Melatonin is a hormone which is generated from pineal gland, and it is responsible for the regulation of wake-sleep cycle. Melatonin is a well-known antioxidant and free radical scavenger to protect against multiple type of tissue damage. While ochratoxin A (OTA) is a mycotoxin found widely in contaminated food and foodstuffs, which causes nephrotoxicity, hepatotoxicity, immunotoxicity, and reproductive damage in humans and animals. In present study we report the toxicity of OTA on porcine oocyte quality and the protective effects of melatonin on OTA-exposed oocytes. Using transcriptome analysis our results show that OTA exposure alters the expression of multiple genes in oocytes, indicating its effect on oocyte maturation. The cellular changes following OTA treatment are examined, and the results show that OTA adversely affects oocyte polar body extrusion, which is confirmed by the delay of Cdc2-mediated cell cycle progression. OTA exposure also disrupts meiotic spindle formation, which is confirmed by altered phosphorylated MAPK expression. RNA-seq screening and further fluorescence staining results show that OTA induces aberrant mitochondria distribution and oxidative phosphorylation defects, which then causes oxidative stress, followed by early apoptosis and autophagy. Treatment with melatonin significantly ameliorates oxidative stress and apoptosis, which further protects cell cycle and spindle formation in OTA-exposed oocytes. Collectively, these results show the protective effects of melatonin against defects induced by OTA during porcine meiotic oocyte maturation.

Destructive development of suburban areas in some metropolises has exposed suburban soils to high risk of potentially toxic trace elements (PTEs) enrichment, which also threatens human and ecosystem health. This study investigated the pollution status, sources and spatial patterns of four PTEs (Pb, Cd, Cr and As) in 1805 soil samples collected from the suburbs of Shanghai in 2015. Nineteen potential sources, including: 6 soil property factors, 10 proximity factors and 3 topography factors, were selected to help explain the PTEs aggregation using logistic regression models from global and local perspectives. The statistical results of PTEs concentration revealed that Cd showed the highest pollution risk in local soils, which was followed by As. Soil property was the primary factor affecting the PTEs (except Cr) enrichment, both identified by global models and local models. The local model particularly emphasized the significant correlation between soil property and PTEs in most parts of the outer suburbs and southeastern inner suburbs. Some proximity factors such as distance to district center and water were negatively correlated with Cd pollution and some topography factors such as elevation and slope were closely related to As pollution. It is worth noting that in the coastal areas, especially Chongming Island, there were obvious PTEs depositions in the soil near the estuary. This study helps to identify the sources of anthropogenic contamination and geogenic enrichment of the four PTEs and their spatial patterns, playing an essential role in formulating regional environmental policies for coastal cities.

Effective and economically viable method to remove elevated metal(loid)s from farm and industrial lands remains a major challenge. In this study, magnetic biochar-based adsorbents with Fe₃O₄ particles embedded in a porous biochar matrix was synthesized via iron (Fe) treated biochar or thermal pyrolysis of Fe treated cedar sawdust. Application and separation of the adsorbent to a multi-contaminated soil slurry simultaneously removed 20–30% of arsenic, cadmium and lead within 24 h. Fast removal of multi-metal(loid)s result from the decrease in all operationally defined fractions of metal(loid)s, not limited to the exchangeable fraction. The direct removal of arsenic-enriched soil particles was observed via micro X-ray fluorescence maps. Furthermore, through comparison of biochars with different production methods, it has been found that magnetization after pyrolysis treatment leads to stronger metals/metalloids adsorption with a higher qₑ (bound sorbate) than other treatments but pyrolysis after magnetization stabilized Fe oxides on the biochar surface, indicating a higher biochar recovery rate (∼65%), and thus a higher metal(loid)s removal efficiency. The stability of Fe oxides on the surface of biochar is the determining factor for the removal efficiency of metal(loid)s from soil.

Exposure to chemicals produced by petrochemical industrial complexes (PICs), such as benzene, ionizing radiation, and particulate matters, may contribute to the development of leukemia. However, epidemiological studies showed controversial results. This systematic review and meta-analysis aimed to summarize the association between residential exposure to PICs and the risk of leukemia incidence, focusing on exposure-response effects. We searched PubMed, Embase, Web of Science, and Cochrane Library databases for studies published before September 1st, 2019. Observational studies investigating residential exposure to PICs and the risk of leukemia were included. The outcome of interest was the incidence of leukemia comparing to reference groups. Relative risk (RR) was used as the summary effect measure, synthesized by characteristics of populations, distance to PICs, and calendar time in meta-regression. We identified 7 observational studies, including 2322 leukemia cases and substantial reference groups, in this meta-analysis. Residential exposure to PICs within a maximal 8-km distance had a 36% increased risk of leukemia (pooled RR = 1.36, 95% CI = 1.14–1.62) compared to controls, regardless of sex and age. In terms of leukemia subtypes, residential exposure to PICs was associated with the risks of acute myeloid leukemia (AML, pooled RR = 1.61, 95% CI = 1.12–2.31) and chronic lymphocytic leukemia (CLL, pooled RR = 1.85, 95% CI = 1.11–6.42). In meta-regression, the positive association occurred after 10 years of follow-up with a pooled RRs of 1.21 (95% CI = 1.02–1.44) and then slightly increased to 1.77 (95% CI = 1.35–2.33) at 30 years after follow-up. No effect modification was found by sex, age, and geographic locations.

