Environmental Engineering Reference
In-Depth Information
istry, sediment toxicity, community status, and/or
tissue chemistry provides important information for
assessing sediment quality conditions. The contin-
gency table presented in Table 7.7 provides a means
of interpreting the data generated from multiple indi-
cators of sediment quality using a weight-of-evidence
approach. The results of these analyses can be used
to estimate the likelihood of impacts of sediment
contamination on aquatic life (sediment-dwelling
organisms), wildlife (vertebrates), or human health.
Table 7.7
Contingency table for assessing impacts of contaminated sediments on aquatic life based on four separate indicators of
sediment quality.
Possible
outcome
Sediment
chemistry
Toxicity
test
Benthic
community
Tissue
chemistry Possible conclusions
1
+
+
+
+
Contaminant-induced impacts on sediment-dwelling organisms and
higher trophic levels are likely to be observed; elevated levels of
sediment-associated contaminants are likely contributing to
sediment toxicity and benthic community impairment; and,
bioaccumulation of sediment-associated contaminants has the
potential to adversely affect aquatic-dependent wildlife and/or
human health.
2
−
−
−
+
Contaminant-induced impacts on higher trophic levels are likely to
be observed; adverse effects on sediment-dwelling organisms are
unlikely to be observed; and, bioaccumulation of sediment-
associated contaminants has the potential to adversely affect
aquatic-dependent wildlife and/or human health.
3
+
−
−
+
Contaminant-induced impacts on higher trophic levels are likely to
be observed; the bioavailability of sediment-associated
contaminants is likely to be limited; and, bioaccumulation of
sediment-associated contaminants has the potential to adversely
affect aquatic-dependent wildlife and/or human health.
4
−
+
−
+
Contaminant-induced impacts on higher trophic levels are likely to
be observed; unmeasured factors (e.g., physical factors or
contaminants) are likely to be contributing to sediment toxicity;
and, bioaccumulation of sediment-associated contaminants has the
potential to adversely affect aquatic-dependent wildlife and/or
human health.
5
−
−
+
+
Contaminant-induced impacts on sediment-dwelling organisms and
higher trophic levels are likely to be observed; adverse effects on
sediment-dwelling organisms are likely due to physical factors and/
or unmeasured chemicals are stressing benthos and toxicity tests
are not sensitive enough to detect effects; and, bioaccumulation
of sediment-associated contaminants has the potential to adversely
affect aquatic-dependent wildlife and/or human health.
6
+
+
−
+
Contaminant-induced impacts on sediment-dwelling organisms and
higher trophic levels are likely to be observed; high variability in
the benthic community metrics may be masking contaminant-
related effects; and, bioaccumulation of sediment-associated
contaminants has the potential to adversely affect aquatic-
dependent wildlife and/or human health.
7
−
+
+
+
Contaminant-induced impacts on sediment-dwelling organisms and
higher trophic levels are likely to be observed; unmeasured
contaminants are likely contributing to sediment toxicity and
benthic impairment; and, bioaccumulation of sediment-associated
contaminants has the potential to adversely affect aquatic-
dependent wildlife and/or human health.
