Investigating the relationship between lead speciation and bioaccessibility of mining impacted soils and dusts

Environmental Science and Pollution Research - Lead (Pb) bioaccessibility measurements have been the subject of much research in recent years, given the desire to develop a cost-effective and...     

Novel Bioactive Chiral Poly(amide–imide)s Containing Different Amino Acids Linkages: Studies on Synthesis, Characterization and Biodegradability

In this paper chiral bioactive poly(amide–imide)s (PAI)s were synthesized from four different diacids containing chiral amino acids with 4,4′-methylene bis(3-chloro 2,6-diethylaniline) as a diamine via direct polycondensation reaction in a system of tetra-n-butylammonium bromide and triphenyl phosphite as a condensing agent. The structures of these polymers were confirmed by FT-IR, ¹H-NMR, specific rotation, elemental and thermogravimetric analysis (TGA) techniques. TGA showed that the 10 % weight loss temperature in a nitrogen atmosphere was more than 378 °C, which indicates that the resulting PAIs have a good thermal stability. The biodegradability of the monomers and prepared polymers was investigated in culture media and soil burial test for assessment of the susceptibility of these compounds to microbial degradation. The results showed that the synthesized monomers and theirs derived polymers are biologically active and nontoxic to microbial growth.     

The association between bisphenol A exposure and type-2 diabetes: a world systematic review

The present study was conducted to systematically review, analyze, and interpret all the relevant evidence in the literature on the possible link between exposure to bisphenol A (BPA) and the risk of type-2 diabetes mellitus (T2DM). We developed a comprehensive search strategy and used it to search Web of Science, Scopus, PubMed, and Google Scholar up to March 31, 2016, producing 3108 hits, of which 13 original papers were included. Findings of these studies were quite controversial; few studies indicated a significant positive association between BPA exposure and T2DM, while some other failed to detect such a relationship. Overall, it can be suggested that chance is unlikely the plausible explanation for the observed association between BPA exposure and T2DM. This was mainly because even in the negative studies some clues could be found in favor of a statistically significant relationship between BPA and T2DM. Additionally, some of the studies had shortcomings in defining the exposure and outcome measures, which, if present, might have led to underestimating the relationship between BPA exposure and T2DM. The theoretical plausibility of such a relationship found earlier in animal studies also supports this point. However, more definitive answer requires the conduct of future longitudinal studies, in which the possible association between BPA exposure and T2DM is assessed over much longer periods of time with more temporally robust BPA measurements. In addition, it would be quite beneficial if future studies be conducted in areas where data is still lacking (e.g., South America, Australia/Oceania, and Europe).

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Comparison of carbon footprints of steel versus concrete pipelines for water transmission

The global demand for water transmission and service pipelines is expected to more than double between 2012 and 2022. This study compared the carbon footprint of the two most common materials used for large-diameter water transmission pipelines, steel pipe (SP) and prestressed concrete cylinder pipe (PCCP). A planned water transmission pipeline in Texas was used as a case study. Four life-cycle phases for each material were considered: material production and pipeline fabrication, pipe transportation to the job site, pipe installation in the trench, and operation of the pipeline. In each phase, the energy consumed and the CO₂-equivalent emissions were quantified. It was found that pipe manufacturing consumed a large amount of energy, and thus contributed more than 90% of life cycle carbon emissions for both kinds of pipe. Steel pipe had 64% larger CO₂-eq emissions from manufacturing compared to PCCP. For the transportation phase, PCCP consumed more fuel due to its heavy weight, and therefore had larger CO₂-eq emissions. Fuel consumption by construction equipment for installation of pipe was found to be similar for steel pipe and PCCP. Overall, steel had a 32% larger footprint due to greater energy used during manufacturing.

Implications: This study compared the carbon footprint of two large-diameter water transmission pipeline materials, steel and prestressed concrete cylinder, considering four life-cycle phases for each. The study provides information that project managers can incorporate into their decision-making process concerning pipeline materials. It also provides information concerning the most important phases of the pipeline life cycle to target for emission reductions.     

