Tar acids, xylenol fraction

Toxicity to terrestrial plants

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to terrestrial plants: short-term (with study design considered suitable for long-term assessment)

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Principles of method if other than guideline:

Additional experiments were carried out in nurtient solutions.

GLP compliance:

not specified

Analytical monitoring:

yes

Details on sampling:

Analytical monitoring at test start and end of exposure and before renewal of test solution

Vehicle:

no

Details on preparation and application of test substrate:

Test substance was dissolved in water, added to soil and thoroughly mixed.

Species:

Lactuca sativa

Plant group:

Dicotyledonae (dicots)

Test type:

early seedling growth toxicity test

Study type:

laboratory study

Substrate type:

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

Limit test:

no

Total exposure duration:

21 d

Remarks:

14 d in soil, 21 d in nutrient solution

Test temperature:

21 ± 4 °C

pH:

7.5 (adjusted with 1 N KCl)

Moisture:

Soil experiment: 25 to 30 % moisture content (80% of the water-holding capacity)

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:

At least 3,2, 10, 32, 100, 320, and 1000 µg/g (nominal) were used.

Reference substance (positive control):

yes

Remarks:

several other test substances

Species:

Lactuca sativa

Duration:

7 d

Dose descriptor:

EC50

Effect conc.:

69 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth

Remarks on result:

other: 95% C.l.: 51-94

Remarks:

soil

Species:

Lactuca sativa

Duration:

14 d

Dose descriptor:

EC50

Effect conc.:

96 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth

Remarks on result:

other: 95% C.l.: 63-147

Remarks:

soil

Species:

Lactuca sativa

Duration:

21 d

Dose descriptor:

EC50

Effect conc.:

50 other: mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth

Remarks on result:

other: 95% C.l.: 42-61

Remarks:

nutrient solution

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

Executive summary:

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 (Hulzebos et al. 1993).

Reference 2

Endpoint:

toxicity to terrestrial plants: short-term

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to same study

Qualifier:

no guideline followed

Principles of method if other than guideline:

Method: Seed germination test

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

not specified

Species:

Lactuca sativa

Plant group:

Dicotyledonae (dicots)

Test type:

seedling emergence toxicity test

Study type:

laboratory study

Substrate type:

other: agar

Limit test:

no

Total exposure duration:

72 h

Test temperature:

30 ± 0.5 °C

Details on test conditions:

5 replicates/concentration, 10 mL agar/seed

Species:

Lactuca sativa

Duration:

3 d

Dose descriptor:

EC50

Effect conc.:

53 other: mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

germination

Result was reported as "0.49 mmol/l" which equals 53 mg/L

Validity criteria fulfilled:

not applicable

Executive summary:

The effect of m-cresol on the germination of lettuce (Lactuca sativa) fruit was tested under laboratory conditions. The EC50 (3d) was 53 mg/L in test solution used for the growth medium (agar) (Reynolds, 1978).

Reference 3

Endpoint:

toxicity to terrestrial plants: short-term (with study design considered suitable for long-term assessment)

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Principles of method if other than guideline:

Additional experiments were carried out in nurtient solutions.

GLP compliance:

not specified

Analytical monitoring:

yes

Details on sampling:

Analytical monitoring at test start and end of exposure and before renewal of test solution

Vehicle:

no

Details on preparation and application of test substrate:

Test substance was dissolved in water, added to soil and thoroughly mixed.

Species:

Lactuca sativa

Plant group:

Dicotyledonae (dicots)

Test type:

early seedling growth toxicity test

Study type:

laboratory study

Substrate type:

other: soil and nutrient solution (and perlite as an unreactive substrate)

Limit test:

no

Total exposure duration:

21 d

Remarks:

14 d in soil, 21 d in nutrient solution

Test temperature:

21 ± 4 °C

pH:

7.5 (adjusted with 1 N KCl)

Moisture:

Soil experiment: 25 to 30 % moisture content (80% of the water-holding capacity)

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:

At least 3,2, 10, 32, 100, 320, and 1000 µg/g (nominal) were used.

Reference substance (positive control):

yes

Remarks:

several other test substances

Species:

Lactuca sativa

Duration:

7 d

Dose descriptor:

EC50

Effect conc.:

67 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth

Remarks on result:

other: 95% C.I.: 52-86

Remarks:

soil

Species:

Lactuca sativa

Duration:

14 d

Dose descriptor:

EC50

Effect conc.:

> 100 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth

Remarks on result:

other: soil

Species:

Lactuca sativa

Duration:

21 d

Dose descriptor:

EC50

Effect conc.:

23 other: mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth

Remarks on result:

other: 95% C.I.: (16-31)

Remarks:

nutrient solution

Validity criteria fulfilled:

not specified

Executive summary:

The toxicity of o-cresol to lettuce seedlings (Lactuca sativa) was determined according to OECD Guideline 208 in soil. The EC50 was 67 mg/kg soil d.w. after 7 d, >100 mg/kg soil d.w. after 14 d (Hulzebos, 1993). The highest effect concentration (EC50 >100 mg/kg) was normalised to an organic carbon content of 3.4% according to TGD (EU 2003), resulting in a corrected EC50 of >242 mg/kg.

