Distribution of fallout cesium-137 in Hawaii

Fukushima-derived radiocesium fallout in Hawaiian soils

Several reactors at the Fukushima Dai-ichi Nuclear Power Plant suffered damage on March 11, 2011, resulting in the release of radiocesium (¹³⁴Cs and ¹³⁷Cs), as well as other radionuclides, into the atmosphere. A week later, these isotopes were detected in aerosols over the state of Hawai'i and in milk samples analyzed on the island of Hawai'i. This study estimated the magnitude of cesium deposition in soil, collected in 2015-2016, resulting from atmospheric fallout. It also examined the patterns of cesium wet deposition with precipitation observed on O'ahu and the island of Hawai'i following the disaster. Fukushima-derived fallout was differentiated from historic nuclear weapons testing fallout by the presence of ¹³⁴Cs and the assumption that the ¹³⁴Cs to ¹³⁷Cs ratio was 1:1. Detectable, Fukushima-derived ¹³⁴Cs inventories ranged from 30 to 630 Bq m^-2 and ¹³⁷Cs inventories ranged from 20 to 2200 Bq m^-2. Fukushima-derived cesium inventories in soils were related to precipitation gradients, particularly in areas where rainfall exceeded 200 mm between March 19 and April 4, 2011. This research confirmed and quantified the presence of Fukushima-derived fallout in the state of Hawai'i in amounts higher than predicted by models and observed in the United States mainland, however the activities detected were an order of magnitude lower than fallout associated with historic sources such as the nuclear weapons testing in the Pacific. In addition, this study showed that areas of highest cesium deposition do not overlap with densely populated or agriculturally used areas.

Radiocaesium fallout behaviour in volcanic soils in Iceland

The retention of 137Cs in various types of Andosols in Iceland was investigated. Soils were sampled at 29 sites with varying precipitation and environmental conditions. Samples were obtained from 0 to 5, 5 to 10, and 10 to 15 cm depths. The amount of radiocaesium present was quite variable, ranging between 300 and 4800 Bq m(-2) and correlated closely to total annual precipitation (r2=0.71). The majority of 137Cs, 82.7% on average, was retained in the uppermost 5 cm of the soil. The greatest penetration of 137Cs was observed for organic Histosols (76.3% in top 5 cm). The Icelandic Vitrisols (barren, poorly developed Andosols) are coarse grained with only 2-5% clay content and contain little organic matter (<1%). Yet these soils retained 74% of 137Cs in the top 5 cm. The results indicate that radiocaesium fallout is strongly retained by colloidal materials characteristic of Andosols, such as allophane and ferrihydrite. Most soils in Iceland are subject to severe and prolonged freezing and waterlogging; despite this, 137Cs is retained in the upper soil horizons and vertical migration is negligible in Icelandic Andosols. However, erosion and aeolian activity can markedly influence the amount and vertical distribution of radiocaesium in Icelandic soils.

137Cs concentration in the environment of Kaiga of south west coast of India

This paper presents the results of 137Cs activity in soil and vegetation obtained through a carefully planned pre-operational survey for the establishment of baseline data on background radiation level and distribution of radionuclides in the environment of Kaiga, in the south west coast of India, where two nuclear power reactors of 235 MWe each are under construction. The vertical profile in soil and the seasonal variation in the activity have been studied. Nine commonly available vegetation species of Kaiga region were analyzed for their 137Cs activity, and the soil-to-plant transfer coefficients were evaluated. Measurements were made by gamma spectrometry method employing a 90 cc HpGe detector and a 3 x 3-inch well type NaI(Tl) detector. Results show significant levels of 137Cs activity in soil samples--ranging from below detection limit (BDL) to 65.4 Bq kg(-1). The mean value of activity observed in 0-5 cm soil profiles of Kaiga environs is significantly higher when compared to the reported values for other environs of India. Depth profile studies show that the 137Cs activity decreases with the increasing soil depth, and it is below detection limit for depths more than 25 cm. The mean value of effective dose commitment due to the presence of 137Cs in soil was 167.2 microSv. Vegetation samples of the region show elevated levels of 137Cs concentration. Epiphytic plants Cymbidium aloifolium (Lo.) Swartz. and Petrobryopsis tumida (Hook.) Dix. have been identified as bio-indicators to monitor the fallout of this radionuclide in the environment of Kaiga. Seasonal variation studies indicate higher fallout of this radionuclide along with rain.

Prominent artificial radionuclide activity in the environment of coastal Karnataka on the southwest coast of India

Studies on radiation level and radionuclide distribution in the environment of coastal Karnataka were undertaken to provide baseline data for the future assessment of the impact of the nuclear and thermal power stations that are being set up in the region and to understand the behaviour of radionuclides in the environment. As part of the programme the concentrations of two important artificial radionuclides, namely 90Sr and 137Cs, have been measured in a number of environmental samples. The concentration of 90Sr is very low in most of the samples. Among the samples analysed for the concentration of 137Cs, soil samples showed elevated levels of activity in some sampling stations. Among the vegetables, brinjal (Solanum melongena. L) showed considerable activity. The internal dose due to intake of 90Sr through diet was 0.42 microSv year(-1) for the vegetarian population and 0.32 microSv year(-1) for the non-vegetarian population. The internal dose due to dietary intake of 137Cs was found to be 0.34 microSv year(-1) and 0.26 microSv year(-1) respectively for the vegetarian and non-vegetarian population. The results are discussed in the light of the literature values reported for other environs of India and abroad and appropriate inferences are drawn.

Improving functional status in arthritis: the effect of social support

We present data from a longitudinal study of patients with symptomatic osteoarthritis (OA) of the knee and/or hip. One component of this study involved interviewers telephoning patients bi-weekly for 6 months to inquire about stressors which they have experienced and to obtain self-assessment of their health. We hypothesized that telephone interviewers (TI) may provide OA patients with social support, and thus improve their functional status. Patients' functional status (physical disability, psychological disability, and pain) improved significantly after 6 months of receiving bi-weekly telephone calls. Since our outcome variables have been shown to be reliable measures of disability over time, and because OA is a progressively degenerative process, one would expect deterioration rather than improvement. Furthermore, since patients reported more social support at 6 months than at baseline, we attributed the improvement in health status to the TIs being viewed as a source of social support to elderly persons who may have support deficits. We suggest that future studies redefine TIs' roles from an unbiased data collector to a provider of social support. TIs should follow their own panel of patients so that continuity can be established. Furthermore, TIs should undergo training about OA, its treatment, common medications and their side effects, and other pertinent information. In this manner, social support may be further enhanced and provide the greatest potential to improve patients' health status.

Cesium: a bibliography update

A brief outline of both industrial and medicinal uses is given. This is followed by a survey of literature on cesium salts for the period between January 1981 to May 1984. The bibliography searched indicates an interesting pharmacological and behavioral effect for Cs-salts in addition to its well known physiological and itopic effects. A pattern of clinical trials suggests the potential of cesium salts in certain cancer therapies, affective disorders, tumor imaging, radiotherapy and certain cardiovascular usages. The need for continued probing into the biological activity of this alkalimetal is suggested.