Activity Of Water Samples Research Articles

MONITORING OF GROUNDWATER CONTAMINATION WITH TRITIUM AFTER A RADIATION ACCIDENT AT A RADIOACTIVE WASTE DISPOSAL SITE

The article analyses the data of long-term monitoring of the level of tritium contamination of groundwater in the area of the radioactive waste disposal site. Tritium is a radioactive isotope of hydrogen, a soft beta emitter. The impressive effect of tritium is due to the biological significance of the molecules into which it incorporates. Radioactive waste storage facilities store a lot of tritium-rich radioactive waste of various origins, a potential tritium source entering the natural environment. Any tritium released appears as tritium water (water that contains tritium in its molecules). Nowadays, the problem of tritium contamination of water ecosystems in the radioactive waste storage facilities’ areas can be considered one of the main issues in radioecology. The study aims to assess the level of safety of underground water in the radioactive waste disposal site area by the level of tritium content based on long-term monitoring data. The object of the study was the content of tritium in the underground water of the first aquifer in the territory of the radioactive waste disposal site (strict regime zone, sanitary and protective zone, and in underground waters of wells outside and in surface water bodies of the natural environment). We tested the tritium activity in water samples using the Triathler 425-034 liquid scintillation radiometer. In 1997, a radiation accident occurred at the radioactive waste disposal site. It led to the penetration of tritium into the first aquifer. Work has been underway to eliminate the accident. Modernisation of the system of wells for monitoring the underground water tritium contamination level also took place. As a result of the performed works, the radiation situation in the accident area has stabilised, and contamination of the aquifer due to the inflow of surface contaminated water from radioactive waste storage facilities has completely stopped. The results of long-term monitoring of tritium content in water of boreholes and wells and natural objects (reservoirs) located outside the sanitary protection zone of the enterprise showed that 27 years after the radiation accident, the radiation situation in the studied area is stable. The total activity of tritium in the aquifer of the monitoring wells is decreasing and has now reached the regulatory level in all but three wells. The concentration of tritium in underground waters (wells) and surface waters (reservoirs) outside the sanitary and protective zone has never exceeded the environmentally safe level during the monitoring period. At present, 89% of the studied monitoring sites (boreholes, natural reservoirs, wells) have tritium content that is within the environmentally safe range. Keywords: radioactive waste disposal site, radiation accident, tritium, aquifers, monitoring, environmental safety.

Analysis of radon concentrations in drinking water in coastal regions of Karnataka, South India.

The measurements of radon activity in water samples from several parts of Karnataka were studied. Drinking water quality is a routine tool in health and environmental research. Radon exposure puts the entire public at risk for radiological damage through inhalation and ingestion. Radon concentrations were measured using the emanometry technique. Estimated 222Rn activity concentration in water has been found to vary from 2.05 to 28.02Bql-1 with an average value of 7.38Bql-1. For all samples under study, the total average annual effective doses are much less than the safe limit of 100μSv y-1.

The contribution of PFAS to thyroid hormone-displacing activity in Dutch waters: A comparison between two in vitro bioassays with chemical analysis

Per- and polyfluoroalkyl substances (PFAS) are a group of xenobiotics that are widely distributed throughout the aquatic environment. Many PFAS are possible thyroid hormone (TH) system disrupting compounds, because they have the capacity to -amongst other- inhibit the TH thyroxine (T4) from binding to its transport protein transthyretin (TTR). This study investigated the occurrence of TH-displacing activity in the Dutch water cycle, and more specifically, the contribution of PFAS to this effect. Over one year of monitoring data of 29 PFAS (linear and branched) showed the continuous presence of PFAS in drinking waters and their surface water sources. Secondly, the FITC-T4 and TTR-TRβ-CALUX bioassays were mutually compared using positive (HPLC-grade water spiked with PFOA) and negative control samples (HPLC-grade water), as well as relative potency factors (RPFs) of up to 20 PFAS congeners. Both assays were found to be suitable for measuring TH-displacing activity in water samples. As a third aim, a field study was performed in the Dutch water cycle that was comprised of samples from drinking water, surface water, PFAS contaminated sites, and 2 wastewater treatment plants. All samples were analyzed with 1. chemical analysis for 29 PFAS, 2. the FITC-T4 bioassay, and 3. the TTR-TRβ-CALUX bioassay. The bioassays mutually showed good correlation (R2 0.85). Bioanalytical equivalent concentrations (BEQ) based on chemically-determined concentrations and RPFs (BEQchem) revealed that analyzed PFAS only explained ≤4.1 % of their activity in water extracts measured by both bioassays (BEQbio). This indicated that as yet unknown compounds contribute to the majority of the measured TH-displacing activity. Moreover, water treatment processes (e.g. DW production from SW) showed a larger contribution of target PFAS to the BEQbio. This could be a first lead to identify unknown compounds that contribute to this activity, and as such, enable the assessment of possible risks associated by the occurrence of TH-displacing activity in water.

