Hydroponic experiment was conducted to appraise variation in the salt tolerance potential of two wheat cultivars (salt tolerant, S-24, and moderately salt sensitive, MH-97) at different growth stages. These two wheat cultivars are not genetically related as evident from randomized polymorphic DNA analysis (random amplified polymorphic DNA (RAPD)) which revealed 28 % genetic diversity. Salinity stress caused a marked reduction in grain yield of both wheat cultivars. However, cv. S-24 was superior to cv. MH-97 in maintaining grain yield under saline stress. Furthermore, salinity caused a significant variation in different physiological attributes measured at different growth stages. Salt stress caused considerable reduction in different water relation attributes of wheat plants. A significant reduction in leaf water, osmotic, and turgor potentials was recorded in both wheat cultivars at different growth stages. Maximal reduction in leaf water potential was recorded at the reproductive stage in both wheat cultivars. In contrast, maximal turgor potential was observed at the boot stage. Salt-induced adverse effects of salinity on different water relation attributes were more prominent in cv. MH-97 as compared to those in cv. S-24. Salt stress caused a substantial decrease in glycine betaine and alpha tocopherols. These biochemical attributes exhibited significant salt-induced variation at different growth stages in both wheat cultivars. For example, maximal accumulation of glycine betaine was evident at the early growth stages (vegetative and boot). However, cv. S-24 showed higher accumulation of this organic osmolyte, and this could be the reason for maintenance of higher turgor than that of cv. MH-97 under stress conditions. Salt stress significantly increased the endogenous levels of toxic ions (Na⁺ and Cl⁻) and decreased essential cations (K⁺ and Ca²⁺) in both wheat cultivars at different growth stages. Furthermore, K⁺/Na⁺ and Ca²⁺/Na⁺ ratios decreased markedly due to salt stress in both wheat cultivars at different growth stages, and this salt-induced reduction was more prominent in cv. MH-97. Moreover, higher K⁺/Na⁺ and Ca²⁺/Na⁺ ratios were recorded at early growth stages in both wheat cultivars. It can be inferred from the results that wheat plants are more prone to adverse effects of salinity stress at early growth stages than that at the reproductive stage.

Suspended particulate matter trigger the production of reactive oxygen species. However, most of the studies dealing with oxidative damage of airborne particles focus on the effects of individual compounds and not real mixtures. In order to study the enzymatic superoxide production resulting from the exposition to a complex mixture, we derived organic extracts from airborne particles collected daily in an urban area and exposed kidney, liver, and heart mammal tissues. After that, we measured DNA damage employing the comet assay. We observed that in every tissue, NADPH oxidase and xanthine oxidase were involved in O₂ ⁻ production when they were exposed to the organic extracts, as the lucigenin’s chemiluminescence decays when enzymes were inhibited. The same trend was observed with the percentage of cells with comets, since DNA damage was higher when they were exposed to same experimental conditions. Our data allow us to hypothesize that these enzymes play an important role in the oxidative stress produced by PAHs and that there is a mechanism involving them in the O₂ ⁻generation.

High concentrations of soluble Mn in electrolytic manganese solid waste (EMSW) in soil cause the severe contamination in China. Calcium oxide and magnesium oxide-dominated stabilizers are suitable for the solidification/stabilization (s/s) of EMSW. However, the long-term performance of s/s using those two types of stabilizer is problematic. The aim of this study was to develop an accelerated aging method to simulate the long-term natural carbonation of solidified/stabilized EMSW. The joint use of accelerated carbonation, leaching test, mineralogical analysis, and microstructural observation was applied to assess the long-term performance of the s/s EMSW system. On an accelerated carbonation test for solidified/stabilized EMSW, an increase in Mn leaching from 13.6 to 408 mg/kg and a 1.5–2.3 decrease in pH was achieved by using CaO-dominated stabilizers, while an increase in manganese (Mn) from 30 to 266 mg/kg and a decrease in pH of 0.17–0.68 was seen using MgO-dominated stabilizers. CaO+Na₃PO₄ and CaO+CaCO₃ were exceptions in that the leaching value of soluble Mn was lower after carbonation. Mineralogical analysis showed that rhodochrosite in the carbonated s/s system was generated not only from the reduction of hausmannite but also from the reversible reaction between Mn(OH)₂ and MnCO₃. Carbonation destroyed the tight particle structure resulting in a porous and loose structure. As for s/s EMSW treated by MgO-dominated stabilizers, carbonation affected the agglomerating structure and mineralogical composition by increasing magnesium (Mg) migration, thereby forming hydromagnesite that had weak binding ability and a nested porous shape. Therefore, carbonation by itself does not cause deterioration to s/s products of the soluble Mn but does have significant effects on the microstructure and mineralogical composition. It is recommended to add Na₃PO₄ or CaCO₃ into a single CaO stabilized EMSW system to prevent aging of the system, allow formation of Mn phosphate precipitates, and improve the absorption and oxidation of soluble Mn(II).

