Health effects associated with long-term occupational exposure of employees of a chlor-alkali plant to mercury

This study aimed to evaluate possible health effects associated with long-term occupational exposure to low levels of mercury vapors. Forty-six subjects exposed to mercury and 65 healthy unexposed employees were studied. The subjects were administered a questionnaire on experienced symptoms and underwent clinical examinations as well as routine biochemical tests. Atmospheric and urinary concentrations of mercury were measured, too. Environmental concentrations of mercury were estimated to be 3.97 ± 6.28 μg/m(3) and urinary concentrations of mercury in exposed and referent groups were 34.30 ± 26.77 and 10.15 ± 3.82 μg/dm(3), respectively. Additionally, symptoms such as somatic fatigue, anorexia, loss of memory, erethism, blurred vision and teeth problems were significantly more common among exposed individuals. These observations indicate that occupational exposure to mercury vapors, even at low levels, is likely to be associated with neurological and psychological symptoms.     

Development of GP and GEP models to estimate an environmental issue induced by blasting operation

Air overpressure (AOp) is one of the most adverse effects induced by blasting in the surface mines and civil projects. So, proper evaluation and estimation of the AOp is important for minimizing the environmental problems resulting from blasting. The main aim of this study is to estimate AOp produced by blasting operation in Miduk copper mine, Iran, developing two artificial intelligence models, i.e., genetic programming (GP) and gene expression programming (GEP). Then, the accuracy of the GP and GEP models has been compared to multiple linear regression (MLR) and three empirical models. For this purpose, 92 blasting events were investigated, and subsequently, the AOp values were carefully measured. Moreover, in each operation, the values of maximum charge per delay and distance from blast points, as two effective parameters on the AOp, were measured. After predicting by the predictive models, their performance prediction was checked in terms of variance account for (VAF), coefficient of determination (CoD), and root mean square error (RMSE). Finally, it was found that the GEP with VAF of 94.12%, CoD of 0.941, and RMSE of 0.06 is a more precise model than other predictive models for the AOp prediction in the Miduk copper mine, and it can be introduced as a new powerful tool for estimating the AOp resulting from blasting.     

Long-term impact of municipal sewage irrigation on treated soil and black locust trees in a semi-arid suburban area of Iran

The effects of municipal sewage irrigation on the soil and black locust (Robinia pseudoacacia L.) tree were studied. For this purpose, two artificial black locust stands under irrigation of municipal sewage and well water were selected in south of Tehran, Iran. Data were collected using technique of systematic random sampling with 4 replicates in each stand. It was found that the growth of black locust tree, as indicated by diameter at breast height, total height, crown length, average crown diameter, basal area and volume, in sewage irrigation stand was much higher than that of well water irrigation stand (P < 0.01). Plant analysis indicated that concentrations of leaf nutrients (N, P, K, Ca, Mg, Na, Fe, Mn, Cu and Zn) were greater in sewage-irrigated trees, without toxicity to the minerals of tree leaf, than those of well waterirrigated trees, and positively correlated with their respective value in soil. Ni, Cr and Pb were not detected in leaf samples. Application of sewage resulted in a 1.5-fold increase in the concentrations of soil nutrients, Ni, Cr and Pb. Among these minerals only Pb and Ni in some soil samples exceeded the toxicity limit. The increase in pH, electrical conductivity (EC) and organic carbon of soil was also observed in sewage irrigation. Results confirm that besides the use as irrigation water, municipal sewages are also a potential source of plant nutrients. However, significant accumulation of heavy metals such as Pb and Ni in soil needs to be monitored.     

Optimization and treatment of wastewater of crude oil desalting unit and prediction of scale formation

In this article, one of Iran’s southwest oil fields that produces 3200 barrels per day (bbl/d) of wastewater from oil and gas processing was investigated. Experimental analysis of oil reservoir water and desalting wastewater disposal of crude oil desalting unit was performed. First, water was treated with a reverse osmosis membrane. As a result, the purified water, with lower total dissolved solids (TDS) and pH, was a suitable candidate for injection into the adjacent wells of the crude oil desalting unit. The effectiveness and compatibility of this wastewater to the formation water of the oil field wells were simulated. Finally, we studied and identified the formation, the amount, and the type of mineral scale deposits. These are the most important problems during water injection into the wells. The analysis shows that the refined water from the reverse osmosis (RO) process was a suitable and low-cost economical option for injection in onshore and offshore fields, due to the low amount of salts, the concentration of susceptible ions in scaling formation, and the appropriate pH. This oil field, which is in the second half of life, requires enhanced oil recovery methods (EOR) for the maintenance of pressure and an increase in oil recovery.