Environmental water extracts differentially activate zebrafish and human nuclear progesterone receptors

Many reports on anti-progestogenic activities in aquatic environments have been published in the past decade. These are monitored mainly by in vitro reporter gene bioassays based upon the human progesterone receptor (PR). However, results obtained by some human in vitro bioassays may not be relevant for aquatic animals, especially fish. The present work aimed to detect fish (anti-)PR activity in waste- and receiving surface waters. In parallel, human (anti-)PR activity was analysed to determine if there was any connection between human and fish (anti-)PR activities. Finally, (anti-)PR activities were linked to the occurrence of progestins in water samples. Human PR agonistic activity was detected in all wastewater and most receiving surface water samples. Nevertheless, zebrafish PR (zfPR) agonistic activity was found in only two influent wastewater samples (max. 117 ng/L 17α,20β-dihydroxy-4-pregnen-3-one [DHP] equivalents). Analysed synthetic progestins and progesterone accounted for 14 % to 161 % of detected human PR (hPR) agonistic activity in water samples. Progesterone also contributed significantly to zfPR agonistic activity (up to 10 %) in raw wastewater. The anti-hPR activity was detected also in most wastewater and some surface water samples, but synthetic progestins did not trigger anti-zfPR activity in excess of LOQ values. In addition, altrenogest, dienogest, and ulipristal acetate were tested for their potency to zfPR for the first time. The activity analyses of both pure substances and environmental samples showed that human and zebrafish progesterone receptors are differentially activated. Therefore, results based on human PR in vitro bioassays could not predict fish PR activities in the environment.

Radon in groundwater sources of Bosso Community in North Central Nigeria and concomitant doses to the public

Realizing the probable health hazards from radon exposure, potable groundwater samples (hand-dug wells and boreholes) in the Bosso community of North Central Nigeria were collected and assayed for radon concentration. Durridge RAD-7 detector together with RAD-H2O accessories was employed in this study. The committed effective dose to different ICRP age groups was computed using various parameters including the annual water consumption characteristics. The mean 222Rn activity in water samples from hand-dug wells and boreholes were 9.81 ± 1.85 Bq/L and 24.78 ± 2.48 Bq/L respectively. The average whole-body committed effective dose due to ingestion and inhalation of waterborne radon from the two groundwater sources are 0.026 mSv/y and 0.067 mSv/y for hand-dug wells and boreholes respectively, which are below the safety threshold of 0.1 mSv/y recommended by the European Union. The results showed that there is no significant radiation threat to public health from inhalation and ingestion of waterborne radon within the community.

The impact of two commonly used neutralizing agents in water sampling bottles on legionella and pseudomonas bacteria recovery

