Accumulation of Pb and Cd in tissue of leek (Allium ampeloprasum persicum) and peppermint (Mentha piperita) treated with sewage sludge of Qods town’s treatment plant, Tehran

This study was carried out to investigate the accumulation of Pb and Cd in tissue of leek (Allium ampeloprasum persicum) and peppermint (Mentha piperita) treated with municipal sewage sludge of Qods town’s treatment plant, Tehran. For this purpose, after soil preparation, sampling of sewage sludge and assessment of the physicochemical properties of the samples, leek and peppermint plants were divided as treatment and control groups. Afterwards, using ICP-OES the concentrations of Pb and Cd were determined in the tissues of peppermint and leek. Results showed that the concentration (mean ± SD) of Pb in the control and treatment groups was 0.26±0.08 and 0.55±0.16 mg/kg, respectively. Pb concentration in peppermint samples was estimated as 0.26±0.06 and 2.41±0.79 mg/kg for control and treatment group, respectively. Moreover, the mean concentration of Cd in control and treatment groups of leek was 0.083±0.003 and 0.26±0.05 mg/kg and for peppermint 0.057±0.002 and 0.14±0.02 mg/kg, respectively. Comparative evaluation of the evaluated treatments showed that except for Cd in leek and peppermint treatment samples, the mean concentrations of Pb and Cd in both vegetables were significantly lower than EPA permissible limits for human consumption. The results of this study indicated that for reducing the health risks of long-term use of sewage sludge as fertilizer, further monitoring should be performed

Accurate capacity factor calculation of waste-to-energy power plants based on availability analysis and design/off-design performance

The aim of this study is to obtain more realistic estimations of the achievable capacity factor and availability of waste-to-energy power plants to better understand their economics, and hence facilitate appropriate deployment. Towards this aim, we introduce Markov analysis and off-design considerations into the calculation of plant performance. Parameters such as increasing failure rates as a result of aging, infant mortality failures, and overhauls are all taken into account with our approach. Meanwhile, the effect of failures on such plant's operating mode is evaluated, and Stodola's cone law is applied to calculate the actual power generation in off-design mode. A system divided into three main sub-components, two steam generation blocks and a power generation block, each of which has its own failure and repair rates, is proposed for this study. The state-space diagram of the proposed system is constructed and simplified, and the transient differential equations governing the state-space diagram are solved numerically. Having obtained the availability of the system and off-design performance, the capacity factor is calculated and compared with actual field data. Also, a new availability-based formulation is presented to obtain the net present value of the cash flow. Results show that by using a time-varying failure rate, the availability of the power plant declines about 23% over 20 years, a significant difference to estimated availability if a constant failure rate was assumed. Our findings highlight that the present price of electricity, $0.057 per kWh, for generation from the plant is insufficient to encourage investment in this technology in Iran at present, and greater deployment will require some form of policy intervention

Intraoperative Fluorescent Imaging of Intracranial Tumors: A Review

A review of fluorescent imaging for intracranial neoplasms is presented. Complete resection of brain cancer is seldom possible because of the goal to preserve brain tissue and the inability to visualize individual infiltrative tumor cells. Verification of histology and identification of tumor invasion in macroscopically normal-appearing brain tissue determine prognosis after resection of malignant gliomas. Therefore, imaging modalities aim to facilitate intraoperative decision-making. Intraoperative fluorescent imaging techniques have the potential to enable precise histopathologic diagnosis and to detect tumor remnants in the operative field. Macroscopic fluorescence imaging is effective for gross tumor detection. Microscopic imaging techniques enhance the sensitivity of the macroscopic observations and provide real-time histological information. Further development of clinical grade fluorescent agents specifically targeting tumor cells could improve the diagnostic and prognostic yield of intraoperative imaging. © 2013 Elsevier B.V

Impact of leachate on groundwater pollution due to non-engineered municipal solid waste landfill sites of erode city, Tamil Nadu, India

<p>Abstract</p> <p>Leachate and groundwater samples were collected from Vendipalayam, Semur and Vairapalayam landfill sites in Erode city, Tamil Nadu, India, to study the possible impact of leachate percolation on groundwater quality. Concentrations of various physicochemical parameters including heavy metals (Cd, Cr, Cu, Fe, Ni, Pb, Fe and Zn) were determined in leachate samples and are reported. The concentrations of Cl^-, NO₃^-, SO₄^2-, NH₄⁺ were found to be in considerable levels in the groundwater samples particularly near to the landfill sites, likely indicating that groundwater quality is being significantly affected by leachate percolation. Further they were proved to be the tracers for groundwater contamination near Semur and Vendipalayam dumpyards. The presence of contaminants in groundwater particularly near the landfill sites warns its quality and thus renders the associated aquifer unreliable for domestic water supply and other uses. Although some remedial measures are suggested to reduce further groundwater contamination via leachate percolation, the present study demands for the proper management of waste in Erode city.</p

The effects of wastewater reuse on potato growth properties under greenhouse lysimeteric condition

In this study, raw and treated wastewaters were reused for potato cultivation in order to verify the effect of wastewater on crop yield, crop’s heavy metals’ concentration as well as some major traits of potato. To this regard, a completely randomized test was designed with five water treatments and three replications. The watering were as follows: raw wastewater (T1), treated wastewater (T2), a combination of 50 % raw wastewater and 50 % fresh water (T3), a combination of 50 % treated wastewater and 50 % fresh water (T4), and fresh water (T5). The experiments were run during October 2009–June 2010 in the greenhouse of Bu-Ali Sina University. The results show that the effects of treatments were significant on the length and number of stems per plant (p < 0.05). The number of nodes and weight of tubers, crop yield and heavy metal (cadmium, nickel and lead) concentration in shoots and tubers were also significant (p < 0.01). The results indicated that the highest length of stem (55.44 cm) was obtained in T2 which had no significant differences from that of T1. The maximum and minimum tuber weights and crop yield were obtained in T1 and T5, respectively. Based on crop yield rate, the watering ranked as follows: T1 > T3 > T2 > T4 > T5. The maximum and minimum heavy metal values were observed in T1 and T5, respectively. Based on the cadmium, nickel and lead accumulations in shoots and tubers (except cadmium in shoots), the watering treatments ranked as: T1 > T3 > T2 > T4 > T5