210Po bioaccumulation in coastal sand dune wild legumes -: Canavalia spp. of southwest coast of India

In view of considerable natural background radioactivity reported from southwest coast of India, the current study documents bioaccumulation of Po-210 in two dominant coastal sand dune perennial mat-forming wild legumes, Canavalia cathartica and C. maritima. Root, stem, leaf, mature beans, dry seeds and rhizosphere sand were analyzed for Po-210 concentration. Po-210 activity decreased in the order of leaves > roots > seeds 4 stems 4 beans. The highest Po-210 activity was recorded in rhizosphere sand samples ( 5.78 - 5.88 Bq kg(-1)) followed by the leaf samples (3.27 - 3.07 Bq kg(-1)), while it was lowest in mature beans (0.13 - 0.20 Bq kg(-1)). Po-210 activities or tissue moisture between plant species were not significantly different ( p > 0.05; t-test). But Po-210 activity vs. moisture differed significantly in all tissues ( p = 0.0001), vegetative tissues (root, stem and leaf) (p = 0.0016), seeds ( p = 0.0393) and proteins in seeds ( p = 2.355 x 10(-6)) indicating the importance of moisture and protein in Po-210 accumulation. Although Po-210 has affinity for proteins, it did not concentrate too much in seed proteins of Canavalia. Concentration of Po-210 in mature beans is at safe levels as fisher folk only consume tender pods occasionally. Po-210 activity in Canavalia is compared with other plant materials. As the landraces of C. cathartica and C. maritima are distributed throughout pantropical coastal areas, the current study emphasizes on considering them as bioindicators to monitor Po-210 in coastal sand dune biomes and in turn the health of coastal population.