Microbiological monitoring may be indicated by the local risk assessment of hospital water systems. When water sampling is carried out, it is imperative that the activity of any residual biocide is completely neutralized. Sodium thiosulphate pentahydrate (Na₂S₂O₃·5H₂O) is commonly used to neutralize oxidizing biocides in water samples for microbiological testing. Ethylenediaminetetraacetic acid dihydrate (Na2EDTA.2H2O) is recommended to neutralize silver-copper ionization treated water samples. However, there are inconsistencies in the recommended effective concentration. Furthermore, sampling bottles dosed with Na2EDTA.2H2O are not commercially available. To investigate the efficacy of Na2EDTA.2H2O as a neutralizing agent compared with sodium thiosulphate (Na₂S₂O₃·5H₂O) on water samples treated with silver and copper ions and to assess the biocidal activity in water samples. An interlaboratory investigation was carried out using simulated water samples spiked with Legionella pneumophila or Pseudomonas aeruginosa with and without silver and copper ions. Bacterial recovery was determined in sterile sampling bottles dosed with either 50 mg/L Na2EDTA.2H2O or 180 mg/L Na₂S₂O₃·5H₂O as the chemical biocide neutralizing agent. Na₂S₂O₃·5H₂O effectively complexed both silver and copper ions and inhibited biocidal activity. The 50 mg/L of Na2EDTA.2H2O continued to demonstrate significant biocidal activity in the spiked samples. This study demonstrated that Na2EDTA.2H2O is not an efficacious neutralizing agent on water samples treated with silver and copper ions. Sample bottles dosed with 180 mg/L Na₂S₂O₃·5H₂O were more effective in neutralizing silver and copper ions generated in water that had been treated by silver-copper ionization systems.

Triple functional small-molecule-protein conjugate mediated optical biosensor for quantification of estrogenic activities in water samples

Establishing biosensors to map a comprehensive picture of potential estrogen-active chemicals remains challenging and must be addressed. Herein, we describe an estrogen receptor (ER)-based evanescent wave fluorescent biosensor by using a triple functional small-molecule–protein conjugate as a signal probe for the determination of estrogenic activities in water samples. The signal probe, consisting of a Cy5.5-labelled streptavidin (STV) moiety and a 17β-estradiol (E2) moiety, acts simultaneously as signal conversion, signal recognition and signal report elements. When xenoestrogens compete with the E2 moiety of conjugate in binding to the ER, the unbound conjugates are released, and their STV moiety binds with desthiobiotin (DTB) modified on the optical fiber via the STV–DTB affinity interactions. Signal probe detection is accomplished by fluorescence emission induced by an evanescent field, which positively relates with the estrogenic activities in samples. Quantification of estrogenic activity expressed as E2 equivalent concentration (EEQ) can be achieved with a detection limit of 1.05 μg/L EEQ by using three times standard deviation of the mean blank values and a linear calibration range from 20.8 to 476.7 μg/L EEQ. The optical fiber system is robust enough for hundreds of sensing cycles. The biosensor-based determination of estrogenic activities in wastewater samples obtained from a full-scale wastewater treatment plant is consistent with that measured by the two-hybrid recombinant yeast bioassay.

In situ measurement of estrogenic activity in various aquatic systems using organic diffusive gradients in thin-film coupled with ERE-CALUX bioassay

Organic-diffusive gradients in thin-film samplers (o-DGT), were developed and applied for accumulation of estrogen and estrogen-like compounds on a XAD18 resin and deployed in situ in the effluents of Beijing Gaobeidian Wastewater Treatment Plant (GWWTP) and Brussels North Wastewater Treatment Plant as well as in several aquatic systems in Belgium, including the Zenne River, the Belgian Oostende Harbor and the North Sea. Estrogenic compounds accumulate on the XAD18 resin and the estrogenic activity of the resin extract was measured with the Estrogen Responsive Elements-Chemically Activated LUciferase gene eXpression (ERE-CALUX) bioassay. With this result and by applying Fick's diffusion law, it is possible to calculate the estrogenic activity in the aquatic system, if the diffusion boundary layer (DBL) is known or negligible compared to the hydrogel diffusive layer thickness. The DBL thickness in our study varied from 0.010 to 0.023 cm and ignoring the DBL thickness would for instance, underestimate the estrogenic activity by 10–20%. Estrogenic activities in the secondary effluent of GWWTP were the highest (29 ± 4 ng E2-equivalents L−1), while the lowest level was found at the Belgian Oostende Harbor (0.05 ± 0.01 ng E2-equivalents L−1). Comparable estrogenic activities in water samples measured by o-DGT and grab sampling were obtained, confirming that o-DGT can be efficiently used in various aquatic systems. The advantage of our sampling and measuring method is that very low, time averaged estrogenic activities can be determined, with a minimum of sample treatment. The risk of sample contamination is very low as well as the cost of the whole analytical procedure.

