In vivo effects of low dose prenatal bisphenol A exposure on adiposity in male and female ICR offspring.

BACKGROUND: Bisphenol A (BPA) is known to exhibit endocrine disrupting activities and is associated with adiposity. We examined the obesogenic effect of prenatal BPA exposure in the present study. METHODS: Pregnant ICR mice were exposed to vehicle or BPA via the drinking water at a dose of 0.5 µg/kg·d throughout the gestation. Obesity-related indexes were investigated in the 12-wk-old offspring. Primary mouse embryonic fibroblasts (MEFs) collected from treated embryos were used to test effects of BPA on adipocyte differentiation. RESULTS: Offspring presented a significantly higher rate of weight gain than the control, with impaired insulin sensitivity and increased adipocyte size. Differentiation of MEFs from BPA-treated mice showed a higher propensity for the adipocyte commitment as well as up-regulation of genes enriched in lipid biosynthesis. TGF-ß signaling pathway was found to modulate obesogenic effect of BPA in MEF model, but estrogen signaling pathway had no effect. CONCLUSIONS: The present study provides strong evidence of the association between prenatal exposure to low dose of BPA and a significant increase in body weight in the offspring mice with a critical role played by TGF-ß signaling pathway. The potential interactions modulating the binding of BPA and TGF-ß that activate its obesogenic effects need to be examined.

A Carotenoid- and Nuclease-Producing Bacterium Can Mitigate Enterococcus faecalis Transformation by Antibiotic Resistance Genes.

Dissemination of antibiotic resistance genes (ARGs) through natural transformation is facilitated by factors that stabilize extracellular DNA (eDNA) and that induce reactive oxygen species (ROS) that permeabilize receptor cells and upregulate transformation competence genes. In this study, we demonstrate that Deinococcus radiodurans can mitigate this ARG dissemination pathway by removing both eDNA and ROS that make recipient cells more vulnerable to transformation. We used plasmid RP4 as source of extracellular ARGs (tetA, aphA, and blaTEM-2) and the opportunistic pathogen Enterococcus faecalis as receptor. The presence of D. radiodurans significantly reduced the transformation frequency from 2.5 ± 0.7 × 10-6 to 7.4 ± 1.4 × 10-7 (p < 0.05). Based on quantification of intracellular ROS accumulation and superoxide dismutase (SOD) activity, and quantitative polymerase chain reaction (qPCR) and transcriptomic analyses, we propose two mechanisms by which D. radiodurans mitigates E. faecalis transformation by ARGs: (a) residual antibiotics induce D. radiodurans to synthesize liposoluble carotenoids that scavenge ROS and thus mitigate the susceptibility of E. faecalis for eDNA uptake, and (b) eDNA induces D. radiodurans to synthesize extracellular nucleases that degrade eARGs. This mechanistic insight informs biological strategies (including bioaugmentation) to curtail the spread of ARGs through transformation.

Acute effects of exposure to fine particulate matter and ozone on lung function, inflammation and oxidative stress in healthy adults.

Both fine particulate matter (PM2.5) and ozone (O3) may have adverse effects on human health. However, previous studies on the effects of air pollutants mainly have focused on susceptible population, and evidence on healthy young adults is limited. We aimed to examine the associations of the two main air pollutants (PM2.5 and O3) with lung function, inflammation and oxidative stress in healthy young adults. We recruited 30 healthy young adults for a longitudinal panel study in Beijing and implemented health examination seven times, including lung function (FEV1 and PEF) and biomarkers of inflammation and oxidative stress (i.e. C-reactive protein, CRP; interleukin-6, IL-6; malondialdehyde, MDA) from December 2019 to May 2021. Hourly ambient air pollutants data were obtained from the closest air quality monitoring station. Linear mixed-effect model was applied to explore the associations between air pollutants and lung function, inflammation and oxidative stress. We observed higher PM2.5 exposure was associated with decrement in lung function and increment in CRP and MDA. Each 10 µg/m3 increase in PM2.5 (lag 2 day) is associated with a 17.06 ml (95% CI: -31.53, -2.58) decrease in FEV1, 46.34 ml/s (95% CI: -76.41, -16.27) decrease in PEF and increments of 2.86% (95% CI: 1.47%, 4.27%) in CRP, 1.63% (95% CI: 0.14%, 3.14%) in MDA respectively. However, there is no significant association between ozone exposure and health indicators. The study suggested that short-term exposure to PM2.5 may decrease lung function and induce inflammation and oxidative stress in healthy adults, but there is no association between O3 and each outcome.

