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3.7 EFFECTS ASSESSMENT FOR THE AIR COMPARTMENT
For the risk assessment of the air compartment biotic and abiotic effects are considered.
3.7.1 Biotic effects
EFFECTS ASSESSMENT
The methodology used for effects assessment (and therefore the risk characterisation) of
chemicals in water and soil cannot be applied yet in the same manner to the atmosphere.
Methods for the determination of effects of chemicals on species arising from atmospheric
contamination have not yet been fully developed, except for inhalation studies with mammals.
It is evident that the quantitative characterisation of risk by comparison of the PECair to PNECair
is not possible at the moment: only a qualitative assessment for air is feasible.
For the air compartment toxicological data on animal species other than mammals are usually
not or only scarcely available. For volatile compounds acute or short-term inhalation tests may
be present. On the basis of these data there may be indications of adverse effects. Short-term
LC50 data can be used for a coarse estimation of the risk a chemical poses for animals.
However, in most cases, it is unlikely that the atmospheric concentration of a chemical will be
high enough to cause short-term toxic effects in the environment, so data on long-term or chronic
toxicity should be considered. For example, a chemical may be dangerous for the atmospheric
environment at a low concentration, if it is classified as R 48 (“Danger of serious damage to
health by prolonged exposure”). Also mutagenic effects and toxic effects on reproduction by a
chemical indicate a toxic potential for terrestrial vertebrates.
Fumigation tests on invertebrates are usually not available. For some existing substances and
biocides investigations on the toxicity to honey bees (Apis mellifera), which are conducted
according to guidelines for the testing of plant protection agents, may be available. In these tests,
it is sometimes difficult to determine the effective concentration and therefore a PNECair cannot
be derived.
Concerning the toxicity for plants, data from tests where a chemical is applied directly via air
(gaseous or deposited) are normally scarce. When toxicity data are available or information is
available that plants might be affected this information must be carefully screened and if
necessary further plant toxicity testing can be requested. When no specific information on
toxicity to plants is available for the substance and considerable air emissions and exposure are
expected the information on related compounds (e.g. toxicity, phys.chem. properties) should be
screened and a decision should be made whether there is reason for concern and whether actual
plant testing should be considered.
Some experience has been obtained over the last years on existing substances for which actual
plant testing has been requested and performed (e.g. Risk assessment reports on
tetrachloroethylene and dibutylphthalate, ECB, 2001). The test protocols have been developed
on a case-by-case basis and varied from relatively simple laboratory test designs that can be
considered as screening tests, to very extensive long-term open-top chambers with a large
variety of species. Further discussion is needed before these test designs can be standardised and
inserted in a more rigid testing strategy for plants.
How the results of the available toxicity test should be used in the actual setting of a PNEC for
plants has yet to be decided on a case-by-case basis. Like with the effects assessments for the
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