Assessment of microbial activity in water based on hydrogen peroxide decomposition rates

This study proposes a new and simple assay that allows rapid assessment of microbial activity in water samples. The assay consists of standardized hydrogen peroxide (H2O2) addition to a water sample and subsequent spectrophotometric determination of H2O2 reduction over time. The H2O2 decomposition rate constant reflects the level of enzymatic activity from planktonic and particle-associated bacteria as well as algae and protozoans. The proof of concept was verified on water samples from recirculating aquaculture systems (RAS), showing that the vast majority of H2O2 decomposition was related to microbial activity. Only 3% of the total H2O2 decomposition was related to abiotic processes when 0.20 μm sterile filtered RAS water was compared with unfiltered RAS water. Planktonic bacteria (size range 0.20–1.6 μm) accounted for 16% of H2O2 decomposition, while bacterial aggregates, particle-associated bacteria and microbiota above 1.6 μm were responsible for the remaining 81%. H2O2 decomposition rate constants were positively correlated to BOD5 (r = 0.893; p < 0.001; n = 18) and to the number of 1–30 μm micro particles (r = 0.909; p < 0.001; n = 72) in RAS water, substantiating the biologically mediated decomposition processes in the water phase. The H2O2 decomposition assay thus represents a new alternative to existing methods that allows rapid (1–2 h) and simple quantification of microbial activity in fresh- and saltwater samples from aquaculture systems. Potential applications of the assay are discussed.

Investigation of radon concentrations in some reservoirs, spring and tap waters in İstanbul, Turkey

The 222Rn activity in water samples from reservoirs, springs and taps in the area of Istanbul, Turkey has been measured with an AlphaGUARD system. The measured concentrations ranged from 0.6 to 3 Bq L−1 for reservoirs, 1.6–14 Bq L−1 for springs and 0.8–1.4 Bq L−1 for taps. These values are compared with similar measurements elsewhere in Turkey and other countries. They lie within recommended safe limits published by WHO and UNSCEAR and, with the exception of three spring water samples, they lie within the more stringent limits set by the USEPA. The resulting annual effective doses due to water ingestion and inhalation are discussed.

Validation of Arxula Yeast Estrogen Screen assay for detection of estrogenic activity in water samples: Results of an international interlaboratory study

Endocrine-active substances can adversely impact the aquatic ecosystems. A special emphasis is laid, among others, on the effects of estrogens and estrogen mimicking compounds. Effect-based screening methods like in vitro bioassays are suitable tools to detect and quantify endocrine activities of known and unknown mixtures.This study describes the validation of the Arxula-Yeast Estrogen Screen (A-YES®) assay, an effect-based method for the detection of the estrogenic potential of water and waste water. This reporter gene assay, provided in ready to use format, is based on the activation of the human estrogen receptor alpha. The user-friendly A-YES® enables inexperienced operators to rapidly become competent with the assay.Fourteen laboratories from four countries with different training levels analyzed 17β-estradiol equivalent concentrations (EEQ) in spiked and unspiked waste water effluent and surface water samples, in waste water influent and spiked salt water samples and in a mixture of three bisphenols. The limit of detection (LOD) for untreated samples was 1.8ng/L 17β-estradiol (E2). Relative repeatability and reproducibility standard deviation for samples with EEQ above the LOD (mean EEQ values between 6.3 and 20.4ng/L) ranged from 7.5 to 21.4% and 16.6 to 28.0%, respectively. Precision results are comparable to other frequently used analytical methods for estrogens.The A-YES® has been demonstrated to be an accurate, precise and robust bioassay. The results have been included in the ISO draft standard.The assay was shown to be applicable for testing of typical waste water influent, effluent and saline water. Other studies have shown that the assay can be used with enriched samples, which lower the LOD to the pg/L range.The validation of the A-YES® and the development of a corresponding international standard constitute a step further towards harmonized and reliable bioassays for the effect-based analysis of estrogens and estrogen-like compounds in water samples.

