Water pollution is one of the most important environmental challenges and also one of the main causes of death in the world. Transporting oil products on roads by trucks and their accidents lead to the release of these chemicals into the environment, resulting in water resources pollution. Thus, the main goal of this study is to evaluate the risk assessment of the water resources pollution in the road of Sanandaj to Marivan, Kurdistan province, Iran. Six scenarios for four types of hazardous materials in two seasons of the years were considered. The road was then segmented, and the probability of accidents in each segment was calculated by the Poisson regression method. Two scenarios were selected for analysis since truck accidents had happened mainly in spring (scenario 1) and winter (scenario 4). According to the results, the total risk of water contamination path is 20%very low, 19% low, 29% moderate, 28% high, and 4% very high. Also, according to scenario 1, 14% of the total area of the study area is very low risk, 23% low risk, 15% medium risk, 6% high risk, and 42% are very high risk. Based on scenario 4, 39% of the total area of the study area has a very low risk, 44% low risk, 13% medium risk, 4% high risk. This simply means that this road is not very suitable for transporting hazardous oil products.

An experiment described in this work aimed to establish the role of bioaugmentation in minimizing adverse outcomes of loamy sand contamination with zinc. The bioaugmentation was conducted with the use of microbial strains being most resistant to the action of zinc, which were isolated from the soil contaminated with 1250 mg Zn²⁺ kg⁻¹ dry matter (DM) of soil after 12-month incubation. The soil was inoculated with 4 strains of bacteria (Bacillus licheniformis KT986159.1, Bacillus sp. KF956639.1, Gordonia amicalis KM113029.1, Leifsonia sp. KJ191763.1) and 4 strains of fungi (Penicillium raperi KC797647.1, Penicillium janthinellum AY373921.1, Penicillium glabrum LT558918.1, Trichoderma harzianum LN714612.1). In the case of the non-contaminated soil, a metal dose of 250 mg Zn²⁺ kg⁻¹ DM of soil contributed to enhanced proliferation and microorganisms and enzymatic activity. In turn, zinc in its highest dose (1250 mg Zn²⁺ kg⁻¹ DM of soil) evoked adverse effects, which were manifested in reduced numbers and diversity of microorganisms and suppressed activity of soil enzymes. This contamination rate stimulated only the proliferation of fungi, but their ecophysiological diversity was reduced either. The bioaugmentation treatment minimized adverse effects of zinc. Unfortunately, the use of autochthonous microorganisms failed to reduce zinc bioavailability in the soil.

Elevated salinity creates degrading conditions for the development of aquatic biota in different regions of the world. There is a need for research on freshwater salinisation in order to understand how this stressor alters ecosystem function and to predict changes in biodiversity globally. Such data are missing from Central Europe, and therefore, the presented study was performed in inland anthropogenic ponds with different salinity levels located in the second largest European hard coal basin. The researcher indicated a positive correlation between water salinity and the biomass and density of macrozoobenthos as well as the percentage of shredders and the abundance of alien species, whereas there was a decrease in taxa diversity and richness and the abundance of filtering and gathering collectors and predators along with increasing salinity. The survey showed that a high level of nutrients and organic matter were also significantly correlated with the distribution of the macroinvertebrate taxa and functional feeding groups. The conducted research confirmed that mining salinisation acts as a strong filter that shapes the biodiversity because it affects the composition, abundance, biomass and functional traits of benthic macroinvertebrates and significantly contributes to the invasion of alien species.

