Once released into the environment, engineered nanomaterials can significantly influence the transformation and fate of organic contaminants. To date, the abilities of composite nanomaterials to catalyze environmentally relevant abiotic transformation reactions of organic contaminants are largely unknown. Herein, we investigated the effects of two nanocomposites – consisting of anatase titanium dioxide (TiO2) with different predominantly exposed crystal facets (i.e., {101} or {001} facets) anchored to hydroxylated multi-walled carbon nanotubes (OH-MWCNT) – on the hydrolysis of 1,1,2,2-tetrachloroethane (TeCA), a common groundwater contaminant, at ambient pH (6, 7 and 8). Both OH-MWCNT/TiO2 nanocomposites were more effective in catalyzing the dehydrochlorination of TeCA than the respective component materials (i.e., bare OH-MWCNT and bare TiO2). Moreover, the synergistic effect of the two components was evident, in that the incorporation of OH-MWCNT increased the TeCA adsorption capacity of the nanocomposites, significantly enhancing the catalytic effect of the deprotonated hydroxyl and carboxyl groups on nanocomposite surfaces, which served as the main catalytic sites for TeCA hydrolysis. The findings may have important implications for the understanding of the environmental implications of composite nanomaterials and may shed light on the design of high-performance nanocomposites for enhanced contaminant removal.

The gut microbiota is important for maintaining homeostasis of the host. Gut microbes represent the initial site for toxicant processing following dietary exposures to environmental contaminants. The diet is the primary route of exposure to polychlorinated biphenyls (PCBs), which are absorbed via the gut, and subsequently interfere with neurodevelopment and behavior. Developmental exposures to PCBs have been linked to increased risk of neurodevelopmental disorders (NDD), including autism spectrum disorder (ASD), which are also associated with a high prevalence of gastrointestinal (GI) distress and intestinal dysbiosis. We hypothesized that developmental PCB exposure impacts colonization of the gut microbiota, resulting in GI pathophysiology, in a genetically susceptible host. Mouse dams expressing two heritable human mutations (double mutants [DM]) that result in abnormal Ca²⁺ dynamics and produce behavioral deficits (gain of function mutation in the ryanodine receptor 1 [T4826I-RYR1] and a human CGG repeat expansion [170–200 CGG repeats] in the fragile X mental retardation gene 1 [FMR1 premutation]). DM and congenic wild type (WT) controls were exposed to PCBs (0–6 mg/kg/d) in the diet starting 2 weeks before gestation and continuing through postnatal day 21 (P21). Intestinal physiology (Ussing chambers), inflammation (qPCR) and gut microbiome (16S sequencing) studies were performed in offspring mice (P28–P30). Developmental exposure to PCBs in the maternal diet caused significant mucosal barrier defects in ileum and colon (increased secretory state and tight junction permeability) of juvenile DM mice. Furthermore, PCB exposure increased the intestinal inflammatory profile (Il6, Il1β, and Il22), and resulted in dysbiosis of the gut microbiota, including altered β-diversity, in juvenile DM mice developmentally exposed to 1 mg/kg/d PCBs when compared to WT controls. Collectively, these findings demonstrate a novel interaction between PCB exposure and the gut microbiota in a genetically susceptible host that provide novel insight into environmental risk factors for neurodevelopmental disorders.

Ammonia oxidation is the rate-limiting step in nitrification process and dominated by ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA). In the present study, a highly enriched culture of AOA was obtained from urban polluted water in Shahe River, Shenzhen, China. The optimum growth conditions were identified by orthogonal analysis as 37 °C, with pH 7.0 and initial ammonia concentration of 1.0 mM. Under these conditions, the highest abundance of AOA was obtained as 4.6 × 10⁷ copies/ng DNA. Growth of AOA in polluted river water showed significant reduction in ammonia concentration in AOA-enriched cultures without antibiotics after 10 days of incubation, while synchronous increase in nitrate concentration was up to 12.7 mg/L. However, AOA-enriched by antibiotic showed insignificant changes in ammonia or nitrite concentration. This study showed that AOB play an important role in ammonia oxidation of polluted river water, and AOA alone showed insignificant changes in ammonia or nitrite concentrations. Therefore, the ammonia oxidation performance of natural water could not be improved by adding high concentration AOA bacterial liquid.