Reference 4

Endpoint:

toxicity to terrestrial plants: short-term

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to same study

Qualifier:

no guideline followed

Principles of method if other than guideline:

Method: Seed germination test

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

not specified

Species:

Lactuca sativa

Plant group:

Dicotyledonae (dicots)

Test type:

seedling emergence toxicity test

Study type:

laboratory study

Substrate type:

other: agar

Limit test:

no

Total exposure duration:

72 h

Test temperature:

30 ± 0.5 °C

Details on test conditions:

5 replicates/concentration, 10 mL agar/seed

Species:

Lactuca sativa

Duration:

3 d

Dose descriptor:

EC50

Effect conc.:

38.9 other: mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

germination

Result was reported as "0.36 mmol/l" which equals 38.9 mg/L

Validity criteria fulfilled:

not applicable

Executive summary:

The effect of o-cresol on the germination of lettuce (Lactuca sativa) fruit was tested under laboratory conditions. The EC50 (3d) was 38.9 mg/L in test solution used for the growth medium (agar) (Reynolds, 1978).

Reference 5

Endpoint:

toxicity to terrestrial plants: short-term

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to same study

Qualifier:

no guideline followed

Principles of method if other than guideline:

Method: Seed germination test

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

not specified

Species:

Lactuca sativa

Plant group:

Dicotyledonae (dicots)

Test type:

seedling emergence toxicity test

Study type:

laboratory study

Substrate type:

other: agar

Limit test:

no

Total exposure duration:

72 h

Test temperature:

30 ± 0.5 °C

Details on test conditions:

5 replicates/concentration, 10 mL agar/seed

Species:

Lactuca sativa

Duration:

3 d

Dose descriptor:

EC50

Effect conc.:

122 other: mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

germination

Result was reported as "1.13 mmol/l" which equals 122 mg/L

Validity criteria fulfilled:

not applicable

Executive summary:

The effect of p-cresol on the germination of lettuce (Lactuca sativa) fruit was tested under laboratory conditions. The EC50 (3d) was 122 mg/L in test solution used for the growth medium (agar) (Reynolds, 1978).

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 and 96 mg/kg soil d.w. after 14 d, representing the most sensitive value.

Key value for chemical safety assessment

Short-term EC50 or LC50 for terrestrial plants:

96 mg/kg soil dw

Additional information

Data on the toxicity to terrestrial plants are available for constituents of Tar acids, Xylenol fraction (CAS 84989-06-0), namely o-, m-, and p-cresol. These data are used to determine the hazard of Tar acids, Xylenol fraction (CAS 84989-06-0) by applying a weight of evidence and an analogue read-across approach. The studies were conducted with seedlings of Lactuca sativa. A worst-case scenario is followed, i.e. for assessment purposes the most sensitive values are considered. For details on the read-across approach please refer to the analogue justification provided in IUCLID section 13.

Effect values determined are listed in the table below:

Source		Species	p-cresol	m-cresol	o-cresol
Hulzebos et al., 1993	Growth inhibition	Lactuca sativa	-	EC50 (14d) = 96 mg/kg soil dw	EC50 (14d) > 242 mg/kg soil dw
Reynolds, 1978	Growth inhibition	Lactuca sativa	EC50 (3d) = 122 mg/L	EC50 (3d) = 53 mg/L	EC50 (3d) = 38.9 mg/L

* TT = toxicity treshold

From the table above it can be seen that available data demonstrate effect values for toxicity to terrestrial plants in a range from 96 to >242 mg/kg soil dw and 38.9 to 122 mg/L. Nevertheless, the test by Reynolds (1978) was designed assessing the influence of the test substances on germination and growth on moist filter paper or agar treated with the substances. As no soil was used in the tests standardization of soil effect data to given soil parameters is not possible. Further, converting the results to an appropriate dimension is not applicable. Therefore the result should not be used for the hazard assessment. Nevertheless, the obtained effect values indicate that p-cresol is of low toxicity to terrestrial plants.

Based on all available information (weight-of-evidence) and following an analogue read-across and considering the above stated the EC50 (14d) of 96 mg/kg soil dw determined for Lactuca sativa (Hulzebos et al., 1993) represents the most sensitive effect value to terrestrial plants for Tar acids, Xylenol fraction (CAS 84989-06-0) and is considered as key value for the chemical safety assessment.