Through analyses of water and sediments, we investigate tungsten and 14 other heavy metals in a stream receiving treated effluents from a semiconductor manufacturer-clustered science park in Taiwan. Treated effluents account for similar to 50% of total annual river discharge and < 1% of total sediment discharge. Dissolved tungsten concentrations in the effluents abnormally reach 400 mu g/L, as compared to the world river average concentration of < 0.1 mu g/L. Particulate tungsten concentrations are up to 300 mu g/g in suspended and deposited sediments, and the corresponding enrichment factors are three orders of magnitude higher than average crust composition. Surprisingly, the estimated amount of tungsten exported to the adjacent ocean is 23.5 t/yr, which can approximate the amount from the Yangtze River should it be unpolluted. This study highlights the urgency of investigating the biological effect of such contamination. (C) 2011 Elsevier B.V. All rights reserved.