Evidence is emerging that environmental exposure to bisphenol S (BPS), a substitute for bisphenol A (BPA), to humans and wildlife is on the rise. However, research on the neurobehavioral effects of this endocrine disruptive chemical is still in its infancy. In this study, we aimed to investigate the effects of long-term exposure to environmentally relevant concentrations of BPS on recognition memory and its mechanism(s) of action, especially focusing on the glutamatergic/ERK/CREB pathway in the brain. Adult female zebrafish were exposed to the vehicle, 17β-estradiol (E2, 1 μg/L), or BPS (1, 10 and 30 μg/L) for 120 days. Fish were then tested in the object recognition (OR), object placement (OP), and social recognition tasks (SR). Chronic exposure to E2 and 1 μg/L of BPS improved fish performance in OP task. This was associated with an up-regulation in the mRNA expression of several subtypes of metabotropic and ionotropic glutamate receptors, an increase in the phosphorylation levels of ERK1/2 and CREB, and an elevated transcript abundance of several immediate early genes involved in synaptic plasticity and memory formation. In contrast, the exposure to 10 and 30 μg/L of BPS attenuated fish performance in all recognition memory tasks. The impairment of these memory functions was associated with a marked down-regulation in the expression and activity of genes and proteins involved in glutamatergic/ERK/CREB signaling cascade. Collectively, our study demonstrated that the long-term exposure to BPS elicits hermetic effects on the recognition memory in zebrafish. Furthermore, the effect of BPS on the recognition memory seems to be mediated by the glutamatergic/ERK/CREB signaling pathway.

We investigated the effect of hypoxic-anoxic range of dissolved oxygen (DO) on metal release/bioavailability at sediment-water interface (SWI) in the Ganga River. Here, we consider eight sites in the main river stem along 518 km; sixty sites downstream two point sources and two tributary confluences covering 630 km; and an incubation experiment to verify these results. We found higher concentrations of metals and bioavailable fractions at SWI at two locations of main stem and up to 700 m, 1000 m, 400 m and 500 m downstream Assi drain, Wazidpur drain, Ramganga confluence and Varuna confluence respectively where DO at SWI (DOₛw) was <2.0 mgL⁻¹. The incubation experiment did show higher levels of metal- and P-release and bioavailability under anoxic-hypoxic range of DO. The risk assessment code and eutrophication index indicated high to very high risks of contaminated river sediment and water to aquatic environment at sites with hypoxic-anoxic range of DOₛw. Further, the principal component analyses separated metals and bioavailable fractions opposite to FDAase indicating greater risk at these locations. The study, which forms the first report on benthic hypoxia/anoxia-driven metal release, potential bioavailability and risk to the Ganga River ecosystem will help understanding how human-driven perturbations influence geochemical cycling of metals and ecosystem responses in large rivers.

Environmentally persistent free radicals (EPFRs) are receiving increasing concern due to their toxicity and ubiquity in the environment. To avoid restrictions imposed when using a high-volume active sampler, this study uses tree leaves to act as passive samplers to investigate the spatial distribution characteristics and sources of airborne EPFRs. Tree leaf samples were collected from 120 sites in five areas around China (each approximately 4 km × 4 km). EPFR concentrations in particles (<2 μm) on the surface of 110 leaf samples were detected, ranging from 7.5 × 10¹⁶ to 4.5 × 10¹⁹ spins/g. For the 10 N.D. samples, they were all collected from areas inaccessible by vehicles. The g-values of EPFRs on 68% leaf samples were larger than 2.004, suggesting the electron localized on the oxygen atom, and they were consistent with the road dust sample (g-value: 2.0042). Significant positive correlation was found between concentrations of elemental carbon (tracer of vehicle emissions) and EPFRs. Spatial distribution mapping showed that EPFR levels in various land uses differed noticeably. Although previous work has linked atmospheric EPFRs to waste incineration, the evidence in this study suggests that vehicle emissions, especially from heavy-duty vehicles, are the main sources. While waste incinerators with low emissions or effective dust-control devices might not be an important EPFR contributor. According to our estimation, over 90% of the EPFRs deposited on tree leaves might be attributed to automotive exhaust emissions, as a synergistic effect of primary exhausts and degradation of aromatic compounds in road dust. With adding the trapping agent into the particle samples (<2 μm), signals of hydroxyl radicals were observed. This indicates that EPFRs collected from this phytosampling method can lead to the release of reactive oxygen species (ROS) once they are inhaled by human beings. Thus, this study helps highlight EPFR “hotspots” for potential health risk identification.

