Pb and 210Pb in a tropical river environment

The Periyar River in south India receives the major share of Pb and ²¹⁰Pb from effluents released by factories along its bank that process monazite ore and rock phosphate. Their distribution in the river system is influenced by the rains during the monsoon and by salinity during the non-monsoon period. The concentration of both Pb and ²¹⁰Pb in the sediments from the backwater zone was observed to increase during the monsoon due to sediment transport from the upstream industrial zone. The water in the backwater zone showed increased levels of Pb and ²¹⁰Pb in the non-monsoon period, due possibly to solubilization from the sediments as a result of salinity changes. The levels of Pb and ²¹⁰Pb in the river water are much lower than the international standards for safe limits in drinking water. No significant concentration of Pb and ²¹⁰Pb above a background level was observed in fish obtained from the river.