In the present study, the field dissipation and transport of quizalofop-p-ethyl by water and sediment runoff were investigated in sunflower experimental cultivation under Mediterranean conditions. The cultivation was carried out in silty clay soil plots with two different slopes of 1 and 5 %. The soil dissipation rate of quizalofop-p-ethyl was fast and can be described by both single first-order (SFO) and Gustafson and Holden (first-order multi compartment (FOMC)) kinetics. The half-life of quizalofop-p-ethyl ranged from 0.55 to 0.68 days and from 0.45 to 0.71 days when SFO and FOMC kinetics were applied, respectively. No herbicide residues were detected below the 10-cm soil layer. A single detection of quizalofop-p-ethyl was observed in runoff water (3 days after application (DAA)) at relatively low concentrations (from 1.70 to 2.04 μg L⁻¹). In sediment, it was detected in the samplings of 3 and 25 DAA at concentrations that never exceeded 0.126 μg g⁻¹. The estimated total losses of quizalofop-p-ethyl as percentage of the initial applied active ingredient were low both in water and sediment (less than of 0.021 and 0.005 %, respectively). Quizalofop-p-ethyl residues were detectable for 18 DAA in the stems and leaves of the plants and 6 DAA in the root system. No herbicide residues were detected in inflorescences and seeds of sunflower plants. Experimental data showed minimal risk for the contamination of soil and adjacent water bodies.

The comparative effectiveness for hexavalent chromium removal from irrigation water, using two selected plant species (Phragmites australis and Ailanthus altissima) planted in soil contaminated with hexavalent chromium, has been studied in the present work. Total chromium removal from water was ranging from 55 % (Phragmites) to 61 % (Ailanthus). After 360 days, the contaminated soil dropped from 70 (initial) to 36 and 41 mg Cr/kg (dry soil), for Phragmites and Ailanthus, respectively. Phragmites accumulated the highest amount of chromium in the roots (1910 mg Cr/kg₍dᵣy ₜᵢₛₛᵤₑ₎), compared with 358 mg Cr/kg₍dᵣy ₜᵢₛₛᵤₑ₎ for Ailanthus roots. Most of chromium was found in trivalent form in all plant tissues. Ailanthus had the lowest affinity for Crⱽᴵ reduction in the root tissues. Phragmites indicated the highest chromium translocation potential, from roots to stems. Both plant species showed good potentialities to be used in phytoremediation installations for chromium removal.

In this paper, we analyze the existence of the environmental Kuznets curve as reported by Kuznets (Am Econ Rev 5:1–28, 1955) by using the methodology proposed by Kejriwal and Perron (J Econ 146:59–73, 2008, J Bus Econ Stat 28:503–522, 2010) and applying Jaunky’s (Energy Policy 39(3):1228–1240, 2011) specification using quarterly data from 1973:1 to 2015:2. We also allow different behaviors across time and identify it by economic sectors. Our results show the existence of the environmental Kuznets curve (EKC) in the USA only when we allow for structural breaks. Interestingly, the industrial sector shows a different pattern than do other economic sectors; with the beginning of the economic crisis, it appears to have abandoned the objective of the environmental stabilization found until then.

