TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin) and BDE-209 (decabromodiphenyl ether) are persistent organic pollutants (POPs) produced by industrial activities and associated with several diseases. TCDD is a known human carcinogen, but few studies investigated about the effects of exposure to both compounds, i.e., whether BDE-209 and TCDD can render tumor cells more aggressive and metastatic. In the current study we investigated if the exposure of B16–F1 and B16–F10 melanoma murine cells to environmental relevant concentrations of TCDD and BDE-209 at 24 h and 15-day exposure modulates the expression of genes related to metastasis, making the cells more aggressive. Both pollutants did not affect cell viability but lead to increase of cell proliferation, including the upregulation of vimentin, MMP2, MMP9, MMP14 and PGK1 gene expression and downregulation of E-cadherin, TIMP2, TIMP3 and RECK, strongly suggesting changes in cell phenotypes defined as epithelial to mesenchymal transition (EMT) in BDE-209 and TCDD-exposed cells. Foremost, increased expression of metalloproteinases and decreased expression of their inhibitors made B16–F1 cells similar the more aggressive B16–F10 cell line. Also, the higher secretion of extracellular vesicles by cells after acute exposure to BDE-209 could be related with the phenotype changes. These results are a strong indication of the potential of BDE-209 and TCDD to modulate cell phenotype, leading to a more aggressive profile.

Elucidating the mechanisms of heavy metal (HM) adsorption on clay minerals is key to solving HM pollution in soil. In this study, the adsorption of four HM atoms (As, Cd, Cr, and Hg) on the illite(001) surface was investigated using density functional theory calculations. Different adsorption configurations were investigated and the electronic properties (i.e., adsorption energy (Eₐd) and electron transfer) were analyzed. The Eₐd values of the four HM atoms on the illite(001) surface were found to be As > Cr > Cd > Hg. The Eₐd values for the most stable adsorption configurations of As, Cr, Cd, and Hg were −1.8554, −0.7982, −0.3358, and −0.2678 eV, respectively. The As atoms show effective chemisorption at all six adsorption sites, while Cd, Cr, and Hg atoms mainly exhibited physisorption. The hollow and top (O) sites were more favorable than the top (K) sites for the adsorption of HM atoms. The Gibbs free energy results show that the illite(001) surface was energetically favorable for the adsorption of As and Cr atoms under the influence of 298 K and 1 atm. After adsorption, there was a redistribution of positions and reconfiguration of the chemical bonding of the surface atoms, with a non-negligible influence around the upper surface atoms. Bader charge analysis shows electrons were transferred from the surface to the HM atoms, and a strong correlation between the valence electron variations and the adsorption energy was observed. HM atoms had a high electronic state overlap with the surface O atoms near the Fermi energy level, indicating that the surface O atoms, though not the topmost atoms around the surface, significantly influence HM adsorption. The above results show illite(001) preferentially adsorbed As among all four investigated HM atoms, indicating that soils containing a high proportion of illite might be more prone to As pollution.

