Radium-228 and Radium-226 levels in a river environment and its modification by human activities

The Periyar River is of prime importance in the economy of Kerala because of the manifold utility of its waters. Consistently high background levels of 228Ra in the river water, which amount to 10% of the maximum permissible concentration in water [(MPC)/sub w/] during the peak and lean flow periods suggests geochemical transport from the drainage areas. Industrial discharges enhance radium levels by an order of magnitude in downstream locations. Monazite and rock phosphate processes change the nuclide ratio in the river environment due to differential inputs. Riverbed sediments carrying the bulk of the radium get displaced to backwaters where partial solubilization takes place because of monsoon flushes. The uptake of radium by fish in industrial and downstream locations in the river was evident. The analysis of paddy indicates higher uptake by soil and hay due to irrigation by river water drawn from downstream and marginal increase of activity in the fertilizer field