Microfiber releasing into urban rivers from face masks during COVID-19.

Face masks play a crucial protective role in preventing the spread of coronavirus disease during the COVID-19 pandemic, but the improper disposal of used face masks also causes an emerging environmental problem, such as microplastic contamination. Here, the aim was to evaluate the improper disposal of used face masks and, subsequently, the potential contribution to microplastic contamination in urban rivers. First, we investigated the occurrence of discarded face masks in Qing River through continuously one-month collection on-site, and the disposable masks with a density of (8.28 ± 4.21) × 10-5 items/m2 with varying degrees of wear and tear were found. Next, the microfibers shedding from two popular types of new disposable masks were tested. The results showed that 50.33 ± 18.50 items/mask of microfibers, ranging from 301 µm to 467 µm in size, were released from the disposal face mask after immersion in ultrapure water for 24-h. It was significantly higher than the KN95 respirator of 31.33 ± 0.57 items/mask, ranging from 273 µm to 441 µm. Besides C and O elements only found in new face masks, some potentially toxic elements were also detected on the surface of discarded face masks, indicating that various environmental contaminations are easy to adsorb on the surface of discarded face masks. The results implied that these discarded face masks in an aquatic environment are emerging sources of microfibers and could act as transport vectors for contaminants, which would aggravate the present microplastic contamination. In conclusion, these findings were expected to raise public awareness of the proper disposal of used face masks to prevent microplastic contamination and the spread of COVID-19 in the environment.

The bacterial community composition and its environmental drivers in the rivers around eutrophic Chaohu Lake, China.

BACKGROUND: Bacterial community play a key role in environmental and ecological processes in river ecosystems. Rivers are used as receiving body for treated and untreated urban wastewaters that brings high loads of sewage and excrement bacteria. However, little is known about the bacterial community structure and functional files in the rivers around the eutrophic Chaohu Lake, the fifth largest freshwater lake in China, has been subjected to severe eutrophication and cyanobacterial blooms over the past few decades. Therefore, understanding the taxonomic and functional compositions of bacterial communities in the river will contribute to understanding aquatic microbial ecology. The main aims were to (1) examine the structure of bacterial communities and functional profiles in this system; (2) find the environmental factors of bacterial community variations. RESULTS: We studied 88 sites at rivers in the Chaohu Lake basin, and determined bacterial communities using Illumina Miseq sequencing of the 16 S rRNA gene, and predicted functional profiles using PICRUSt2. A total of 3,390,497 bacterial 16 S rRNA gene sequences were obtained, representing 17 phyla, and 424 genera; The dominant phyla present in all samples were Bacteroidetes (1.4-82.50 %), followed by Proteobacteria (12.6-97.30 %), Actinobacteria (0.1-17.20 %). Flavobacterium was the most numerous genera, and accounted for 0.12-80.34 % of assigned 16 S reads, followed by Acinetobacter (0.33-49.28 %). Other dominant bacterial genera including Massilia (0.06-25.40 %), Psychrobacter (0-36.23 %), Chryseobacterium (0.01-22.86 %), Brevundimonas (0.01-12.82 %), Pseudomonas (0-59.73 %), Duganella (0.08-23.37 %), Unidentified Micrococcaceae (0-8.49 %). The functional profiles of the bacterial populations indicated an relation with many human diseases, including infectious diseases. Overall results, using the ß diversity measures, coupled with heatmap and RDA showed that there were spatial variations in the bacterial community composition at river sites, and Chemical oxygen demand (CODMn) and (NH4+ )were the dominant environmental drivers affecting the bacterial community variance. CONCLUSIONS: The high proportion of the opportunistic pathogens (Acinetobacter, Massilia, Brevundimonas) indicated that the discharge of sewage without adequate treatment into the rivers around Chaohu Lake. We propose that these bacteria could be more effective bioindicators for long-term sewage monitoring in eutrophic lakes.

