Arsenic (As) is the most hazardous soil contaminant, which inactivates metabolic enzymes and restrains plant growth. To withstand As stress conditions, use of some alleviative tools, such as arbuscular mycorrhizal (AM) fungi and silicon (Si), has gained importance. Therefore, the present study evaluated comparative and interactive effects of Si and arbuscular mycorrhiza-Rhizophagus irregularis on phytotoxicity of arsenate (As V) and arsenite (As III) on plant growth, ROS generation, and antioxidant defense responses in pigeonpea genotypes (Tolerant-Pusa 2002; Sensitive-Pusa 991). Roots of As III treated plants accumulated significantly higher total As than As V supplemented plants, more in Pusa 991 than Pusa 2002, which corresponded to proportionately decreased plant growth, root to biomass ratio, and oxidative burst. Although Si nutrition and AM inoculations improved plant growth by significantly reducing As uptake and the resultant oxidative burst, AM was relatively more efficient in upregulating enzymatic and non-enzymatic antioxidant defense responses as well as ascorbate–glutathione pathway when compared with Si. Pusa 2002 was more receptive to Si nourishment due to its ability to establish more efficient mycorrhizal symbiosis, which led to higher Si uptake and lower As concentrations. Moreover, +Si+AM bestowed better metalloid resistance by further reducing ROS and strengthening antioxidants. Results demonstrated that the genotype with more efficient AM symbiosis in As-contaminated soils could accrue higher benefits of Si fertilization in terms of metalloid tolerance in pigeonpea.

The aim of the study was the biomonitoring of the chronic exposure to Pb by measuring its levels in blood, urine, and hair of battery workers. Blood lead (BPb), urinary lead (UPb), hair lead (HPb), and urinary δ-aminolevulinic acid (UALA) levels were determined for 52 workers in a battery plant and compared to those of 20 non-occupational exposed subjects (controls). BPb and UPb levels were determined by graphite furnace atomic absorption spectrometry (GFAAS). HPb levels were measured by triple quadrupole ICP-MS and UALA levels were determined using cation exchanger column. The measured levels were significantly higher compared to the controls exceeding the OSHA cutoff values (p < 0.01). The GM mean levels of BPb, UPb, UALA, and HPb of workers were 715 μg L⁻¹, 331 μg L⁻¹, 16.3 mg g⁻¹, and 234 μg g⁻¹, respectively. The GM mean levels of BPb, UPb, UALA, and HPb of controls were 93.6 μg L⁻¹, 36.3 μg L⁻¹, 1.9 mg g⁻¹, and 1.8 μg g⁻¹, respectively. Significant correlations were observed between BPb and UALA (r = 0.630, p = 0.000), UPb and UALA (r = 0.566, p = 0.000), and between BPb and HPb (r = 0.466, p = 0.004). The significant correlation between BPb and HPb suggests the usefulness of hair for assessing occupational exposure particularly when the study area presents medium to high levels of Pb pollution. The association between Pb biomarkers and potential confounding factors revealed significant influence of the occupational factor over smoking and alcohol consumption. The results of this study urge for the reinforcement of the implemented engineering controls and safety measures in order to reduce exposure and to address the health issues related to Pb poisoning.

This study investigated the influence of membrane property and feed water organic matter quality on the permeate flux and water quality during gravity-driven membrane (GDM) filtration. GDM filtration was continuously carried out over 500 days at hydrostatic pressure of 65 mbar in dead-end mode without any back-flushing or membrane cleaning. Three ultrafiltration (UF) membranes (PES-100 kDa, PVDF-120 kDa, and PVDF-100 kDa) and one microfiltration (MF) membrane (PTFE-0.3 μm) were tested for treating lake water with varied organic matter qualities due to algal growth. The fluxes of the four membranes rapidly decreased to ~8 L/(m² × h) within a week of GDM filtration. The flux variations were quite similar for the four membranes during the entire GDM filtration, indicating that membrane property has a little effect on the flux. The flux strongly depends on the feed water organic matter quality. The average flux in treating low organics containing water (7–60 days) was ~5 L/(m² × h) and decreased to ~2 L/(m² × h) in treating high organics containing water (60–300 days). The accumulation of algal-derived biopolymers was mainly responsible for the flux decline by forming biofilms with high permeation resistance. The average flux in 300–500 days increased to ~3.5 L/(m² × h) when the feed water contained lower levels of biopolymers and higher levels of easily biodegradable organics, which created open and heterogeneous biofilms with lower permeation resistance. Removal efficiency for Escherichia coli was more than 5 log, while the removal efficiency for total bacterial cells was 1 log–2 log for the four membranes, indicating some bacterial regrowth after the filtration. Removal efficiency for the MS2 phage was 2.4 log and 1.5 log for the fouled PES-UF and PTFE-MF membranes.

