BACKGROUND RADIATION LEVELS NEAR A MINERAL SAND MINING FACTORY IN SRI LANKA: CORRELATION OF RADIATION MEASUREMENTS WITH MICRONUCLEI FREQUENCY.

Lanka Mineral Sands Ltd (LMS) is a company operating in Pulmoddai, Sri Lanka, mining for rare earth minerals along with monazite which contains thorium that emits ionizing gamma and alpha radiation on decay. The objective of the study was to determine the background radiation levels and selected radionuclides and then to correlate these levels with the frequency of micronuclei (MN) among persons residing in the vicinity of LMS. A cross-sectional study was conducted among persons of both sexes between 35 and 45 years of age residing in the vicinity of LMS. Background radiation measurements were obtained by a survey metre, and gamma spectrometry was done on soil samples. Five millilitres of venous blood was drawn for cytokinesis-blocked MN assay. Background radiation levels measured by the survey metre; 232Th, 226Ra and 210Pb mass activities in soil were highest in the samples collected from the LMS. The background radiation measurements positively correlated with MN frequency although the magnitude of the correlation was small (r = 0.176, p = 0.04). This implies that chronic long-term exposure to low-dose radiation may result in genotoxicity. Prospective large-scale studies are recommended to evaluate the long-term effect of exposure to low-dose radiation at Pulmoddai.

Prawn biomonitors of nutrient and trace metal pollution along Asia-Pacific coastlines.

To assess coastal ecosystem status and pollution baselines, prawns were collected from the commercial catches of eight Asia-Pacific countries (Australia, Bangladesh, Indonesia, Myanmar, Philippines, Pakistan, Sri Lanka and Thailand). Samples collected from 21 sites along regional coastlines were analysed for trace metal and stable isotopic compositions of H, C, N, O and S. A combination of simple averaging and multivariate analyses was used to evaluate the data. Sites could be assigned to easily recognise polluted and unpolluted groups based on the prawn results. Some filter-feeding clams were also collected and analysed together with the benthic-feeding prawns, and the prawns generally had lower trace metal burdens. Climate change effects were not strongly evident at this time, but altered ocean circulation and watershed run-off patterns accompanying future climate change are expected to change chemical patterns recorded by prawns along these and other coastlines. Stable isotopes, especially (15)N, can help to distinguish between relatively polluted and unpolluted sites.