Will a Non-antibiotic Metalloid Enhance the Spread of Antibiotic Resistance Genes: The Selenate Story.

The rapid emergence of antibiotic resistance genes (ARGs) has become an increasingly serious threat to public health. Previous studies illustrate the antibiotic-like effect of many substances. However, whether and how commonly used or existing non-antibiotic metalloids (e.g., selenate) would enhance ARG spread remains poorly known. Here, we tracked the long-term operation of a bioreactor continuously fed with selenate for more than 1000 days. Metagenomic sequencing identified 191 different ARGs, of which the total abundance increased significantly after the amendment of selenate. Network analyses showed that ARGs resisting multiple drugs had very similar co-occurrence patterns, implying a potentially larger health risk. Host classification not only indicated multidrug-resistant species but also distinguished the mechanism of ARG enrichment for vertical transfer and horizontal gene transfer. Genome reconstruction of an ARG host suggested that selenate and its bioreduction product selenite could stimulate the overproduction of intracellular reactive oxygen species, which was confirmed by the direct measurement. Bacterial membrane permeability, type IV pilus formation, and DNA repair and recombination were also enhanced, together facilitating the horizontal acquirement of ARGs. Overall, this study for the first time highlights the ARG emergence and dissemination induced by a non-antibiotic metalloid and identifies ARG as a factor to consider in selenate bioremediation.

Urinary polycyclic aromatic hydrocarbons and sex hormones in children and adolescents: Evidence from NHANES.

BACKGROUND: Evidences showed that polycyclic aromatic hydrocarbons (PAHs) do harm to human body. However, the association between PAHs and sex hormones in children and adolescents remains unclear. OBJECTIVES: The study aims to investigate the associations between PAHs and sex hormones in the general children and adolescent population. METHODS: 967 participants aged 6-19 with complete data of PAHs exposure biomarkers, covariates and sex hormones [total testosterone (TT), estradiol (E2) and sex hormone binding globulin (SHBG)] were recruited from National Health and Nutrition Examination Survey (NHANES), 2013-2016. Free androgen index (FAI) was calculated with TT/SHBG. Multivariate linear regression models were performed in six subgroups (male children, male adolescents, male late adolescents, female children, female adolescents and female late adolescents) to estimate the associations between sex hormone alterations and PAHs exposure. RESULTS: In male puberty adolescents, weighted multivariate linear regression indicated that negative trends for 2-Hydroxynaphthalene, 1-Hydroxyphenanthrene, 2&3-Hydroxyphenanthrene and E2 (2-Hydroxynaphthalene: ß: -0.104, 95%CI: -0.180, -0.029, P < 0.01; 1-Hydroxyphenanthrene: ß: -0.112, 95%CI: -0.206, -0.018, P = 0.019; 2&3-Hydroxyphenanthrene: ß: -0.125, 95%CI: -0.232, -0.018, P = 0.022), while exposure to 2-Hydroxynaphthalene was related to TT reduction (ß: -0.099, 95%CI: -0.177, -0.020, P = 0.014). Same pattern between 2&3-Hydroxyphenanthrene and E2 alteration (2&3-Hydroxyphenanthrene: ß: -0.139, 95%CI: -0.236, -0.041, P < 0.01) was also observed in male late adolescents. In male children, we determined that 1-Hydroxyphenanthrene was negatively associated with SHBG (ß: -0.121, 95%CI: -0.205, -0.037, P < 0.01), while the same patterns were observed in male puberty children. We did not observe any significant result in female subgroups. All these results above were determined to have q value < 0.05. CONCLUSION: PAHs exposure was associated with the alterations of sex hormones in male adolescents and children. Considering the cross-sectional study design, further large-scale epidemiological study is necessary.

Long-Term Trends in Acid Neutralizing Capacity under Increasing Acidic Deposition: A Special Example of Eutrophic Taihu Lake, China.

