Global NEST Journal

To discriminate the specific response of ion toxicity versus osmotic stress on altering leaf solute contents, contributing of organic and/or inorganic components in osmotic adjustment and its reflection on plant performances under ionic and osmotic stresses, two cotton (Gossypium barbadense L.) cultivars, Giza 90 and Giza 83, were subjected to iso-osmotic concentration (–0.57 and –1.05 MPa) created by; NaCl, KCl and polyethylene glycol-6000. The three used osmotica altered seedling length, chlorophyll, leaf dry weight, relative water content, organic and inorganic solutes and proline. Contribution of organic solutes to osmotic adjustment tittered among the two cultivars, it was higher in PEG˃ KCl˃ NaCl in Giza 83, suggesting that the character of osmotic adjustment via salt attuned to high yield with moderate ion toxicity is effectively achieved by KCl than NaCl. At high-stress intensities, regardless to cultivar, the salt stress-induced nutritional imbalance, leaf chlorosis than osmotic stress that could be attributed to specific ion toxicity, not to osmotic stress of salt. In salt sensible cultivar only NaCl, among different osmotica, reduced leaf K+ content implying that avoidance of Na-induced K+ deficiency in leaf might stimulate salt tolerance in cotton. In our study, the capacity of plants to regulate their metabolic and physiological functions had superiority in water stress tolerance rather than osmotic adjustment.

Recent studies have indicated that PAEs (phthalic acid esters) are significant environmental pollutants with carcinogenic, teratogenic, and mutagenic effects. Urban soils can act as both a source and sink for city contaminants. This paper takes Changji, Xinjiang in Northwest China as the study area and explores the pollution characteristics and health risks of PAEs in the urban soils of arid areas. The analysis results indicate average concentration occurrences of 13.77 mg/kg and ranges from 0.29 to 119.72 mg/kg in the study area. Dibutyl phthalate (DBP) and di-(2-ethylhexyl) phthalate (DEHP) were the predominant PAEs in the urban soil of Changji. The highest average PAEs concentration appeared in winter, followed by autumn and spring and the lowest in summer; the seasonal variation was significant. The climate characteristics of arid regions and seasonal variations of source emissions were the primary influencing factors. The theoretical values of the non-carcinogenic and carcinogenic risk of PAEs were relatively small, all within the acceptable range. Values of non-carcinogenic risk and carcinogenic risk to children were much higher than the risks to adults. Children were the vulnerable groups most at risk for harmful pollutants, and the safety of their living environment should be the focus of more attention.

The commercial imidacloprid (IMD) insecticide [1-(6-chloro-3-pyridinyl) methyl-4,5-dihydro-N-nitro-1H-imidazole-2-amine] is widely used for the enhancement of crop production, but the intensive use of this insecticide has caused serious environmental problems. This work presents an electrochemical process for the removal of this insecticide using galvanostatic electrolysis at modified tantalum surface by lead dioxide film anode (Ta(PbO2)) anode. The electrolytic process was monitored by chemical oxygen demand (COD). The influence of operating parameters, such as current density, initial concentration of IMD, temperature and initial pH value was investigated. The COD decay follows a pseudo first-order kinetic and the process was under mass transport control. COD removal reach 97% when using an apparent current density of 100 mA cm−2, initial COD of 953 mg L−1 and at 25 °C after 4.5 h electrolysis time.

In order to investigate the effect of treated wastewater on heavy metals and fecal coliform in plant and soil, a field experiment was conducted in RCBD with three treatments in four replications during 2016-2017 in Borkhar, Isfahan (Iran). Treatments including well water, semi-treated wastewater and combination of well water and wastewater were applied in consecutive cultivation of wheat and forage corn. The amount of heavy metals in the soil did not change after two seasons of wastewater application compared to well water. The amount of fecal coliform in both plants was increased in the irrigation water treatment compared to the well water, which was more evident in the corn plant, which is related to the high moisture content of this plant at harvest stage. Due to the improvement of soil nutrient concentrations after two seasons of continuous application of wastewater and no increase in the amount of heavy metals in the soil, the use of wastewater for agricultural production is permissible. But according to the fecal coliform index, it is recommended not to be used for the production of crops harvested at high humidity and conditions for the survival of pathogens.