DOI: http://dx.doi.org/10.1065/jss2001.09.026 ---
In the risk assessment of industrial chemicals, an assessment
of the risk to soil should be performed whenever relevant
inputs occur via the following pathways: application of
sewage sludge, wet or dry deposition, application as a pesticide
constituent (e.g. solvent or metabolite), irrigation.
An evaluation of the results for 34 chemicals from the first EU
priority list showed that only 35% of the risk assessments for
the terrestrial compartment were performed on the basis of at
least 2 valid tests with soil organisms. In the vast majority of
cases, the equilibrium partitioning method was used to extrapolate
from aquatic to soil toxicity. However, no indications exist
for a correlation between aquatic and terrestrial toxicity. Moreover,
the exposure routes for soil organisms (uptake via pore
water, air included in soil pores, ingestion of soil particles) are
much more complex than those for aquatic organisms.
As a new approach, it is therefore suggested that, in cases of
relevant exposure (e.g. estimated or measured concentrations
of >10 g/kg), an assessment should generally be performed on
the basis of valid terrestrial tests rather than on an extrapolation
from the aquatic toxicity. It is recommended that prolonged
exposure tests should be used already for an initial assessment
of substances that have a strong tendency to adsorb on soil particles
and thus a long residence time in soil.
A decision scheme for the risk assessment of industrial chemicals
in soil is presented, trigger values, testing strategies as well
as assessment factors for derivation of a Predicted No Effect
Concentration (PNEC soil ) are discussed. An example of a terrestrial
risk assessment for substances from the first EU priority
list is given in order to illustrate current practice. |
