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A comparative bioassessment of sediment toxicity in lentic
and lotic ecosystems of the North American Great Lakes
M, Munawara, R Dermotta,
LH McCarthyb, S.F. Munawarc,
H.A. van Stama
aFisheries
and Oceans Canada, Great Lakes Laboratory for Fisheries and
Aquatic Science, 867 Lakeshore Road P.O. Box 5050, Burlington,
Ontario, Canada L7R 4A6
bDepartment
of Applied Chemical and biological Sciences. Ryerson Polytechnic
University, Toronto, Ontario. MSB 2K3 Canada
cAquatic
Ecosystem Health and Management Society. P.O. Box 85388 Brant
Plaza Postal Outlet, Burlington, Ontario, Canada L7R 4K5
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Abstract
The bioavailability of sediment bound contaminants
in lentic (Hamilton Harbour, Lake Ontario) and lotic (Detroit River
connecting Lakes St. Clair and Erie) environments were assessed
by a battery of multi-trophic tests using laboratory grown organisms.
Hamilton Harbour is a hyper-eutrophic and highly contaminated environment
due to extensive urban and industrial growth, while the Detroit
River has been implicated as a major source of contaminants to Lake
Erie. An array of sites across Hamilton Harbour and the Detroit
River were selected, including the mouth of the Rouge River as well
as the Trenton Channel-the contaminated western arm of the Detroit
River. Multi-trophic acute assays were conducted using Daphnia
magna, Hyalella azteca, Diporeia hoyi, and Lumbriculus
variegatus. While the tests were consistent in determining the
most toxic hot spots, variability existed in the sensitivities of
test organisms to discriminate among less contaminated sites. The
most toxic sediment in the Detroit River was at the mouth of the
Rouge River, while the site in Windermere basin in Hamilton harbour
was found to be deleterious. The results indicated that the toxicity
in a lotic ecosystem such as the Detroit River was caused by both
the bottom sediments and the mobile seston component which contributed
to the water-borne toxicity. Conversely, lentic and undisturbed
ecosystems such as Hamilton Harbour contain ranch of their toxic
component in the bottom sediments and not in the overlying water
column. The multi-trophic battery of test approach adopted in our
study appears to be effective in detecting and discriminating differential
sensitivities of sediment bound contaminants in both lentic and
lotic ecosystems. This battery of tests approach needs continued
modification, development, and improvement to keep the assays up-to-date,
sensitive, cost effective and adaptable in discriminating complex
mixtures of sediment bound contaminants found in natural ecosystems.
© 1999 Published by Elsevier Science Ltd and AEHMS. All rights
reserved.
Keywords: Detroit River; Hamilton Harbour; Contaminants; Toxic
chemicals; Bioassays
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