Clayey soils have been used as liners at the base of waste deposits due to their geotechnical characteristics and capacity to adsorb metallic cations. However, a number of soils may not possess all required properties to ensure contaminant retention and therefore require additives. This study investigated whether the addition of commercial peat to a tropical residual soil (from the Ribeira Valley, Brazil) could improve its lead (Pb) and cadmium (Cd) adsorption capacity for its use as a liner in mining waste disposal. Pure soil and 10 and 20% soil-peat mixtures were compared. The application of peat increased the organic matter (OM) content (from 9 g kg⁻¹ in soil to 58 g kg⁻¹ in the 20% soil-peat mixture) and the cationic exchange capacity (CEC) (from 41.4 mmolc dm⁻³ in soil to 143.1 mmolc dm⁻³ in the 20% soil-peat mixture). Batch equilibrium test results revealed that the maximum Pb adsorption capacity of 623.6 μg g⁻¹ also increased (to 1089.1 and 1270.0 μg g⁻¹ in the 10 and 20% soil-peat mixtures, respectively). The soil Cd adsorption capacity of 261.2 μg g⁻¹ increased to 304.0 and 631.3 μg g⁻¹, respectively, with increasing peat proportions. The results suggest that peat can improve soil liner performance in waste deposits. Soil-peat mixtures are alternatives for minimizing potentially toxic metal contamination with available and low-cost materials.

Hydroxypropyl cellulose-g-poly (acrylicacid-co-2-acrylamido-2-methyl-1-propane sulfonic acid)/laterite (HPC-g-P (AA-co-AMPS)/laterite) with excellent water (salt) absorbency, water retention performance, re-swelling property, and fast water absorption rate was prepared by free-radical polymerization. The structure and morphology of the synthetic materials were characterized by FTIR, SEM, and TGA. The water absorbency of superabsorbent resin in different salt solutions was studied, and it was proved that the superabsorbent resin was more sensitive to salt solutions. The swelling kinetic mechanism of superabsorbent resin was explained by pseudo-second-order swelling kinetic model. The effects of the ratio of laterite to loess on water evaporation and the content of superabsorbent resin on soil water evaporation and shrinkage of soil crust were studied.

In the present investigation, the spatial distribution of the nest of White Stork Ciconia ciconia was examined. Spearman’s rank-order correlations test and the principal component analysis (PCA) were applied to a total of 227 nests recorded in the Guerbes-Sanhadja wetland eco-complex, northeastern of Algeria, over seven sites, for which the percentage of occupied nests reaches 89% (202 nest were occupied). Our goals are twofold: to explore the variation and distribution of the structure supporting the nest and to explain their spatial variability. The Spearman’s rank-order correlation test show that steel electricity poles had non-significant correlations with tree, and only concrete electricity poles structure had statistically significant positive correlation with mobile phone antennas structure (R = 0.757; at p < .05), and the roofs of houses had statistically significant positive correlation with mobile phone antennas structure (R = 0.825; at p < .05). According to the PCA results, it was observed that the PC1, which explains 50.86% of the total inertia, further represents and synthesizes the dominant structure supporting the nest, i.e., tree, steel electricity poles, and concrete electricity poles, which were strongly correlated with PC1, having a component loading nearly equal to 0.766, 0.821, and − 0.929, respectively, while the PC2, which explains 30.30% of the total inertia, includes the structure rarely recorded in the studied region, i.e., wooden electricity poles and the roofs of houses.