Six years of data (2012–2017) at an urban site-Srinagar in the Northwest Himalaya were used to investigate temporal variability, meteorological influences, source apportionment and potential source regions of BC. The daily BC concentration varies from 0.56 to 40.16 μg/m³ with an inter-annual variation of 4.20–7.04 μg/m³ and is higher than majority of the Himalayan urban locations. High mean annual BC concentration (6.06 μg/m³) is attributed to the high BC observations during winter (8.60 μg/m³) and autumn (8.31 μg/m³) with a major contribution from Nov (13.88 μg/m³) to Dec (13.4 μg/m³). A considerable inter-month and inter-seasonal BC variability was observed owing to the large changes in synoptic meteorology. Low BC concentrations were observed in spring and summer (3.14 μg/m³ and 3.21 μg/m³), corresponding to high minimum temperatures (6.6 °C and 15.7 °C), wind speed (2.4 and 1.6 m/s), ventilation coefficient (2262 and 2616 m²/s), precipitation (316.7 mm and 173.3 mm) and low relative humidity (68% and 62%). However, during late autumn and winter, frequent temperature inversions, shallow PBL (173–1042 m), stagnant and dry weather conditions cause BC to accumulate in the valley. Through the observation period, two predominant diurnal BC peaks were observed at ⁓9:00 h (7.75 μg/m³) and ⁓21:00 h (6.67 μg/m³). Morning peak concentration in autumn (11.28 μg/m³) is ⁓2–2.5 times greater than spring (4.32 μg/m³) and summer (5.23 μg/m³), owing to the emission source peaks and diurnal boundary layer height. Diurnal BC concentration during autumn and winter is 65% and 60% higher than spring and summer respectively. During autumn and winter, biomass burning contributes approximately 50% of the BC concentration compared to only 10% during the summer. Air masses transport considerable BC from the Middle East and northern portions of South Asia, especially the Indo-Gangetic Plains, to Srinagar, with serious consequences for climate, human health, and the environment.

Wastewater treatment plants (WWTPs) are considered one of the important sources of aquatic/terrestrial microplastic (MP) pollution. Therefore, the abundance and properties of MPs in the wastewater and sludge of an urban WWTP in Bursa Turkey were investigated. The amount, properties, and removal of MPs were evaluated. The results showed that the average abundance of MPs was 135.3 ± 28.0 n/L in the influent and 8.5 ± 4.7 n/L in the effluent, with a 93.7% removal rate, MP was removed and transferred to the sludge. The daily MP amount released in the aquatic environment is calculated as 525 million MPs, and the annual amount is 1.9 × 10¹¹ MPs. The abundance of MPs in the sludge thickening and sludge filter cake is 17.9 ± 2.3 and 9.5 ± 2.3 n/g dry weight (dw), respectively. The sludge disposal amount of WWTP is 81.5 tons/day and the approximate amount of MP accumulated in the sludge per year is calculated as 2.8 × 10¹¹ MPs. In wastewater and sludge samples, fragment dominant shape, black main colour, and 500–1000 μm sizes are the most common size. The main MP types in wastewater samples at the influent are polypropylene (PP, 36.8%), polyethylene (PE, 31.0%), polystyrene (PS, 11.8%), polyethylene terephthalate (PET, 8.0%), and polyamide (PA, 7.1%), at the effluent (PE, 33.0%), (PP, 52.5%), and (PS, 8.2%). In the sludge cake, the distribution is (PE, 40.8%), (PP, 27.6%), (PS, 18.7%) and (PET, 8.0%). The results of this study show that MPs are removed from wastewater with high efficiency by treatment processes and a significant amount accumulates in the sludge. Therefore, it is suggested that to integrate advanced treatment processes into urban WWTPs and use effective sludge disposal management practices to reduce the amount of MP released into the environment with effluent and sludge.

The 2015 Paris agreement aims to cut greenhouse gas emissions and keep global temperature rise below 2 °C above pre-industrial levels. Reducing CH₄ emissions from leaking pipelines presents a relatively achievable objective. While walking and driving surveys are commonly used to detect leaks, the detection probability (DP) is poorly characterized. This study aims to investigate how leak rates, survey distance and speed, and atmospheric conditions affect the DP in controlled belowground conditions with release rates of 0.5–8.5 g min⁻¹. Results show that DP is highly influenced by survey speed, atmospheric stability, and wind speed. The average DP in Pasquill–Gifford stability (PG) class A is 85% at a low survey speed (2–11 mph) and decreases to 68%, 63%, 65%, and 60% in PGSC B/C, D, E/F, and G respectively. It is generally less than 25% at a high survey speed (22–34 mph), regardless of stability conditions and leak rates. Using the measurement data, a validated DP model was further constructed and showed good performance (R2: 0.76). The options of modeled favorable weather conditions (i.e., PG stability class and wind speed) to have a high DP (e.g., >50%) are rapidly decreased with the increase in survey speed. Walking survey is applicable over a wider range of weather conditions, including PG stability class A to E/F and calm to medium winds (0–5 m s⁻¹). A driving survey at a low speed (11 mph) can only be conducted under calm to low wind speed conditions (0–3 m s⁻¹) to have an equivalent DP to a walking survey. Only calm wind conditions in PG A (0–1 m s⁻¹) are appropriate for a high driving speed (34 mph). These findings showed that driving survey providers need to optimize the survey schemes to achieve a DP equivalence to the traditional walking survey.

