A history of metal pollution in the Upper Gulf of Thailand

Sediment cores were taken from the Upper Gulf of Thailand and 5-cm strata were analysed for cadmium, chromium, copper, lead, zinc and aluminium. At the Chao Phrya River mouth area, enriched concentrations of cadmium and lead were observed at the top end of the cores. On applying the sedimentation rates found by the ²¹⁰Pb method, these layers were found to correspond to the past 30 years. No enrichment was found for chromium, copper or zinc.