While North America and Europe have been recovering from acidification, China is experiencing impacts of acid deposition. The Taihu region is a seriously impacted area by acid rain in China, with the average rainfall pH < 5. However, the acid neutralizing capacity (ANC) and pH of Taihu Lake have significantly increased over the past 60 years (p < 0.05). Analyses showed that watershed neutralization by carbonates and in-lake alkalinization by algae activities were the two major reactions responsible for the increase. In the Taihu basin, the dominant carbonate bedrocks are the major source of base cations (particularly Ca2+ and Mg2+) and act as the acidification buffer. In addition, our field measurements across the lake showed that the pH values were significantly higher in algal bloom waters than in areas without blooms. This observation was further supported by our statistical analysis showing that the Taihu ANC and pH were significantly correlated with the chlorophyll increase (p < 0.05; 1985-2015). However, our regression analysis indicated that the base cations in the watershed would be depleted by the early 2040s if the acid deposition continues at the current rate. Our results suggest that interactions between human accelerated weathering, watershed geochemistry, and in-lake algae activities significantly impact the water chemistry of the lake. We urgently recommend an "integrated and balanced" recovery plan for the lake ecosystem.

Adsorption kinetics of benzotriazole and its derivatives by nano Zn-Al-O.

Benzotriazole and its derivatives are important industrial auxiliaries, which are serious pollution sources in the natural aquatic environment. Benzotriazole and its derivatives adsorption by a novel nano absorbent (nano Zn-Al-O binary metal oxide, named as ZAO) being explored as an effective water treatment method, was carried out in this study. Results showed that benzotriazole and its derivatives were all effectively adsorbed from water by ZAO. Removal efficiencies of benzotriazole, 5-methyl-benzotriazol and 5,6-dimethyl-benzotriazole with 5 g/L adsorbent dosage achieved 89%, 81% and 92%, respectively. The adsorption kinetics and isotherm models were used to express the adsorption process and discuss the adsorption mechanism. The adsorption kinetics well followed pseudo-second-order model, indicating that chemical adsorption dominated the adsorption. Adsorption isotherm was well expressed by Freundlich model. Structure characteristics of benzotriazole and its derivatives had great effect on their adsorption. Hydrogen-bond interaction was considered as the main mechanism for the surface adsorption. However, hydrophobic interactions played an important role in 5,6-dimethyl-benzotriazole adsorption due to its weak polarity.

Tissue accumulation of microplastics and potential health risks in human.

Microplastics have become ubiquitous throughout the environment. Humans constantly ingest and inhale microplastics, increasing concerns about the health risks of microplastic exposure. However, limited data impedes a full understanding of the internal exposure to microplastics. Herein, to evaluate microplastic exposure via the respiratory and digestive systems, we used laser direct infrared spectroscopy to identify microplastics >20 µm in size in different human tissues. Consequently, 20-100 µm microplastics were concentrated in all tissues, with polyvinyl chloride (PVC) being the dominant polymer. The highest abundance of microplastics was detected in lung tissue with an average of 14.19 ± 14.57 particles/g, followed by that in the small intestine, large intestine, and tonsil (9.45 ± 13.13, 7.91 ± 7.00, and 6.03 ± 7.37 particles/g, respectively). The abundance of microplastics was also significantly greater in females than in males (p < 0.05). Despite significant diversity, our estimation showed that the lungs accumulated the highest amounts of microplastic. Moreover, PVC particles may cause potential health risks because of their high polymer hazard index and maximal risk level. This study provides evidence regarding the occurrence of microplastics in humans and empirical data to support assessments of the health risks posed by microplastics.

Mechanism of BDE209-induced impaired glucose homeostasis based on gene microarray analysis of adult rat liver.

Several persistent organic pollutants are reported to be potentially associated with the risk of human diabetes that has become rapidly epidemic in China currently. 2,2',3,3',4,4',5,5',6,6'-decabromodiphenyl ether (BDE209) is commercially most important both in the production and in the use of polybrominated diphenyl ethers (PBDEs). It might bioaccumulate in wildlife and human and is the only PBDEs mixture still used today. In the present study, male adult rats treated with BDE209 (0, 0.05, 1, and 20 mg/kg) for 8 weeks were used to explore the effects of BDE209 on glucose homeostasis and possible mechanisms; 0.05 mg/kg of BDE209 induced dose-related hyperglycemia. Then, we performed the full-genome gene expression microarrays, gene ontology analysis, and pathway analysis in this group and control. BDE209 induced 1,257 liver gene transcript changes, and 18 canonical pathways were significantly enriched. Four of them were involved in immune diseases, including autoimmune thyroid disease, graft-versus-host disease, allograft rejection, and type I diabetes mellitus (T1MD), which was confirmed by the decrease in serum insulin. Subsequently, gene act network and gene co-expression network found that some MHC molecules and TNF-α were involved in T1DM pathway, which was then confirmed by the increase in serum TNF-α. Additionally, reduced glutathione and superoxide dismutase in plasma indicated that oxidative damage might partly contribute to BDE209-induced hyperglycemia. The results of this study provide some new experimental evidence that the exposure to high levels of BDE209 may contribute to the onset of diabetes in human populations. Further work needs to be done to confirm this link.

