Chemical mixtures represent environmentally-realistic exposures of contaminants to aquatic biota. However, there remains a limited understanding of how toxicant mixtures may impact biological function, relative to their individual components. In the current study, oxidative stress responses of the freshwater galaxiid fish inanga (Galaxias maculatus) were examined following exposure to the pro-oxidant trace metal cadmium (2 or 9 μg L⁻¹), and the anti-oxidant pharmaceutical drug diclofenac (770 μg L⁻¹), individually or in simple binary mixtures. Cadmium exposure in the absence of diclofenac significantly decreased renal catalase activity, increased hepatic catalase activity, decreased renal superoxide dismutase (SOD) and decreased glutathione-S-transferase activity, effects that are suggestive of anti-oxidant defense inhibition and/or generation of increased reactive oxygen species. Diclofenac exposure in the absence of cadmium resulted in a decreased renal lipid peroxidation, consistent with its known anti-oxidant properties. The presence of waterborne diclofenac altered the effects of cadmium on catalase activity in the liver, SOD activity in the gill, and lipid peroxidation in the liver. Co-exposure with cadmium modulated diclofenac effects on lipid peroxidation in the kidney. These data indicate the capacity of each of these toxicants to offset biological effects of the other when both co-occur in urban waters at specific concentrations. This study also demonstrates the complexity of outcomes in contaminant mixtures, even when these stressors are presented as simple binary combinations.

There is growing recognition of a potential role for environmental and climatic factors in influencing cardiovascular risk. It has been speculated that temperature variability (TV) is a risk factor for cardiac arrhythmia but evidence is limited.To quantify the geographic and demographic variations in the association between TV and hospitalization for cardiac arrhythmia in Brazil during 2000–2015.Data on hospitalization for arrhythmia and weather conditions were collected from 1,814 cities. TV was calculated as the standard deviation of daily maximum and minimum temperatures during exposure days. A time-stratified case-crossover approach was applied to examine the city-specific association between TV and hospitalization for arrhythmia. City-specific estimates were pooled at the national and regional levels using a random-effect meta-analysis. Stratified analyses were conducted by sex, three age-groups (0–64, 65–74 and ≥75 years), and three arrhythmia subtypes (paroxysmal tachycardia, atrial fibrillation and flutter, and other arrhythmias).There were 447,667 arrhythmia-related hospitalizations during 2000–2015. The odds ratio of hospitalization per 1 °C increase in TV peaked on 0–1 days’ exposure [1.012 (95% confidence interval: 1.010–1.015)]. There were no substantial differences in effect estimates of TV₀₋₁ by region, age or sex, except for the non-significant association observed in the north. However, women were more affected by prolonged TV exposure than men. For the three arrhythmias subtypes, only paroxysmal tachycardia and other arrhythmias were sensitive to TV. Assuming a causal relationship, 35,813 (95%CI: 18,302−51,665) cases were attributable to TV₀₋₁ in Brazil during 2000–2015, accounting for 8.0% (95%CI: 4.1–11.5%) of hospitalizations for cardiac arrhythmia.At a population-level exposure to TV was associated with increased risk of arrhythmia-related hospitalization in Brazil, with the relationship equally distributed across most residents but varied by arrhythmia subtypes. Our findings add to the accumulating evidence-base that climatic factors can influence cardiovascular outcomes in populations.

Atmospheric stability significantly influences the accumulation and dispersion of air pollutants in the near-surface atmosphere, yet few stability metrics have been applied as predictors in statistical PM₂.₅ concentration mapping practices. In this study, eleven stability metrics were derived from radiosonde soundings collected in eastern China for the time period of 2015–2018 and then applied as independent predictors to explore their potential in favoring the prediction of PM₂.₅. The statistical results show that the in situ PM₂.₅ concentration measurements correlated well with these stability metrics, especially at monthly and seasonal timescales. In contrast, correlations at the daily timescale differed markedly between stability metric and also varied with seasons. Nevertheless, the modeling results indicate that incorporating these stability metrics into the PM₂.₅ modeling framework rendered small contribution to PM₂.₅ prediction accuracy, yielding an increase of R² by < 5% and a reduction of RMSE by < 1 μg/m³ on average. Compared with other stability indices, the inversion depth and intensity appeared to have relative larger benefiting potential. In general, our findings indicate that including these stability metrics would not result in significant contribution to the PM₂.₅ prediction accuracy in eastern China since their effects could be partially overwhelmed or offset by other predictors such as AOD and boundary layer height.