Phosphorous in the environment: characteristics with distribution and effects,removal mechanisms,treatment technologies,and factors affecting recovery as minerals in natural and engineered systems

Environmental Science and Pollution Research - Phosphorus (P), an essential element for living cells, is present in different soluble and adsorbed chemical forms found in soil, sediment, and water....     

The Fate of Hydrogen Peroxide as an Oxygen Source for Bioremediation Activities within Saturated Aquifer Systems

ABSTRACT

In situ bioremediation is an innovative technique for the remediation of contaminated aquifers that involves the use of microorganisms to remediate soils and groundwaters polluted by hazardous substances. During its application, this process may require the addition of nutrients and/or electron acceptors to stimulate appropriate biological activity. Hydrogen peroxide has been commonly used as an oxygen source because of the limited concentrations of oxygen that can be transferred into the groundwater using above-ground aeration followed by reinjection of the oxygenated groundwater into the aquifer or subsurface air sparging of the aquifer. Because of several potential interactions of H₂O₂ with various aquifer material constituents, its decomposition may be too rapid, making effective introduction of the H₂O₂ into targeted treatment zones extremely difficult and costly. Therefore, a bench-scale study was conducted to determine the fate of H₂O₂ within subsurface aquifer environments. The purpose of this investigation was to identify those aquifer constituents, both biotic and abiotic, that are most active in controlling the fate of H₂O₂. The decomposition rates of H₂O₂ were determined using both equilibrated water samples and soil slurries. Results showed H₂O₂ decomposition to be effected by several commonly found inorganic soil components; however, biologically mediated catalytic reactions were determined to be the most substantial.     

Eco-Friendly, Vascular Shape and Interpenetrating Poly (Acrylic Acid) Grafted Pectin Hydrogels; Biosorption and Desorption Investigations

The synthesis and characterization of poly (acrylic acid) grafted pectin hydrogel followed by biosorption and desorption characteristics of cadmium, as a model heavy metal, have been studied. The grafted eco-friendly pectin based interpenetrating hydrogel was prepared in the presence of gluteraldehyde crosslinker under N₂ atmosphere and characterized using ¹H-NMR, FTIR, TGA and SEM techniques. Gluteraldehyde was found to form one-arm and two-arm crosslinks in the copolymer. Upon grafting, two-dimensional sheet structures bounded to tubular and vascular cylindrical rods were observed. The biosorption and desorption data, determined experimentally, were fitted to pseudo-second order reaction kinetics. At higher ionic strength values, the maximum metal uptake value (q _max) was lowered and pseudo-second order rate constant (k ₂) was increased. Whereas, at higher pH values the maximum metal uptake value (q _max) was increased and Pseudo-second order rate constant (k ₂) was decreased. 0.1?M HCl solution was a suitable eluent to regenerate the hydrogel surface and recover the adsorbed cadmium metal ions. Pectin based copolymer could be used as an efficient candidature biosorbent for the recovery of cadmium metal ions from aqueous solutions.     

Organophosphate dichlorvos induced dose-related differential alterations in lipid levels and lipid peroxidation in various regions of the fish brain and spinal cord

The effect of dichlorvos (DDVP) (0-0, dimethyl 2:2-dichlorovinyl phosphate), on various lipid fractions and lipid peroxidation in the discrete areas of the brain and spinal cord were studied in the fresh water teleost (Heteropneustes fossilis). Fishes were exposed to three different doses (3.0, 6.0 and 9.0 ppm) of DDVP daily for 7 days. Dose-related increase in the levels of total lipids, cholesterol and esterified fatty acids was detected in the fore brain, optic lobes, cerebellum, medulla oblongata and spinal cord. However, phospholipids were significantly decreased in the aforementioned regions of the central nervous system. The rate of lipid peroxidation was significantly increased in all the regions of the CNS.