Nitrous oxide (N2O) is a devastating greenhouse gas mainly released from soils to the atmosphere. Pasture soils, particularly acidic in nature, are large contributors of atmospheric N2O through deposition of urine-N. Devising strategies for reducing N2O emissions in acidic soils are the utmost need of the time. Therefore, the present study was carried out to investigate the possible efficacy of dolomite application to reduce N2O emissions from urine treated acidic soil. Application of urine to soil enlarged the production of NH4+-N, NO3−-N, microbial biomass C (MBC) and dissolved organic C (DOC), resulting in higher N2O emissions as compared to the control (soil only). The highest N2O emission rate (1.35 μg N2O-N kg−1 h−1) and cumulative flux (408 μg N2O-N kg−1) occurred in urine only treated soil. Dolomite addition, especially higher application dose, greatly reduced N2O emissions through improved soil pH. The results suggest that increasing pH of acidic soils is a good applicable approach for reducing N2O emissions from urine-treated soils.

Environmentally persistent free radicals (EPFRs) are a new class of environmental risk substances that can stably exist in atmospheric particles and pose a potential threat to human health. In this study, electron paramagnetic resonance (EPR) spectroscopy was used to study the concentration levels, species characteristics, and sources of EPFRs in PM₂.₅ in Xi'an in 2017. The results showed that the concentrations of EPFRs in PM₂.₅ in Xi'an in 2017 ranged from 9.8 × 10¹¹ to 6.9 × 10¹⁴ spins/m³. The highest concentration of EPFRs occurred in winter when the average concentration was 2.1 × 10¹⁴ spins/m³. The lowest concentration of EPFRs occurred in autumn when the average concentration was 7.0 × 10¹³ spins/m³. According to the annual average atmospheric concentration of EPFRs, the amount of EPFRs inhaled by people in Xi'an is equivalent to approximately 5 cigarettes per person per day and approximately 23 cigarettes per person per day in winter when haze occurs. The results of the study on the EPFR characteristics show that the EPFRs in PM₂.₅ in Xi'an are mainly C-center organic radicals that are primarily non-decaying types, accounting for approximately 75% and 85% of total concentration of EPFRs in autumn and winter, respectively. Finally, a correlation analysis was used to explore the origins of EPFRs in PM₂.₅. Significant positive correlations were found between EPFRs and SO₂, NO₂ and the thermally derived OC3 and OC4 carbonaceous components. The results suggested that coal-fired and traffic may be important sources of EPFRs in PM₂.₅ in Xi'an. In addition, EPFRs are significantly positively correlated with O₃ in summer, suggesting that some EPFRs may also originate from secondary processes. This study provides important basic data and evidence for further assessments of the potential health risks of EPFRs in PM₂.₅ and the development of effective air pollution control measures.

