Perfluorooctanoic acid (PFOA) is widely distributed in various environmental media and is toxic to organisms. This study demonstrated that PFOA induces hepatotoxicity in the frog and evaluated the role of CYP3A and the Nrf2-ARE signaling pathway in regulating responses to PFOA-induced hepatotoxicity. Rana nigromaculata were exposed to 0, 0.01, 0.1, 0.5, or 1 mg/L PFOA solutions in a static-renewal system for 14 days. Liver tissue samples were collected 24 h after the last treatment. Hepatic histology was observed by HE staining and transmission electron microscopy. The oxidative stress levels in the liver were measured. The expression levels of CYP3A, Nrf2, NQO1, and HO-1 mRNA were measured by quantitative reverse transcription–polymerase chain reaction. PFOA-treated frog liver tissue exhibited diffuse cell borders, cytoplasmic vacuolization, broken nuclei, nuclear chromatin margination, and swollen mitochondria. In addition, the livers of PFOA-treated frogs showed a significantly elevated content of reactive oxygen species, malondialdehyde, glutathione and glutathione S-transferase activity compared to the livers of control frogs. However, the glutathione peroxidase activities concomitantly decreased in PFOA-treated frogs compared to those in the control group. Furthermore, compared with control frogs, the expression levels of CYP3A, Nrf2, and NQO1 mRNA significantly increased in PFOA-treated frogs. HO-1 mRNA expression remarkably increased only in groups treated with 0.5 or 1 mg/L PFOA. Our results indicate that PFOA induces hepatotoxicity in a dose-dependent manner. Furthermore, the results of the comparison analysis between different gender groups illustrated that PFOA is more toxic to female frogs than male frogs. Our results demonstrated that PFOA causes liver damage and that CYP3A enhances PFOA-induced female frogs hepatotoxicity are more virulent than male through biotransformation, and the activation of the Nrf2-ARE pathway is induced to protect against hepatotoxicity in Rana nigromaculata, all of which provide the scientific basis for the protection of amphibians against environmental contaminants.

Productive coastal and estuarine habitats can be degraded by contaminants including persistent organic pollutants (POPs) such as PCBs, dioxins, and organochlorine insecticides to the extent of official designation as contaminated sites. Top-predatory wildlife may continue to use such sites as the habitat often appears suitable, and thus bioaccumulate POPs and other contaminants with potential consequences on their health and fitness. Victoria and Esquimalt harbours are located on southern Vancouver Island, British Columbia (BC) and are federally designated contaminated sites due mainly to past heavy industrial activities, such as from shipyards and sawmills. We collected scat samples from river otters (Lontra canadensis) throughout an annual cycle, and combined chemical analysis with DNA genotyping to examine whether the harbour areas constituted a contaminant-induced ecological trap for otters. We confirmed spatial habitat use by radio telemetry of a subsample of otters. Fifteen percent of otter scat contained PCB concentrations exceeding levels considered to have adverse effects on the reproduction of mink (Neovison vison), and there were significant positive correlations between concentrations of PCBs and of thyroid (T3) and sex (progesterone) hormones in fecal samples. Radio telemetry data revealed that otters did not show directional movement away from the harbours, indicating their inability to recognize the contaminated site as a degraded habitat. However, analysis and modeling of the DNA genotyping data provided no evidence that the harbour otters formed a sink population and therefore were in an ecological trap. Despite the highly POP-contaminated habitat, river otters did not appear to be adversely impacted at the population level. Our study demonstrates the value of combining chemical and biological technologies with ecological theory to investigate practical conservation problems.

This study presents the air pollution findings of the submicron (PM1) and fine (PM2.5) particulate matter. The submicron particles are entirely absorbed by the human body and they cause the greatest health risk. For the PM2.5 concentration, there are yearly and/or daily limit values regulations by the European Union (EU) and World Health Organization (WHO). There are no such regulations for PM1 but for health risk reason the knowledge of its concentration is important. This paper presents the seasonal concentration contribution of PM1 and PM2.5, their chemical composition and assessed three basic sources. Daily samples of both fractions were collected from 2nd July 2016 to 27th February 2017 in Krakow, Poland. Apart from PM1 and PM2.5 the concentration of 16 elements, 8 ions and BC for each samples were measured. Based on these chemical species the positive matrix factorization (PMF) receptor modeling was used for the determination of three main sources contribution to the PM1 and PM2.5 concentrations. Daily average concentrations of PM2.5 were 12 μg/m3 in summer and 60 μg/m3 in winter. For PM1 it was 6.9 μg/m3 in summer and 17.3 μg/m3 in winter. These data show a significant difference in percentage contribution of PM1 in PM2.5 in summer (58%) and in winter (29%).For the combustion source, the concentrations calculated from PMF modeling in winter were 4.8 μg/m3 for PM1 and 31 μg/m3 for PM2.5. In summer, the concentrations were smaller than 1 μg/m3 for both fractions. Secondary aerosols' concentration for PM1 was 3.4 μg/m3 in summer and 11 μg/m3 in winter - for PM2.5 these were 7.1 μg/m3 and 17 μg/m3 respectively. The third source - soil, industry and traffic together, had small seasonal variation: for PM1 it was from 1.4 to 1.8 μg/m3 and for PM2.5 from 4.7 to 7.9 μg/m3.

