The effluent stream of the anaerobic digestion processes, the digestate, accommodates high residual organic content that needs to be further treated before discharge. Anaerobic treatment of digestate would not only reduce the residual organic compounds in digestate but also has a potential to capture the associated biogas. High-rate anaerobic reactor configurations can treat the waste streams using lower hydraulic retention times which requires less footprint opposed to the conventional completely stirred tank reactors. This study investigated the high-rate anaerobic treatment performance and the associated biogas capture from the digestate of a manure mixture composed of 90% laying hen and 10% cattle manures in fixed-film reactors. The results indicated that it was possible to reduce total chemical oxygen demand content of the digestate by 57–62% in 1.3–1.4 days of hydraulic retention time. The corresponding biogas yields obtained were in the range of 0.395–0.430 Lbiogas/g VSadded which were found to be comparable to many raw feedstocks. Moreover, significant total phosphorus reduction (36–47%) and greenhouse gas capture (over 14.5–18.1 tCO2e/d per m3 digestate) were also recorded in the anaerobic fixed-film reactors.

Aerosol black carbon (BC) is the second strongest contributor to global warming, after CO₂, and it is linked to many adverse health effects. A sampling campaign of 15 months was carried out in León (Spain) in order to evaluate the scavenging of BC with an ensemble aethalometer-disdrometer. The aethalometer provides the concentration of equivalent black carbon (eBC), and the disdrometer, the raindrop size distribution. A total of seventy-five rain events were studied and in 73% of them there was an effective (eBCᵢₙᵢₜᵢₐₗ > eBCfᵢₙₐₗ) scavenging, with a mean decrease of 48 ± 37% in long rain events (>8 h) and 39 ± 38% in short rain events. The scavenging of BC is strongly related to its source. Thus, the scavenging coefficient (SC) mean value of the BC from fossil fuel (eBCff) for short and long rain events was 5.1 10⁻⁵ and 1.3 10⁻⁵ s⁻¹, respectively. For the BC from biomass burning (eBCbb), the SC values were 1.6 10⁻⁴ and 2.8 10⁻⁵ s⁻¹ in short and long events, respectively. There was a significant positive correlation between the SC and the number of drops with diameters between 0.375 and 2.5 mm. Rain scavenging of eBC was analyzed depending on the air mass origin obtaining an effective scavenging for air masses from Atlantic, Arctic and Africa. A linear model (R² = 0.72) was built to estimate the ΔeBC values with variables from an aethalometer, a disdrometer and a weather station: eBC concentration before rain, swept volume and precipitation accumulated. A Kolmogorov-Smirnov statistical test confirmed the goodness of fit of the model to the measured data.

Over 80,000 endocrine-disrupting chemicals (EDCs) are considered emerging contaminants (ECs), which are of great concern due to their effects on human health. Quantitative structure-activity relationship (QSAR) models are a promising alternative to in vitro methods to predict the toxicological effects of chemicals on human health. In this study, we assessed a deep-learning based QSAR (DL-QSAR) model to predict the qualitative and the quantitative effects of EDCs on the human endocrine system, and especially sex-hormone binding globulin (SHBG) and estrogen receptor (ER). Statistical analyses of the qualitative responses indicated that the accuracies of all three DL-QSAR methods were above 90%, and greater than the other statistical and machine learning models, indicating excellent classification performance. The quantitative analyses, as assessed using deep-neural-network-based QSAR (DNN-QSAR), resulted in a coefficient of determination (R²) of 0.80 and predictive square correlation coefficient (Q²) of 0.86, which implied satisfactory goodness of fit and predictive ability. Thus, DNN was able to transform sparse molecular descriptors into higher dimensional spaces, and was superior for assessment qualitative responses. Moreover, DNN-QSAR demonstrated excellent performance in the discipline of computational chemistry by handling multicollinearity and overfitting problems.

The ecological impacts of insecticides in aquatic areas around agricultural lands have long been ignored in the regulation scheme of pesticides in Japan. Upon the scheme, the predicted concentration of an insecticide in the main stream of a river is the only parameter considered, suggesting that the ecological impacts of insecticides on local biodiversity around agricultural fields are underestimated. To fill this knowledge gap, we measured insecticide concentrations in surface water and sediment in aquatic areas around paddy fields at 35 locations across Japan. Among the 18 insecticides considered, 15 were detected somewhere in Japan and their concentrations were generally higher in the southwestern region in Japan (e.g. Hiroshima, Saga, or Kagoshima prefectures). Most insecticides were accumulated at higher concentrations in sediment than in surface water, consistent with previous studies. We also detected insecticides applied to nursery boxes at high concentrations in surrounding aquatic areas, although such application is generally considered to have low environmental risks. In addition, derivatives of fipronil, which have similar toxicity as that of fipronil, were often detected in sediment at higher concentrations than fipronil itself. Concentrations of dinotefuran in water at two sampling points were higher than the 5% hazardous concentration (HC5), indicating a possibility of a risk of acute toxicity to aquatic organisms. Our findings indicate that ecological risk assessments of insecticides and their derivatives should be expanded to include concentrations in sediment and water around paddy fields as well.

