Mechanochemical activation for lead extraction from spent cathode ray tube

Journal of Material Cycles and Waste Management - In this study, a mechanochemical activation technique to effectually extract lead from the funnel glass of cathode ray tube (CRT) is proposed. A...     

Optimizing safety-constrained solvent selection for process systems with economic uncertainties

Solvents are very commonly used in industrial facilities for a multitude of reasons. Traditionally, solvent selection has been based on minimizing the process operating cost while satisfying a set of operational requirements. Regrettably, safety considerations have typically been overlooked during the design phase. In this paper, a systematic approach is introduced to integrate safety issues into solvent selection and provides a computationally effective method for establishing tradeoffs between the economic and safety objectives. In order to quantify the risk associated with the solvent, we focus on the potential spillage of the solvent and introduce a risk index that is a function of the amount of solvent used and stored, as well as the Permissible Exposure Limit (PEL) dictated by regulatory directives. An optimization formulation is developed and the associated mathematical program solved to select optimal solvents and blends while incorporating economic, technical, and safety considerations. Tradeoff (Pareto) curves are developed to represent the multi-objective optimization results and tradeoffs. Furthermore, economic-data uncertainty and variability over expected ranges are included in the optimization formulation to conduct an insightful sensitivity analysis. Finally, an illustrative case study is considered via increasing levels of complexity in order to evaluate the proposed optimization method which considers both operating cost and safety risk implications in the presence of economic uncertainties.     

A Multi‐Agency Nutrient Dataset Used to Estimate Loads,Improve Monitoring Design,and Calibrate Regional Nutrient SPARROW Models1

Saad, David A., Gregory E. Schwarz, Dale M. Robertson, and Nathaniel L. Booth, 2011. A Multi‐Agency Nutrient Dataset Used to Estimate Loads, Improve Monitoring Design, and Calibrate Regional Nutrient SPARROW Models. Journal of the American Water Resources Association (JAWRA) 47(5):933‐949. DOI: 10.1111/j.1752‐1688. 2011.00575.x Abstract: Stream‐loading information was compiled from federal, state, and local agencies, and selected universities as part of an effort to develop regional SPAtially Referenced Regressions On Watershed attributes (SPARROW) models to help describe the distribution, sources, and transport of nutrients in streams throughout much of the United States. After screening, 2,739 sites, sampled by 73 agencies, were identified as having suitable data for calculating long‐term mean annual nutrient loads required for SPARROW model calibration. These sites had a wide range in nutrient concentrations, loads, and yields, and environmental characteristics in their basins. An analysis of the accuracy in load estimates relative to site attributes indicated that accuracy in loads improve with increases in the number of observations, the proportion of uncensored data, and the variability in flow on observation days, whereas accuracy declines with increases in the root mean square error of the water‐quality model, the flow‐bias ratio, the number of days between samples, the variability in daily streamflow for the prediction period, and if the load estimate has been detrended. Based on compiled data, all areas of the country had recent declines in the number of sites with sufficient water‐quality data to compute accurate annual loads and support regional modeling analyses. These declines were caused by decreases in the number of sites being sampled and data not being entered in readily accessible databases.     

Impact assessment of subsurface drainage on waterlogged and saline lands

Waterlogging and salinity due to seepage from canals have polluted land and environment in various parts of Pakistan. A sustainable environment requires urgent remedial measures for this problem. The research in this paper presents the impacts of the Fourth Drainage Project, Faisalabad on the twin problem of waterlogging and salinity. Monitoring of the project was made on regular basis. The key performance indicators for the project include the lowering of water table, improvement of water quality and soil salinity, increase in area under cultivation, cropping intensity, and socioeconomic status of the project population. Data regarding water levels and discharge from the drain pipes were collected to monitor the impact on waterlogging. Soil samples were tested to evaluate the impact of drainage on land. It has been found that the percentage of the contaminated land in the project area has considerably been decreased, while the cropping intensities have been increased.     

Umbelliferone ameliorates ulcerative colitis induced by acetic acid via modulation of TLR4/NF-κB-p65/iNOS and SIRT1/PPARγ signaling pathways in rats

Environmental Science and Pollution Research - Ulcerative colitis (UC) is a common chronic, idiopathic inflammatory bowel disease associated with inflammatory perturbation and oxidative stress....     

