Tag Archives: radionuclides

Assessment of Water Treatment for Radium Removal and NORM Formation, Estonia

Hill L, Suursoo S, Kiisk M, Jantsikene A, Nilb N, Munter R, Realo E, Koch R, Putk K, Leier M, Vaasma T, Isakar K. Long-term monitoring of water treatment technology designed for radium removal-removal efficiencies and NORM formation. J Radiol Prot. 2017 Dec 6;38(1):1-24. doi: 10.1088/1361-6498/aa97f2.

A drinking water treatment plant in Viimsi, Estonia, was monitored over three years for iron, manganese, radium-226, radium-228, as well as their daughter nuclides, in order to determine the efficiency of the treatment process, gain an insight into the removal mechanisms and interactions between radium, iron, and manganese, and assess the overall longevity and performance of the technology along with the possible build-up of NORM in the treatment process. During the study, samples were collected from raw water, first and second stage filtrate, consumer water, backwash water and filter materials. The results show consistent removal efficiency for iron and manganese, as well as an average of over 85% removal for radium with a slight decline over time. The backwash process has been optimised for maximum radium removal from the filters, while keeping concentrations in the backwash water below exemption levels. However, the accumulation of radium and thorium occurs in the filter material, exceeding exemption levels in the top layer of the filter columns in less than a year. By the end of the observation period, activity concentrations in the top layer of the columns were above 30 000 Bq kg-1 for Ra-226 and Ra-228, and around 15 000 Bq kg-1 for Th-228. Radionuclides are not homogenously distributed in the filter columns. In order to estimate the average activity concentrations in the filter media, the height distribution of radionuclides has to be accounted for. Two years and two months after commissioning the treatment plant, the average activity concentrations of Ra isotopes in the filter columns were in the range 10 000 Bq kg-1, while Th-228 activity concentration was roughly 3500 Bq kg-1.

Radiocesium in Cistern Waters, Croatian Coast

Franic Z, Marovic G, Petrinec B, Branica G. Post-Chernobyl Investigations of Radiocesium Activity Concentrations in Cistern Waters along the Croatian Coast of the Adriatic Sea. Health physics. 2017 Sep;113(3):167-174. doi: 10.1097/HP.0000000000000685.

The results of long-term investigations into the post-Chernobyl period of radiocesium activity concentrations in cistern waters along the Croatian coast of the Adriatic Sea are presented. The Cs activity concentrations in cistern water samples were in excellent correlation with fallout activities. The observed mean residence time of Cs in cistern waters was estimated to be 6.9 ± 0.8 y. Cesium-137 radioecological sensitivity for the period 1988-1997 for cistern water was estimated to be 1.17 × 10 Bq y L/(Bq m). The annual total effective dose incurred by Cs and Cs that a hypothetical adult person drinking 1 L of cistern water per day would receive was estimated to be < 1 mSv in 1986, decreasing to 3.6 μSv in 2015.

Protective Action and Planning Guidance for Radiological Incidents

img-1

img-2

Oxidatively Modified Carbon (OMC) Removes Radioactive Elements

Artur Khannanov, Vadim V. Nekljudov, Airat Kiiamov, Ayrat M. Dimiev. Oxidatively modified carbon as efficient material for removing radionuclides from water. Carbon, Volume 115, May 2017, Pages 394–401http://dx.doi.org/10.1016/j.carbon.2017.01.025

There is a constant need to develop advantageous materials for removing radioactive waste from aqueous systems. Here we propose a new carbon-based material prepared by oxidative treatment of various natural carbon sources. The as-prepared oxidatively modified carbon (OMC) has an oxygen-rich surface, and retains its particulate granular texture. It has relatively low cost and can be used in traditional filtration columns. The sorption ability of OMC toward several metal cations is demonstrated. It is especially efficient toward Cs+ cations, the species that are among the most difficult to remove from the waters at the Fukushima nuclear plant. 

Polonium-210 in Drinking Water

Seiler R. 210Po in drinking water, its potential health effects, and inadequacy of the gross alpha activity MCL. The Science of the Total Environment. 2016 Jun 28. pii: S0048-9697(16)30974-3. doi: 10.1016/j.scitotenv.2016.05.044.

