The use of sediment cores to reconstruct historical trends in contamination of estuarine and coastal sediments

Most studies using sediment cores to reconstruct the contamination history of coastal and estuarine areas around the world have dealt with trace metals, and only a few have focused on organic contaminants. Almost without exception, the studies published up to 1990 have shown that sediment contamination increased in the late 1800s, accelerated in the 1940s, and reached a plateau or a maximum in the 1960–1970s. For some pollutants, such as Pb, a decrease in concentration occurred in the 1980s, following the implementation of new discharge and emission regulations. Little is known, however, about concentration trends from the mid-1980s to present and about the effect of legislation recently passed to protect the environment.