Multistep, microvolume resin fractionation combined with 3D fluorescence spectroscopy for improved DOM characterization and water quality monitoring.

Conventionally, resin fractionation (RF) method has been widely used to characterize dissolved organic matter (DOM) found in different source waters based on general and broad DOM fractions grouping. In this study, a new refined method using multistep, microvolume resin fractionation combined with excitation emission matrix fluorescence spectroscopy (MSM-RF-EEMS) was developed for further isolation and characterization of subfractions within the primary DOM fractions separated from using the conventional RF method. Subsequently, its feasibility in indicating the occurrence of urban pollution in source waters was also assessed. Results from using the new MSM-RF-EEMS method strongly illustrated that several organic subfractions still exist within the regarded primary pure hydrophobic acid (HoA) fraction including the humic- and fulvic-like organic matters, tryptophan- and tyrosine-like proteins. It was found that by using the MSM-RF-EEMS method, the organic subfractions present within the primary DOM fraction could be easily identified and characterized. Further validation on the HoA fraction using the MSM-RF-EEMS method revealed that the constant association of EEM peak T1 (tryptophan) fraction could specifically be used to indicate the occurrence of urban pollution in source water. The correlation analysis on the presence of EEM peak T2 (tyrosine) fraction could be used as a supplementary proof to further verify the presence of urban pollution in source waters. These findings on using the presence of EEM peaks T1 and T2 within the primary HoA fraction would be significant and useful for developing a sensory device for online water quality monitoring.

Identification of microplastics in human placenta using laser direct infrared spectroscopy.

Microplastics are ubiquitous in the environment, including in food and drinking water. Consequently, there is growing concern about the human health risks associated with microplastic exposure through diet. However, the occurrence of microplastics in the human body, particularly in mothers and fetuses, is incompletely understood because of the limited amount of data on their presence in the body and the human placenta. This study evaluated the presence and characteristics of microplastics in 17 placentas using laser direct infrared (LD-IR) spectroscopy. Microplastics were detected in all placenta samples, with an average abundance of 2.70 ± 2.65 particles/g and a range of 0.28 to 9.55 particles/g. Among these microplastics, 11 polymer types were identified. The microplastics were mainly composed of polyvinyl chloride (PVC, 43.27 %), polypropylene (PP, 14.55 %), and polybutylene succinate (PBS, 10.90 %). The sizes of these microplastics ranged from 20.34 to 307.29 µm, and most (80.29 %) were smaller than 100 µm. Most of the smaller microplastics were fragments, but fibers dominated the larger microplastics (200-307.29 µm). Interestingly, the majority of PVC and PP were smaller than 200 µm. This study provides a clearer understanding of the shape, size, and nature of microplastics in the human placenta. Importantly, these data also provide crucial information for performing risk assessments of the exposure of fetuses to microplastics in the future.

Simultaneous antibiotic removal and mitigation of resistance induction by manganese bio-oxidation process.

