Removal naturally occurring radionuclides from drinking water using a filter specifically designed for Drinking Water Treatment Plants.

The occurrence of naturally occurring radionuclides in drinking water can pose health hazards in some populations, especially taking into account that routine procedures in Drinking Water Treatment Plants (DWTPs) are normally unable to remove them efficiently from drinking water. In fact, these procedures are practically transparent to them, and in particular to radium. In this paper, the characterization and capabilities of a patented filter designed to remove radium from drinking water with high efficiency is described. This filter is based on a sandwich structure of silica and green sand, with a natural high content manganese oxide. Both sands are authorized by Spanish authorities to be used in Drinking Water Treatment Plants. The Mn distribution in the green sand was found to be homogenous, thus providing a great number of adsorption sites for radium. Kinetic studies showed that the 226Ra adsorption on green sand was influenced by the content of major cations solved in the treated water, but the saturation level, about 96-99%, was not affected by it. The physico-chemical parameters of the treated water were unaltered by the filter. The efficiency of the filter for the removal of 226Ra remained unchanged with large water volumes passed through it, proving its potential use in DWTP. This filter was also able to remove initially the uranium content due to the presence of Fe2O3 particles in it, although it is saturated faster than radium.

Proposed improvements to existing water monitoring systems in automatic radiological warning networks.

The main objective of automatic environmental radiation warning networks is to quantify a set of radiological parameters corresponding to the medium being monitored (water, air, etc) in the shortest possible time so as to be able to provide rapid and precise information on the medium's radiological status, and on any alterations that may occur and their severity. Specifically, in this paper we present the substantial improvements that have been carried out in an automatic near-real-time radiation monitoring of a water system belonging to Radiation Alert Network of Extremadura (RARE) in southwest Spain. These improvements are based on the incorporation of (i) a gamma spectrometry system with solid scintillation detectors and compact digital electronics, (ii) continuous measurement of the water flow that is being monitored, (iii) improvements in the maintenance tasks required to optimise the operation of this type of equipment and (iv) the controlled and automated collection of water samples so that, in the case of a possible radiological anomaly, it will be possible to perform ulterior specific complementary determinations in a low-background laboratory.

Calibration of an air monitor prototype for a radiation surveillance network based on gamma spectrometry.

The objective of this work is to present the improvements that have been made in quasi-real-time air radioactivity concentration monitors which were initially based on overall activity determinations, by incorporating gamma spectrometry into the current prototype. To this end it was necessary to develop a careful efficiency calibration procedure for both the particulate and the gaseous fractions of the air being sampled. The work also reports the values of the minimum detectable activity calculated for different isotopes and acquisition times.

Radiological and multi-element analysis of sediments from the Proserpina reservoir (Spain) dating from Roman times.

The Proserpina dam was built in Roman times to provide drinking water to Emerita Augusta (today's Mérida in SW Spain). During maintenance work, a sediment core was extracted, offering an excellent opportunity to analyze the historical environmental impacts of the dam and its reservoir over the 2000 years since Roman times. In order to establish an accurate chronology, (14)C ages were determined by accelerator mass spectrometry (AMS). Core samples were assayed for their content in uranium and thorium series isotopes, (40)K, and the anthropogenic radionuclides (137)Cs, (90)Sr, and (239+240)Pu. Potassium-40 presented the highest activity level and was not constant with depth. The uranium and thorium series were generally in equilibrium, suggesting there had been no additional input of natural radionuclides. The presence of (137)Cs was only found in relation with the global fallout in the early 1960s. Multi-element assays were performed using the PIXE and PIGE techniques. Some variations in the multi-element concentrations were observed with depth, but the sediment core could be considered as clean, and no presumptive anthropogenic pollutants were found. Nevertheless, an unusually high Zn content was detected at depths corresponding to pre-Roman times, due to geological anomalies in the area.