Cs-137 contamination of plants used for traditional medicine and implications for human exposure

This paper discusses the use of medicinal plants in traditional medicine pr actices in the Marshall Islands and measurement data of Cs-137 in, plants u sed in medicinal remedies. This previously unexplored contribution to radia tion exposure was recognized as one of several potentially important consid erations in determining present-day risks to the Marshallese population fro m residual weapons' test radioactivity in the environment. The leaves or fr uit of five species of plants were sampled at 14 of the 29 atolls of the Ma rshall Islands. Cs-137 concentrations were measured in 295 samples. The con centration of Cs-137 in, each species generally decreased with increasing d istance and decreasing latitude from the atomic weapons testing area in the northern area of the country. Of the species sampled, Polypodium scolopend ria exhibited the highest mean Cs-137 concentration by several fold. Other species could not be differentiated in terms of Cs-137 uptake. The results of calculations to assess possible radiation doses under specific intake sc enarios indicate that at most locations in the Marshall Islands, ingestion of these plants for medicinal purposes will not contribute significantly to the total dose received (above background), although the frequency and amo unt of consumption of these plants is not well known. This study provides t he first information of its kind for the assessment of radiation dose to Ma rshall Islands' residents from locally grown plants used in traditional med icine. (C) 1999 Elsevier Science Ltd. All rights reserved.