『Abstract
Metal pollution, in combination with other environmental stressors
such as acid deposition and climate change, may disturb metal
biogeochemical cycles. To investigate the influence of dissolved
organic carbon, acidity and seasonality on metal geochemistry,
this study has described concentrations of 19 metals as they pass
through an acidified forested catchment on the Precambrian Shield
in south-central Ontario, Canada. Metal, dissolved organic carbon
(DOC) and sulphate (SO42-) concentrations
fluctuate throughout the catchment compartments as the water passes
through and interacts with vegetation, soils and bedrock. Relationships
among metals, DOC and SO42- are
most pronounced in compartments where DOC and SO42-
exhibit high variability, namely in the throughfall, organic horizon
soil water, and wetland-draining stream. Metal, DOC and SO42- concentrations varied seasonally
in the streams, and temporal coherence occurred among metal, DOC
and SO42- concentrations in the
organic horizon soil water and the wetland-draining stream (PC1).
In the wetland-draining stream, the highest DOC, Cr, Cu, Fe, Pb,
and V concentrations occur in the summer, whereas concentrations
of SO42- and most other metals
peak in the fall after a period of drought. Despite the rural
location, provincial water quality objectives for surface water
were exceeded for many metals when the peak fall values occurred.
Keywords: Acidity; Dissolved organic carbon; Forest catchment;
Metal; Seasonality; Wetland』
Introduction
Materials and methods
Site description
Monitoring and sample collection
Chemical analysis
Statistical analysis
Results
Concentrations
Multiple regressions
Seasonal variability
Discussion
Bulk deposition
Throughfall
Forest floor
Mineral soil and upland stream
Swamp wetland and main stream
Seasonal variability of metal concentrations
Exceedances of surface water guidelines for metals
Summary of metal behaviour
Acknowledgments
Appendix
References