Vegetation associated with lacustrine systems in Northern Patagonia was studied for heavy metal and trace element contents, regarding their elemental contribution to these aquatic ecosystems. The research focused on native species and exotic vascular plant Salix spp. potential for absorbing heavy metals and trace elements. The native species studied were riparian Amomyrtus luma, Austrocedrus chilensis, Chusquea culeou, Desfontainia fulgens, Escallonia rubra, Gaultheria mucronata, Lomatia hirsuta, Luma apiculata, Maytenus boaria, Myrceugenia exsucca, Nothofagus antarctica, Nothofagus dombeyi, Schinus patagonicus, and Weinmannia trichosperma, and macrophytes Hydrocotyle chamaemorus, Isöetes chubutiana, Galium sp., Myriophyllum quitense, Nitella sp. (algae), Potamogeton linguatus, Ranunculus sp., and Schoenoplectus californicus. Fresh leaves were analyzed as well as leaves decomposing within the aquatic bodies, collected from lakes Futalaufquen and Rivadavia (Los Alerces National Park), and lakes Moreno and Nahuel Huapi (Nahuel Huapi National Park). The elements studied were heavy metals Ag, As, Cd, Hg, and U, major elements Ca, K, and Fe, and trace elements Ba, Br, Co, Cr, Cs, Hf, Na, Rb, Se, Sr, and Zn. Geochemical tracers La and Sm were also determined to evaluate contamination of the biological tissues by geological particulate (sediment, soil, dust) and to implement concentration corrections.

The present study was done to elucidate the effects of vanadium (V) on photosynthetic pigments, membrane damage, antioxidant enzymes, protein, and deoxyribonucleic acid (DNA) integrity in the following chickpea genotypes: C-44 (tolerant) and Balkasar (sensitive). Changes in these parameters were strikingly dependent on levels of V, at 60 and 120 mg V L⁻¹ induced DNA damage in Balkasar only, while photosynthetic pigments and protein were decreased from 15 to 120 mg V L⁻¹ and membrane was also damaged. It was shown that photosynthetic pigments and protein production declined from 15 to 120 mg V L⁻¹ and the membrane was also damaged, while DNA damage was not observed at any level of V stress in C-44. Moreover, the antioxidant enzyme activities such as superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) were increased in both genotypes of chickpea against V stress; however, more activities were observed in C-44 than Balkasar. The results suggest that DNA damage in sensitive genotypes can be triggered due to exposure of higher vanadium.

Emerging contaminants including pharmaceuticals are a class of compounds that are causing great concern due to several environmental problems. Conventional water and wastewater treatments do not achieve high removal efficiencies for many of these drugs. Therefore, the present work investigated the removal of ibuprofen (IBP) by heterogeneous photocatalysis using TiO₂ irradiated with artificial UV light or solar radiation. The treated solutions were tested against Daphnia similis and Raphidocelis subcapitata, which are species commonly used as bioindicators of environmental conditions. The results indicated that IBP removal reached 92 % after 1 h of treatment using artificial UV and 1000 mg L⁻¹ of TiO₂, which was the optimum catalyst concentration in the range studied (20–1000 mg L⁻¹). TOC removal reached up to 78 % after 60 min of treatment using TiO₂/artificial UV. Ecotoxicological bioassays indicated that the treated solutions had acute effects, with 30 % immobilization of D. similis and 40 % growth inhibition of R. subcapitata.

The water in and air above swimming pools often contain high levels of disinfection byproducts (DBPs) due to chemical reactions between chlorine- or bromine-based disinfectants and organic/inorganic matter in the source water and released from swimmers. Exposure to these DBPs, though inevitable, can pose health threats to humans. In this study, DBPs in tap water (S1), and water from a chlorinated indoor swimming pool before (S2) and after swimming (S3) were measured. The brominated species constituted the majority of DBPs formed in S1, S2, and S3. Trihalomethanes (THMs) in S3 was 6.9 (range 2.9–11.1) and 1.4 (range 0.52–2.9) times those in S1 and S2, respectively; and the haloacetic acids (HAAs) in S3 was 4.2 (range 2.5–7.5) and 1.2 (range 0.6–2.6) times those in S1 and S2, respectively. The mean THMs in air above the swimming pool before (S2-A) and after swimming (S3-A) were 72.2 and 93.0 μg/m³, respectively, and their ranges were 36.3–105.8 and 44.1–133.6 μg/m³, respectively. The average percentages of bromide incorporation (BI) into THMs in S1, S2, and S3 were 3.0, 9.3, and 10.6 %, respectively; and the BI into HAAs in S1, S2, and S3 were 6.6, 12.0, and 12.2 %, respectively. Several models were trained for predicting the BI into THMs and HAAs. The results indicate that additional information is required to develop predictive models for BI in swimming pools.