Sedimentation rates and heavy metals in a macrotidal salt marsh: Bay of Fundy, Canada

Abstract

Macrotidal salt marshes play an important role in sedimentary processes in estuaries and can act as a sink for fine sediments and contaminants. This study examines sedimentation rates and the history of heavy metal accumulation in the Allen Creek salt marsh in the Bay of Fundy, Canada. Pb-210 and Cs-137 measurements and accelerated mass spectrometer (AMS) dating indicate a sedimentation rate of about 1.1 cm/year, which is consistent with independent observations. Elevated normalized concentrations of As in the upper section of the deposit may reflect an increase in organic matter content while a consistent decrease in Mn toward the surface of the section may be due to a decrease in natural supply. A peak in metal concentrations in the early to mid twentieth century is attributed to inputs from local foundries.