The toxicity effect of metals on Chlamydomonas strains having a higher tolerance level for oxidative stress is important to investigate for better understanding their tolerance capacity. In this study, the toxicity of HgCl₂ was determined on two very high light resistant (VHLᴿ) mutant strains of Chlamydomonas, CC-3723 and CC-3724, and on the wild-type CC-125. All strains were exposed to 1–7 μM of HgCl₂ during 24–72 h. The results showed that VHLᴿ mutants were less affected by the effect of HgCl₂ than CC-125, due to a better ability to detoxify the level of intracellular reactive oxygen species (ROS) generated by Hg. In particular, the effect of 3 μM of HgCl₂ inhibited completely the growth rate of CC-125 at 24 h, which was correlated with a high accumulation of Hg and a strong level of ROS. From 48 to 72 h, the growth rate was recovered for all strains, which was stronger for VHLᴿ mutants than the wild-type by 50% at 48 h, when compared to 24 h. In addition, the extracytoplasmic polyP level decreased significantly compared to the control for all strains treated to 3 μM of HgCl₂ during 24–48 h. These results suggested that the polyP did participate to the tolerance for Hg through its cellular sequestration. Furthermore, the analysis of cellular morphology showed that VHLᴿ mutants formed palmelloid colonies of 4–5 cells under 3 μM of HgCl₂ at 48 h, reducing the surface contact with Hg. Therefore, VHLᴿ mutants were more tolerant than the wild-type to the effect of low concentrations of HgCl₂ (1 and 3 μM).

Soil contamination by pharmaceutical and personal care products (PPCPs) has attracted the attention of many researchers. Continued release of these products into the environment can compromise the health of non-target organisms as well as interfere in ecological interactions between species. We hypothesized that contamination of the soil by these products affects the gut microbiota of macrodecomposers that live in symbiosis with these microorganisms and therefore interferes with the assimilation of nutrients by these animals. Therefore, this study aims to evaluate the effects of soil contaminated by triclosan (TCS) and chlorhexidine (CHX) by analyzing changes in nutrient assimilation and in the assimilation pattern of carbon sources from the Balloniscus selowii gut microbiota. The food consumption rate in B. selowii was not altered by biocides, and assimilation rate as well as assimilation efficiency (%) decreased under triclosan treatment. Based on the results obtained, the soil and gut microbiota demonstrated similar response to each study treatment when compared to other treatments. However, there were no significant differences in the diversity, evenness, and richness values. Dehydrogenase activity showed no significant differences between TCS and CHX exposure and control. In this study, exposure to TCS and CHX biocides changed the metabolic profile of the soil microbiota and consequently of the B. selowii digestive tract. With TCS exposure, this change was enough to affect the assimilation of nutrients by B. selowii. The continuous release of antimicrobials such as chlorhexidine and triclosan into the environment may compromise the health of non-target organisms and interfere with symbiotic relationships.

High blood pressure (BP) is known as the main determinant of high cerebrovascular disease levels in China. Many studies discovered the associations between short-term exposure to PM₂.₅ and BP, while most of those focused on low or medium PM₂.₅ concentration. The aim of this study was to reveal the association between extremely high level ambient PM₂.₅ exposure and BP. We conducted a repeated-measures panel study in Beijing, China, during December 1, 2016 to December 28, 2016. BP was monitored daily for all 133 participants. Daily concentration of PM₂.₅ was obtained from local monitoring sites. A linear mixed-effect model combined with the distributed lag non-linear model was used to evaluate the associations between PM₂.₅ and daily variations in BP. This study showed short-term exposure to PM₂.₅ that was significantly associated with increased DBP (on lags of 0–8 days, Beta = 0.12, 95% confidence interval 0.04, 0.20). The single day effect of PM₂.₅ on DBP had a 2-day lag, and the cumulative effect lags 5 days. The effects of PM₂.₅ on SBP and DBP on hypertensive adults were significant. The cumulative effect of PM₂.₅ on SBP and DBP had 2 rapidly increasing periods in hypertensive adults: lags of 0–2 days and lags of 0–7 days to lags of 0–11 days. Our study revealed that short-term exposure in the extreme high level of ambient PM₂.₅ may increase BP among adults. Hypertensive adults may more sensitive than normotensive adults. The periodic high concentration of ambient PM₂.₅ might magnify the effect of PM₂.₅ on BP increase.

