Environmental Engineering Reference
In-Depth Information
Table 9.2. Bioassays proposed for use at Tier 2 of the ERA
Biological test
Application
Bait lamina
Measures activity of microbes in the soil; measure of
general soil health
Nitrogen mineralisation
Measures the rate at which nitrogen is mineralised in a
soil; provides a measure of general soil health
Earthworm reproduction
Sub-lethal test, demonstrates whether worms can survive
at a given contaminant concentration, but are unable to
reproduce properly; may be used as surrogate for chronic
contaminant effects on a range of soil invertebrates
Earthworm neutral red
retention time
Measures cellular damage (lysosomal integrity) in
earthworms; may be used as surrogate for chronic
contaminant effects on a range of soil invertebrates
Collembolan
reproduction
Sub-lethal test, demonstrates whether springtails can
survive at a given contaminant concentration, but are
unable to reproduce properly; may be used as
surrogate for chronic contaminant effects on a range of
soil invertebrates
Plant seedling
emergence
Measures the degree of successful emergence of
seedlings from seed; three test species are used:
tomato, cabbage and wheat, but may be used as
surrogates for other plant species of interest
Plant growth
Measures growth rate of plants (tomato, cabbage and
wheat) growing on contaminated soils; may be used as
surrogates for other plant species of interest
and their use is therefore not appropriate. Similarly, the tests described above
have physical and chemical limitations (some are pH sensitive, some are
soil matrix sensitive etc.) and will not be suitable for deployment at all sites.
Ideally the risk assessor will have made this decision while doing the desk
study, and will agree this with the relevant natural conservation agency and
other stakeholders.
Ecological surveys
It is recommended that a preliminary ecological survey, probably an extended
phase 1 habitat survey ( JNCC
1993
), is performed as part of the desk study and
development of the CSM. At Tier 2, more detailed information is required to
assess whether significant harm (or SPOSH) is being caused by contaminants at
a site (Environment Agency
2008a
,
b
).
A number of information sources are available to help inform the ecosurvey,
and these should be consulted when planning the survey. For sites of special
scientific interest (SSSI), Natura 2000 sites, Ramsar sites and national nature
