In the 21st century, severe droughts associated with climate change will increase biomass burning (BB) in Brazil caused by the human activities. Recent droughts, especially in 2005, 2010, and 2015, caused strong socioeconomic and environmental impacts. The 2015 drought considered the most severe since 1901, surpassed the 2005 and 2010 events in respect to area and duration. Herein, based on satellite data, the 2005, 2010 and 2015 drought impacts on wildfire episodes and carbon monoxide (CO) variability during the dry and the dry-to-wet transition seasons were examined. The BB occurrences in the dry season were fewer during 2015 than during 2005 (−44%) and 2010 (−47%). Contrasting, the BB events in the dry-to-wet transition season, were higher during 2015 than during 2005 (+192%) and 2010 (+332%). The BB outbreaks were concentrated in the southern and southwestern Amazon during 2005, in the Cerrado region during 2010, and mainly in the central and northern Amazon during 2015, an area normally with few fires. The CO concentration showed positive variations (up to +30%) occurred in the southern Amazon and central Brazil during the 2005 and 2010 dry seasons, and north of 20 °S during the 2015–2016 dry-to-wet transition season. The BB outbreaks and the CO emissions showed a considerable spatiotemporal variability among the droughts of 2005, 2010, and 2016, first of them driven by local conditions in the tropical North Atlantic (TNA), characterized by warm than normal sea surface waters and the other two by the El Niño occurrences.

Maternal transfer toxicity of chemicals has mainly focused in fish on the chemical transfer from maternal generation to offspring, and limited information is available for the evaluation of effects of chemicals from a biological transfer perspective. In this study, first-generation (F0) zebrafish larvae (D. rerio) were exposed to 0, 50, 500 or 5000 ng/L TDCIPP from 14 days post fertilization (dpf) to 120 dpf. F0-generation zebrafish were paired, and F1-generation embryos were collected and continuously exposed to the same concentrations of TDCIPP until 150 dpf. F1-generation females were then paired with unexposed adult males, and maternal transfer effects on survival rate and body length were evaluated. Results demonstrated that maternal exposure to TDCIPP for two generations significantly decreased body length of F2-generation larvae, suggesting the occurrence of maternal transfer toxicity. The transfer of TDCIPP from maternal generation to offspring was evident, but microinjection of equal amounts of TDCIPP did not affect survival and body length of zebrafish larvae. Furthermore, maternal exposure to TDCIPP changed the concentrations of partial mRNAs and proteins in their eggs, and those changes were linked to maternal transfer toxicity (e.g., growth inhibition). These results suggested that in zebrafish changes in biological transfer may explain, at least in part, the observed maternal transfer toxicity of TDCIPP.

We studied arid desert soils from Namibia (Rosh Pinah) that were contaminated with up to 7 mg kg⁻¹ of thallium (Tl) via dust emitted from a local flotation tailing dam. Chemical extractions of waste and soil materials indicated that most of the Tl is strongly bound, in accordance with X-ray diffraction and X-ray absorption spectroscopy data that point to the predominant association of Tl with metal sulfides and phyllosilicates. The isotope fractionation factor ε²⁰⁵Tl of the soil samples (from −0.4 to +3.8) shows a positive linear relationship (R² = 0.62) with 1/Tl, indicative for the mixing of two major Tl pools, presumably anthropogenic Tl and geogenic Tl. The ε²⁰⁵Tl value for the topmost soil samples (∼+3) closely matches the ε²⁰⁵Tl value for post-flotation waste particles with a diameter of <0.05 mm, whereas the bulk flotation waste exhibits a significantly larger ε²⁰⁵Tl value (∼+6). These variations are in accordance with predominant atmospheric transfer of Tl from the tailings to the adjacent soils via fine (dust) particles. The identified minimal Tl alteration in soils indicates that only a small part of the Tl could be potentially released and passively enter the vegetation, local population and/or food chain in the long term. From this viewpoint, Tl does not represent such an important environmental concern as other (abundant) contaminants at the locality. Furthermore, there could be a relevance for other alkaline desert soils, including those where Tl pollution plays a major role.

The coagulation behaviors of humic acid (HA) with Cs+ (10–500 mM), Sr2+ (0.8–10.0 mM) and Eu3+ (0.01–1.0 mM) at different pH values (2.8, 7.1 and 10.0) were acquired through a dynamic light scattering (DLS) technique combined with spectroscopic analysis and molecular dynamic (MD) simulations. The coagulation rate and the average hydrodynamic diameter (<Dh>) increased significantly as the concentration of nuclides increased. <Dh> could be scaled to time t as <Dh>∝ ta at higher Sr2+ concentrations, which shows that HA coagulation is consistent with the diffusion-limited colloid aggregation (DLCA) model. Trivalent Eu3+ induced HA coagulation at a much lower concentration than bivalent Sr2+ and monovalent Cs+. The coagulation value ratio of Sr2+ and Eu3+ to Cs+ is almost proportional to Z−6, indicating that the HA coagulation process is generally consistent with the Schulze-Hardy rule. Spectroscopic analysis indicated that the complexation between nuclides and carboxylic/phenolic groups of HA molecules played important roles in the coagulation of HA. MD modelling suggested that Sr2+ and Eu3+ ions increased the coagulation process through the formation of intra- or inter-molecular bridges between negatively charged HA molecules, whereas for Cs+, no inter-molecular bridges were formed. This work offers new insight into the interactions between HA and radionuclides and provides a prediction for the roles of HA in the transportation and elimination of radionuclides in severely polluted environments.