The ability of a soil to sustain infiltration rates and to attenuate pollutants is critical for the design and operation of Managed Aquifer Recharge/Soil Aquifer Treatment and phyto-treatment schemes, also referred to as “Blue Infrastructures”. We investigated the buffering capacity of a sediment sample and a peat soil sample for nutrients and selected pharmaceutical compounds and its evolution under continuous infiltration of secondary treated wastewater (TWW) in column experiments. Samples were obtained from two blue infrastructures, the Sant’Alessio Induced River Bank Filtration plant and the San Niccolò large-scale phyto-treatment plant in Italy, and were mainly different in their organic carbon contents (0.9 and 48%, respectively). In the column experiments, a constant infiltration rate of about 0.5 L/d was maintained for 6 months. After 4 months of operation, diclofenac and carbamazepine were spiked into the TWW to evaluate their fate. Water quality was monitored by periodic water sampling from the column inflow, at sampling ports along the column length, and at the outflow. Hydraulic conductivity (K) was also monitored. The hydraulic conductivity of the Sant’Alessio sediment decreased by a factor of 10 during the first 10 days of infiltration and then stabilized, while for the San Niccolò K (initially lower) remained constant for 50 days until it decreased following a change of the redox condition in the column. The different redox conditions, due to the two different soils tested, influenced also the concentration and mobility of PO₄³⁻, Fe, Mn, and NPOC, and the speciation of the redox sensitive elements (nitrogen and sulfur). NOPC and phosphate were enriched during the filtration through San Niccolò peat soil (from 2 to 4 times, respectively), while they were buffered by the Sant’Alessio sediment (from 0.2 to 0.4 times, respectively). Diclofenac removal (69% and below 20% for San Niccolò and Sant’Alessio, respectively) was related to sorption and degradation processes and it was lower than the removal of carbamazepine in both soils (76 and 35%). The buffer capacity differences between the two soils were higher for diclofenac (62%) than carbamazepine (35%). Nevertheless, since no apparent degradation of carbamazepine was detected in both soils, its persistence in the soil may have a larger impact in case of desorption, posing contamination risk to groundwater. The results highlight the importance of the soils or sediments to be used as medium in such nature-based solutions for their operations. They also offer an approach to, e.g., tailor man-made soil layers in infiltration basins. We strongly suggest that soil characteristics and test duration are carefully considered in designing these infrastructures, when nature-based processes are the choice for dealing with reuse of treated wastewater management issues.

The use of alunite as an adsorbent for the removal of dye was the aim of this report. Mixing the alunite with different salts may allow adsorption with higher efficiency. In the present study, the thermal decomposition product of alunite-potassium chloride mixture (TDPA-KCl) was used efficiently and inexpensively to remove Reactive Blue 49 (RB49) dye. The adsorption capacity of TDPA-KCl was found to be affected by pH, temperature, adsorbent amount, calcination temperature, dye concentration, and ionic strength. The highest RB49 adsorption yield was obtained at an initial pH of 2 and an equilibrium was reached within 20 min using 80 mg of adsorbent. The most suitable kinetic model was found as the pseudo-second-order and compatible isotherm was determined as the Langmuir model. The optimum adsorption capacity was found as 119.10 mg g⁻¹ at 40 °C. ∆G°, ∆H°, and ∆S° values were calculated. A positive value of ∆H° stated that the adsorption is exothermic and spontaneous. In addition, ∆G° showed a more negative value when temperature was increased. Column studies indicated that TDPA-KCl could be effectively used for five cycles without any loss in its desorption potential. Breakthrough studies also supported a favorable adsorption of RB49 onto TDPA-KCl. This study showed that TDPA-KCl is a practical, efficient, and inexpensive adsorbent to remove reactive dyes from wastewater.

A novel magnetic attapulgite–biochar composite (MABC) derived from natural attapulgite, cauliflower leaves, and FeCl₃ was successfully prepared as a low-cost adsorbent for oxytetracycline (OTC) removal from aqueous solution. Characterization experiments by different techniques suggested that attapulgite clay particles and Fe₃O₄ nanoparticles were successfully covered on the MABC surface. Compared with the pristine biochar (CLB) and attapulgite–biochar composite (ABC), MABC had the largest surface area, well-developed pore structure, and more surface oxygen-containing functional groups which could interact with organic pollutant via hydrogen bonding, π–π electron coupling, complexation, and ion exchange. The maximum adsorption capacity of MABC by the Langmuir model was 33.31 mg/g, which was dramatically higher than that of CLB and ABC. The effects of solution initial pH had little difference on the adsorption of OTC because of the buffering effect. Adsorbent-regeneration studies of MABC exhibited good reusability and separation property. All the results indicated that MABC could be used as a potential adsorbent because of its easy preparation and separation, high efficiency, wide pH range application, and abundant and cheap raw materials in the global ecosystem. Graphical abstract

