Simultaneous determination of specific alpha and beta emitters by LSC-PLS in water samples

Simultaneous determination of 210Pb and 90Sr and 210Po isolation in sludge samples using a plastic scintillation resin

This study describes a new and fast method for separating ²¹⁰Po from ²¹⁰Pb and ⁹⁰Sr, before simultaneously measuring the individual activities of the latter two radionuclides using a plastic scintillation resin (PSresin) in sludge samples taken from a drinking water treatment plant. This method speeds up the analysis process significantly by simultaneously measuring ²¹⁰Pb and ⁹⁰Sr in a single step. The method is reproducible and has a relative standard deviation of less than 25% for ²¹⁰Pb, ²¹⁰Po and ⁹⁰Sr. The method was satisfactorily validated with an intercomparison sample and applied to sludge samples from a drinking water treatment plant. The minimum detectable activities for 0.9 g of sludge are 5.5 Bq/kg and 8 Bq/kg for ²¹⁰Pb and ⁹⁰Sr respectively when measured for 180 min, and 0.5 Bq/kg for ²¹⁰Po when measured for 5000 min.

DECLAB: a software for liquid scintillation spectra deconvolution

The deconvolution of liquid scintillation (LS) spectra is meaningful in several scenarios like supporting incomplete radiochemical separations, for screening purposes and determining different isotopes of the same element, which is explored in this paper for the case of 89Sr/90Sr. In this paper DECLAB, an online application for liquid scintillation spectra analysis is presented. The software considers the classical calibration modes like constant efficiency and quenching curve and furthermore, the deconvolution of multicomponent spectra by means of Partial Least Square Regression. DECLAB is designed to analyse Perkin Elmer Wallac Quantulus 1220 spectra. However, in further upgrades, the applicability of this tool will be extended to other LS spectrometers.

A review of the analytical methodology to determine Radium-226 and Radium-228 in drinking waters

Radium-228 (228Ra) and Radium-226 (226Ra) isotopes in drinking water are significant from the aspect of radiation protection and human health. In this paper, the three most common preconcentration methods, i.e.coprecipitation, absorption and evaporation, were reviewed with emphasis on routinely measurement techniques. The reviewed measurement techniques include low background γ-spectrometry, α-spectrometry and liquid scintillation counting. The γ-spectrometry technique is the good selection, when the maximum sensitivity is considered. The Environmental Protection Agency guideline has provided the maximum concentration level 0.74 Bq/L for 226Ra and 228Ra. Also, the World Health Organization guideline limit is 1 Bq/L and 0.1 Bq/L for 226Ra and 228Ra, respectively.

Simultaneous determination of 226Ra, 228Ra and 210Pb in drinking water using 3M Empore™ RAD disk by LSC-PLS

A procedure for the rapid and simultaneous determination of ²²⁶Ra, ²²⁸Ra and ²¹⁰Pb in drinking water by means of extraction with a 3M Empore™ Radium RAD disk and liquid scintillation spectrometry is described. The selective elution of ²¹⁰Pb from the RAD disk and a multivariate calibration using partial least squares regression (PLS) are tested as methods to avoid overlap in the spectra between ²²⁸Ra and ²¹⁰Pb. The validated procedure was tested with mixtures of radionuclides and interlaboratory materials; finally, it was applied to natural waters.

FRNA Bacteriophages as Viral Indicators of Faecal Contamination in Mexican Tropical Aquatic Systems

A particular challenge to water safety in populous intertropical regions is the lack of reliable faecal indicators to detect microbiological contamination of water, while the numerical relationships of specific viral indicators remain largely unexplored. The aim of this study was to investigate the numerical relationships of FRNA-bacteriophage genotypes, adenovirus 41, and human adenoviruses (HADV) in Mexican surface water systems to assess sewage contamination. We studied the presence of HADV, HADV41 and FRNA bacteriophage genotypes in water samples and quantified by qPCR and RT-qPCR. Virus and water quality indicator variances, as analyzed by principal component analysis and partial least squared regression, followed along the major percentiles of water faecal enterococci. FRNA bacteriophages adequately deciphered viral and point source water contamination. The strongest correlation for HADV was with FRNA bacteriophage type II, in water samples higher than the 50^th percentiles of faecal enterococci, thus indicating urban pollution. FRNA bacteriophage genotypes I and III virus indicator performances were assisted by their associations with electrical conductivity and faecal enterococci. In combination, our methods are useful for inferring water quality degradation caused by sewage contamination. The methods used have potential for determining source contamination in water and, specifically, the presence of enteric viruses where clean and contaminated water have mixed.