Inspecting the influence of renewable energy and R&D in defending environmental quality: evidence for California

Environmental Science and Pollution Research - The United Nations’s Sustainable Development Goals (SDGs) is international cooperation that aims to climate change mitigation, and encourage the...     

Tetracycline removal enhancement with Fe-saturated nanoporous montmorillonite in a tripartite adsorption/desorption/photo-Fenton degradation process

The adsorption and photo-Fenton degradation of tetracycline (TC) over Fe-saturated nanoporous montmorillonite was analyzed. The synthesized samples were characterized using XRD, FTIR, SEM, and XRF analysis, and the adsorption and desorption of TC onto these samples, as well as the antimicrobial activity of TC during these processes, were analyzed at different pH. Initially, a set of adsorption/desorption experiments was conducted, and surprisingly, up to 50% of TC adsorbed was released from Mt structure. Moreover, the desorbed TC had strong antibacterial activity. Then, an acid treatment (for the creation of nanoporous layers) and Fe saturation of the montmorillonite were applied to improve its adsorption and photocatalytic degradation properties over TC. Surprisingly, the desorption of TC from modified montmorillonite was still high up to 40% of adsorbed TC. However, simultaneous adsorption and photodegradation of TC were detected and almost no antimicrobial activity was detected after 180 min of visible light irradiation, which could be due to the photo-Fenton degradation of TC on the modified montmorillonite surface. In the porous structures of modified montmorillonite high, ˙OH radicals were created in the photo-Fenton reaction and were measured using the Coumarin technique. The ˙OH radicals help the degradation of TC as proposed in an oxidation process. Surprisingly, more than 90% of antimicrobial activity of the TC decreased under visible light (after 180 min) when desorbed from nanoporous Fe-saturated montmorillonite compared to natural montmorillonite. To the best of our knowledge, this is the first time that such a high TC desorption rate from an adsorbent with the least residual antimicrobial activity is reported which makes nanoporous Fe-saturated montmorillonite a perfect separation substance of TC from the environment.

     

Adaptation of maize to climate change impacts in Iran

Adaptation is a key factor for reducing the future vulnerability of climate change impacts on crop production. The objectives of this study were to simulate the climate change effects on growth and grain yield of maize (Zea mays L.) and to evaluate the possibilities of employing various cultivar of maize in three classes (long, medium and short maturity) as an adaptation option for mitigating the climate change impacts on maize production in Khorasan Razavi province of Iran. For this purpose, we employed two types of General Circulation Models (GCMs) and three scenarios (A1B, A2 and B1). Daily climatic parameters as one stochastic growing season for each projection period were generated by Long Ashton Research Station-Weather Generator (LARS?WG). Also, crop growth under projected climate conditions was simulated based on the Cropping System Model (CSM)-CERES-Maize. LARS-WG had appropriate prediction for climatic parameters. The predicted results showed that the day to anthesis (DTA) and anthesis period (AP) of various cultivars of maize were shortened in response to climate change impacts in all scenarios and GCMs models; ranging between 0.5 % to 17.5 % for DTA and 5 % to 33 % for AP. The simulated grain yields of different cultivars was gradually decreased across all the scenarios by 6.4 % to 42.15 % during the future 100 years compared to the present climate conditions. The short and medium season cultivars were faced with the lowest and highest reduction of the traits, respectively. It means that for the short maturing cultivars, the impacts of high temperature stress could be much less compared with medium and long maturity cultivars. Based on our findings, it can be concluded that cultivation of early maturing cultivars of maize can be considered as the effective approach to mitigate the adverse effects of climate.     

Modified dehydrogenase enzyme assay for evaluation of the influence of Hg,Cd, and Zn on the bacterial community structure of a wastewater treatment plant

In this study, a traditional assay was modified to evaluate the effect of Hg, Cd, and Zn on the bacterial community of a sequencing batch reactor and activated sludge plants and heavy metal-resistant bacterial species were determined. After the isolation of metal-resistant bacteria, their 16S rRNA gene fragments were sequenced. The BLAST program was used to compare the resulting 16S rRNA sequences with those in GenBank database to identify the isolated bacterial species. Hg was found to be the most toxic metal for both bacterial communities investigated. Sequence batch reactor bacteria were comparatively more resistant to Hg, Cd, and Zn than those from activated sludge. The resistant strains were close to the members of genus Pseudomonas, Kocuria, Stenotrophomonas, Enterococcus, and Staphylococcus. The modified dehydrogenase enzyme assay seems to be simple, robust, and competent for evaluation of the impact of metals on bacterial activity. Sequencing batch reactor systems should be preferred over activated sludge when wastewaters containing hazardous metals are to be treated.     

