Anthropogenic Lead Pollution in the Ocean

Abstract

Since the industrial revolution in the eighteenth to nineteenth centuries, humans have greatly increased the flux of lead (Pb) to the atmosphere and ocean, mainly through the combustion of coals and leaded gasoline. Although such anthropogenic Pb emissions gave little harmful consequences in the open ocean, there have been apparent changes in Pb concentration and its stable isotopic ratios in seawater. Time-series Pb records in the surface oceans have been and will be constructed by the measurement of not only seawaters but corals recording the past seawater Pb during their growth. The Pb concentrations in the North Atlantic surface water, which showed tenfold increase between 1880 and 1970 reflecting the anthropogenic Pb inputs, have decreased drastically since the middle of 1970s due to the prohibition of leaded gasoline in U.S. and European countries. On the other hand, surface waters of northern and tropical Indian Ocean as well as those in the western Pacific Ocean showed significantly higher Pb concentrations than those of the North Atlantic Ocean, implying recent rapid industrialization and a late phase-out of leaded gasoline in developing countries in Asia.