No evidence of exposure to environmental estrogens in two feral fish species sampled from the Yarra River, Australia: A comparison with Northern Hemisphere studies

Environmental estrogens originate from a variety of sources including sewage treatment plant (STP) effluents and adverse physiological effects (endocrine disruption) have been observed in several fish species sampled downstream of STP discharges. In this study we examined common carp (Cyprinus carpio) and roach (Rutilis rutilis) for signs of exposure to environmental estrogens in the iconic Yarra River, Melbourne, Australia. The Yarra River flows through the city of Melbourne and more than 2 million people live within the catchment. Two STPs discharge water into the Yarra River within the middle reaches, and the areas immediately downstream of these discharge locations were the focus of this study. Carp and roach were chosen as test species since both have been utilised extensively for endocrine disruption research throughout Europe, North America and Asia, and data from various international studies was used for comparison with the results of the present study.Neither species showed evidence of exposure to environmental estrogens, with no elevation of plasma vitellogenin levels in males and no incidence of intersex gonads. Most physiological endpoints in both species from this study were within ranges reported in carp and roach from reference sites in other studies, however some degenerative histological changes in both male and female gonads were observed. Surface water samples showed no estrogenic activity (measured by the yeast-estrogen screen, YES), but did display strong anti-estrogenic and weak androgenic activity (measured by the yeast-androgen screen, YAS).Whilst the results show no evidence of impacts from environmental estrogens in the Yarra River, the presence of both anti-estrogenic and androgenic activity in water samples, as well as some gonadal changes in carp is concerning and indicates that our focus needs to broaden, in order to look for biological impacts in resident fauna that might be due to environmental pollutants other than environmental estrogens.

Determination of estrogenic activity in the river Chienti (Marche Region, Italy) by using in vivo and in vitro bioassays

Environmental estrogen-like compounds (i.e. xenoestrogens) are a variety of pollutants, ranging from synthetic to natural occurring molecules, that are found in surface and waste waters over a wide range of concentrations. In aquatic environment, the overall estrogenic activity is often due to the presence of a mixture of chemicals and their degraded products which can induce synergistic effects. Current strategies for monitoring estrogen-like chemicals are based on the use of a battery of in vivo and in vitro ecotoxicological tests. In this regard, the aim of the present work was to carry out a bio-monitoring study for testing estrogenicity of the Chienti river (Marche Region, Italy) by using both an E-screen and a vitellogenin (Vtg) induction assay in juvenile goldfish. Three sites were used for analysis, localized at the mouth (sampling point 1), in the middle (sampling point 2) and at the origin (sampling point 3) of Chienti river. For most of the water samples (i.e. samples collected at sampling points 2 and 3), clear estrogenic activity was detected in the E-screen assay suggesting different proliferation activities in function of the collecting site. In contrast, the Vtg ELISA demonstrated that water samples collected from each sampling point were estrogenic. Overall, we showed for the first time that the estrogenic activities in water samples from the Chienti river were significant in both in vivo and in vitro; we also observed a different sensitivity between bioassays.

Selection of the appropriate radionuclide source for the efficiency calibration in methods of determining gross alpha activity in water

Measuring the gross alpha activity in water samples is a rapid, straightforward way of determining whether the water might contain a radionuclide concentration whose consumption would imply a total indicative dose (TID) greater than some reference limit – currently set at 0.1 mSv/y in Europe. There are several methods used for such measurements. Two of them are desiccation with the salts being deposited on a planchet, and coprecipitation. The main advantage of these two methods is their ease of implementation and low cost of preparing the source to measure. However, there is considerable variability in the selection of the most suitable radioactive reference standard against which to calculate the water's gross alpha activity. The goal of this paper is to propose the most appropriate reference radionuclides to use as standards in determining gross alpha activities with these two methods, taking into account the natural radioactive characteristics of a wide range of waters collected at different points in Spain. Thus, the results will be consistent with each other and representative of the sum of alpha activities of all the alpha-emitters contained in a sample.

