Modelling natural and enhanced trace metal concentrations in sediments of Cleveland Bay, Australia

Abstract

The major element and trace metal analytical results of a strong acid digestion have been used to model natural and enhanced trace metal concentrations in surface sediment samples from Cleveland Bay. The natural ranges in concentration of cadmium, cobalt, copper, nickel, lead and zinc in sediments have been modelled by multiple linear regression using major elements as independent variables. Sites that exceed the upper 95% prediction interval of the regression model of the natural range in concentration are classified as enhanced. Enhancement of sites by metals derived from anthropogenic sources is characterized by enhancement of cadmium, copper, lead or zinc, and can be identified by Principle Components Analysis. Sites that contain metals derived from anthropogenic sources occur within the intertidal and near-shore sediments of western Cleveland Bay. No evidence of trace metals derived from anthropogenic sources was found within the sediments of the central bay.