Cigarette smoke is an important indoor air pollutant which has deleterious effects on human health. Continued daily exposure to cigarette smoke has been attributed to the risk factor of ocular surface diseases. However, the mechanisms underlying the ocular surface damage are not fully elucidated. In this study, exposure to cigarette smoke extract (CSE) induced a dose- and time-dependent cytotoxicity in human corneal epithelial (HCE) cells, supported by the observation of reduced cell viability, increased apoptotic cells, elevated intracellular oxidative stress and loss of mitochondrial transmembrane potential. In addition, CSE exposure led to the impairment of proteostasis and autophagy, which resulted in the accumulation of ubiquitinated proteins as aggregates in peri-nuclear spaces. Furthermore, the autophagy inducer, cysteamine was shown to attenuate the CSE induced cell damage, oxidative stress and mitochondrial dysfunction in HCE cells. Moreover, cysteamine inhibited the formation of ubiquitin-positive aggregates around the peri-nuclear region, through regulating the autophagic activity of HCE cells. Similar to in vitro experiments, cigarette smoke induced proteostasis and autophagy impairment in corneal epithelial cells could be rescued by cysteamine in a cigarette smoke-exposed murine model. Therefore, this study may provide first evidence that dysfunction of autophagy contributes to the pathogenesis of ocular surface diseases associated with cigarette smoke exposure. Besides, it also suggests the potential therapeutic value of cysteamine in the prevention and treatment of cigarette smoke induced ocular surface injury.CSE induces cytotoxicity and accumulation of ubiquitinated proteins in HCE cells due to impairment of proteostasis and autophagy, which can be rescued by cysteamine.

There is still no consensus over the specific effects of metal-based nanoparticles when compared with the conventional metal salts. Here, the accumulation and toxicity of ZnO-NPs and ZnCl2 in Enchytraeus crypticus over time (1–14 d) were investigated using a sand-solution exposure medium and applying a toxicokinetics and toxicodynamics approach. For both Zn forms, body Zn concentration in the organisms was dependent on both the exposure concentration and exposure time, with equilibrium being reached after 7–14 days of exposure. Generally, the uptake and elimination rate constants (Ku and Ke1) were smaller for ZnO-NPs (5.74–12.6 mg kg−1d−1 and 0.17–0.39 d−1) than for ZnCl2 (8.32–40.1 mg kg−1d−1 and 0.31–2.05 d−1), suggesting that ionic Zn was more accessible for E. crypticus than nanoparticulate Zn. Based on external exposure concentrations, LC50s for ZnO-NPs and ZnCl2 decreased with time from 123 to 67 Zn mg L−1 and from 86 to 62 Zn mg L−1, reaching an almost similar ultimate value within 14 d. LC50s based on body Zn concentrations were almost constant over time (except for 1 d) for both ZnO-NPs and ZnCl2, with overall LC50body of Zn being 1720 and 1306 mg kg−1 dry body weight, respectively. Body Zn concentration, which considers all available pathways, was a good predictor of dynamic toxicity of ZnCl2, but not for ZnO-NPs. This may be attributed to the specific internal distribution and detoxification mechanisms of ZnO-NPs. The particles from ZnO-NPs dominated the accumulation (>75%) and toxicity (∼100%). Our results suggest that dynamic aspects should be taken into account when assessing and comparing NPs and metals uptake and consequent patterns of toxicity.

Thousands of chemicals exist in hydraulic-fracturing (HF) fluids and wastewater from unconventional oil gas development. The carcinogenicity of these chemicals in HF fluids and wastewater has never been systematically evaluated.In this study, we assessed the carcinogenicity of 1,173 HF-related chemicals in the HF chemical data from the US Environmental Protection Agency (EPA).We linked the HF chemical data with the agent classification data from the International Agency for Research on Cancer (IARC) at the World Health Organization (WHO) (N = 998 chemicals) to evaluate human carcinogenic risk of the chemicals and with the Carcinogenic Potency Database (CPDB) from Toxnet (N = 1,534 chemicals) to evaluate potential carcinogenicity of the chemicals.The Chemical Abstract Service Registry Numbers (CASRNs) for chemicals were used for data linkage. Among 1,173 chemicals, 1,039 were identified only in HF fluids, 97 only in wastewater, and 37 in both. Compared with IARC, we found information of 104 chemicals, and 48 of them may have potentially carcinogenic risk to human, among which 14 are definitely carcinogenic, 7 probably carcinogenic, and 27 possibly carcinogenic. Using the CPDB data, it suggests that 66 chemicals are potentially carcinogenic based on rats and mouse models.Conclusions Our evaluation suggests that exposure to some chemicals in HF fluids and wastewater may increase cancer risk, and the identified chemicals could be selected as the priority list for drinking water exposure assessment or cancer-related health studies.