A broad-spectrum fungicide, dichlofluanid is widely used in antifouling paints and agricultural pesticides. In this study, the acute and chronic effects of sublethal concentrations, namely, no observable effect concentration (NOEC) and 50% lethal concentration (LC₅₀) of dichlofluanid (1/10 NOEC, NOEC, 1/10 LC₅₀, and LC₅₀) were evaluated on the marine mysid, Neomysis awatschensis. Acute toxicity test (96 h) showed higher sensitivity to dichlofluanid in juvenile mysids (LC₅₀ 3.1 μg L⁻¹) than adults (LC₅₀ 24.5 μg L⁻¹), with lower survival rate and reduction in food consumption. Exposure with dichlofluanid considerably induced oxidative imbalance, as NOEC (0.006 μg L⁻¹ for juveniles and 0.074 μg L⁻¹ for adults) and 1/10 LC₅₀ values increased intracellular concentrations of malondialdehyde and glutathione, and the enzymatic activities of catalase and superoxide dismutase, whereas exposure to LC₅₀ value decreased the values of oxidative parameters. Enzymatic activity of acetylcholinesterase decreased considerably when exposed to LC₅₀ value. In the case of chronic effects, exposure to NOEC for 4 weeks markedly decreased the juvenile survival rate, while adults showed tolerance. Multigenerational monitoring in response to NOEC showed a significant growth retardation with an increase in intermolt duration as well as a decrease in the number of newborn mysids from females of the third generation. Consistent exposure to environmentally relevant sublethal concentrations of dichlofluanid would be detrimental to mysid individuals and the survival of the mysid population.

Finding an appropriate satellite image as simultaneous as possible with the sampling time campaigns is challenging. Fusion can be considered as a method of integrating images and obtaining more pixels with higher spatial, spectral and temporal resolutions. This paper investigated the impact of Landsat 8-OLI and Sentinel-2A data fusion on prediction of several toxic elements at a mine waste dump. The 30 m spatial resolution Landsat 8-OLI bands were fused with the 10 m Sentinel-2A bands using various fusion techniques namely hue-saturation-value (HSV), Brovey, principal component analysis (PCA), Gram-Schmidt (GS), wavelet, and area-to-point regression kriging (ATPRK). ATPRK was the best method preserving both spectral and spatial features of Landsat 8-OLI and Sentinel-2A after fusion. Furthermore, the partial least squares regression (PLSR) model developed on genetic algorithm (GA)-selected laboratory visible-near infrared-shortwave infrared (VNIR–SWIR) spectra yielded more accurate prediction results compared to the PLSR model calibrated on the entire spectra. It was hence, applied to both individual sensors and their ATPRK-fused image. In case of the individual sensors, except for As, Sentinel-2A provided more robust prediction models than Landsat 8-OLI. However, the best performances were obtained using the fused images, highlighting the potential of data fusion to enhance the toxic elements’ prediction models.

