Optimal design of additional sampling pattern for drinking-water quality control

A crucial step in complementary studies of the water quality determination is to design the additional sampling pattern or, in other words, to determine the number and location of the additional samples. Since location and number of samples highly affect decisions’ uncertainties, and because sampling process is quite costly and time-consuming, optimization of the sampling pattern will enhance the efficiency and productivity. Solution of such an optimization problem requires defining an objective function and constraints. There exist many previous studies regarding locating additional samples in other environmental problems wherein the objective function is defined as the minimization of the kriging variance (based on the problem nature), but the point is that kriging variance is not sensitive to local variability. Since manner and extent of small-scale variations are both important and necessary in water quality studies, it is required to resolve this shortcoming of the traditional objective function. Solution is to make use of the combined variance consisting of kriging and local variances. In this study, the applicability and efficiency of the minimization of combined variance as the objective function of the additional sampling was adopted and proved for a salt marsh (east of Iran) on the basis of a simulated annealing-based algorithm. It was shown, practically, that the locational distribution of additional sampling points is quite logical and more compatible with experts’ proposed methods using this objective function (compared to the traditional one).     

Induction of apoptosis and cytokine markers in colon cancer cells by magnesium oxide (MgO) nanoparticles

Magnesium oxide nanoparticles (MgONP) are predominantly utilized in industrial products. This study was undertaken to elucidate the mechanisms underlying toxic effect of MgONP in human colon cancer (HT 29) cells over 48 hr period. Cytotoxicity was evaluated by using MTT and neutral red uptake assays. Data demonstrated that MgONP reduced cell viability in concentration- and time-dependent manner. MgONP induced oxidative stress by decreasing glutathione (GSH) concentrations and elevation of reactive oxygen species (ROS) and lipid peroxidation levels. Increased caspase-3 enzyme activity and greater condensed, damaged chromosome was observed following MgONP exposure in HT 29 cells. The level of interleukin-4 (IL-4), tumor necrosis factor (TNF-α), and DNA fragmentation were significantly higher in MgONP incubated cells. The results showed that MgONP-induced toxicity in HT 29 cells may be mediated through oxidative stress.     

Numerical modelling of the groundwater inflow to an advancing open pit mine: Kolahdarvazeh pit,Central Iran

The groundwater inflow into a mine during its life and after ceasing operations is one of the most important concerns of the mining industry. This paper presents a hydrogeological assessment of the Irankuh Zn-Pb mine at 20 km south of Esfahan and 1 km northeast of Abnil in west-Central Iran. During mine excavation, the upper impervious bed of a confined aquifer was broken and water at high-pressure flowed into an open pit mine associated with the Kolahdarvazeh deposit. The inflow rates were 6.7 and 1.4 m³/s at the maximum and minimum quantities, respectively. Permeability, storage coefficient, thickness and initial head of the fully saturated confined aquifer were 3.5?×?10^?4 m/s, 0.2, 30 m and 60 m, respectively. The hydraulic heads as a function of time were monitored at four observation wells in the vicinity of the pit over 19 weeks and at an observation well near a test well over 21 h. In addition, by measuring the rate of pumping out from the pit sump, at a constant head (usually equal to height of the pit floor), the real inflow rates to the pit were monitored. The main innovations of this work were to make comparison between numerical modelling using a finite element software called SEEP/W and actual data related to inflow and extend the applicability of the numerical model. This model was further used to estimate the hydraulic heads at the observation wells around the pit over 19 weeks during mining operations. Data from a pump-out test and observation wells were used for model calibration and verification. In order to evaluate the model efficiency, the modelling results of inflow quantity and hydraulic heads were compared to those from analytical solutions, as well as the field data. The mean percent error in relation to field data for the inflow quantity was 0.108. It varied between 1.16 and 1.46 for hydraulic head predictions, which are much lower values than the mean percent errors resulted from the analytical solutions (from 1.8 to 5.3 for inflow and from 2.16 to 3.5 for hydraulic head predictions). The analytical solutions underestimated the inflow compared to the numerical model for the time period of 2–19 weeks. The results presented in this paper can be used for developing an effective dewatering program.     

Evaluation of anthropogenic effects on water quality and bacterial diversity in Rawal Lake,Islamabad