The government of China has announced an ambitious plan to expand the mandatory use of ethanol blended gasoline fuels by 2020. Given the dissimilarity in fuel properties between China and other countries with ethanol blending practices, it is necessary to assess the energy and environmental impacts of ethanol blending. In this study, we prepared two types of ethanol blended fuels (E10, with ethanol contents of approximately 10%) with lower contents of aromatics (ELA) and olefins (ELO), respectively, compared with the market China 5 gasoline. Nine in-use gasoline vehicles varying by manufacturer, engine technology, model year, and emission standard level were analyzed using a chassis dynamometer, which followed the Worldwide Harmonized Light Vehicles Test Cycle (WLTC). Two major positive effects from using E10 fuels could be observed in this study. First, tested turbocharged gasoline direct injection (GDI) vehicles could gain reductions in CO₂ emission, fuel consumption and energy consumption by switching to the higher-octane-number ELO. This finding, along with the engine development trends in the automotive industry (e.g., downsizing and higher compression ratio), may have a synergistic effect to deliver greater energy efficiency in the future. Second, the two ethanol blended fuels could be more effective in reducing the particle mass (PM) and particle number (PN) emissions than the levels of using China 5 gasoline. Notably, the benefit of using ELO was more significant, with average emission reductions of 35% for the PM and of 44% for the PN. However, ELA and ELO possibly increased emissions of gaseous pollutants for certain vehicles in the study, but the intra-vehicle differences between the various fuel groups were not statistically significant (not significant, p > 0.05, t-test). We suggest that more measurements under various environmental conditions and comprehensive air quality simulations should be conducted to better understand the environmental impacts of ethanol blending in China.

Fifty-six groundwater samples were taken from the island of Favignana to evaluate the interaction between the groundwater and seawater, as well as the deterioration factors for the aquifers, using the combined hydrogeochemical and multivariate statistical approaches. Results show that the order of the groundwater chemistry in the study area was Na+> Ca2+>Mg2+>K+ and Cl->HCO3−>SO42->NO3−. The groundwater samples were in the moderate saline zone to highly saline zone and indicate that the groundwater of the island of Favignana was recharged with seawater. The spatial distribution maps of Cl− and NO3− show that most of the groundwater samples had high concentrations of Cl− and NO3− in the study area. The ionic ratio diagrams, such as Na+/Cl− versus Cl−, Mg2+/Ca2+ versus Cl− and Ca2+/HCO3− versus Cl−, and other hydrogeochemical plots reveal that the groundwater chemistry of the study was primarily controlled by the seawater intrusion and reverse ion exchange process, with a small contribution from carbonate dissolution. Additionally, the NO3−/Cl− versus Cl− diagram and principal component analysis (PCA) show that the contamination of nitrate in the study area was due to human activities (i.e. agriculture and domestic sewage disposal). The outcome of the present research could be helpful for groundwater resource management in coastal environments.

Polychlorinated biphenyls (PCBs) have been detected as prevalent environmental contaminants in water, food and biota. Previous studies in vitro have shown that a variety of sorbent materials, including carbon, can sorb PCBs; however, PCB sorbents that can be added to food or drinking water to decrease toxin bioavailability in humans and animals have not been reported. To address this problem, we have developed a broad-acting and highly effective sorbent for PCBs using montmorillonite clays reported to be safe for consumption in animals and humans. In this study, calcium montmorillonite clays were acid processed (APMs) and the interactions of six PCB congeners (PCB 77, 126, 153, 157, 154 and 155) on the surfaces of APMs were characterized. Computational models and isothermal analyses were used to derive surface capacities and affinities, delineate mechanisms and predict the thermodynamics of sorption. To confirm the safety and predict the efficacy of APMs against individual PCBs and common mixtures (Aroclors 1254 and 1260), we have also used a living organism (Hydra vulgaris) that is sensitive to toxins. APMs significantly protected hydra against the toxicity of PCBs and Aroclors. This finding was supported by studies showing tight binding; high capacity, affinity, and enthalpy; and a low therapeutic dose.