The ameliorative effect of kaempferol against CdCl2- mediated renal damage entails activation of Nrf2 and inhibition of NF-kB

Environmental Science and Pollution Research - This study evaluated the nephroprotective effect of kaempferol against cadmium chloride (CdCl2) -induced nephropathy in rats. It also investigated if...     

Assessment of arsenic level in the hair of the nonoccupational Egyptian population: pilot study.

Arsenic level of hair samples of apparently healthy Egyptian was measured by means of hydride atomic absorption spectrophotometery. It ranged between 0.04 and 1.04 mg As/kg hair, about 55% of the analysed hair samples were within the range of allowable values (0.08-0.25 mg As/kg hair), but 45% were not. There were no considerable sex-related differences (0.303 and 0.292 mg As/kg hair for males and females, respectively). Different educational levels did not influence it either, when the effect of the age had been excluded. Children and adolescents proved to be more susceptible to arsenic as their mean levels (0.353 microg/g), and were significantly higher than those in the adults (0.233 microg/g). Smoking and some dietary habits had an important role in the elevation of arsenic levels among the nonoccupational Egyptian population: 60% of smokers and 66.7% of indoor passive smokers had arsenic levels >0.25 mg As/kg hair. Arsenic levels were also dependent on the kind of smoking, as hair arsenic of the subject smoking molasses tobacco was found to be significantly higher than that of cigarette smokers (0.459 and 0.209 mg As/kg hair, respectively). The frequency of meat and fish consumption per week was also found to be positively, significantly correlated with arsenic levels. On the other hand, the frequency of consumption of fruits, fresh and cooked vegetables, milk and milk products per week beneficially influenced the arsenic level of the hair samples examined. Arsenic content of the consumed water in Egypt was 0.001 mg/l, which is below the maximum drinking water level allowed by World Health Organisation (WHO). Therefore, the arsenic content of domestic tap water hardly contributed to the arsenic exposure of the Egyptian population in the regions of the study. It is likely that exposure routes by smoking, fish and animal protein consumption are the principal cause of arsenic accumulation in the general Egyptian population.     

Swelling related to ettringite crystal formation in chromite ore processing residue

Several million tons of Chromite Ore Processing Residue (COPR) were deposited at two sites in New Jersey and Maryland, USA, and over time they exhibited extensive heaving phenomena. Ettringite, a needle-shaped mineral and an expansive mineral commonly recognized in the literature concerning cement- and soil, has been identified extensively in numerous COPR samples collected from these sites. It was therefore believed that ettringite formation and its crystal growth are strongly associated with COPR heaving. We investigated the correlation between ettringite and the heaving phenomena in COPR materials that contained no initial ettringite. Two identical COPR samples were exposed to a 4% w/w sulfate solution (25°C, 50°C) in a confined swell test apparatus. Both swell test samples were analyzed by means of X-ray powder diffraction. The peak intensities of newly formed ettringite were more pronounced in the sample tested at 50°C, and swell development was only observed in this sample. Scanning electron microscopy analyses revealed well-crystallized ettringite needles exceeding 40 μm in length for this sample, while ettringite crystals less than 15 μm in length formed in the sample tested at 25°C. Therefore, the results suggest that the quantity of ettringite and the extent of crystallization play a key role in the heave of COPR.     

Status of electronic waste recycling techniques: a review

Environmental Science and Pollution Research - The increasing use of electrical and electronic equipment leads to a huge generation of electronic waste (e-waste). It is the fastest growing waste...     

The Effect of Sewage Discharge On Water Quality Off the Coast of Alexandria in Spring and Summer

Water samples were taken from 7 transects at El-Anfushy, Eastern Harbour, El-Ebrahymea, Stanly, Gleem, Sidi-Bishr and El-Asafra along the coast off Alexandria. the area lies between latitude 31°10' and 31°20' N and longitude 29°55' and 30° E. Nitrate, nitrite, ammonium, urea, dissolved inorganic phosphate, silicate and pH values were measured with average values 1,13, 0.43, 1.41, 1.21, 1.71, 7.16 μmol l^-1, respectively. the investigated area is considered to be eutrophic. Levels of nutrients measured in 1991 are all significantly higher than those found in the same area in 1976.