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Kardash E.,The National Physical Laboratory of Israel INPL | Kuselman I.,The National Physical Laboratory of Israel INPL | Pankratov I.,National Water Monitoring Laboratory | Elhanan S.,National Water Monitoring Laboratory
Accreditation and Quality Assurance | Year: 2013

A proficiency testing (PT) scheme was designed for measurements of pH and electrolytic conductivity (EC) of groundwater in Israel. A groundwater sample was used for preparation of test items fit-for-intended-use. The interlaboratory experiment was organized taking into account changes of the test item properties which occurred after sampling due to presence of CO2 in the groundwater. A total of 34 PT participants reported pH measurements results, while 29 of them reported results of EC measurements. The pH results were normally distributed. However, a significant bias of the pH consensus value of the PT participants from the metrologically traceable certified value (obtained by the National Physical Laboratory of Israel) was detected. This bias was caused by the drift of the measurement response due to water stirring and CO2 degassing from the sample during the measurement process. The bias of the EC consensus value from the metrologically traceable one was negligible, in spite of an abnormal distribution of the EC results of the PT participants. © 2013 Springer-Verlag Berlin Heidelberg.

Pankratov I.,National Water Monitoring Laboratory | Elhanany S.,National Water Monitoring Laboratory | Henig S.,National Water Monitoring Laboratory | Zaritsky S.,National Water Monitoring Laboratory | And 2 more authors.
Accreditation and Quality Assurance | Year: 2010

A proficiency testing (PT) scheme was developed for a limited number of analytical laboratories participating in the analysis of natural water in Israel. Three fit-for-intended-use reference materials (RMs) were prepared for a pilot PT from natural water: RM-blank and two in-house reference materials (IHRMs) with seven analytes fortified to achieve different levels of analyte concentrations. The measurands for the PT participants were the traceable spike values certified in the IHRMs, i.e., added mass concentrations of the analytes. The RM-blank and IHRMs were found to be homogeneous and stable over 11 days, the time necessary for the experimental part of the PT. The RMs were distributed to the PT participants as unknown test items similar to routine samples. The test results were evaluated using their deviations from the IHRM-certified values. Eight Israeli laboratories took part in the interlaboratory comparison. Individual laboratory performance and metrological compatibility of the PT results of the participants, as a local group of laboratories, were evaluated for every analyte. © 2010 Springer-Verlag.

Zentner E.,Ben - Gurion University of the Negev | Gerstl Z.,Institute of Soils | Weisbrod N.,Ben - Gurion University of the Negev | Lev O.,Hebrew University of Jerusalem | And 5 more authors.
Vadose Zone Journal | Year: 2015

Six boreholes were drilled during the course of a year to a depth of 2 m beneath the water table, located at a depth of about 28 m, under agricultural land sprinkler irrigated with treated sewage effluents in the Coastal Plain aquifer of Israel to determine the extent of penetration of 20 pharmaceuticals and personal care products (PPCPs) into the unsaturated zone. The fields were planted to turf and had different histories of effluent irrigation. From each borehole, 7 to 21 samples were taken for analysis of PPCPs, as was the underlying groundwater. Nine PPCPs (carbamazepine and its metabolite 10-hydroxy-10,11-dihydrocarbamazepine, acridone and acridine, venlafaxine, sulfamethoxazole, oxcarbazepine, O-desmethylvenlafaxine, and caffeine) were detected in the vadose zone of the study area to a depth of 27 m. For example, the detected concentrations of carbamazepine were up to 109 ng/kg, of caffeine up to 36,700 ng/kg, and of venlafaxine up to 50 ng/kg. Only five of the compounds (carbamazepine, acridone, venlafaxine, sulfamethoxazole, and caffeine) were found in the underlying groundwater with concentrations in the nanogram per liter range. The results of this work show that significant amounts of PPCPs can penetrate even a thick vadose zone of 27 m with sections containing up to 50% clay and up to 0.40% soil organic C. Venlafaxine, for example, penetrated the vadose zone at an average velocity of 2.8 to 4 m/yr. Irrigation with treated sewage effluents or contaminated water should be carefully considered if the penetration of PPCPs into groundwater is undesirable. © Soil Science Society of America.

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