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Chemical and statistical regression analysis on groundwater at five fields (17 sampling wells) located in Dhamar city, the central highlands of Yemen, was carried out. Samples were collected from the ground water supplies (tube wells) during the year 2015. Physical parameters studied include (values between bracket s represents the measured mean values) temperature (T, 25°), total dissolved solids (TDS, 271.47), pH (7.5), and electrical conductivity (EC, 424.18). The chemical parameters investigated include total hardness (TH, 127.45), calcium (Ca2+, 32.89), magnesium (Mg2+, 11.03), bicarbonate (HCO3̶, 143.84), sulphate (SO42-, 143.84), sodium (Na+, 35.11), potassium (K+, 6.28) and Chloride (Cl ̵, 22.69). The results were compared with drinking water quality standards issued by Yemen standards for drinking water. Except for T° and pH, all other measured parameters fall below the minimum permissible limits. The correlation between various physio-chemical parameters of the studied water wells was performed using Principal Component Analysis (PCA) method. The obtained results show that all water samples are potable and can be safely used for both drinking and irrigation purposes. This comes in agreement with the public notion about groundwater of Dhamar Governorate. Sodium Absorption Ratio (SAR) values were calculated and found below 3 except for one drill. The results revealed that systematic calculations of correlation coefficients between water parameters and regression analysis provide a useful means for rapid monitoring of water quality.International Journal of EnvironmentVolume-6, Issue-4, Sep-Nov 2017, page: 56-71

The present study reports the characterization of four degradation products from ezetemibe (EZB) through liquid chromatography-tandem mass spectrometry (LC-MS/MS) and the development of a validated and stability-indicating reversedphase ultra-performance liquid chromatographic method for the determination of EZB in the presence of its process-related impurities in bulk drugs. The forced decomposition of EZB was carried out and studied under acidic, basic, oxidative, photolytic and thermal conditions. The degradation of EZB was observed under basic and acidic conditions, and four degradation products (DPs) were formed. Successful chromatographic separation of EZB and its degradation products were successfully separated through chromatography with a Waters Acquity HSST3 C18 stationary phase (50 × 2.1 mm, 1.7 m). The analytes were detected with a PDA detector set at 230 nm. The figures of merit for this method were adequate. The assay remained linear from concentrations of 0.09 g mL −1 to 600 g mL −1 for EZB and its four DPs (r 2 = 0.99914, 0.99945, 0.99917, 0.99923 and 0.99936 for EZB, Imp-A, Imp-B, Imp-C, and Imp-D, respectively). The method precision, which was expressed as the %RSD, ranged from 0.2 to 1.0 for the four impurities. The DPs from EZB were characterized by LC-MS/MS, and the most likely degradation and fragmentation pathways for EZB and its DPs were proposed.