HY were relatively low. Risk assessment by the risk quotient method indicated that the five drugs of abuse and their metabolites were not likely to exert biological effects on the aquatic ecosystems at current levels in the surface water. However, the potential adverse effect of drugs of abuse and their metabolites on ecosystem functioning and human health should not be neglected.

Occurrence and distribution of antibiotics, antibiotic resistance genes in the urban rivers in Beijing, China

The occurrence and distribution of sulfonamide and tetracycline, corresponding bacterial resistant rate and resistance genes (ARGs) and two integrase genes were investigated in seven urban rivers in Beijing, China. The total concentration of sulfonamide and tetracycline ranged from 1.3 × 101–1.5 × 103 ng/L and 3.9 × 101–5.4 × 104 ng/L for water, and 1.0 × 100–2.7 × 102 and 3.1 × 101–1.6 × 102 ng/g for sediment, respectively. The sul resistant rate was 2–3 times higher than tet resistant rate in both surface water and sediment. The average rate of sul resistance and tet resistance were up to 81.3% and 38.6% in surface water, 89.1% and 69.4% in the sediment, respectively. The sul1, tetA and tetE genes were predominant in term of the absolute abundance. The absolute abundance of ARGs in Wenyu River and Qinghe River, which were close to the direct discharging sites, were 5–50 times higher than those in the other investigated urban rivers, suggesting that the source release played an important role in the distribution of ARGs. The sul1 and sul2 genes had positive correlation (p < 0.05) with sulfonamides, and the tet resistance genes was significantly correlated with tetracyclines (p < 0.05), indicating that some ARGs and antibiotics in the urban rivers had identical sources of pollution. Considering principal component analysis, sampling sites (QH5, QH6, B1, B2, B3 and BX2) intimated that a complex interplay of processes govern fate and transport of ARGs in the junction of rivers. These results are significant to understand the fate, and the contribution of ARGs from the source release. In view of the large-scale investigation of urban rivers system in Beijing, it reflected the bacterial resistance in sewage drainage system. Such investigation highlights the management on controlling the pollutant release which was seemed as a major driving force for the maintenance and propagation of many ARGs during the development of urbanization in the future.

Occurrence and fate of antibiotics in advanced wastewater treatment facilities and receiving rivers in Beijing, China

The occurrence and removal of 13 antibiotics were investigated in five wastewater treatment plants (WWTPs) with advanced wastewater treatment processes in Beijing, China. Most of the target antibiotics were detected in the secondary and tertiary effluents, with the concentrations of 4.8–1106.0 and 0.3–505.0 ng·L−1. Fluoroquinolone antibiotics showed relatively high concentrations in all samples (782–1814 ng·L−1). Different tertiary treatment processes showed discrepant antibiotics removal performances. Ozonation process was found more effective in removing target antibiotics compared to the coagulation-flocculation-sedimentation process and sand filtration process. Investigation of the target antibiotics in three typical urban rivers in Beijing was carried out to understand antibiotics occurrence in surface water environment. Eight antibiotics were detected in the studied rivers, with highest concentration of antibiotics in the river which was mainly replenished by reclaimed water. This study showed the necessity of employing more effective advanced treatment facilities to further reduce the discharge amount of antibiotics.

Occurrence of Selected Pharmaceuticals and Caffeine in Sewage Treatment Plants and Receiving Rivers in Beijing, China

The occurrence of nine different types of pharmaceuticals and caffeine were analyzed in various units of three wastewater treatment plants (WWTPs) and their receiving rivers in Beijing, China. Analyte concentrations were determined using ultra performance liquid chromatograph-tandem quadruple mass spectrometers (UPLC-MS/MS) and multiple-reaction monitoring. The studied pharmaceuticals and caffeine were found in all the WWTPs and receiving rivers. Their concentrations in the WWTP influents varied from 38 ng/L of sulpiride to 89.5 microg/L of caffeine, and those in the effluents ranged from 27 ng/L of sulpiride to 2.7 microg/L of erythromycin. Typically, the biological treatment appeared more effective in the removal of pharmaceuticals and caffeine than primary treatment in a WWTP. For an individual compound, the overall removal efficiency varied from one WWTP to the next. Mean values ranged from no removal of carbamazepine to 99.8% removal of caffeine. Most of the compounds in the receiving rivers were present at similar or higher concentrations compared to those in the WWTP effluents. The data set for this study does not include variations in concentrations along receiving waters because there were other point and nonpoint sources discharging to these rivers. The preliminary aquatic environmental risk assessment showed that carbamazepine, erythromycin, and trimethoprim is a potential chronic environmental risk in water bodies in Beijing, China, and is worth further investigation.