Little information is available about effect of particle size and crystal structure of nTiO₂ on their trophic transfer. In this study, 5 nm anatase, 10 nm anatase, 100 nm anatase, 20 nm P25 (80% anatase and 20% rutile), and 25 nm rutile nTiO₂ were selected to investigate the effects of size and crystal structure on the toxicity, bioconcentration, and trophic transfer of nTiO₂ to algae and daphnia. In the exposed daphnids, metabolic pathways affected by nTiO₂ and nTiO₂-exposed algae (nTiO₂-algae) were also explored. The 96 h IC₅₀ values of algae and the 48 h LC₅₀ values of daphnia were 10.3, 18.9, 43.9, 33.6, 65.4 mg/L and 10.5, 13.2, 37.0, 28.4, 60.7 mg/L, respectively, after exposed to nTiO₂-5A, nTiO₂-10A, nTiO₂-100A, nTiO₂-P25, and nTiO₂-25R, respectively. The bioconcentration factors (BCFs) for 0.1, 1, and 10 mg/L nTiO₂ in daphnia ranged from 21,220 L/kg to 145,350 L/kg. The nTiO₂ biomagnification factors (BMFs) of daphnia fed with 1 and 10 mg/L nTiO₂-exposed algae were consistently greater than 1.0 (5.7–122). The results show that the acute toxicity, BCF, and BMF all decreased with increasing size or rutile content of nTiO₂. All types of nTiO₂ were largely accumulated in the daphnia gut and were not completely depurated within 24 h. At the molecular level, 22 Kyoto Encyclopedia of Genes and Genomes (KEGG) metabolic pathways of daphnia were impacted by the nTiO₂ and nTiO₂-algae treatments, including glutathione metabolism, aminoacyl-tRNA biosynthesis, among others. Six and four KEGG metabolic pathways were significantly disturbed in daphnids exposed to nTiO₂ and nTiO₂-algae, respectively, indicating the presence of algae partially alleviated the negative impact of nTiO₂ on metabolism. These findings increase understanding of the impacts of physicochemical properties of nTiO₂ on the food chain from molecular scale to that of the whole organism, and provide new insight into the ecological effect of nanomaterials.

Depending on their concentrations, sizes, and types, particulate matters of biological origins (bioPM) significantly affect human health. However, for different air environments, they are not well characterized and can vary considerably. As an example, we investigated the bioPM differences at an urban (Beijing) site and a rural (Wangdu) site in the North China Plain (NCP) using an online monitoring instrument, an ultraviolet aerodynamic particle sizer (UV-APS), the limulus amebocyte lysate (LAL) assay, and a high-throughput sequencing method. Generally, lower concentrations of viable bioPM (hourly mean: 1.3 × 10³ ± 1.6 × 10³ m⁻³) and endotoxin (0.66 ± 0.16 EU/m³) in Beijing were observed compared to viable bioPM (0.79 × 10⁵ ± 1.4 × 10⁵ m⁻³) and endotoxin (15.1 ± 23.96 EU/m³) at the Wangdu site. The percentage of viable bioPM number concentration in the total PM was 3.1% in Beijing and 6.4% in Wangdu. Approximately 80% of viable bioPM was found to be in the range from 1 to 2.5 μm. Nevertheless, the size distribution patterns for viable bioPM at the Beijing and Wangdu sites differed and were affected by PM pollution, leading to distinct lung deposition profiles. Moreover, the distinct diurnal variations in viable bioPM on clean days were dimmed by the PM pollution at both sites. Distinct bacterial community structures were found in the air from the Beijing and Wangdu sites. The bacterial community in urban Beijing was dominated by genus Lactococcus (49.5%) and Pseudomonas (15.1%), while the rural Wangdu site was dominated by Enterococcus (65%) and Paenibacillus (10%). Human-derived genera, including Myroides, Streptococcus, Propionibacterium, Dietzia, Helcococcus, and Facklamia, were higher in Beijing, suggesting bacterial emission from humans in the urban air environment. Our results show that different air harbors different biological species, and people residing in different environments thus could have very different biological particle exposure.

An understanding of the dispersion and level of emissions source of atmospheric pollutants; whether point, area or volume sources, is required to inform policies on air pollution and day-to-day predictions of pollution level. Very few studies have carried out simulations of the dispersion pattern and ground-level concentration of pollutants emitted from real-world gas flares. The limited availability of official data on gas flares from the oil and gas industries makes accurate dispersion calculations difficult. Using ADMS 5 and AERMOD, this study assessed the sensitivity of dispersion and ground-level concentration of pollutants from gas flares in the Niger Delta to prevailing meteorological condition; fuel composition; and flare size. Although, during the non-WAM (West African Monsoon) months (November and March), the simulated ground-level concentrations of pollutants from a single flare are lower, the dispersion of pollutants is towards both the inland and coastal communities. In the WAM months, the ground-level concentrations are higher and are dispersed predominantly over the inland communities. Less buoyant plumes from smaller flares (lower volume flow rates) and/or flaring of fuel with lower heat content results in higher ground-level concentrations in areas closer to the flare. Considering the huge number of flares scattered around the region, a mitigation of the acute local pollution level would be to combine short stacks flaring at lower volume flow rates to enhance the volume flow rate of a single exhaust, and hence, the buoyancy of the plume exiting the stack.