Recent studies have demonstrated the occurrence of microplastic fibers (MFs) in soil environments. To determine whether MFs are harmful for soil biota, we evaluated toxic effects on terrestrial snails (Achatina fulica) after 28 d exposure to polyethylene terephthalate MFs at concentrations of 0.01–0.71 g kg−1 (dry soil weight). Digestion kinetics experiments on 24 snails showed that MFs can be ingested and excreted within 48 h. We found the appearance of cracks and deterioration on the surface of MFs after depuration by the digestive system. Prolonged exposure to 40 snails showed that 0.14–0.71 g kg−1 MFs caused an average reduction of 24.7–34.9% food intake and 46.6–69.7% excretion. 0.71 g kg−1 MFs induced significant villi damage in the gastrointestinal walls of 40% snails, but did not influence the histology of the liver and kidney. Moreover, 0.71 g kg−1 MFs exposure reduced glutathione peroxidase (59.3 ± 13.8%) and total antioxidant capacity (36.7 ± 8.5%), but elevated malondialdehyde level (58.0 ± 6.4%) in the liver, which indicates oxidative stress is involved in the toxic mechanism. Our results suggest that MFs have adverse impacts on the fitness of soil organisms, and highlight the ecological risks of microplastic pollution in terrestrial ecosystems.

We have previously reported on the ubiquitous presence of perchlorate in the deposited and airborne fine dusts of Malta and shown that the source of the chemical in the dusts of this small central Mediterranean island is fireworks. There are no local geologic or anthropogenic sources of perchlorate other than firework manufacture and display. The hypothesis was tested that ground-deposited perchlorate will be mobilized in runoff and would partly migrate to the water table and eventually also affect tap water, one third of which being derived from groundwater. Forty four percent of 36 groundwater samples contained perchlorate above detection limit with mean and median values of 1.09 and 1.1 μg L−1. Sixty-two percent of 16 runoff samples collected during storms contained perchlorate above detection limit with mean and maximum concentrations, respectively, of 50.8 and 129 μg L−1, values which are far too high to be explained by atmospheric inputs given that rainwater perchlorate levels are typically <3 μg L−1. Between 42 and 89% of the tap waters analyzed in three sampling campaigns contained perchlorate above detection limit and had mean concentrations ranging from 0.4 to 1.6 μg L−1 suggesting contamination levels similar to those reported from China but lower than levels reported from the USA. The phenomenon of contamination of the water resources of Malta by perchlorate is probably unique in that it results not from geologic or industrial inputs but from an intense and prolonged pyrotechnic activity that is deeply rooted in the popular culture of the islanders.

A novel carbonaceous material (NCM), prepared by the pyrolyzation of the oily sludge of tank bottom, was proposed to remove Cr(VI) from a synthetic solution for the first time. The effects of initial Cr(VI) concentration, NCM dosage and initial solution pH on Cr(VI) removal and the adsorption kinetics, the adsorption isothem were investigated. The removal mechanism was studied by comparing the surface properties of NCM before and after the Cr(VI) removal. The results showed that NCM can effectively remove Cr(Ⅵ) from the synthetic solution with the increase of solution pH at equilibrium. At the initial Cr(Ⅵ) concentrations of 40, 100, 150 and 250 mg/L and NCM dosages of 1, 3, 6 and 8 g/L with initial solution pH of 2, the removal efficiency of Cr(VI) was 95.5, 96.8, 95.2 and 81.2%, and the solution pH at equilibrium reached 2.3, 3.5, 5.8 and 7.5, respectively. NCM was suitable for Cr(Ⅵ) removal while the initial Cr(VI) concentration was less than 100 mg/L and initial solution pH was lower than 2.5. Most of Cr(VI) was removed by the reduction of Fe2+ and S2− in NCM to Cr(III) and with the generation of stable FeCr2O4. Some Cr(VI) may be removed by reacting with Fe2+ and Ca2+ to produce CaCrO4 and FeCrO4 on the NCM surface. The dissolution of CaAl2Si2O8 and CaS in the solution increased the solution pH at equilibrium. NCM has been proved to be a material with dual functions both chemical reduction and adsorption.