An integrated multi criteria approach for landfill siting in a conflicting environmental, economical and socio-cultural area

Landfill site selection is a complicated multi criteria land use planning that should convince all related stakeholders with different insights. This paper addresses an integrating approach for landfill siting based on conflicting opinions among environmental, economical and socio-cultural expertise. In order to gain optimized siting decision, the issue was investigated in different viewpoints. At first step based on opinion sampling and questionnaire results of 35 experts familiar with local situations, the national environmental legislations and international practices, 13 constraints and 15 factors were built in hierarchical structure. Factors divided into three environmental, economical and socio-cultural groups. In the next step, the GIS-database was developed based on the designated criteria. In the third stage, the criteria standardization and criteria weighting were accomplished. The relative importance weights of criteria and subcriteria were estimated, respectively, using analytical hierarchy process and rank ordering methods based on different experts opinions. Thereafter, by using simple additive weighting method, the suitability maps for landfill siting in Marvdasht, Iran, was evaluated in environmental, economical and socio-cultural visions. The importance of each group of criteria in its own vision was assigned to be higher than two other groups. In the fourth stage, the final suitability map was obtained after crossing three resulted maps in different visions and reported in five suitability classes for landfill construction. This map indicated that almost 1224 ha of the study area can be considered as best suitable class for landfill siting considering all visions. In the last stage, a comprehensive field visit was performed to verify the selected site obtained from the proposed model. This field inspection has confirmed the proposed integrating approach for the landfill siting.     

Removal of textile dyes from water by the electro-Fenton process

An environmentally friendly electrochemical treatment, electro-Fenton process, was applied to the depollution of a synthetic dismissal composed of three dyes, yellow drimaren, congo red and methylene blue, frequently used in textile and dyehouses. Here, we show that those dyes and their mixture are quickly degraded under current controlled electrolysis conditions, leading to an almost complete mineralization. The results show the efficiency of electro-Fenton process to quickly degrade aqueous effluents polluted by synthetic organic dyes.     

Toxicity of Nerium oleander leaf extract in mice

Non-lethal dose of 70% ethanol extract of the Nerium oleander dry leaves (1000 mg/kg body weight) was subcutaneously injected into male and female mice once a week for 9 weeks (total 10 doses). One day after the last injection, final body weight gain (relative percentage to the initial body weight) had a tendency, in both males and females, towards depression suggesting a metabolic insult at other sites than those involved in myocardial function. Multiple exposure of the mice to the specified dose failed to express a significant influence on blood parameters (WBC, RBC, Hb, HCT, PLT) as well as myocardium. On the other hand, a lethal dose (4000 mg/kg body weight) was capable of inducing progressive changes in myocardial electrical activity ending up in cardiac arrest. The electrocardiogram abnormalities could be brought about by the expected Na+, K(+)-ATPase inhibition by the cardiac glycosides (cardenolides) content of the lethal dose.     

Green chemistry approach to analysis of formic acid and acetic acid in aquatic environment by headspace water-based liquid-phase microextraction and high-performance liquid chromatography

A simple and totally organic-free (green) method, viz. headspace water-based liquid-phase microextraction combined with high-performance liquid chromatography-ultraviolet detection has been successfully developed for analysis of formic acid and acetic acid in environmental water samples. A microdrop of an aqueous solution of sodium hydroxide was suspended from the tip of a microsyringe needle over the headspace of the stirred sample solution containing the analytes at pH 1.0 for a given time. The microdrop was then retracted into the microsyringe, diluted with HPLC mobile phase, and injected to HPLC. Optimum efficiency has been achieved for: 3.0 µL NaOH microdrop (0.1 mol L^?1) exposed for 15 min over the headspace of an aqueous sample of 6.5 mL at 55 °C, containing 15% w/v of Na₂SO₄, adjusted to pH = 1.0 and stirred at 750 rpm. Under these conditions, enrichment factors of 162 and 187, limits of detection of 0.3 and 0.1 µg L^?1 (S/N = 3) with dynamic linear ranges of 1–500 and 0.5–500 µg L^?1 were obtained for formic acid and acetic acid, respectively. A reasonable repeatability (5.8% ≤ RSD ≤ 8.8%, n = 6) and satisfactory linearity (r² ≥ 0.997) illustrated the performance of the method.     

Genetic diversity,clonality and connectivity in the scleractinian coral Pocillopora damicornis: a multi-scale analysis in an insular,fragmented reef system

Clonality and genetic structure of the coral Pocillopora damicornis sensu lato were assessed using five microsatellites in 12 populations from four islands of the Society Archipelago (French Polynesia) sampled in June 2008. The 427 analysed specimens fell into 132 multilocus genotypes (MLGs), suggesting that asexual reproduction plays an important role in the maintenance of these populations. A haploweb analysis of ITS2 sequences of each MLG was consistent with all of them being conspecific. Genetic differentiation was detected both between and within islands, but when a single sample per MLG was included in the analyses, the populations turned out to be nearly panmictic. These observations provide further evidence of the marked variability in reproductive strategies and genetic structure of P. damicornis throughout its geographic range; comparison with results previously obtained for the congeneric species Pocillopora meandrina underlines the importance of life history traits in shaping the genetic structure of coral populations.     

Performance evaluation of using evacuated tubes solar collector,perforated fins,and pebbles in a solar still – experimental study and CO2 mitigation analysis

Environmental Science and Pollution Research - The combination of various methods of increasing evaporation rate can highly impact the performance of solar desalination. This investigation aims to...