High-throughput screening assay for the environmental water samples using cellular response profiles

Chemical and physical analyses are commonly used as screening methods for the environmental water. However, these methods can only look for the targeted substance but may miss unexpected toxicants. Furthermore, the synergistic effects of mixture cannot be detected. In order to set up the assay criteria for determining various biological activities at a cellular level that could potentially lead to toxicity of environmental water samples, a novel test based on cellular response by using Real-Time Cellular Analyzer (RTCA) is proposed in this study. First, the water sample is diluted to a series of strengths (80%, 60%, 40%, 30%, 20% and 10%) to get the multi-concentration cellular response profile. Then, the area under the cellular response profile (AUCRP) is calculated. Comparing to the normal cell growth of negative control, a new biological activity index named Percentage of Effect (PoE) has been presented which reflects the cumulative inhibitory activity of cell growth over the log-phase. Finally, a synthetical index PoE50 is proposed to evaluate the intensity of biological activities in water samples. The biological experiment demonstrates the effectiveness of the proposed method.

Contrasting Effects of Singlet Oxygen and Hydrogen Peroxide on Bacterial Community Composition in a Humic Lake

Light excitation of humic matter generates reactive oxygen species (ROS) in surface waters of aquatic ecosystems. Abundant ROS generated in humic matter rich lakes include singlet oxygen (1O2) and hydrogen peroxide (H2O2). Because these ROS differ in half-life time and toxicity, we compared their effects on microbial activity (14C-Leucine incorporation) and bacterial community composition (BCC) in surface waters of humic Lake Grosse Fuchskuhle (North-eastern Germany). For this purpose, experiments with water samples collected from the lake were conducted in July 2006, September 2008 and August 2009. Artificially increased 1O2 and H2O2 concentrations inhibited microbial activity in water samples to a similar extent, but the effect of the respective ROS on BCC varied strongly. BCC analysis by 16S rRNA gene clone libraries and RT-PCR DGGE revealed ROS specific changes in relative abundance and activity of major bacterial groups and composition of dominating phylotypes. These changes were consistent in the three experiments performed in different years. The relative abundance of Polynucleobacter necessarius, Limnohabitans-related phylotypes (Betaproteobacteria), and Novosphingobium acidiphilum (Alphaproteobacteria) increased or was not affected by photo-sensitized 1O2 exposure, but decreased after H2O2 exposure. The opposite pattern was found for Actinobacteria of the freshwater AcI-B cluster which were highly sensitive to 1O2 but not to H2O2 exposure. Furthermore, group-specific RT-PCR DGGE analysis revealed that particle-attached P. necessarius and Limnohabitans-related phylotypes exhibit higher resistance to 1O2 exposure compared to free-living populations. These results imply that 1O2 acts as a factor in niche separation of closely affiliated Polynucleobacter and Limnohabitans-related phylotypes. Consequently, oxidative stress caused by photochemical ROS generation should be regarded as an environmental variable determining abundance, activity, and phylotype composition of environmentally relevant bacterial groups, in particular in illuminated and humic matter rich waters.

Sources of variability in the determination by evaporation method of gross alpha activity in water samples

Abstract Determining the gross alpha activity concentration of water samples is one way to screen for waters whose radionuclide content is so high that its consumption could imply surpassing the Total Indicative Dose as defined in European Directive 98/83/EC. One of the most commonly used methods to prepare the sources to measure gross alpha activity in water samples is desiccation. Its main advantages are the simplicity of the procedure, the low cost of source preparation, and the possibility of simultaneously determining the gross beta activity. The preparation of the source, the construction of the calibration curves, and the measurement procedure itself involve, however, various factors that may introduce sufficient variability into the results to significantly affect the screening process. We here identify the main sources of this variability, and propose specific procedures to follow in the desiccation process that will reduce the uncertainties, and ensure that the result is indeed representative of the sum of the activities of the alpha emitters present in the sample.