Ambient particulate matter (PM) exposure is associated with pulmonary and cardiovascular diseases; however, there is scant research linking data on animal and human cells. The objective of this study was to investigate these associations. Vascular remodeling plays a crucial role in both pulmonary and cardiovascular diseases. Therefore, we conducted a transcriptomic analysis using vascular smooth muscle cells (VSMCs) to identify potential regulators or markers of PM exposure. We demonstrated that fine and coarse PM increased VSMC proliferation in mice. We conducted a genome-wide cDNA microarray analysis, followed by a pathway analysis of VSMCs treated with coarse PM for durations of 24, 48, and 72 h. Sixteen genes were discovered to be time-dependently upregulated and involved in VSMC proliferation. Osteopontin (OPN) is indicated as one of the regulators of these upregulated genes. Both fine and coarse PM from industrial and urban areas significantly increased OPN expression in VSMCs and macrophages. Moreover, oropharyngeal instillation of fine and coarse PM for 8 weeks increased the VSMCs in the pulmonary arteries of mice. OPN level was consistently increased in the lung tissues, bronchoalveolar lavage fluid, and serum of mice. Moreover, we analyzed the plasma OPN levels of 72 healthy participants recruited from the studied metropolitan area. Each participant wore a personal PM2.5 sampler to assess their PM2.5 exposure over a 24 h period. Our results indicate that personal exposure to fine PM is positively correlated with plasma OPN level in young adults. The data obtained in this study suggest that exposure to fine and coarse PM may cause pulmonary vascular lesions in humans and that OPN level may be a biomarker of PM exposure in humans.

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.

Pesticide residues most likely coexist with antibiotics due to the application of animal-based fertilizers in agriculture. In this study, the degradation and enantioselectivity of beta-cypermethrin in soil and chicken manure-amended soil were investigated. The effects of oxytetracycline on the soil microbial community were also estimated. The results showed that the half-life of beta-cypermethrin in the soil was 16.9 days and that the (+)-enantiomer was degraded preferentially in both pairs of enantiomers. The metabolites cis/trans-DCCA(3-(2′,2′-dichlorovinyl)-2,2-dimethylcyclopropane carboxylic acid) and 3-PBA (3-Phenoxybenzoic acid) were detected. The trans-DCCA concentrations ranged from 0.094 to 0.120 mg/kg, which were higher than the concentrations of cis-DCCA (0.091–0.120 mg/kg) and 3-PBA (0.022–0.061 mg/kg). In the presence of oxytetracycline, beta-cypermethrin degradation was inhibited slightly, while the enantioselectivity was not affected. Oxytetracycline increased the enrichment and persistence of the metabolites. Addition of chicken manure decreased the cis-DCCA residue levels in the soil and alleviated the effect of oxytetracycline; however, chicken manure increased the accumulation and persistence of 3-PBA. In addition, oxytetracycline perturbed the structure of the soil microbial community. The abundance of Proteobacteria increased, while the abundances of Firmicutes and Actinobacteria decreased. These changes might affect the biodegradation of beta-cypermethrin and its metabolites. Combined pollution with antibiotics should be considered for its potential impact on pesticide residues.

The major objective of the current study is to estimate the groundwater quality and identify the likely sources of contamination in Chandigarh, India. Total 80 groundwater samples were collected from different locations and at various depths in the study area. Further, physcio-chemical analysis was done to estimate pH, electrical conductivity (EC), total dissolved solids, total hardness (TH), total alkalinity (TA), Na+, K+, Cl−, SO42−, PO43− and NO3−. The groundwater samples collected from shallow water sources were observed to contain higher amount of dissolved salts. EC, TA, Cl−, TH, Na+, and K+ were found relatively higher in the shallow aquifer (<150 ft). Based on the location of pollution sources at the surface and consecutive geo-statistical distribution of physicochemical characteristics, this study suggests that non-scientific disposal of municipal solid waste,dumping of industrial waste and agricultural activities, in the nearby areas, could lead to deterioration of groundwater of shallow aquifer. These observations were also confirmed using various water quality indices and outcomes of multivariate modeling, including principal component analysis. Health risk assessment for nitrates indicated that 29 groundwater samples pose non-carcinogenic health risk for children due to dermal and oral exposure. Hence, there is a need to establish a system for regularly assessing the groundwater quality so as to minimize public health risks.