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- ItemPredictive modeling of haloacetonitriles under uniform formation conditions(Water Research, 2021-05-31)The objective of this study was to develop models to predict the formation of HANs under uniform formation conditions (UFC) in chlorinated, choraminated, and perchlorinated/chloraminated waters of different origins. Model equations were developed using multiple linear regression analysis to predict the formation of dichloroacetonitrile (DCAN), HAN4 (trichloroacetonitrile [TCAN], DCAN, bromochloroacetonitrile [BCAN], and dibromoacetonitrile [DBAN]) and HAN6 (HAN4 plus monochloroacetonitrile, monobromoacetonitrile). The independent variables covered a wide range of values, and included ultraviolet absorbance, dissolved organic carbon, dissolved organic nitrogen, SUVA254, bromide, pH, oxidant dose, contact time, and temperature. The r2 values of HAN4 and HAN6 models of NOM, AOM, and EfOM impacted waters were within the range of 60-88%, while the r2 values of HAN4 and DCAN models for both groundwater and distribution systems were lower, in the range of 41-66%. The r2 values for the DCAN model were mostly higher in the individual types as compared to the cumulative analysis of all source water data together. This was attributed to differences in HAN precursor characteristics. For chlorination, among all variables, pH was found to be the most significant descriptor in the model equations describing the formation of DCAN, HAN4, and HAN6, and it was negatively correlated with HAN formation in the distribution system, groundwater, AOM, and NOM samples, while it showed an inverse relationship with HAN6 formation in effluent organic matter (EfOM) impacted waters. During chloramination, pH was the most influential model descriptor for DCAN formation in the NOM. Prechlorination dose was the most predominant parameter for prechlorination/chloramination, and it was positively correlated with HAN4 formation in AOM impacted waters.
- ItemCinnamon bark water-infusion as an in-vitro inhibitor of β-hematin formation(Academic Journals, 2015-10-10)Malaria remains one of the prominent public health problems that lead to severe morbidity and mortality in many developing countries around the globe. New antimalarial drugs are urgently needed due to the emergence of antimalarial-resistant strains of Plasmodium falciparum. In previous studies, we tested several plants extracts that are capable of inhibiting β-hematin formation, with efficiency similar to chloroquine. In the current study, the effect of cinnamon ethanol and water extracts on inhibiting β- hematin formation was studied. Powdered cinnamon extracts and bark in a stick form were investigated using various extraction methods. A semi-quantitative in vitro method, based on the inhibition of ferriprotoporphyrin IX (FP) bio-crystallization developed by Deharo et al. (2002) was utilized. Water extracts of cinnamon revealed potential activity even at low concentration of infusions, which was manifested by a high capability to inhibit β-hematin formation in vitro.
- ItemDetermination of trace heavy metals in harvested rainwater used for drinking in Hebron (south West Bank, Palestine) by ICP-MS(Springer, 2014-07-26)Rainwater samples harvested for drinking from the west part of Hebron (south of West Bank in Palestine), the largest city in the West Bank, were analyzed for the content of different trace heavy metals (Cr, Mn, Co, Ni, Cu, Zn, Mo, Ag, Cd, Bi, and Pb) by inductively coupled plasma mass spectrometry (ICPMS). This study was conducted to determine the water quality of harvested rainwater used for drinking of south West Bank (case study, Hebron area).A total of 44water samples were collected in November 2012 from 44 house cisterns used to collect rainwater from the roofs of houses. The samples were analyzed for their pH, temperature, electrical conductivity, total dissolved solids, and different heavy metal contents. The pH of all water samples was within the US Environmental Protection Agency limits (6.5–8.5), while some water samples were found to exceed the allowed WHO limit for total dissolved solids (TDSs) in drinking water. Results showed that concentrations of the heavy metals vary significantly between the 44 samples. Results also showed that the concentration of five heavy metals (Cr, Mn, Ni, Ag, and Pb) is higher than the WHO limits for these heavy metals in drinking water. Overall, our findings revealed that harvested rainwater used for drinking of this part of south West Bank is contaminated with heavy metals that might affect human health.
- ItemAssessment of Groundwater Pollution with Heavy Metals in North West Bank/Palestine by ICP-MS(Scientific Research, 2014-01-06)Groundwater of North West Bank in Palestine was assessed for pollution with trace metals by ICP/MS. The samples were analysed for their pH, electrical conductivity, total dissolved solids, and different trace metals content. The pH, electrical conductivity, and total dissolved solids of all water samples were found to be within the US Environmental protection Agency limits. Results showed that the concentration of nine trace metals (Cr, Mn, Ni, Cu, Zn, Mo, Pb, Cd, and Al) is within the WHO limits in drinking water (50, 500, 20, 2000, 3000, 70, 10, 3, and 200 ug/L, respectively), however six metals of them (Cr, Mn, Ni, Cu, Mo, and Al) were detected in 100% of the samples, while Pb, Cd, and Zn were detected in 80%, 60%, and 20% of the samples, respectively. On the other hand, Tl which is a very toxic heavy metal with allowed WHO limits of 0.01 - 1 ug/L is detected in 100% of the water samples analysed with a range of 0.02 - 0.12 ug/L. It indicates that such concentration levels of Tl would be harmful to the human being drinking the water. In general, 82% of all samples analysed contained one or more of the 12 metals studied each in varying concentration. Results of this study suggest a possible risk to the people of the study area given the toxicity of heavy metals, and the fact that for many people in the study area, groundwater is a main source of their water supply.
- ItemMethod development and validation of simultaneous determination of seventeenmetals in water by ICP/MS(Council for Innovative Research, 2013)A simple, precise, accurate, and sensitive method is developed and validated for simultaneous determination of seventeen metals (Li, Sr, Ba, Tl, Pb, Bi, Al, K, Cr, Mn, Co, Ni, Cu, Zn, Mo, Ag, and Cd) in water by ICP-MS. The optimum conditions of the ICP-MS are as follows: nebulizer gas (argon) flow rate: 0.9 L/min, auxiliary gas (argon) flow 0.3 L/min, plasma (argon) gas flow: 15 L/min, reaction gas flow (helium) 4mL/min. This method is validated according to the requirements for new methods, which include linearity and range, accuracy, precision, selectivity, limit of detection (LOD), and limit of quntitation (LOQ). The current method demonstrates good linearity over the range of 1-1000 ppb with r2 greater than 0.999 for the seventeen metals. The recovery of the metals from water samples ranges from 97.5 to 101.7%. The method is selective where minimal interferences between the metals is observed (CeO/Ce = 1%, and Ce+2/Ce+1 = 1%), and with good resolution (0.8 amu at 10% height). The method is also precise where the RSD of the responses (cps) of replicates of the metals at three concentration levels is less than 1%. Low LOD and LOQ of metals using this method enable the detection and quantitation of these metals at low concentrations. Real water samples from West Bank in Palestine (groundwater) were analyzed for their trace metals content using this method.