Gross &amp;#945 and &amp;#946 Activity Concentration and Estimation of Adults and Infants Dose intake in Surface and Ground Water of Ten Oil Fields Environment in Western Niger Delta of Nigeria

The oil and gas rich Niger Delta region of Nigeria is characterized by environmental degradation leading to environmental pollution from oil and gas activities. This study examined the gross α and β activity in thirty (river/stream, well and tap) water samples collected from ten oil fields in the Western Niger Delta region of Nigeria. The counting system employed in this analysis is the Gas-flow proportional counter {Eurisys Measure IN20 low- background multiple (eight) channel counter}. Gross alpha activity concentration range from 0.01±0.002 to 0.7±0.01 (0.15±0.003) Bql-1, 0.01±0.003 to 0.5±0.01 (0.1±0.003)Bql-1and 0.02±0.001 to 35.1±1.1 (4.1±0.1) Bql-1 while beta activity concentration ranged from 1.1±0.04 to 13.2±0.1 (6.0±0.1) Bql-1, 0.7±0.1 to 54.7±1.3 (8.9±0.2)Bql-1 and 0.7±0.03 to 151.2±1.8 (40.1±0.9)Bql-1 for well, tap and river waters respectively. Correlation value between α and β activities in well, tap and river water is 0.025, 0.047 and 0.512 respectively. The results show that except for the alpha activity in the tap water samples, the average natural activity concentrations of α- and β-emitting radionuclides in the samples are slightly above the WHO recommended limit. For all samples the gross β activities are higher than the corresponding gross α activities. The mean effective equivalent dose intake per year due to alpha activity in the water samples for adults and infants are: 76.4±1.8 and 20.9±55μSvy-1, 54.6±1.3 and 14.9±0.4 μSvy-1, and 2118±70 and 584±19.2μSvy-1 in well, tap, and river water samples respectively. The results obtained for dose intake are below the WHO recommended reference level of 0.1mSvy-1, except for the water sample from Uzere river. This study indicates that the water sources evaluated, especially the rivers, are contaminated radiologically. @JASEM

Trigger values for investigation of hormonal activity in drinking water and its sources using CALUX bioassays

To screen for hormonal activity in water samples, highly sensitive in vitro CALUX bioassays are available which allow detection of estrogenic (ERα), androgenic (AR), progestagenic (PR), and glucocorticoid (GR) activities. This paper presents trigger values for the ERα, AR, PR, and GR CALUX bioassays for agonistic hormonal activities in (drinking) water, which define a level above which human health risk cannot be waived a priori and additional examination of specific endocrine activity may be warranted. The trigger values are based on 1) acceptable or tolerable daily intake (ADI/TDI) values of specific compounds, 2) pharmacokinetic factors defining their bioavailability, 3) estimations of the bioavailability of unknown compounds with equivalent hormonal activity, 4) relative endocrine potencies, and 5) physiological, and drinking water allocation factors. As a result, trigger values of 3.8ng 17β-estradiol (E2)-equivalents (eq)/L, 11ng dihydrotestosterone (DHT)-eq/L, 21ng dexamethasone (DEX)-eq/L, and 333ng Org2058-eq/L were derived. Benchmark Quotient (BQ) values were derived by dividing hormonal activity in water samples by the derived trigger using the highest concentrations detected in a recent, limited screening of Dutch water samples, and were in the order of (value) AR (0.41)>ERα (0.13)>GR (0.06)>PR (0.04). The application of trigger values derived in the present study can help to judge measured agonistic hormonal activities in water samples using the CALUX bioassays and help to decide whether further examination of specific endocrine activity followed by a subsequent safety evaluation may be warranted, or whether concentrations of such activity are of low priority with respect to health concerns in the human population. For instance, at one specific drinking water production site ERα and AR (but no GR and PR) activities were detected in drinking water, however, these levels are at least a factor 83 smaller than the respective trigger values, and therefore no human health risks are to be expected from hormonal activity in Dutch drinking water from this site.

On the use of different scintillation cocktails for determining gross alpha and beta activities in water samples

Gross alpha and beta indices for water samples are generally measured in environmental radioactivity laboratories. Liquid scintillation spectrometers can be used to determine these indices but different factors could affect the measurements. Several scintillation cocktails and different radionuclides have been used for calibration. Quenching effects must be considered for each cocktail because the results can be different depending of the calibration and cocktail used.