The urbanization and industrialization of cities around the coastal region of the Bohai Sea have produced large amounts of sewage sludge from sewage treatment plants. Research on the biodegradation of nonylphenol (NP) and the influencing factors of such biodegradation during sewage sludge composting is important to control pollution caused by land application of sewage sludge. The present study investigated the effect of aeration on NP biodegradation and the microbe community during aerobic composting under two intermittent aeration treatments in a full-scale plant of sewage sludge, sawdust, and returned compost at a ratio of 6:3:1. The results showed that 65% of NP was biodegraded and that Bacillus was the dominant bacterial species in the mesophilic phase. The amount of NP biodegraded in the mesophilic phase was 68.3%, which accounted for 64.6% of the total amount of biodegraded NP. The amount of NP biodegraded under high-volume aeration was 19.6% higher than that under low-volume aeration. Bacillus was dominant for 60.9% of the composting period under high-volume aeration, compared to 22.7% dominance under low-volume aeration. In the thermophilic phase, high-volume aeration promoted the biodegradation of NP and Bacillus remained the dominant bacterial species. In the cooling and stable phases, the contents of NP underwent insignificant change while different dominant bacteria were observed in the two treatments. NP was mostly biodegraded by Bacillus, and the rate of biodegradation was significantly correlated with the abundance of Bacillus (r = 0.63, p < 0.05). Under aeration, Bacillus remained the dominant bacteria, especially in the thermal phase; this phenomenon possibly increased the biodegradation efficiency of NP. High-volume aeration accelerated the activity and prolonged the survival of Bacillus. The risk of organic pollution could be decreased prior to sewage sludge reuse in soil by adjusting the ventilation strategies of aerobic compost measurements.

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal).This article has been retracted at the request of the authors due to the results of a detailed investigation of the data quality conducted by the Central Analytical Laboratory (CAL) after relocation to the University of Wisconsin (UW) – Wisconsin State Laboratory of Hygiene. Using a subset of the 30 samples with the highest bromide ion (Br-) concentrations, the CAL at UW found 6 samples that could not be verified or were incorrect. Because the extent of the incorrect data is unknown, the NADP Executive Committee voted unanimously in May 2019 to discontinue public access to these data, and they decided to sequester all Br- data prior to June 2018. These issues were not obvious to the authors when the paper was written.The authors apologize for the inconvenience caused.

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal).This article has been retracted at the request of the Editors-in-Chief.The authors have plagiarized part of a paper that had appeared in Plant, Cell & Environment, 29 (2006) 1532–1544. https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-3040.2006.01531.x The images that were reused were: Fig. 1e, 1f, 1g, 1h, 2a, 2b, 2e, 2f.One of the conditions of submission of a paper for publication is that authors declare explicitly that their work is original and has not appeared in a publication elsewhere. Re-use of any data should be appropriately cited. As such this article represents a severe abuse of the scientific publishing system. The scientific community takes a very strong view on this matter and apologies are offered to readers of the journal that this was not detected during the submission process.

Major sources of petroleum hydrocarbons in the south of Caspian Sea (Anzali city) have been investigated through an approach which combines Gas Chromatography–Mass Spectrometry with Principal Component Analysis (PCA) and Multivariate Curve Resolution-Alternating Least Squares chemometric methods. Terpane, catagenetic hopane and sterane hydrocarbons were analyzed in the street dust, filtered sediments of runoff, soluble runoff water and river sediment samples as well as in automobiles exhaust, tires, asphalt, engine oil, gasoline and diesel samples, as possible sources of these hydrocarbons. PCA and MCR-ALS results showed that a large part of the analyzed hydrocarbons in street dust, runoffs and in some of the river sediment samples can be explained by the proposed known sources, while the observed variation of hydrocarbon concentrations in many of the river sediment samples was not much affected by the proposed known sources, and they were most probably receiving other pollution sources not included in our study. This study also has shown that results obtained from hydrocarbon marker molecular ratios, to identify petroleum pollution sources in the environments, are in agreement with those obtained from pollution sources resolved by MCR-ALS simultaneous analysis of all samples and variables.

