The effect of biochar on severity of soil water repellency of crude oil-contaminated soil

Environmental Science and Pollution Research - Crude oil contamination adversely affects soil water repellency. In this study the effect of biochar on this soil characteristic has been investigated...     

Investigation on removal pathways of Di 2-ethyl hexyl phthalate from synthetic municipal wastewater using a submerged membrane bioreactor

Highly hydrophobic Di 2-ethyl hexyl phthalate (DEHP) is one of the most prevalent plasticizers in wastewaters. Since its half-life in biological treatment is around 25 days, it can be used as an efficiency indicator of wastewater treatment plant for the removal of hydrophobic emerging contaminants. In this study, the performance of submerged membrane bioreactor was monitored to understand the effect of DEHP on the growth of aerobic microorganisms. The data showed that the chemical oxygen demand (COD) and ammonia concentration were detected below 10 and 1.0 mg/L, respectively for operating conditions of hydraulic retention time (HRT) = 4 and 6 hr, sludge retention time (SRT) = 140 day and sludge concentration between 11.5 and 15.8 g volatile solid (VS)/L. The removal efficiency of DEHP under these conditions was higher and ranged between 91% and 98%. Results also showed that the removal efficiency of DEHP in biological treatment depended on the concentration of sludge, as adsorption is the main mechanism of its removal. For the submerged membrane bioreactor, the pore size is the pivotal factor for DEHP removal, since it determines the amount of soluble microbial products coming out of the process. Highly assimilated microorganisms increase the biodegradation rate, as 74% of inlet DEHP was biodegraded; however, the concentration of DEHP inside sludge was beyond the discharge limit. Understanding the fate of DEHP in membrane bioreactor, which is one of the most promising and futuristic treatment process could provide replacement for conventional processes to satisfy the future stricter regulations on emerging contaminants.     

Unwanted metals and hydrophobic contaminants in bioreactor effluents are associated with the presence of humic substances

Biological treatment of landfill leachate is challenging due to the presence of complex compounds. Here, we treated an old landfill leachate using a membrane bioreactor under the following conditions: 24 h for hydraulic retention, 65 days of sludge retention and an average organic load rate of 1.71 ± 0.16 g/L/day. We observed a high removal of ammonia, phosphorous and some metals. However, removal of organic carbon was incomplete. Despite a major removal of suspended solids, hydrophobic and volatile hydrophilic compounds, high concentration of fulvic acid and hydrophilic contaminants was found in the effluent. Overally, we demonstrate that the presence of humic substances in the effluent is associated with the detection of arsenic, copper and chromium and di(2-ethylhexyl) phthalate.     

Application of catastrophe loss modelling to promote property insurance in developing countries

Many mega cities in developing countries are exposed to the sources of natural catastrophes, particularly seismic activity. A high level of seismic hazard in some of these places, coupled with a relatively high degree of vulnerability within the built environment, can result in dire human and economic consequences. This paper contains examples of such potentially disruptive factors in relation to Tehran, Iran. It presents preliminary seismic loss estimates for residential buildings in a pilot area of northern Tehran. The paper briefly investigates the effectiveness of risk management measures and loss compensation mechanisms before assessing the feasibility of an insurance‐based risk transfer instrument for managing potential seismic losses among residential buildings in Tehran. It goes on to suggest how probabilistic catastrophe loss modelling can help local insurers to manage their portfolios and facilitate risk sharing among insurance companies and households. Finally, the paper addresses the question of how catastrophe loss modelling can help to strengthen the penetration of property insurance in developing countries.     

Evaluating the relationship between the respiratory exposure to the benzene with the primary damages of deoxyribonucleic acid and total antioxidant capacity in one of the oil companies in Iran

Environmental Science and Pollution Research - Benzene is a carcinogenic chemical substance which causes the injuries and damages through producing the free radicals in DNA (deoxyribonucleic acid)...     

Geochemical fractions and phytoavailability of Zinc in a contaminated calcareous soil affected by biotic and abiotic amendments

Many studies have conducted to determine the best management practice to reduce the mobility and phytoavailability of the trace metals in contaminated soils. In this study, geochemical speciation and phytoavailability of Zn for sunflower were studied after application of nanoparticles (SiO₂ and zeolite, with an application rate of 200 mg kg^?1) and bacteria [Bacillus safensis FO-036b(T) and Pseudomonas fluorescens p.f.169] to a calcareous heavily contaminated soil. Results showed that the biotic and abiotic treatments significantly reduced the Zn concentration in the aboveground to non-toxicity levels compared to the control treatment, and the nanoparticle treatments were more effective than the bacteria and control treatments. The concentration of CaCl₂-extractable Zn in the treated soils was significantly lower than those of the control treatment. The results of sequential extraction showed that the maximum portion of total Zn belonged to the fraction associated with iron and manganese oxides. On the contrary, the minimum percent belonged to the exchangeable and water-soluble Zn (F₁). From the environmental point of view, the fraction associated with iron and manganese oxides is less bioavailable than the F₁ and carbonated fractions. On the basis of plant growth promotion, simultaneous application of the biotic and abiotic treatments significantly increased the aboveground dry biomass yield and also significantly reduced the CaCl₂-extractable form, uptake by aboveground and translocation factor of Zn compared to the control treatment. Therefore, it might be suggested as an efficient strategy to promote the plant growth and reduce the mobile and available forms of toxic metals in calcareous heavily contaminated soils.     

Correction to: Evaluating the relationship between the respiratory exposure to the benzene with the primary damages of deoxyribonucleic acid and total antioxidant capacity in one of the oil companies in Iran

Environmental Science and Pollution Research -