ANTHROPOGENIC INFLUENCES ON HYDROCARBON CONTENTS OF SEDIMENTS DEPOSITED IN EASTERN LAKE-ONTARIO SINCE 1800

The amounts and types of extractable hydrocarbon components in sedimen t cores from the Rochester Basin of eastern Lake Ontario provide a rec ord of environmental changes that have accompanied the settlement and population growth of the surrounding land areas. Sediments deposited p rior to the mid-1800s contain low concentrations of hydrocarbons that are dominated by land-plant wax components. Concentrations begin to ri se in the late 1800s as erosion of soil and nutrients from watershed a reas accelerated. This pattern continues into modern times. Episodes o f enhanced aquatic productivity are sometimes recorded in twentieth-ce ntury sediments by the dominance of algal hydrocarbons, but land-plant components typically predominate. Petroleum residues begin to appear in sediments deposited in the late 1800's but remain minor constituent s of the hydrocarbon contents of modern sediments in the Rochester Bas in.