Can Gio district is located in the coastal area of Ho Chi Minh City, southern Vietnam. Discharge of wastewater from Ho Chi Minh City and neighboring provinces to the rivers of Can Gio has led to concerns about the accumulation of trace metals (As, Cu, Cr, Ni, Pb, and Zn) in the coastal sediments. The main objective of this study was to assess the distribution of As, Cu, Cr, Ni, Pb, and Zn in surface and core sediments and to evaluate the contamination status in relation to local background values, as well as the potential release of these selected trace metals from sediments to the water environment. Sediment characteristization, including determination of fine fraction, pH, organic matter, and major elements (Al, Fe, Ca, K, Mg, and S), was carried out to investigate which parameters affect the trace metal enrichment. Fine fraction and Al contents were found to be the controlling proxies affecting the distribution of trace metals while other sediment characteristics did not show any clear influence on trace metals’ distribution. Although As concentrations in the sediments were much higher compared to its reference value in other areas, the enrichment factor based on local background values suggests minor contamination of this element as well as for Cr, Cu, and Pb. Risk assessment suggested a medium to very high risk of Mn, Zn, and Ni under acidification. Of importance is also that trace metals in sediments were not easily mobilized by organic complexation based on their low extractabilities by ammonium-EDTA extraction.

In the study, the nexus among energy consumption, foreign direct investment (FDI), economic growth, and trade openness is examined by newly developed Fourier ADL (2017) and ARDL tests cover the period 1980–2015 in Turkey. Findings indicated that energy consumption, FDI, economic growth, and trade openness are cointegrated. In addition, it is determined that an increase in economic growth and trade openness positively affects energy consumption both in the long-term and short-term but FDI has only a positive effect in the long-term. VECM causality results indicated that FDI, economic growth, and trade openness are the causes of energy consumption in the long-term. In this context, Turkish policymakers should change the composition of FDI through various incentive policies to provide energy efficiency. FDI inflows should be shifted from sectors using dirty technology to clean technologies such as the information technology and services sector. In addition, increasing FDI that included green technology and renewable energy sources may promote energy efficiency in Turkey.

Synthetic pesticides are largely decried. A common attitude against the synthetic agrochemicals is to avoid, criticise or ban these substances. Along with chemical pesticides to defend crops from bioagressors are microorganisms, semiochemical and natural substances used as plant protection products including biocontrol agents (BCAs) and crop protection products in organic production. Nevertheless, a natural substance status does not confer or imply safety, security or absence of residues (in the context of plant protection). Although in this paper we do not consider the toxicological perspective of highly toxic chemicals with adverse effects on humans and non-target organisms sprayed on crops, we have applied ourselves to working on the safe use of synthetic agrochemicals. Thus, along with biopesticides (either BCA or others) allowed in organic farming, we show that some synthetic chemical pesticides may be used in safe manner. HIGHLIGHTS: • Synthetic agrochemicals are widely criticised. • Some pesticide usages are not sprayed on crops. • Some biocontrol agents are of synthetic origin.

Some obese individuals have normal metabolic profile, and some normal-weight persons have impaired metabolic status. Our hypothesis was that one of the potential underlying factors for such differences in cardiometabolic profiles might be the exposure to some environmental chemicals. This study aimed to investigate the association of serum bisphenol A (BPA) and phthalate metabolites with cardiometabolic risk factors in children and adolescents independent of their weight status. This case–control study was conducted on a subsample of 320 participants of a national school-based surveillance program in Iran. We measured serum BPA and phthalate metabolites by gas chromatography mass spectrophotometry. We compared them in children and adolescents with and without excess weight and those with and without cardiometabolic risk factors (80 in each group). We categorized the concentrations of chemicals to tertiles and then we applied logistic regression models after adjustment for potential confounding factors. The concentrations of BPA and some metabolites of phthalates were significantly different in the four groups studied. MEHP concentration was associated with higher odds ratio of cardiometabolic risk factors in participants with normal weight (OR, 95% CI 2.82, 1.001–7.91) and those with excess weight (OR, 95% CI 3.15, 1.27–7.83). MBP concentration increased the odds ratio of cardiometabolic risk factors only in normal weight children and adolescents (OR, 95% CI 6.59, 2.33–18.59, P < 0.001). In participants without cardiometabolic risk factor, MMP and MEHHP were significantly associated with increased risk of excess weight (OR, 95% CI 5.90, 1.21–28.75 and 7.82, 1.5–41.8, respectively). This study showed that the association of BPA and phthalate with cardiometabolic risk factors is independent of the weight status. Our findings suggest that the metabolic impairment in some normal weight children and normal metabolic profile of some obese children can be, in part, related to exposure to these environmental chemicals. Graphical abstract