     

Assessment of anticipated performance index of some deciduous plant species under dust air pollution

Environmental Science and Pollution Research - Green vegetation improvement is an economical strategy to mitigate dust air pollution. The anticipated performance index (API) is considered a main...     

An eco-friendly and simple sol-gel autocombustion method for synthesis of copper hexaferrite nanostructures: characterization and photocatalytic activity for elimination of water contaminations

Environmental Science and Pollution Research - In this work, copper hexaferrite (CuFe12O19) nanostructures are successfully synthesized by the sol-gel autocombustion route. Two natural reagents...     

The long-term effect of exposure to respirable particulate matter on the incidence of myocardial infarction: a systematic review and meta-analysis study

Environmental Science and Pollution Research - Although several studies have investigated the long-term association of respirable particulate matter (PM?≤?10&nbsp;µm)...     

In Vitro and In Vivo Anticancer Activity of Ferula Gummosa Essential Oil Nanoemulsions (FGEO-NE) for the Colon Cancer Treatment

This survey was performed to aim of synthesize Nano emulsion from Ferula gummosa essential oil (FEGO-NE) and to evaluate its anti-tumor effect. First, Ferula gummosa essential oil was analyzed by GC–MS method, and then the Nano emulsion was synthesized as O/W and after characterization by DLS, Zeta potential, AFM, FESEM and TEM methods, its toxicity was evaluated by MTT method. Then its pro-apoptotic effects were evaluated by qPCR (Caspase3, 9, Bax and Bcl-2) method and AO/PI staining. The cancer induction model was used to evaluate the antitumor effects in Balb/C mice. The anti-angiogenic and antioxidant effects were evaluated by qPCR (VEGF, CAT and SOD) method. The results of physicochemical studies showed the formation of droplet with dimensions of 24.6 nm, dispersion index of 0.41 and zeta potential of ? 28.5 mV with a spherical morphology. The Nano emulsion synthesized at a concentration of 2.9 μg/mL inhibited about 50% of ht-29 cells, while up to a concentration of 4 μg/mL showed no inhibitory effect on normal cells. Increase of caspase 3, 9 and Bax and decrease of BCL-2 gene expression along with increase of apoptotic cells in AP/PI staining confirmed induction of apoptosis by FEGO-NE. The FEGO-NE showed an inhibitory effect on angiogenesis and an additive effect on the expression of antioxidant genes. In addition, the reduction of tumor volume (69.72% in 14 days) in samples treated with FEGO-NE was confirmed. The results of this study showed that FEGO-NE by various mechanisms are able to inhibit cancer cells and have a reducing effect on induced tumors in the in vivo model. These results suggest FEGO-NEs as a suitable candidate for cancer therapy studies.

     

Seasonal variations of polycyclic aromatic hydrocarbons in coastal sediments of a marine resource hot spot: the case of pars special economic energy zone,Iran

Environmental Geochemistry and Health - Polycyclic aromatic hydrocarbons (PAHs) are an important group of compounds of major environmental concern, which are in the class of persistent organic...     

Carbon and energy taxation for CO<Subscript>2</Subscript> mitigation: a CGE model of the Malaysia

Malaysia has made a pledge to reduce voluntarily her carbon dioxide-equivalent (CO₂-e) gas emission’s intensity of gross domestic product by up to 40 % based on 2005 levels by 2020. The country is considering implementing economic instruments, among others, to assist the achievement of emission reduction targets while contributing towards the nation’s energy security and sustainable development goals. This paper develops a computable general equilibrium model with explicit energy-emission linkages to appraise the economy-wide and welfare impacts of carbon and energy tax policies to reduce CO₂ emissions in Malaysia. Results indicate that the negative macroeconomic impacts of carbon and energy taxes are small relative to the quantum of emission reduction. A Hicksian welfare criterion is utilized to determine the impact of revenue natural shifts in carbon and energy taxes. Revenue neutrality assumptions show that carbon taxation is the best choice when it can provide a double dividend if the generated revenue is used for the purpose of consumption subsidy on household purchases. The notion of the double dividend is confirmed when the change in the consumption structure will result in a welfare improvement, while CO₂ emission is decreased effectively. The study also found that carbon tax policy results in greater emission reductions relative to energy taxes, while the use of renewable energy will increase more substantially.