Benzene kresoxim-methyl (BKM) is an important methoxyacrylate-based strobilurin fungicide widely used against various phytopathogenic fungi in crops. Uptake, translocation and accumulation of BKM in vegetables remain unknown. This study was designed to investigate uptake, translocation, and accumulation of ¹⁴C-BKM and/or its potential metabolites in Chinese flowering cabbage and water spinach. ¹⁴C-BKM can be gradually taken up to reach a maximum of 44.4% of the applied amount by Chinese flowering cabbage and 34.6% by water spinach at 32 d after application. The ¹⁴CO₂ fractions released from the hydroponic plant system reached 37.8% for cabbage and 45.8% for water spinach, respectively. Concentrations of ¹⁴C in leaves, stems and roots all gradually increased as vegetables growing, with relative 44.9% (cabbage) and 26.8% (water spinach) of translocated from roots to edible leaves. In addition, ¹⁴C in leaves was mainly accumulated in the bottom leaves, which was visualized by quantitative radioautographic imaging. The bioconcentration factor of ¹⁴C ranged from 7.1 to 38.2 mL g⁻¹ for the cabbage and from 8.6 to 24.6 mL g⁻¹ for the water spinach. The translocation factor of BKM ranged from 0.10 to 2.04 for the cabbage and 0.10–0.46 for the water spinach throughout the whole cultivation period, indicating that the cabbage is easier to translocate BKM from roots to leaves and stems than water spinach. In addition, the daily human exposure values of BKM in both vegetables were much lower than the limited dose of 0.15 mg day⁻¹. The results help assess potential accumulation of BMK in vegetables and potential risk.

The existence of micropollutants (MPs) including pathogens in waters poses great risks to ecological safety and human health. Sulfate radical (SO4•−)‒based advanced oxidation processes (AOPs) have attracted considerable attention in water treatment for both disinfection and removal of emerging MPs. Here, we investigated the SO4•−‒mediated kinetic and mechanistic aspects of simultaneous inactivation of Enterococcus faecalis (E. faecalis) and degradation of carbamazepine (CBZ), a typical MP with high occurrence in wastewater. In the absence of CBZ, (73.8 ± 2.3) % E. faecalis were inactivated after 12 min of treatment, while in the presence of CBZ, (68 ± 1.6) % of E. faecalis were inactivated, exhibiting similar inactivation efficiency with or without MP. The second‒order rate constant (k) of E. faecalis reacting with SO4•− was determined to be (5.42 ± 0.64) × 10⁹ M⁻¹ s⁻¹. In addition, two distinct types of disinfection models, one based on the quenching ratio (Q model) and the other on steady‒state concentration of SO4•− (R model), were developed to predict the inactivation kinetics of E. faecalis. Both models exhibited good performance for describing the disinfection of E. faecalis with RMSE of 0.065 and 0.048, respectively. Our kinetic experimental and modelling results on bacterial disinfection and degradation of CBZ were projected to offer valuable insight into future developments for typical wastewater scenarios where microorganisms and MPs coexist.

The use of the phenicol antibiotic florfenicol in livestock can select for the optrA gene, which also confers resistance to the critically important oxazolidinone antibiotic linezolid. However, the occurrence and dissemination of florfenicol and linezolid cross-resistance genes in anaerobic treatment systems for livestock waste are unknown. Herein, the phenotypes and genotypes (optrA, fexA, fexB, and cfr) of florfenicol and linezolid cross-resistance were investigated in 339 enterococci strains isolated from lab- and full-scale mesophilic anaerobic digestion systems treating swine waste. It was found that optrA, fexA, and fexB were frequently detected in isolated enterococci in both systems by PCR screening, whereas cfr was not detected. The most abundant gene was optrA, which was detected in 73.5% (n = 50) and 38.9% (n = 23) of enterococci isolates in the full-scale influent and effluent, respectively. Most strains carried more than two resistance genes, and the average percentage of co-occurrence of optrA/fexA was 16.6%. Based on minimum inhibitory concentrations of the enterococci strain phenotypes, 85.7%, 77.5%, and 77.5% of strains in influent were resistant to chloramphenicol, florfenicol, and linezolid, respectively, while 56.3%, 65.2%, and 13% in the effluent isolates were found, respectively, which was consistent with the genotype results. The phenotypes and genotypes of florfenicol and linezolid resistance were relative stable in the enterococci isolated from the influent and effluent in lab-scale anaerobic digestion system. The findings signify the enterococci isolates harboring the optrA gene remained in effluents of both full- and lab-scale swine waste anaerobic digestion system; hence, effective management strategies should be implemented to prevent the discharge of antibiotic resistance from the livestock waste treatment systems.

