Mercury Uptake by Eastern Oysters (Crassostrea virginica) in Oyster Restoration Project of the New York Harbor

Abstract

The Billion Oyster Project is a New York City-wide effort to reintroduce eastern oysters back into the New York Harbor and help improve water quality by reducing heavy metal concentrations in the environment. In particular, the bioaccumulation of mercury in oyster tissue was investigated in the New York Harbor oysters acquired from two sites. Mercury levels exceed the standard Environmental Protection Agency-recommended levels as the New York Harbor oysters exhibit mercury levels ranging from 0.36 ± 0.05 to 0.55 ± 0.08 μg Hg g−1 dry weight. In an ideal scenario, one billion of these oysters are roughly projected to capture a maximum of 110 g of mercury from the New York Harbor by 2030, assuming an average uptake of 0.55 μg Hg g−1 dry weight for every oyster added to the reef. In addition to the bioaccumulation of mercury within the oyster tissue, stunted physical growth of the oysters and abnormal discoloration of the tissue indicate the presence of other heavy metals. This study demonstrates the promising role that eastern oysters play in removing heavy metals, such as mercury, from their water environment and preview significant and measurable impacts on the ecosystem.