Unformatted text preview: rial test
organisms for soils.
Environment Canada ha s a test method for earthworms
(Environment Canada 2004).
Respiratory Various routes of exposure include oral, dermal and
respiratory ( Figure 3-16). The dermal route is often
exploited in the use of treated surfaces. Death as an
endpoint is relatively easily assessed in insects but
reproductive effects may also be measured. As the
responses are usually quantal, probit analysis can be
used for statistical analysis.
3.2.3 Terrestrial systems, vertebrates Laboratory mammals and birds are most commonly used as surrogates for terrestrial wildlife
(See Chapter 2, Section 2.6.2 and Chapter 4, Section
4.2.1). In most cases, oral toxicity is measured, either
Routes of uptake of toxic substances in
as a dose or as a concentration in the diet. Most of the
data for terrestrial vertebrates is generated in response
to the regulatory requirements for pesticides. Long -term feeding studies for either chronic or
lifetime exposures may also be undertaken.
Experimentally, exposure is largely through the diet or by direct gavage but, in the environment,
exposure may be through several routes, including dermal, respiratory and oral ( Figure 3-17).
Exposure through drinking water (contaminated puddles) can also be tested. Exposure through
preening in birds has been considered but is not routinely applied as a test method. Measures of
effect such as death, reproduction, carcinogenicity, teratogenicity, neurotoxicity and
physiological responses are usually considered. As the responses are usually quantal, probit
analysis can be used for statistical analysis. Non quantal analysis may be applied to some
measures of effect. Test methods for pesticides are published by the U.S. EPA (CFR 2004). 3.2.4 Aquatic systems, algae
Tests on aquatic algae and
commonly required for the
(Lewis 1990) for general
methods and interpretation of
results. The use of Lemna spp
as a representative aquatic
macrophyte has been criticized
as it is not rooted and does not
Routes of exposure for terrestrial vertebrates
produce seeds. It is, however,
relatively easy to grow.
Environment Canada has a test method for duckweed
(Environment Canada 1999a).
Routes of exposure are usually through the aquatic matrix. Measures of effect for algae are
number of cells, chlorophyll content and carbon assimilation (photosynthesis). For macrophytes,
number of fronds, internodal growth, chlorophyll c ontent and weight are common measures of
effect. Statistical treatment is usually a non -quantal graphical analysis of percent of control
3.2.5 Aquatic systems, invertebrates Aquatic invertebrates are quite widely used because of the ease of production and because of
their small size.
These methods have been extensively described in the lit erature
(Parrish 1984, Environment Canada 1990b, a, 1992...
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