The main objective of the present study was to investigate possible links between sub-individual and supra-individual levels (i.e. population level) biomarkers in D. magna exposed to sublethal concentrations of the insecticide chlorpyrifos (CPF). To achieve the aim, 8-day old individuals were exposed for 96 h to two environmentally relevant concentrations of CPF (50 and 250 ng/L). Sub-individual level effects were investigated by measuring the activity of antioxidant (SOD, CAT, and GPx) and detoxifying (GST) enzymes, as well as by measuring the acetylcholinesterase (AChE) inhibition. In addition, the effects at supra-individual level were assessed by using a video-tracking system and analyzing changes in swimming capabilities (i.e. percentage of activity time, distance moved, and velocity). Our data have shown that daphnids exposed to both CPF concentrations were in a condition of stress which was highlighted by changes in both sub- and supra-individual biomarkers. Moreover, our results highlighted that the lowest tested CPF concentration did not modulate the antioxidant and detoxifying enzymes, whereas, an inhibition of AChE and a decrease of some parameters related to swimming behaviour (distance moved and velocity) were noted. On the contrary, significant changes in all the sub-individual biomarkers were measured at the highest tested concentration. In addition, organisms recovered the movement capability (distance moved) and also activate a mechanism of avoidance (increased swimming velocity). On the other hand, a reduction in the percent of active time was measured and this was attributed to the energy spent by organisms to activate antioxidant and detoxifying enzymes and the mechanism of avoidance. Based on these results, our study suggests the existence of a link between sub- and supra-individual levels, as the activation or non-activation in the antioxidant and detoxifying enzymes activities can led to different modifications of the swimming behaviour in D. magna.

Observed levels of lipid/lipoproteins are known to be associated with exposure to perfluoroalkyl substances (PFAS). In order to evaluate and update these associations among US children aged 6–11 years, data (N = 458) from National Health and Nutrition Examination Survey for 2013–2014 were used. The associations between the observed levels of total cholesterol, high density lipoprotein (HDL) cholesterol, and non-HDL cholesterol and selected PFAS were studied. PFAS data were available for perfluorononanoic acid (PFNA), perfluorohexane sulfonate (PFHxS), linear isomer of perfluorooctanoic acid (PFOA), linear isomer of perfluorooctane sulfonate (PFOS), monomethyl branch isomer of PFOS, and sum of PFAS. Regression models were fitted to evaluate these associations. A statistically significant (p = 0.03) positive association between the levels of linear isomer of PFOS and total cholesterol was observed. A 10% increase in the levels of linear isomer of PFOS measured in ng/L was found to be accompanied by a 0.03–0.42% increase in the levels of total cholesterol measured in mg/dL. For PFNA, girls in the first quartile of PFNA were found to have lower adjusted levels for total cholesterol than the girls in the fourth quartile of PFNA (152.6 vs. 164.7 mg/dL, p < 0.01). Also, non-Hispanic blacks in the first quartile of PFNA were found to have lower adjusted levels for total cholesterol than the non-Hispanic blacks in the fourth quartile of PFNA (143.4 vs. 160.5 mg/dL, p = 0.04). A negative association between branch isomer of PFOS and non-HDL cholesterol was also observed (β = −0.0066, p = 0.04). The adjusted levels of non-HDL cholesterol were higher in the second quartile of ∑PFAS than in the fourth quartile of ∑PFAS (103.0 vs. 97.5 mg/dL, p < 0.01). Linear PFOS and possibly PFNA are associated with total cholesterol in the most recent NHANES childhood sample. Concentrations of PFAS and associations with cholesterol have both decreased compared to previous literature.

This study investigated selected steroidal and phenolic endocrine disrupting compounds (EDCs) in the surface water of the Bahe River (China) using gas chromatography mass spectrometry (GC-MS). Their effect on the wild sharpbelly Hemiculter leucisculus was investigated. The concentrations of 4-t-octylphenol, nonylphenol, bisphenol-A, estrone, 17 β-estradiol, 17 α-Ethinylestradiol, and estriol were up to 126.0, 634.8, 1573.1, 55.9, 23.9, 31.5, and 5.2 ng L⁻¹ in the surface water, and up to 26.4, 103.5, 146.9, 14.2, 9.3, 13.8, and 1.3 ng g⁻¹ in the fish muscle tissue, respectively. High estrogen equivalent levels and hazard quotients were found in the middle and lower reaches of the river, and the pollution in these regions caused enhanced growth conditions, inhibition of gonad growth, and suppression of spermatogenesis in H. leucisculus. The up-regulation of Vitellogenin mRNA expression in male fish, collected from relatively heavily EDCs contaminated areas, indicates a potential estrogenic effect. The differential expression profiles of genes related to steroidogenesis at all sampling sites suggests that these endpoints may play an important role for the pollution monitoring of estrogenic EDCs in the Bahe River.

