Potential Anthropogenic Influences on Trace Metal Distributions in the North Atlantic

• Published in: Canadian Journal of Fisheries and Aquatic Sciences
• Main Authors: Yeats, P. A., Bewers, J. M.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1983
• Subjects: Aquatic Science; Ecology, Evolution, Behavior and Systematics; North Atlantic; Northwest Atlantic
• Online Access: http://dx.doi.org/10.1139/f83-318; http://www.nrcresearchpress.com/doi/pdf/10.1139/f83-318

This paper discusses the application of geochemical understanding of an estuarine and marginal sea environment to an assessment of marine contamination by trace metals. The estuaries and Gulf of St. Lawrence are used as an analogue of a section of the nearshore and continental shelf environment in which metal fluxes, in both dissolved and particulate form, can be estimated. Estuarine and nearshore removal of 99% of the particulate matter, >97% of the particulate Fe and Mn, and 25–50% of the Ni, Co, Cu, Zn, and Cd discharges are indicated. The dissolved Mn efflux is augmented slightly within the gulf. A generic coastal zone model is used to examine the magnitude of exchanges between particulate and dissolved metal phases during transport between the freshwater and deep marine environments. This model is also used to compare global river discharges with metal accumulations in nearshore and pelagic sediments. The current influxes of Zn and Cd to the ocean greatly exceed their rates of sedimentation. The imbalance for Zn may merely be due to limited and inaccurate measurements of Zn in continental runoff. The Cd imbalance, however, appears to be real and reflects a major increase in the mobilization of this metal. Finally, oceanic metal distributions are examined for evidence of contamination of the northwest Atlantic by metals of anthropogenic origin.