Microbial degradation to remove residual antibiotics in wastewater is of growing interest. However, biological treatment of antibiotics may cause resistance dissemination by mutations and horizontal gene transfer (HGT) of antibiotic resistance genes (ARGs). In this study, a Mn(Ⅱ)-oxidizing bacterium (MnOB), Pseudomonas aeruginosa MQ2, simultaneously degraded antibiotics, decreased HGT, and mitigated antibiotic resistance mutation. Intracellular Mn(II) levels increased during manganese oxidation, and biogenic manganese oxides (BioMnOx, including Mn(II), Mn(III) and Mn(IV)) tightly coated the cell surface. Mn(II) bio-oxidation mitigated antibiotic resistance acquisition from an E. coli ARG donor and mitigated antibiotic resistance inducement by decreasing conjugative transfer and mutation, respectively. BioMnOx also oxidized ciprofloxacin (1 mg/L) and tetracycline (5 mg/L), respectively removing 93% and 96% within 24 h. Transcriptomic analysis revealed that two new multicopper oxidase and one peroxidase genes are involved in Mn(II) oxidation. Downregulation of SOS response, multidrug resistance and type Ⅳ secretion system related genes explained that Mn(II) and BioMnOx decreased HGT and mitigated resistance mutation by alleviating oxidative stress, which makes recipient cells more vulnerable to ARG acquisition and mutation. A manganese bio-oxidation based reactor was constructed and completely removed tetracycline with environmental concentration within 4-hour hydraulic retention time. Overall, this study suggests that Mn (II) bio-oxidation process could be exploited to control antibiotic contamination and mitigate resistance propagation during water treatment.

Microplastics transferring from abiotic to biotic in aquatic ecosystem: A mini review.

Microplastics have been detected in global aquatic ecosystems, so it is vital to understand the bioaccumulation and biomagnification of microplastics for ecological risk assessment. However, variability between studies, including sampling, pretreatment processes, and polymer identification methods have made it difficult to draw definitive conclusions. Alternatively, the compilation and statistical analysis of available experimental and investigation data provides insight into the fates of microplastics in an aquatic ecosystem. To reduce bias, we performed a systematic literature retrieval and compiled these reports on microplastic abundance in the natural aquatic environment. Our results indicate that microplastics are more abundant in sediments than in water, mussels, and fish. There is a significant correlation between mussels and sediments, but not between water and mussels or between water/sediment and fish. Bioaccumulation of microplastics appears to occur through water, but the route of biomagnification is unclear. More sound evidence is required to fully understand the biomagnification of microplastics in aquatic environments.

Air pollution exposure and the risk of macrosomia: Identifying specific susceptible months.

Birth weight is an important indicator of future growth and development for newborns. Few studies investigated the potential effects of air pollutants on macrosomia and their susceptible windows. We included 38,971 singleton full-term births from Beijing HaiDian Maternal and Child Health Hospital between 2014 and 2018, and assessed the associations of air pollutants exposure during preconception and pregnancy with macrosomia as well as the corresponding susceptible windows. The concentrations of air pollutants (PM2.5, PM10, SO2, NO2, CO and O3) for participants were calculated by the data from the nearest monitoring stations. Distributed lag models (DLM) incorporating logistic regression models were used to estimate the associations between air pollutants exposure during the 3 months before conception and pregnancy period and the risk of macrosomia, identifying susceptible windows of air pollutants. Weighted quantile sum (WQS) regression was applied to estimate the joint effect of air pollutants. A 10 µg/m3 increase in PM2.5 exposure from 3rd to 8th gestational month was positively associated with the risk of macrosomia, with the strongest effect in the 6th month (OR = 1.010, 95 % CI: 1.002-1.019). For a 10 µg/m3 increase in SO2, the windows of significant exposure were from the 1st preconception month to the 3rd gestational month, with the strongest effect in the 2nd month (OR = 1.030, 95 % CI: 1.010-1.049). We also observed the significant positive associations were in the 5th-8th gestational months for PM10, the 8th-9th gestational months for NO2 and the 3rd-7th gestational months for CO respectively. WQS regression also indicated a positive association between co-exposure to air pollutants and macrosomia. Our results suggest air pollution exposure is associated with increased risk of macrosomia. The windows of exposure for susceptibility to the risk of macrosomia vary between air pollutants. The susceptible exposure windows were middle and late pregnancy for PM, CO and NO2, while for SO2, early pregnancy is the window of vulnerability. Our findings provide the evidence that air pollution exposure is an independent risk factor for macrosomia and a basis for targeted environment policy.

Relationships between environmental factors and N-cycling microbes reveal the indirect effect of further eutrophication on denitrification and DNRA in shallow lakes.