Global burden of disease estimates reveal that people in Nigeria are living shorter lifespan than the regional or global average life expectancy. Ambient air pollution is a top risk factor responsible for the reduced longevity. But, the magnitude of the loss or the gains in longevity accruing from the pollution reductions, which are capable of driving mitigation interventions in Nigeria, remain unknown. Thus, we estimate the loss, and the gains in longevity resulting from ambient PM2.5 pollution reductions at the local sub-national level using life table approach. Surface average PM2.5 concentration datasets covering Nigeria with spatial resolution of ∼1 km were obtained from the global gridded concentration fields, and combined with ∼1 km gridded population of the world (GPWv4), and global administrative unit layers (GAUL) for territorial boundaries classification. We estimate the loss or gains in longevity using population-weighted average pollution level and baseline mortality data for cardiopulmonary disease and lung cancer in adults ≥25 years and for respiratory infection in children under 5. As at 2015, there are six “highly polluted”, thirty “polluted” and one “moderately polluted” States in Nigeria. People residing in these States lose ∼3.8–4.0, 3.0–3.6 and 2.7 years of life expectancy, respectively, due to the pollution exposure. But, assuming interventions achieve global air quality guideline of 10 μg/m3, longevity would increase by 2.6–2.9, 1.9–2.5 and 1.6 years for people in the State-categories, respectively. The longevity gains are indeed high, but to achieve them, mitigation interventions should target emission sources having the highest population exposures.

Obesity and exposure to particular matter (PM) have become two leading global threats to public health. However, the exact mechanisms and tissue-specificity of their health effects are largely unknown. Here we investigate whether a metabolic challenge (early nutritional obesity) synergistically interacts with an environmental challenge (PM exposure) to alter genes representing key response pathways, in a tissue-specific manner. Mice subjected to 7 weeks obesogenic nutrition were exposed every other day during the final week and a half to aqueous extracts of PM collected in the city of London (UK). The expression of 61 selected genes representing key response pathways were investigated in lung, liver, white and brown adipose tissues. Principal component analysis (PCA) revealed distinct patterns of expression changes between the 4 tissues, particularly in the lungs and the liver. Surprisingly, the lung responded to the nutrition challenge. The response of these organs to the PM challenge displayed opposite patterns for some key genes, in particular, those related to the Nrf2 pathway. While the contribution to the variance in gene expression changes in mice exposed to the combined challenge were largely similar among the tissues in PCA1, PCA2 exhibited predominant contribution of inflammatory and oxidative stress responses to the variance in the lungs, and a greater contribution of autophagy genes and MAP kinases in adipose tissues. Possible involvement of alterations in DNA methylation was demonstrated by cell-type-specific responses to a methylation inhibitor. Correspondingly, the DNA methyltransferase Dnmt3a2 increased in the lungs but decreased in the liver, demonstrating potential tissue-differential synergism between nutritional and PM exposure. The results suggest that urban PM, containing dissolved metals, interacts with obesogenic nutrition to regulate diverse response pathways including inflammation and oxidative stress, in a tissue-specific manner. Tissue-differential effects on DNA methylation may underlie tissue-specific responses to key stress-response genes such as catalase and Nrf2.

Given that cadmium (Cd) uptake by plants is linked to transpiration rate and activity of antioxidant enzymes and further that silicon (Si) can regulate them, it was hypothesized that improved Si nutrition could reduce Cd concentration in plants. Thus, present study was carried out to elucidate the positive effect of Si nutrition on the growth, activities of antioxidant enzymes and tissue cadmium (Cd) concentration in Cd-tolerant (Iqbal-2000) and Cd-sensitive wheat (Triticum aestivum L.) cultivars. Fifteen days after seedling transplantation, 15 μM Cd stress alone and in combination with 0.6 mM Si was applied. Silicon application improved root and shoot dry matter of Cd-sensitive cultivar Sehar-2006 while the effect was non-significant in Cd-tolerant cultivar Iqbal-2000. Silicon-treated Cd-sensitive cultivar showed marked improvements in chlorophyll content and photosynthesis, while stomatal conductance and transpiration rate decreased by Si application. Silicon treatment enhanced the activities of enzymatic antioxidants including catalase, ascorbate peroxidase, guaiacol peroxidase and superoxide dismutase and the increase was higher for Cd-tolerant cultivar Iqbal-2000. Although Si nutrition depressed malondialdehyde (MDA) content in both Cd-stressed cultivars, the response was more evident in Cd-sensitive Sehar-2006. Lower lipid peroxidation was related to Si-induced increase in antioxidant activities only in Cd-sensitive cultivar. Silicon application decreased Cd accumulation in the roots and shoots of both the cultivars. The decrease in shoot Cd was associated with a decrease in Cd uptake by roots and Cd translocation from roots to shoots. Overall, it is concluded that Si suppressed Cd contents by decreasing transpiration rate in Cd-sensitive cultivar and by increasing antioxidant activity in Cd-tolerant cultivar.