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An examination of trace metal contamination and land use in an urban watershed McCallum, Donald Wayne
Abstract
The Brunette River Watershed is intensely urbanized, occupying 7200 hectares in the geographic centre of the Greater Vancouver Regional District in British Columbia. This study examines lake, stream, and street sediment trace metal contaminant history in the watershed in relation to changing land uses. Contamination of Burnaby Lake surface sediments with Pb, Cu, Zn, and Cd is indicated by their respective enrichment factors of 10, 6, 3.8, and 1.5. Chromium, Ni, Mg, Fe, and Mh are not enriched in the surface sediments. Calculated fluxes of Pb, Cu, and Zn entering Burnaby Lake are from 3 to 10 times higher than measured in two comparable urban lakes. Stream contamination is indicated by the failure of all 33 stream stations to meet watershed sediment criteria for Pb, Cu, and Zn and 13 stream stations for Hg. Trace metal concentrations in Burnaby Lake sediments increased steadily from 1950, during a period of rapid urbanization. A sharp peak in Cu, Cr, Cd, and Ni concentrations in 1970 is related to industrial discharges in the Still Creek area at the time. Lead has decreased over the past 20 years in lake, stream, and street sediments as a result of the removal of the Pb additive, TEL, from gasoline. During this time, Zn, Cu, Mn, and Hg increased in stream sediments by 45 , 81, 130, and 290 percent respectively. Land use changes since 1973 have been small compared to demographic and traffic changes. Lake sediment contaminant profiles and spatial patterns of stream and street sediment contamination indicate that traffic contributes a large proportion of the Pb, Cu, and Zn loading to the watershed. The large Mn increases in stream sediments since 1973 may be related to in-stream chemical transformations, possibly resulting from usage of the gasoline additive, MMT. Increases in stream sediment Hg levels may be related to point-source emissions originating outside the watershed. Permeable land cover in the upland areas has mitigated some of the effects of nonpoint source pollution generated in more densely populated lower river reaches and has contributed to a relatively healthy aquatic habitat in the eastern region of the watershed. Much of the recent reduction in permeable land cover has occurred in these upland areas.
Item Metadata
Title |
An examination of trace metal contamination and land use in an urban watershed
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Creator | |
Publisher |
University of British Columbia
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Date Issued |
1995
|
Description |
The Brunette River Watershed is intensely urbanized, occupying 7200 hectares in the
geographic centre of the Greater Vancouver Regional District in British Columbia. This study
examines lake, stream, and street sediment trace metal contaminant history in the watershed
in relation to changing land uses.
Contamination of Burnaby Lake surface sediments with Pb, Cu, Zn, and Cd is
indicated by their respective enrichment factors of 10, 6, 3.8, and 1.5. Chromium, Ni, Mg, Fe,
and Mh are not enriched in the surface sediments. Calculated fluxes of Pb, Cu, and Zn
entering Burnaby Lake are from 3 to 10 times higher than measured in two comparable urban
lakes. Stream contamination is indicated by the failure of all 33 stream stations to meet
watershed sediment criteria for Pb, Cu, and Zn and 13 stream stations for Hg.
Trace metal concentrations in Burnaby Lake sediments increased steadily from 1950,
during a period of rapid urbanization. A sharp peak in Cu, Cr, Cd, and Ni concentrations in
1970 is related to industrial discharges in the Still Creek area at the time. Lead has
decreased over the past 20 years in lake, stream, and street sediments as a result of the
removal of the Pb additive, TEL, from gasoline. During this time, Zn, Cu, Mn, and Hg
increased in stream sediments by 45 , 81, 130, and 290 percent respectively. Land use
changes since 1973 have been small compared to demographic and traffic changes.
Lake sediment contaminant profiles and spatial patterns of stream and street
sediment contamination indicate that traffic contributes a large proportion of the Pb, Cu, and
Zn loading to the watershed. The large Mn increases in stream sediments since 1973 may be
related to in-stream chemical transformations, possibly resulting from usage of the gasoline
additive, MMT. Increases in stream sediment Hg levels may be related to point-source
emissions originating outside the watershed.
Permeable land cover in the upland areas has mitigated some of the effects of nonpoint
source pollution generated in more densely populated lower river reaches and has
contributed to a relatively healthy aquatic habitat in the eastern region of the watershed.
Much of the recent reduction in permeable land cover has occurred in these upland areas.
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Extent |
13886276 bytes
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Genre | |
Type | |
File Format |
application/pdf
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Language |
eng
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Date Available |
2009-01-16
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Provider |
Vancouver : University of British Columbia Library
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Rights |
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.
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DOI |
10.14288/1.0050348
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URI | |
Degree | |
Program | |
Affiliation | |
Degree Grantor |
University of British Columbia
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Graduation Date |
1995-05
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Campus | |
Scholarly Level |
Graduate
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Aggregated Source Repository |
DSpace
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Item Media
Item Citations and Data
Rights
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.