Attenuated backscatter profiles retrieved by the space borne active lidar CALIOP on-board CALIPSO satellite were used to measure the vertical distribution of smoke aerosols and to compare it against the ECMWF planetary boundary layer height (PBLH) over the smoke dominated region of Indo-Gangetic Plain (IGP), South Asia. Initially, the relative abundance of smoke aerosols was investigated considering multiple satellite retrieved aerosol optical properties. Only the upper IGP was selectively considered for CALIPSO retrieval based on prevalence of smoke aerosols. Smoke extinction was found to contribute 2–50% of the total aerosol extinction, with strong seasonal and altitudinal attributes. During winter (DJF), smoke aerosols contribute almost 50% of total aerosol extinction only near to the surface while in post-monsoon (ON) and monsoon (JJAS), relative contribution of smoke aerosols to total extinction was highest at about 8 km height. There was strong diurnal variation in smoke extinction, evident throughout the year, with frequent abundance of smoke particles at lower height (<4 km) during daytime compared to higher height during night (>4 km). Smoke injection height also varied considerably during rice (ON: 0.71 ± 0.65 km) and wheat (AM: 2.34 ± 1.34 km) residue burning period having a significant positive correlation with prevailing PBLH. Partitioning smoke AOD against PBLH into the free troposphere (FT) and boundary layer (BL) yield interesting results. BL contribute 36% (16%) of smoke AOD during daytime (nighttime) and the BL-FT distinction increased particularly at night. There was evidence that despite travelling efficiently to FT, major proportion of smoke AOD (50–80%) continue to remain close to the surface (<3 km) thereby, may have greater implications on regional climate, air quality, smoke transport and AOD-particulate modelling.

Approximately 3 billion people world-wide are exposed to air pollution from biomass burning. Herein, particulate matter (PM) emitted from artisanal cashew nut roasting, an important economic activity worldwide, was investigated. This study focused on: i) chemical characterization of polycyclic aromatic hydrocarbons (PAHs) and oxygenated (oxy-) PAHs; ii) intracellular levels of reactive oxygen species (ROS); iii) genotoxic effects and time- and dose-dependent activation of DNA damage signaling, and iv) differential expression of genes involved in xenobiotic metabolism, inflammation, cell cycle arrest and DNA repair, using A549 lung cells. Among the PAHs, chrysene, benzo[a]pyrene (B[a]P), benzo[b]fluoranthene, and benz[a]anthracene showed the highest concentrations (7.8–10 ng/m³), while benzanthrone and 9,10-anthraquinone were the most abundant oxy-PAHs. Testing of PM extracts was based on B[a]P equivalent doses (B[a]Pₑq). IC₅₀ values for viability were 5.7 and 3.0 nM B[a]Pₑq at 24 h and 48 h, respectively. At these low doses, we observed a time- and dose-dependent increase in intracellular levels of ROS, genotoxicity (DNA strand breaks) and DNA damage signaling (phosphorylation of the protein checkpoint kinase 1 – Chk1). In comparison, effects of B[a]P alone was observed at micromolar range. To our knowledge, no previous study has demonstrated an activation of pChk1, a biomarker used to estimate the carcinogenic potency of PAHs in vitro, in lung cells exposed to cashew nut roasting extracts. Sustained induction of expression of several important stress response mediators of xenobiotic metabolism (CYP1A1, CYP1B1), ROS and pro-inflammatory response (IL-8, TNF-α, IL-2, COX2), and DNA damage response (CDKN1A and DDB2) was also identified. In conclusion, our data show high potency of cashew nut roasting PM to induce cellular stress including genotoxicity, and more potently when compared to B[a]P alone. Our study provides new data that will help elucidate the toxic effects of low-levels of PAH mixtures from air PM generated by cashew nut roasting.