Polonium-210 (210Po) is a naturally-occurring, carcinogenic member of the 238U decay series and the granddaughter of 210Pb. It has a half life of 138.4days and is rarely found in drinking water at levels exceeding 5mBq/L because it strongly binds to aquifer sediment. When the current US Maximum Contaminant Level (MCL) covering 210Po was promulgated in December 2000, very little was known about its occurrence and the processes responsible for mobilizing it. More is now known about the processes that mobilize 210Po from sediments and a review of recent occurrence data show that it may not be as rare in the US as the US Environmental Protection Agency (USEPA) thought in 2000. Worldwide, only about 2200 analyses for 210Po in drinking water were identified, with activities exceeding 500mBq/L being found only in Finland, India, Sweden, and the US. The median of 400 210Po analyses from the US is 4.75mBq/L and >10% of the samples exceed 500mBq/L. Current compliance-monitoring regulations in the US essentially guarantee that210Po contamination will not be detected except in very contaminated wells. Major problems with the US Gross Alpha Activity MCL include the volatility of 210Po and extended holding times and sample-compositing methods that can allow the majority of 210Po in a sample bottle to decay before analysis. In light of new information, the radionuclide rule should be changed and direct measurements of210Po should be made in all public-water supply wells to rule out its presence. Much of the important biological and toxicological research on 210Po is more than four decades old and new laboratory research using modern tools is needed. Biological and epidemiological investigations of known contaminated areas are needed to assess the effect 210Po exposure is having on animals and humans consuming the water.

Uranium and Thorium in Drinking Water, Rajasthan, India

Duggal V, Rani A, Balaram V. ASSESSMENT OF AGE-DEPENDENT RADIATION DOSE DUE TO INTAKE OF URANIUM AND THORIUM IN DRINKING WATER FROM SIKAR DISTRICT, RAJASTHAN, INDIA. Radiation Protection Dosimetry. 2016 Mar 30. pii: ncw070.

The concentrations of238U and232Th have been determined in drinking water samples collected from the Sikar district of Rajasthan State, India. The samples have been analysed by using high-resolution inductively coupled plasma mass spectrometry.238U content in water samples ranged from 8.20 to 202.63 µg l-1and232Th content ranged from 0.57 to 1.46 µg l-1 The measured238U content in 25 % of the analysed samples exceeded the World Health Organization (WHO) and United States Environmental Protection Agency drinking water guidelines of 30 µg l-1and 12.5 % of the samples exceeded the 60 µg l-1Indian maximum acceptable concentration recommended by the Atomic Energy Regulatory Board, India. The annual effective doses (µSv y-1) due to ingestion of238U and232Th for different age groups were also calculated. The results compared with the recommended value reported by the WHO.

Immune System Effects of Strontium-90

Synhaeve N, Musilli S, Stefani J, Nicolas N, Delissen O, Dublineau I, Bertho JM. Immune System Modifications Induced in a Mouse Model of Chronic Exposure to 90Sr. Radiation research. 2016 Mar 1.

Strontium 90 (90Sr) remains in the environment long after a major nuclear disaster occurs. As a result, populations living on contaminated land are potentially exposed to daily ingesting of low quantities of 90Sr. The potential long-term health effects of such chronic contamination are unknown. In this study, we used a mouse model to evaluate the effects of 90Sr ingestion on the immune system, the animals were chronically exposed to 90Sr indrinking water at a concentration of 20 kBq/l-1, for a daily ingestion of 80-100 Bq/day-1. This resulted in a reduced number of CD19+ B lymphocytes in the bone marrow and spleen in steady-state conditions. In contrast, the results from a vaccine experiment performed as a functional test of the immune system showed that in response to T-dependent antigens, there was a reduction in IgG specific to tetanus toxin (TT), a balanced Th1/Th2 response inducer antigen, but not to keyhole limpet hemocyanin (KLH), a strong Th2 response inducer antigen. This was accompanied by a reduction in Th1 cells in the spleen, consistent with the observed reduction in specific IgG concentration. The precise mechanisms by which 90Sr acts on the immune system remain to be elucidated. However, our results suggest that 90Sr ingestion may be responsible for some of the reported effects of internal contamination on the immune system in civilian populations exposed to the Chernobyl fallout.