m-cresol

Toxicity to terrestrial plants

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to terrestrial plants: long-term

Data waiving:

exposure considerations

Justification for data waiving:

the study does not need to be conducted because direct and indirect exposure of the soil compartment is unlikely

Justification for type of information:

No experimental study on toxicity to plants is available. In accordance with column 2 of REACH Annex X of Regulation EC 1907/2006performing of a study is not necessary, as the risk assessment does not indicate the need to investigate further the effects of the substance on terrestrial organisms. According to Guidance Document R.7c (v3.0; 2017) it is stated, that for readily biodegradable substances which are not directly applied to soil it is generally assumed that the substance will not enter the terrestrial environment and as such there is no need for testing of soil organisms is required. Additionally, the substance cannot be regarded as adsorptive with a log Kow of 1.96 (logKow < 3) and logKoc of 1.54 (log Koc < 5) and is not toxic to aquatic organisms. Hence, the risk to soil organisms exposed to the substance is acceptable based on the PNECsoil calculated using the Equilibrium Partitioning Method and does not need to be refined using long-term tests.

Principles of method if other than guideline:

not applicable; expert judgement on long-term toxicity

A long-term toxicity test on plants is not relevant according to column 2 of Annex X of Regulation EC 1907/2006, as the risk assessment does not indicate the need to investigate further the effects of the substance on terrestrial organisms (please refer to the Chemical Safety Report). The risk to soil organisms exposed to the substance is acceptable based on the PNECsoil calculated using the Equilibrium Partitioning Method and does not need to be refined using long-term tests.

Reference 2

Endpoint:

toxicity to terrestrial plants: short-term

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 208 (Terrestrial Plants Test: Seedling Emergence and Seedling Growth Test)

Deviations:

no

GLP compliance:

not specified

Analytical monitoring:

yes

Vehicle:

no

Species:

Lactuca sativa

Plant group:

Dicotyledonae (dicots)

Test type:

early seedling growth toxicity test

Study type:

laboratory study

Substrate type:

other: soilo and solution (and perlite as an unreactive substrate)

Limit test:

no

Remarks:

14 d in one laboratory, 21 in the other

Test temperature:

21 +/- 4 °C

Details on test conditions:

parallel tests in two institutes in the Netherlands
16:8 h light:dark 6500 lx fluorescent tubes

Nominal and measured concentrations:

analytical monitoring at start and end of test

Species:

Lactuca sativa

Duration:

7 d

Dose descriptor:

EC50

Effect conc.:

68 mg/kg soil dw

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

growth

Species:

Lactuca sativa

Duration:

14 d

Dose descriptor:

EC50

Effect conc.:

96 mg/kg soil dw

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

growth

Species:

Lactuca sativa

Duration:

21 d

Dose descriptor:

EC50

Effect conc.:

50 other: mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

growth

For most of the examined phenols (including m-cresol) applied concentrations 
dropped but remained larger than 50 % of the nominal values.

Validity criteria fulfilled:

not specified

Conclusions:

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.

Executive summary:

The short-term toxicity of m-cresol to lettuce (Lactuca sativa) was examined by Hulzebos (1993). 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)”.

Description of key information

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. 
The effect concentration was normalised to an OC content of 3.4% , resulting in a corrected EC50 of 233 mg/kg.
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.

Additional information

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)".