Traditional views indicate that eutrophication and subsequent algal blooms favor denitrification and dissimilatory nitrate reduction to ammonium (DNRA) in lake ecosystems. However, lakes tend to show an increasing propensity for inorganic nitrogen (N) limitation as they become more eutrophic. Thus, the influence of further eutrophication on denitrification and DNRA in eutrophic lakes are unclear due to the uncertainty of N availability. To fill this gap, we investigated the genes abundance (AOA, AOB, nirS, nirK and nrfA) and the composition of N-cycling microbes through quantitative PCR and 16S rRNA sequencing analysis, respectively, in 15 shallow eutrophic lakes of the Yangtze-Huaihe River basin, China. The results indicated that denitrification and DNRA rates could be modulated mainly by their functional gene abundances (nirS, nirK and nrfA), followed by the environmental factors (sediment total organic carbon and nitrogen). Denitrification rates significantly increased from slightly to highly eutrophic lakes, but DNRA rates were not. An explanation is that nitrification provided ample nitrate for denitrification, and this cooperative interaction was indicated by the positive correlation of their gene abundances. In addition, Pseudomonas and Anaeromyxobacter was the dominant genus mediated denitrification and DNRA, showing the potential to perform facultative anaerobic and strict anaerobic nitrate reduction, respectively. High level of dissolved oxygen might favor the facultatively aerobic denitrifiers over the obligately anaerobic fermentative DNRA bacteria in these shallow lakes. Chlorophyll a had a weak but positive effect on the gene abundances for nitrification (AOA and AOB). Further eutrophication had an indirect effect on denitrification and DNRA rates through modulating the genes abundances of N-cycling microbes.

[Distribution Characteristics and Risk Assessment of PPCPs in Surface Water and Sediments of Lakes in the Lower Reaches of the Huaihe River].

In order to understand the occurrence characteristics and ecological risks of pharmaceuticals and personal care products (PPCPs) in surface water and sediments of Hongze Lake and Gaoyou Lake in the lower reaches of the Huaihe River, 43 surface water and sediment samples from 23 sampling sites were collected, and 61 PPCPs were detected in the samples. The concentration level and spatial distribution of target PPCPs in Hongze Lake and Gaoyou Lake were analyzed, the distribution coefficient of typical PPCPs in the water/sediment system in the study area was calculated, and the ecological risk of target PPCPs was evaluated using the entropy method. The results showed that the PPCPs in surface water of Hongze Lake and Gaoyou Lake were 1.56-2534.44 ng·L-1 and 3.32-1027.47 ng·L-1, respectively, and those in sediment were 1.7-926.7 ng·g-1 and 1.02-289.37 ng·g-1, respectively. The concentrations of lincomycin (LIN) in surface water and doxycycline (DOX) in sediment were the highest, and antibiotics were the main components. The spatial distribution of PPCPs was higher in Hongze Lake and lower in Gaoyou Lake. The distribution characteristics of typical PPCPs in the study area showed that typical PPCPs tended to stay in the water phase, and there was a significant correlation between lg Koc and lg Kd, indicating that total organic carbon (TOC) played an important role in the distribution of typical PPCPs in the water/sediment system. The ecological risk assessment results showed that the ecological risk of PPCPs to algae in surface water and sediment was significantly higher than that of fleas and fish, the ecological risk value of PPCPs in surface water was higher than that in sediment, and the ecological risk of Hongze Lake was higher than that of Gaoyou Lake.

Water quality criteria and ecological risk assessment for copper in Liaodong Bay, China.

The establishment of water quality criteria (WQC) for copper (Cu) was used as the basis for an ecological risk assessment of marine Cu pollution in Liaodong Bay, China. Published ecotoxicity data for Cu were obtained and supplemented with the results of acute Cu toxicity tests. The marine WQC for Cu in Liaodong Bay was developed using a species sensitivity distribution method with a safety factor of 2.0 and the USEPA acute-to-chronic ratio method. The ecological risk of Cu in Liaodong Bay was assessed by comparing the seawater Cu concentrations with the developed WQC. The results of this study showed that the acute and chronic Cu concentrations in Liaodong Bay were 3.31 and 2.18 µg/L, respectively. Comparison of the WQC to Cu concentrations in the bay resulted in risk quotients slightly >1.0 and typically ≤2.0. These data suggest that certain organisms in Liaodong Bay are at risk. These results can assist in the development of a pollution control management approach for the bay.