Organic contaminants are frequently detected in fresh crops and can cause severe damage to human health. To help control this risk, we introduce a diffusion-based model framework for estimating the removal efficiency for organic contaminants in fresh crops using a simple water soaking method. The framework was developed based on the diffusion coefficient of the organic contaminants, and its application indicates that the removal factor (RF) for organic contaminants has an inverse-exponential relationship with log Kₒw (Kₒw is the octanol-water partition coefficient), which thermodynamically restricts the removal efficiency for chemicals with large steady state log Kₒw. Additionally, the diffusion coefficient of the chemical in water affects the kinetic removal efficiency. For example, the RF simulated for glyphosate, which has a relatively high diffusion coefficient, is 0.592 (61.9% of the steady state RF) after soaking for 1 h, while the RF of lindane is 0.224, which is only 25.0% of the steady state RF. However, if a refreshing method is applied, the RF of lindane can be significantly improved even if more potatoes are used in the water bowl, and this has been demonstrated theoretically with the refreshing function. Model validation indicates that the macro properties of crops, e.g., the active area through which crop tissues interact with water, have a larger impact on the results than do the micro-properties of crops and the physiochemical properties of the organic contaminants. Comparison of our results with those of other studies shows that the simulated ranges for some pesticides compare well with experimental data collected using other household washing methods. However, for other pesticides such as HCB and DDT, the simulated results and current studies are inconsistent due to physical interactions between the water and crop tissues not considered in our model.

Vernal pools are ephemeral wetlands that provide critical habitat to many listed species. Pesticide fate in vernal pools is poorly understood because of uncertainties in the amount of pesticide entering these ecosystems and their bioavailability throughout cycles of wet and dry periods. The Pesticide Water Calculator (PWC), a model used for the regulation of pesticides in the US, was used to predict surface water and sediment pore water pesticide concentrations in vernal pool habitats. The PWC model (version 1.59) was implemented with deterministic and probabilistic approaches and parameterized for three agricultural vernal pool watersheds located in the San Joaquin River basin in the Central Valley of California. Exposure concentrations for chlorpyrifos, diazinon and malathion were simulated. The deterministic approach used default values and professional judgment to calculate point values of estimated concentrations. In the probabilistic approach, Monte Carlo (MC) simulations were conducted across the full input parameter space with a sensitivity analysis that quantified the parameter contribution to model prediction uncertainty. Partial correlation coefficients were used as the primary sensitivity metric for analyzing model outputs. Conditioned daily sensitivity analysis indicates curve number (CN) and the universal soil loss equation (USLE) parameters as the most important environmental parameters. Therefore, exposure estimation can be improved efficiently by focusing parameterization efforts on these driving processes, and agricultural pesticide inputs in these critical habitats can be reduced by best management practices focused on runoff and sediment reductions.

Eleven years, January 2008 to June 2019, of hourly nitrogen dioxide (NO₂) levels recorded at El Arenosillo observatory (Southwestern Europe) were analyzed. Annual averages ranged between 4 μg m⁻³ and 6 μg m⁻³ with peaks exceeding 40 μg m⁻³. A slight monthly variation was observed with maximum and minimum values in the cold (∼6 μg m⁻³) and warm (∼4 μg m⁻³) seasons respectively. A diurnal pattern was found with a weak amplitude (∼3 μg m⁻³). The monthly trends were investigated using surface observations and OMI (Ozone Monitoring instrument) satellite measurements. An unexpected upward trend was obtained in the last five years. The periods with elevated NO₂ concentrations in the last years were analyzed, showing an increase in its frequency and concentrations, linked with the upward trend observed. The weather conditions in these NO₂ peaks were studied using local surface meteorology, mean sea level pressure and wind fields from the data reanalysis of ERA5. The transport of NO₂ was explored using TROPOMI (Tropospheric Monitoring Instrument) measurements. The events occurred under conditions governed by high-pressure systems, which induced weak synoptic airflows or the development of mesoscale processes. Four scenarios of NO₂ transport were identified, associated with weak synoptic flows from inland or Southern Portugal and with mesoscale processes. The gulf of Cadiz plays an important role as a reservoir where the NO₂ coming from the south of Portugal, the Western Mediterranean Basin and urban-industrial areas can be accumulated and later transported inland. A strong correlation was found between the increase of NO₂ observed in the last years and positive anomalies of the temperature and geopotential height at 850 and 500 hPa levels. These findings could indicate that the causes of the changes in the NO₂ would be attributed to alterations in the weather patterns associated with a warmer climate.