Aquatic environments can be easily contaminated due to anthropogenic activities that may affect local biota. Microalgae are abundant and have an important role on the food chain. Consequently, they stand out as promising models for studies of contaminants. This study investigated the cytotoxic effects of atrazine and copper (separate and mixture) exposure in microalgae Desmodesmus communis, as well as its cellular defense due to ABC (ATP-binding cassette) proteins activity against the xenobiotics. We analyzed two different ABC proteins activity pathways: P-gp, which is responsible for nonspecific substance efflux, and MRP that is associated with metals efflux. It was observed that the microalgae exposure to atrazine (90 nM) and copper (141 nM) has been considered cytotoxic. When contaminants were mixed, only the combination of both highest concentrations tested was cytotoxic. The P-gp blocker, verapamil, demonstrated that the contaminants tested caused proteins inhibition. However, the MK-571 (MRP blocker) did not block pump activity. There was an inverse relationship between ABC protein activity and cytotoxicity; non-cytotoxic conditions suggest increased activity of microalgae defense proteins.

The accumulation of heavy metals by crops irrigated with wastewater has been considered as a serious environmental problem in many developing countries, where the wastewater irrigation has emerged as a common practice. In this research, we were concerned with the highly toxic metal lead (Pb) in water, agricultural soils, and wheat crops, and the possible risk on human health in the peripheral agricultural regions of Punjab, Pakistan. Various types of irrigated water (ground, sewage, industrial), soil, and wheat plant (root, shoot, grain) samples of five different varieties (Seher-2006, Punjab-2011, Faislabad-2008, Watan, and Galaxy-2013) were collected from seven different districts and then pooled up to make one composite sample and analyzed for Cd concentration. The various pollution and mobility indices (pollution load index, enrichment factor, daily intake of metal, health risk index, translocation factor, bioaccumulation factor, and bio-concentration factor) were also calculated. The descending order for Pb concentration was as follows: water>soil>wheat plant. The range of concentration of Pb in all types of water, soil, and wheat plant (root, shoot, grains) samples was (7.05–7.83 mg/l), (6.32–7.74 mg/kg), (3.23–4.82, 1.14–2.75, 0.09–0.51 mg/kg), respectively. The concentration of Pb in all types of water samples exceeded the maximum permissible limit. There were values found to be < 1.00 in all the pollution and mobility indices for all types of samples. These results reveal that high levels of Pb in irrigated water may pollute the soil and wheat plants of these regions in the near future, if various control measures have not been taken. It may pose a great health risk to the local human and animal populations. Preventive measures should be taken to reduce heavy metal pollution of irrigation water and soils to protect both human and animal health in various regions of Punjab, Pakistan.

Narrabeen Lagoon is recognized as an Intermittently Closed and Open Lake or Lagoon (ICOLL) and is the largest coastal lagoon (2.2 km²) in the Sydney metropolitan region. The catchment (53 km²) supports five major river systems, and land use comprises of 56% residential, 42% parkland and 2% light industry, commercial, hospital and education. An initial screening environmental assessment was undertaken using sedimentary metals to determine the magnitude of anthropogenic change and level of ecological risk posed by these contaminants. Results illustrated an unusual example of an estuary significantly influenced by human-induced change, but exhibiting minimal ecological risk. This anomaly was due to high anthropogenic metal concentrations in the fine fraction of surficial sediment, which was considerably diluted by abundant metal-poor coarse material resulting in reduced adverse ecological impact for total sediment. Predictive modelling to 2020 suggested that Pb concentrations will decline and Cu and Zn levels will increase slightly. Modelling of river discharge and analyses of fluvial sedimentary metals suggested stormwater derived from the most urbanized catchments and a major roadway combined with poor flushing explained surficial sediment metal distributions in the lagoon.

Air pollution has an important impact on both human health and sustainable economic development. The relationship of the current account, which is an important carrier of international economic activity, with air pollution has rarely been discussed by scholars. This paper aims to investigate how air pollution affects the current account and the mechanism of this effect. We conducted a theoretical analysis of the relationship between air pollution and the current account by adopting an extended form of the life-cycle model. Then, we used panel data (2000–2017) from 159 countries and the panel double fixed-effect method to empirically test the theoretical outcomes. We found that an increase in the degree of air pollution in a country leads to the deterioration of the domestic current account. In addition, air pollution changes the current account by affecting the demographic structure, following the “air pollution→demographic structure→current account” mechanism. The study also tested the robustness of the benchmark results by solving endogeneity problems, subsample regression and controlling measurement errors. Our findings are an important expansion and innovation for the research about the current account and have important implications for external economic equilibrium and sustainable economic development.