Pollution of the potentially toxic elements (PTEs) is a major concern in the metal ore-mining environment. Active polymetallic industries and mines cause great continuous devastation of both terrestrial and aquatic environments on a local and regional scale. This study investigated the pollution of surface water and groundwater in the area containing six large-scale iron ore mines, which have been in operation for more than a few decades. In order to assess the PTEs pollution, the spatial and temporal distributions of 13 different PTEs (Al, As, Co, Li, Mn, Mo, Ni, Pb, Rb, Se, Si, Sr, and Zn) were measured in 42 water samples collected from the multi-aquifer system including three distinct aquifers (upper alluvial aquifer (UAA), lower alluvial aquifer (LAA), and hard-rock aquifer (HRA)) of the Gohar-Zamin mining area in Iran. The highest concentrations of total dissolved solids (TDS = 164,000 mg/l) and PTEs were measured in HRA. Three trends were identified between the PTE concentration and increasing of TDS based on Spearman correlation analysis: (1) an increasing trend for Al, Co, Li, Mn, Rb, Se, Sr, and Ni; there were strong positive correlations in HRA between TDS and Mn (0.83), Al (0.65), Co (0.74), Li (0.90), Ni (0.83), Rb (0.91), Se (0.82), and Sr (0.84), suggesting a common origin for these elements; (2) no obvious trend for As and Mo, no correlation was founded between As and Mo with other PTEs and TDS, indicating a natural geogenic origin and mutual dependencies of these elements; and (3) a decreasing trend for Si, Zn, and Pb; TDS had a significantly negative correlation with the PTEs and attributing to different chemical properties of infiltrated groundwater. In the principal component analysis (PCA), the first PC that covers 85.09% of the total observed variance is mainly attributed the groundwater salinization. This component is composed of Al, Co, Li, Mn, Rb, Se, Sr, and Ni. The second PC contains elements As and Mo. This PC explain 14.4% of total variance and may be referred to natural origin of PTEs. Si, Zn, and Pb are in the third principal component and cover 9.64% of the variance of the data. Third PC have been attributed to lithogenic and/or primary water chemistry factors. The PTE pollution were evaluated based on heavy metal evaluation index (HEI), heavy metal pollution index (HPI), and degree of contamination (Cd). The results indicated that all of the groundwater samples collected from HRA had HEI, HPI, and Cd values greater than 21, 264, and 14 (highly pollution limits of indices), respectively, and were classified as highly polluted groundwater. HPI values within the UAA, LAA, and salt playa (SP) were lower than the critical level of 100, suggesting a threshold for the drinking water pollution. Moreover, HEI and Cd with values of less than 10 and 7 suggested low-level pollution in UAA, LAA, and SP. However, the contaminated level of PTEs exceeded the WHO standard for drinking water in HRA only. Since groundwater in HRA is a brine with the high values of PTEs, pumping of this water out to the surrounding natural environment may cause harmful impacts on the environment and perhaps living species in Bahram-e-Goor protected area. Graphical abstract

Titanium dioxide nanoparticles (TiO₂ NPs) are widely found in consumer and industrial products, contributing to their prevalent presence in our surroundings. In this study, several miRNAs in the immuno-related pathways were found to be dysregulated in RAW264.7 cells after 24-h exposure to TiO₂ NPs, including miR-29b-3p, which had not been previously found to be associated with the dysregulation of immunity after exposure to TiO₂ NPs. The KEGG pathway and GO enrichment analysis suggested that miR-29b-3p functioned both in the T and B cell receptor signaling pathways. The NFAT5 gene was predicted to regulate miR-29b-3p using the MiRDB online database. The expression of miR-29b-3p and NFAT5 was found to be inversely correlated using qRT-PCR and western blotting analysis. Dual-luciferase reporter gene assays demonstrated the precise regulatory relationship between miR-29b-3p and NFAT5. The upregulation of miR-29b-3p was found to reinforce the apoptosis of cells, while no changes were found in terms of the cell cycle or cell proliferation, using MTT, cell apoptosis, and cycle detection experiments. Our results demonstrate that miR-29b-3p is involved in the response of RAW264.7 cells to exposure to TiO₂, proving evidence for the further study of the toxicity and mechanisms of nano-TiO₂ exposure.

Climate change is major challenge in modern era and requires key attention to the researcher, globally. Carbon (‘C’) sequestering through agroforestry is one of the ways to mitigate the carbon reduction and provide safeguards to the environment for livelihood. The present study was conducted on Grewia optiva tree which is dominated in agroforestry systems of Tehri Garhwal Himalaya (Uttarakhand) in different villages at three altitudes, i.e., upper altitudes (UA), middle altitude (MA), and lower altitude (LA) ranged from 500 to 1500 m amsl. Soil moisture, water holding capacity (WHC), bulk density (BD), and soil organic carbon (SOC) reported highest in LA compared to MA and UA, which might be because of all eroded material deposited in LA . Further, nitrogen storage in UA is higher due to comparatively low temperature significantly lower the microbial activities for N2O emission than MA and LA. The low nitogen in LA might be due to higher nitrification and/or denitrification rate. The same also supported by low carbon content (energy sources to microbial activity) in LA. The density of Grewia optiva in agroforestry was high in LA; however, total tree carbon was highest in MA (20.8 t/ha) followed by UA (20.4 t/ha) and LA (19.1 t/ha) while annual shoot carbon was highest in LA (2.43 t/ha) followed by MA (1.08 t/ha) and UA (0.77 t/ha). Further, carbon credit likely to be earned from the agroforestry under G. optiva is estimated as 553,702 Euro. Therefore, Grewia optiva is strongly recommending for agroforestry which will further help in socioeconomic development and carbon-reducing strategies in mitigating future climate.