of bioaugmentation strategies are an obstacle for damage mitigation caused by oil spills in marine environments. Cells added to the contaminated sites are quickly lost by low adherence to the contaminants, rendering ineffective. This study used two hydrocarbonoclastic species - Rhodococcus rhodochrous TRN7 and Nocardia farcinica TRH1 cells - growing in mineral medium containing hexadecane to evaluate cell distribution in a crude-oil contaminated marine water. Cell affinity to hydrophobic compounds was quantified using Microbial Adhesion to Hydrocarbons test and analysis of fatty acids profile was performed using the Microbial Identification System. Bioremediation simulations were set up and cell populations of both strains were quantified by Fluorescent in situ Hybridization. R. rhodochrous and N. farcinica reached up to 97% and 60% of adhesion to hexadecane, respectively. The carbon source had more influence on the fatty acid profiles of both strains than the microbial species. The presence of 45.24% of 13:0 anteiso on total fatty acids in R. rhodochrous and 12.35% of saturated fatty acids with less than 13 carbons atoms in N. farcinica, as well as the occurrence of fatty alcohols only in presence of hexadecane in both species, are indicators that fatty acid changes are involved in the adaptation of the cells to remain at the water/oil interface. Cell quantification after bioremediation simulations revealed an increase in the density of both species, suggesting that the bioremediation strategies resulted on the increase of hydrocarbonoclastic species and up to 27.9% of all prokaryotic microbial populations in the microcosms were composed of R. rhodochrous or N. farcinica. These findings show the potential of application of these two bacterial strains in bioaugmentation of hydrocarbon-contaminated marine ecosystems.R. rhodochrous TRN7 and N. farcinica TRH1 hydrocarbonoclastic strains modify the fatty acid profile and increases density, optimizing hydrocarbons biodegradation.

Human exposure to particulate matter (PM) originating from air pollution is inevitable since more and more population is present in large cities that are characterized by poor air quality. The impact on human health is evident and we need to intensify research regarding this problem to get molecular insight into versatile effects of chronic exposure to PM inducing organism responses and initiating the development of selected disorders. Herein, the impact of standard PM representing urban pollution on the structure and function of human serum albumin (HSA) was evaluated by the application of various analytical techniques. HSA was selected due to its high likeliness of being exposed to PM because of the abundance of this protein in blood. The studies were focused mainly on the inorganic residue of PM resulting from removing organic components by a low-temperature plasma. To mimic physiological conditions, dialysis technique was used to simulate the release of nanoparticles and ions from PM to aqueous environment under, which in turn may interact with biomolecules inside the living system. Capture of metals from the bulk suspension was found for many metals like Al, Fe, Zn and Pb in quantities of more than 1 mol of metal ions per mole of HSA. No significant structural changes of the protein upon dialysis with PM were observed, however, an increase in the thermal stabilization of the HSA structure was observed. Moreover, the interaction of HSA dialyzed in the presence of PM with selected drugs (warfarin, aspirin) was negatively affected, indicating a lower affinity of drugs towards the protein, even though only small conformational changes of the PM exposed protein were observed. Our findings point to a possible interference of air pollutants with the drugs taken by patients living in highly polluted areas.

In China, excessive phosphorus (P) application in protected vegetable fields has led to high legacy P stores. Soil amendment with alum or dolomite is one of many best management practices (BMPs) used to reduce P losses in calcareous soils. However, both the kinetics and mechanisms of P sorption and soil available P in amended soils are understudied. Herein, both aspects were looked at under controlled conditions. Firstly, a sorption study which coupled P concentrations with poorly-crystalline Al hydroxides and dolomite was conducted. Results from this batch experiment showed that P sorption on poorly-crystalline Al hydroxides was homogenous and occurred mainly via displacement of inner-sphere hydroxyl (Al–OH) instead of the formation of AlPO₄. However, the amount of sorbed P reached maximum sorption of 73.1 mg g⁻¹ and did not change with further increase in P concentration. It was observed that P adsorbed onto the dolomite surface at low P concentrations, whereas hydroxyl replacement and uneven cluster precipitation of Ca₃(PO₄)₂ occurred at high P concentrations. A second 90 day incubation experiment investigated changes to soil available P and sorption-desorption across variable rates of amendments (0–50 g kg⁻¹). Results showed that alum amendment at a rate of 50 g kg⁻¹ decreased soil CaCl₂–P and Olsen-P concentrations by 91.9% and 57.8%, respectively. However, Olsen-P increased when the dolomite rates were <20 g kg⁻¹. Phosphorus sorption-desorption of the amended soil showed alum had higher P sorption efficiency than dolomite at low addition rates (<10 g kg⁻¹). However, soil amended with high dolomite rates (>10 g kg⁻¹) could sorb more P in comparison with alum when P concentrations were increased. The P status of the amended soil was closely connected to the P sorption mechanisms on mineral amendments, soil P concentrations and soil properties.