Water quality and bacterial diversity in the surface water of Rawal Lake was investigated for a period of 8 months to evaluate the pollution load from anthropogenic effects of surrounding areas. Rawal Lake in Islamabad, Pakistan is an artificial reservoir that provides the water needs for the residents of Rawalpindi and Islamabad. Grabbed water samples were collected according to standard protocols from ten different locations of the lake and tributaries keeping in view the recharge points from adjacent areas. Temperature, pH, electrical conductivity, dissolved oxygen, total dissolved solids, hardness, alkalinity, and turbidity of water samples were determined to study the water quality characteristics. The physicochemical parameters showed higher values at the tributaries as compared to the sampling locations within the lake such as values of hardness and alkalinity were 298 and 244 mg/L, respectively, at the tributary of the Nurpur stream. Bacterial strains were isolated by streaking on differential and selective growth media by observing colony morphology and other biochemical tests such as Gram reaction, oxidase, and catalase test. Template DNA was prepared from pure cultivated bacteria and 16S rRNA gene analysis was performed using universal primers for bacteria. Sequencing was performed by using BigDye terminator cycle sequencing kit. Sequences of nearest relative microbial species were identified by using basic local alignment search tool and used as reference sequences for phylogenetic analysis. Phylogenetic trees were inferred using the neighbor-joining method. Sequencing and phylogenetic characterization of microbes showed various phylotypes, of which Firmicutes, Teobacteria, and Proteobacteria were predominant.     

A Multi‐Scale Analysis of Low‐Rise Apartment Water Demand through Integration of Water Consumption,Land Use,and Demographic Data

Over the past decades, multi‐unit housing developments have been vastly expanded across urban areas due to the population growth. To properly supply water to this growing sector, it is essential to understand the determinants of its water use. However, this task has largely remained unexplored through the empirical study of water demand mainly due to the scarcity of data in this sector. This study integrated apartment water consumption, property characteristics, weather, water pricing, and census microdata to overcome this issue. Using a rich source of GIS‐based urban databases in Auckland, New Zealand, the study developed a large dataset containing the information of 18,000 low‐rise apartments to evaluate the determinants of water use both in the household scale and aggregated scale. The household‐scale demand analysis helped to assess the heterogeneity in responses to the demand drivers specifically water price across different consumer groups, whereas the aggregated analysis revealed the determinants behind the spatial variation in water demand at the census area unit level. Through applying panel data models, the study revealed the household size as the most important determinant of apartment water use in Auckland, where other socioeconomic factors, building features, and water pricing were not significant determinants. This knowledge of determinants of water demand can help water planners to better manage water demand in the compact urban environments.     

Sulfonated tea waste: A low-cost adsorbent for purification of biodiesel

In the present work, the crude biodiesel produced from spent fish frying oil through alkaline catalyzed transesterification was purified using a low-cost adsorbent viz. sulfonated tea waste. After separating the glycerol, the crude biodiesel was purified using the suggested adsorbent. Various methods of purification using the said adsorbent were applied such as purification using adsorption column chromatography and shaking methods. The results showed that purification using adsorption column chromatography exhibited the bst result. Properties of the purified fuels were determined and found conformed to those specified by the ASTM standards. For the sake of comparison, purification using zeolite and water washing method was also investigated. The result indicated that the suggested adsorbent was more successful on purification of the crude biodiesel compared to other methods.     

Recruiting chemical grafting method for surface modification of stainless steel to fabricate a selective sorbent for solid phase microextraction of mercury metal ion

Environmental Science and Pollution Research - Keeping selectiveness and efficiency in view with solid-phase microextraction (SPME) of metal ions, this work was aimed at synthesis of a novel...     

Biofuel types and membrane separation

Environmental Chemistry Letters - Global warming induced by greenhouse gases is major issue worldwide. There is therefore a need to develop renewable sources of energy, such as biofuels. Here, we...     

Spatial analysis of mortality rate of pedestrian accidents in Iran during 2012–2013

Objectives: Considering the high mortality rate of pedestrians in traffic accidents in Iran, the present study aimed to determine the high-risk and low-risk areas of accidents resulting in pedestrian deaths and the spatial analysis of their mortality rates.

Methods: This cross-sectional study included 4,371 deceased pedestrians reported by the Legal Medicine Organization in Iran from March 2012 to March 2013. For spatial analysis, the collected data were entered into ArcGIS software version 10.2 and a spatial map of the mortality rate was drawn according to the distribution of data in the provinces. Using this software, high-risk and low-risk areas were identified by calculating the spatial autocorrelation of the data. The Moran’s index of road accident patterns was surveyed and high-risk and low-risk points were identified using the local Getis index.

Results: The age-standardized incidence rate was 6.8 per 100,000. After analyzing the data using ArcGIS software, the local Moran’s index showed a cluster pattern with a high mortality rate in 3 provinces of Mazandaran, Gilan, and Qazvin. In identifying high-risk and low-risk points, the local Getis index showed 3 hot spots with a confidence interval of 99% in Qom, Qazvin, and Mazandaran and 5 hot spots with a 95% confidence interval in Markazi, Tehran, Zanjan, Gilan, and Golestan provinces.

Conclusions: According to the cluster pattern of accidents in the 3 provinces and the presence of hot spots in 9 provinces, it is necessary to identify factors that increase the risk of death in the study provinces in order to reduce the mortality rate among pedestrians due to traffic accidents. Therefore, to reduce the pedestrian mortality rate, especially in high-risk provinces, some studies need to be conducted to determine the risk factors in pedestrian mortality.