The plastic debris that washes ashore and litters the shoreline often undergoes weathering under sunlight exposure, such that it fragments to form nanoplastics and microplastics, but the fragmentation rate for many thermoplastics is unknown. In this study, three major thermoplastics were exposed to simulated sunlight in an accelerated weathering chamber to evaluate the speed of photooxidation-induced fragmentation. The initiation of photooxidation-induced fragmentation extrapolated from the accelerated weathering chamber to real sunlight exposure in South Korea followed the order of PS (< 1 year) > PP (< 2 years) > LDPE (> 3 years). The surface cracks created by photooxidation were not directly reflected in the initiation of fragmentation of thermoplastics. The initiation of fragmentation was faster in PS than other polymers, but the total abundance of particles produced, and increasing ratio (exposure/non-exposure) were comparable or lower than those of PP. The increasing ratio pattern between nanoplastics and small microplastics of PP differed noticeably from other polymers. The initiation of nanoplastic and small-microplastic fragmentation determined in this study will be useful for the further estimation of secondary microplastic production by weathering and thus for decision-making regarding methods for the timely removal of plastic litter in the environment.

Bisphenol A (BPA) is a representative endocrine disrupting compound used in a vast array of consumer products, and are being frequently substituted by its analogues, bisphenol S (BPS) and bisphenol F (BPF). We aimed to examine the association between urinary bisphenol levels with obesity and lipid profiles in the general population to comprehensively evaluate its potential of metabolic disturbance. A representative sample of 1046 US adults from the National Health and Nutrition Examination Survey (2013–2016) and 3268 Korean adults from the Korean National Environmental Health Survey (2015–2017) was analyzed. We examined the exposure levels of bisphenols and determined their associations with obesity, high-density lipoprotein cholesterol (HDL-C) and triglyceride (TG) levels, and hypercholesterolemia prevalence through multiple linear, and binary/ordinal logistic regression models. In both populations, high BPA levels (lowest tertile vs. 2nd, 3rd tertiles) showed corresponding associations with lipid profile and obesity. BPA levels were associated with decreased HDL-C levels (Q3: β = −0.053, p = 0.08 (US); Q2: β = −0.030, p-0.03), increased TG levels (Q3: β = 0.121, p = 0.029 (US); Q3: β = 0.089, p = 0.021, and higher odds for obesity (Q3: OR = 1.58, 95% CI: 1.06, 2.35 (US); Q3: OR = 1.41, 95% CI: 1.11, 1.78). Higher BPS levels were positively associated with obesity status, especially in US men (Q2: OR = 1.84, 95% CI: 1.15, 2.96) and Korean women (Q3: OR = 1.27, 95% CI: 0.99, 1.64). A significant decrease in HDL-C (Q3: β = −0.088, p = 0.01) and elevated odds for obesity at higher BPF levels (Q3: OR = 1.60, 95% CI: 1.00, 2.56) was observed in US women. The findings of our study indicate that BPA and its analogues, BPS and BPF, are associated with lipid metabolism disorders in addition to obesity in adults. Given the increase in exposure to BPA alternatives, continuous biomonitoring, and further investigation of their health effects through prospective cohort studies are warranted.

Polychlorinated naphthalenes (PCNs) are highly toxic and persistent organic pollutants that can cause adverse effects in the environment and on human health. PCNs have been detected in remote areas because of their long-range transportation. Bees and bee products are commonly used as biomonitors for various pollutants in the environment. However, information on PCNs in apiaries is scarce. The aim of this study was to evaluate the occurrences of PCNs in bees and bee products from apiaries located in different geographical regions of China, and to identify potential pollution sources and assess exposure risks to humans. Our results showed that the average Σ₇₅PCNs concentrations in bees, pollen, and wax were 74.1, 96.3, and 141 pg/g dry weight, respectively. The homologue and congener profiles of PCNs in bees, pollen, and wax were similar, and di- and tri-chlorinated naphthalenes (>60%) were the predominant homologues. The concentrations and distributions of PCNs in bees, pollen, and wax varied among different geographical regions, but their occurrences were correlated with PCN metallurgical sources in China. The health risks of PCNs in pollen were evaluated, and both carcinogenic and non-carcinogenic risks of PCNs exposure to humans through the diet were low.