17α-ethinyl estradiol (EE2) is a synthetic compound widely used in the generation of contraceptive pills. EE2 is present in the urine of women taking contraceptives and its presence has been confirmed at increasing concentrations contaminating rivers all over the world. Because of this cycle, it can entry the human food chain when watering plants. A negative influence of EE2 on fertility and reproductive capacity of wildlife was already suggested. The short-term impact of exposure to contaminating EE2 on pregnancy outcome has not been addressed.Pregnant mice were exposed to either 0.005 μg (concentrations found in water) or 5 μg EE2/kg (contraceptive dose) body weight/day from gestation day 1–7 by oral gavage. Control mice received a 0.1% ethanol solution. High frequency ultrasound imaging was used to follow-up fetal and placental growth in vivo. Doppler measurements were utilized to analyze blood flow parameters in uterine and umbilical arteries. Mice were sacrificed at gd5, 10, and 14. We show that most fetuses of mothers exposed to the high EE2 dose die intrauterine at gd10, with implantation sizes beginning to be smaller already at gd8. Mothers exposed to the low EE2 dose show an impaired remodeling of the spiral arteries, a higher placental weight and pups that are large for gestational age. The insulin-like growth factor system that regulates fetal and placental growth and development is affected by the EE2 treatment.Our results show that a short-term exposure to EE2 during early pregnancy has severe consequences for fetal growth and survival depending on the dose. Exposition to synthetic estrogens affects placenta growth and angiogenesis. These findings urge to the study of mechanisms dysregulated upon environmental exposition to estrogens.

Concerns have been raised regarding the ecotoxicity of ionic liquids (ILs) owing to their wide usage in numerous fields. Three imidazolium chloride ILs with different numbers of methyl substituents, 1-decyl-imidazolium chloride ([C10IM]Cl), 1-decyl-3-methylimidazolium chloride ([C10MIM]Cl), and 1-decyl-2,3-dimethylimidazolium chloride ([C10DMIM]Cl), were examined to assess their effects on growth, photosynthesis pigments content, chlorophyll fluorescence, photosynthetic and respiration rate, and cellular ultrastructure of Scenedesmus obliquus. The results showed that algal growth was significantly inhibited by ILs treatments. The observed IC50,48h doses were 0.10 mg/L [C10IM]Cl, 0.01 mg/L [C10MIM]Cl, and 0.02 mg/L [C10DMIM]Cl. The chlorophyll a, chlorophyll b, and total chlorophyll content declined, and the chlorophyll fluorescence parameters, minimal fluorescence yield (F0), maximal fluorescence yield (Fm), maximum quantum yield of PSII photochemistry (Fv/Fm), effective quantum yield of PSII [Y(II)], non-photochemical quenching (NPQ) and non-photosynthetic losses yield [Y(NO)] were notably affected by ILs in a dose-dependent manner. ILs affected the primary photosynthetic reaction, impaired heat dissipation capability, and diminished photosynthetic efficiency, indicating negative effects on photosystem II. The photosynthetic and respiration rates of algal cells were also reduced due to the ILs treatments. The adverse effects of ILs on plasmolysis and chloroplast deformation were examined using ultrastructural analyses; chloroplast swelling and lamellar structure almost disappeared after the [C10MIM]Cl treatment, and an increased number of starch grains and vacuoles was observed after all ILs treatments. The results indicated that one-methyl-substituted ILs were more toxic than non-methyl-substituted ILs, which were also more toxic than di-methyl-substituted ILs. The toxicity of the examined ILs showed the following order: [C10IM]Cl < [C10DMIM]Cl ≤ [C10MIM]Cl.