Benzene, toluene and xylene (BTX) belong to an important group of aromatic volatile organic compounds (VOCs) that are usually emitted from various sources. BTX play a vital role in the tropospheric chemistry as well as pose health hazard to human beings. Thus, an investigation of ambient benzene, toluene and xylene (BTX) was conducted at urban and rural sites of Gorakhpur for a span of one year in order to ascertain the contamination levels. The sampling of BTX was performed by using a low-flow SKC Model 220 sampling pump equipped with activated coconut shell charcoal tubes with a flow rate of 250 ml/min for 20–24 h. The analysis was in accordance with NIOSH method 1501. The efficiency of pump was checked weekly using regulated rotameters with an accuracy of ±1%. The samples were extracted with CS₂ with occasional agitation and analyzed by GC-FID. The total BTX concentration ranged from 3.4 μg m⁻³ to 45.4 μg m⁻³ with mean value 30.95 μg m⁻³ and median 24.8 μg m⁻³. The mean concentration of total BTX was maximum during winter (39.3 μg m⁻³), followed by summer (28.4 μg m⁻³) and monsoon season (25.1 μg m⁻³). The mean concentration of BTX at urban site (11.8 μg m⁻³) was higher than that at rural site (8.8 μg m⁻³). At both the sites, T/B and X/B ratios were highest in monsoon and lowest in winters. Toluene against benzene plot shows R² value of 0.96 and 0.49 at urban and rural sites respectively. Higher R² value at urban site clearly indicates similar sources of emission for benzene and toluene. At both the sites, the estimated integrated lifetime cancer risk (ILTCR) for benzene exceeded the threshold value of 1E-06 whereas the individual hazard quotients (HQ) for BTX did not exceed unity at any of the sites.

Biochar has been used for immobilizing heavy metals in soils due to its abundant surface functional groups and mineral components. However, as carbonaceous material, biochar in soils is susceptible to natural aging, which could alter its structural properties and ability to retain heavy metals. In this study, the impacts of pre- and post-application aging on the properties of dairy manure and sawdust biochars and the significance of different mechanisms of complexation with surface functional groups and mineral precipitation for Cd immobilization in soils were investigated. The simulated natural aging including 25 dry-wet cycles and 25 freeze-thaw cycles decreased the pH of biochar from 8.2 to 10.7 to 7.5–9.7 while increased the release of dissolved organic carbon from 4.1 to 10.9 to 5.9–21.3 mg L⁻¹, O/C ratios from 0.09 to 0.30 to 0.17–0.33, and O-containing functional groups, especially -OH and -C=O groups. New minerals such as CaC₂O₄ and MgO·MgCO₃ were formed during freeze-thaw cycles. The capacity of pre-aged biochars to immobilize Cd in soils decreased from 57-70% to 53–63%, compared to that of fresh biochar, which was mainly due to decrease of CdCO₃ or Cd₃(PO₄)₂ precipitation as evidenced by XRD and MINTEQ modeling. By contrast, post-aging of biochar application in soil with dry-wet and freeze-thaw cycling had little effect on the biochar's alkalinity while increased the O/C ratios from 0.10 to 0.24 to 0.15–0.27 and intensity of O-containing functional groups. The immobilization capacity of biochars for Cd in soil increased from 44-68% to 59–73% due to the enhanced surface complexation with O-containing groups. In short, biochar subjected to pre-aging had a reduced capacity to immobilize Cd, while biochars with post-aging in soil increased its Cd immobilization capacity as a soil amendment.

The concentrations, profiles, and spatial distributions of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in soil and sediment samples from several typical plastic solid waste (PSW) recovery sites (particularly from areas in which PSW is burned openly) in China were investigated. The results showed that burning PSW directly influenced PCDD/F concentrations immediately around the burning area. All of the samples in which soil contained black burning residue, collected from immediately around burning areas, had PCDD/F concentrations (mean 21708 ng kg⁻¹) and toxic equivalent (TEQ) concentrations (mean 2140 ng I-TEQ kg⁻¹ or 1877 ng WHO₂₀₀₆-TEQ kg⁻¹) more than 100 times higher than the concentrations in samples collected away from burning areas (mean 222 ng kg⁻¹, 8.75 ng I-TEQ kg⁻¹, 7.96 ng WHO₂₀₀₆-TEQ kg⁻¹). Principal component analysis and hierarchical cluster analysis indicated that the PCDD/F concentrations in seven soil samples from near PSW burning areas were influenced by PSW burning but that the PCDD/Fs in these soil samples may have had other or multiple sources. PCDD/F distributions at PSW recovery sites have been investigated in few previous studies. The results presented here indicate that appropriate measures should be taken to decrease the ecological risks posed by PSW recovery and to prevent, control, and remediate PCDD/F and other chemical contamination caused by PSW recovery.