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EC number: 203-398-6
CAS number: 106-44-5
There is no study on chronic toxicity towards terrestrial plants available using p-cresol as test substance and a read-across from m-cresol is applied.The toxicity of m-cresol to lettuce seedlings (Lactuca sativa) was determined according to OECD Guideline 208 in soil. The EC50 was 69 mg/kg soil d.w. after 7 d, 96 mg/kg soil d.w. after 14 d and 50 mg/L solution after 21 d of incubation .However, in case of only one test result is available, the risk assessment should be performed both on this test result and on the basis of the outcome of the aquatic toxicity data. Therefore the equilibrium partitioning method with the PNEC for aquatic organisms is also taken into account for assessment.
There is no study on chronic toxicity towards terrestrial plants
available using p-cresol as test substance.
In order to get a comprehensive data set for p-cresol a read-across from
m-cresol is applied, in accordance with the following justification:
Justification for the read-across approach:
Data from substances who’s physicochemical, toxicological and
ecotoxicological properties are likely to be similar or follow a regular
pattern as a result of structural similarity may be used in a
read-across approach in order to avoid unnecessary animal testing. It
can be stated that the 3 cresols act as a prime example of substances
that are suitable for read-across. Cresols are isomers and, thus ideally
fulfill the recommended criteria of structural similarity. In its
chemical structure, a cresol molecule has a methyl group substituted
onto the benzene ring of a phenol molecule, by different arrangement of
the -CH3 groups are three structural isomers possible. (ortho-cresol,
meta-cresol and para-cresol). Of particular importance to environmental
effects are the values for partition coefficient (log Kow), vapour
pressure, water solubility and dissociation constant. The values of the
isomers are very close together, resulting in the same environmental
fate and behaviour. Further, with regard to the bioderadation behavior,
all 3 cresols are readily biodegradable. Concerning aquatic toxicity of
the cresols on aquatic species, a large number of experimental results
from tests with fish, invertebrates and algae are available, indicating
a similar toxicity of all isomers, with p-cresol being slightly more
toxic in acute tests: Based on the similarities in the results mentioned
above the read-across approach is therefore scientifically justified.
Several studies of toxicity of m-cresol towards terrestrial plants were
found in the literature. The scope of the terrestrial effects assessment
under the adopted REACH regulation is restricted to soil organisms in a
narrow sense and does not actually include adverse effects on soil
functions that are only indirectly linked to the biota in soils. Some
tests were designed assessing the influence of m-cresol on germination
and growth on moist filter paper or agar treated with the substance. As
no soil was used in the tests standardisation of soil effect data to
given soil parameters is not possible. Further, converting the results
to an appropriate dimension is not applicable. Therefore the results
should not be used for the hazard assessment. Using soil, short-term
toxicity of m-cresol to lettuce (Lactuca sativa) was examined. The test
compound was incorporated into soil according to OECD-guideline 208. The
organic matter of 2 soil types used was given as 1.4 to 1.8 %. Lettuce
seed was sown and the weight of the crops (above-ground biomass) was
measured after 7 and 14 days. After an exposure period of 14 days, a
nominal EC50 of 96 mg/kg soil (dry weight) was obtained. According to
TGD (EU 2003), the effect concentration (EC50 96 mg/kg) is corrected for
a standard soil with a content of organic matter of 3.4 % resulting in a
corrected EC50 of 233 mg/kg. The authors stated that “at the end of the
test, the concentrations of most phenols in soil had dropped to a low
value ( < 20% of the initial analysed concentrations) ".
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.
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