For plant growth, cadmium (Cd) is a toxic and easily accumulated element but silicon (Si) is beneficial. To explore the alleviating effect of Si on Cd toxicity to plants in Cd-contaminated calcareous soil, the effect of Si on Cd absorption was investigated for cucumber organs in pot experiments. The Cd concentration of cucumber organs using an atomic absorption spectrophotometer. The Si significantly inhibited Cd uptake by cucumber organs and was most effective for Si application of 100–200 mg kg⁻¹. On the whole, the translocation factors of stems and leaves did not vary significantly, but substantially varied in fruit. The distribution pattern of Cd content in different cucumber organs follows: root > stem > leaf > > fruit. For Cd content in soil ≤ 3 mg kg⁻¹, the Cd content in cucumber fruit was lower than the maximum limit of Cd content in fresh vegetables in China (GB2762-2017) for Si application of 100–300 mg kg⁻¹. However, with the Cd treatment of 5 mg kg⁻¹, the content of Cd in cucumber fruit exceeded this limit, even though Si alleviated Cd toxicity to some extent. Therefore, Si had a substantial alleviating effect on Cd uptake in cucumber, effectively reduced Cd toxicity to cucumber in calcareous soil. The study may help us understand the mechanism for silicon-mediated Cd tolerance in calcareous soil and provide theoretical basis for the application of silicon in the production of crops in alkaline soil polluted by Cd.

Camphor leaf (CL) was widely used to extract camphor oil and thus led to abundant forestry waste. In order to reduce pollution, the waste CL was used to prepare bio-adsorbent for Pb(II) removal after alkali treatment and functional modification. The effects of solution pH, initial Pb(II) concentration, contact time and solution temperature were investigated on adsorption process to evaluate the potential application in heavy metal ions’ removal. It was found that the massive hydroxyl groups released and plenty of micro-pores formed after the alkali treatment of CL bio-adsorbent, which obviously increased the Pb(II) adsorption. And the adsorption performance promoted continually after further functional modification by ionized 1,2,3,4-butanetetracarboxylic acid (BTCA). The increase of pH was favourable for the adsorption even though the precipitation effect was deducted. Linear fitting method was more suitable to describe the adsorption process than nonlinear fitting method, including adsorption isotherms and adsorption kinetics research. The adsorption thermodynamics was better to be described by nonlinear fitting method due to its lower root mean square error (RMSE) value and higher R² value. Among which, the adsorption isotherm and adsorption kinetics were fitted well to Langmuir model and pseudo-second-order model, respectively. The adsorption thermodynamics was exothermic in nature and the process was spontaneous at low solution temperature. The adsorption mechanism was revealed as the combination of dominant chemical adsorption and assistant physical adsorption.

Small omnivorous fish often dominate in subtropical shallow lakes, and they may affect the community structure of aquatic organisms on at least two trophic levels. However, in the study of aquatic food webs in subtropical lakes, most ecologists have focused on the effects of large-sized omnivorous species (e.g. common carp), studies of small-sized species being scarce. We conducted a mesocosm experiment with two treatments (fish presence and absence) to examine the effects of a small-sized omnivore, bitterling (Acheilognathus macropterus), on phytoplankton, zooplankton and benthic macroinvertebrates. Our results showed that bitterling presence significantly increased the chlorophyll a concentration and biomass of phytoplankton, which became dominated by cyanobacteria (mainly Aphanizomenon spp.) that accounted for >99% of both total phytoplankton abundance and biomass. Both the abundance and biomass of zooplankton were also higher in the fish-present treatment, but small rotifers became dominant, and the zooplankton:phytoplankton biomass ratio decreased, indicating less grazing on phytoplankton. Moreover, both the abundance and biomass of benthic macroinvertebrates (tubificids) were higher in the bitterling-present treatment than in the controls, which is opposite to the situation found when omni-benthivorous fish (e.g. crucian carp) dominate. Higher biomass of tubificids may, in turn, result in higher sediment nutrient release. Our study suggests that A. macropterus, and maybe also other bitterling species, can alter both pelagic and benthic assemblages via both top-down and bottom-up control effects and lead to more turbid water in eutrophic lakes. Thus, more attention should be paid to these small omnivorous species in the restoration and management of shallow subtropical lakes.

Organophosphate esters (OPEs) are widely used as fire retardants, so they are almost ubiquitous pollutants. Recent studies had found that OPEs were detectable in human blood samples. However, the studies on the presence of OPEs in hypertensive patients were limited. In this study, 12 OPEs were detected and analyzed in plasma samples collected from hypertensive patients (case group) and unpaid blood donors (control group). The values of ∑12 OPEs concentrations ranged from ND to 8.84 μg/L and ND to 20.11 μg/L in the case group and control group, respectively, with the average concentrations of 0.62 μg/L and 1.46 μg/L, respectively. Triethyl phosphate (TEP) was detected as the most abundant chemical in the case group while triphenyl phosphate (TPHP) in the control group. Correlation analysis showed that there was a significant correlation among OPEs. The correlation coefficients and principal component analysis (PCA) indicated different sources and/or metabolism existed between the case group and control group. Diastolic blood pressure (DBP) was associated with TEP concentration (p < 0.05) in hypertensive patients. Clustering analysis showed that a trend of OPEs exposure and hypertension. This study provided data on the composition profile of OPEs in plasma and human exposure to OPEs, which was the first to identify the association of OPEs with hypertension.