Sodium 1H-benzotriazolide

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:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 208 (Terrestrial Plants, Growth Test)

Version / remarks:

2006-07-19

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Product name: 1,2,3 Benzotriazole Fine Granular
- Source (i.e. manufacturer or supplier) and lot/batch number of test material:
Connect Chemicals, Ratingen, Germany, Batch 190720
- Purity, including information on contaminants, isomers, etc.: 99.9 %

RADIOLABELLING INFORMATION (if applicable)
no

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: Store cool (SDS)
- Stability and homogeneity of the test material in the vehicle/solvent under test conditions (e.g. in the exposure medium) and during storage: stable
- Stability in the medium, i.e. sensitivity of the test material to hydrolysis and/or photolysis: assumed stable
- Solubility and stability of the test material in the solvent/vehicle and the exposure medium: assumed stable, Water solubility (25 °C): 20 g/L
- Reactivity of the test material with the incubation material used (e.g. plastic ware): assumed no reactivity

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
please refer to following sections

FORM AS APPLIED IN THE TEST (if different from that of starting material)
same as starting material

INFORMATION ON NANOMATERIALS
no nanomaterial

TYPE OF BIOCIDE/PESTICIDE FORMULATION (if applicable)
no biocide/pesticide

OTHER SPECIFICS
n/a

Analytical monitoring:

yes

Remarks:

Analytical method was validated according SANCO 3029/99 rev.4 (11/07/2000).

Details on sampling:

- Concentrations: The highest application solution per species was analysed regarding the test item Benzotriazole for verification of test item concentrations.
- Sampling method: direct sampling
- Sample storage conditions before analysis: no storage

Vehicle:

no

Details on preparation and application of test substrate:

The test item was applied as an aqueous stock solution (onion: 0.28 g test item/L water; tomato: 2.80 g test item/L water; sunflower: 3.73 g test item/L water; oat, turnip, mung bean: 4.48 g test item/L water). The volume of stock solution required to obtain the desired concentrations was filled up to 50 mL water and mixed thoroughly with the required amount of dry mass test substrate adjusted to ca. 20 % water holding capacity. Subsequently, the test substrate was adjusted to 40 % WHC with water and mixed thoroughly.

Species:

Allium cepa

Plant group:

Monocotyledonae (monocots)

Details on test organisms:

- Common name: Onion
- Plant family: Amaryllidaceae
- Source of seed: Kiepenkerl, Germany
- Cultivar: Stuttgarter Riesen
- Seed storage: in the dark at room temperature (20 ± 5 °C), protected from moisture

Species:

Avena sativa

Plant group:

Monocotyledonae (monocots)

Details on test organisms:

- Common name: Oat
- Plant family: Poaceae
- Source of seed: KWS Lochow, Germany
- Cultivar: Sommerhafer KWS Contender
- Seed storage: in the dark at room temperature (20 ± 5 °C), protected from moisture

Species:

Zea mays

Plant group:

Monocotyledonae (monocots)

Details on test organisms:

- Common name: Corn
- Plant family: Poaceae
- Source of seed: KWS Lochow, Germany
- Cultivar: Ronaldinio
- Seed storage: in the dark at room temperature (20 ± 5 °C), protected from moisture

Species:

Brassica rapa

Plant group:

Dicotyledonae (dicots)

Details on test organisms:

- Common name: Turnip
- Plant family: Brassicaceae
- Source of seed: Carolina Biological Supply Company, USA
- Cultivar: rapid-cycling
- Seed storage: in the dark at room temperature (20 ± 5 °C), protected from moisture

Species:

Helianthus annuus

Plant group:

Dicotyledonae (dicots)

Details on test organisms:

- Common name: Sunflower
- Plant family: Asteraceae
- Source of seed: Kiepenkerl, Germany
- Cultivar: Pacino
- Seed storage: in the dark at room temperature (20 ± 5 °C), protected from moisture

Species:

other: Solanum lycopersicum

Plant group:

Dicotyledonae (dicots)

Details on test organisms:

- Common name: Tomato
- Plant family: Solanaceae
- Source of seed: Enza Zaden Deutschland GmbH & Co. KG, Germany
- Cultivar: Moneyberg
- Seed storage: in the dark at room temperature (20 ± 5 °C), protected from moisture

Species:

Phaseolus aureus

Plant group:

Dicotyledonae (dicots)

Details on test organisms:

- Common name: mung bean
- Plant family: Fabaceae
- Source of seed: SPERLI Samen, Sperli GmbH, Germany
- Seed storage: in the dark at room temperature (20 ± 5 °C), protected from moisture

Test type:

seedling emergence and seedling growth test

Study type:

laboratory study

Substrate type:

natural soil

Limit test:

no

Total exposure duration:

16 d

Remarks:

14 days: Onion, Oat, Sunflower, Mung Bean;
15 days: Tomato, Corn;
16 days: Turnip

Number of days is related to days post-emergence.

Post exposure observation period:

n/a

Test temperature:

20.5 – 22.5 °C

pH:

5.7

Moisture:

60 – 80 %

Details on test conditions:

TEST SYSTEM
- Testing facility: Fraunhofer Institute for
Molecular Biology and Applied Ecology (IME)
Auf dem Aberg 1
57392 Schmallenberg, Germany
- Test container (type, material, size): round, non-porous plastic container, diameter of 85-95mm; glass fibre wick (from water reservoir and passing through the bottom of the container) to ensure consistent soil moisture
- Amount of soil: 300g moist soil
- Method of seeding: planting within one hour after test item application, all seeds were of same size class, not imbibed. Test substrate was moistened to 60% water holding capacity. On the following day, the glass firbe wicks were connected to a reservoir of deionized water to ensure consistent soil moisture.
- No. of seeds per container: 5
- No. of replicates per treatment group: 4 (oat, corn, turnip, mung bean, sunflower, tomato) or 5 (onion)
- No. of replicates per control: 4 (oat, corn, turnip, mung bean, sunflower, tomato), 7 (onion)

SOURCE AND PROPERTIES OF SUBSTRATE (if soil)
- Name: certified RefeSol 01-A; batch IME 05
- Soil texture (if natural soil)
- USDA: 6.2% clay, sandy loam; DIN: 7.0% clay, loamy sand Sl2
- pH: 5.7
- Organic carbon (%): 1.0
- Maximum water holding capacity (in % dry weigth):
- Pretreatment of soil: 2mm sieve
- Storage (condition, duration): outdoor in high grade stainless steel basins with drainage and ground contact

GROWTH CONDITIONS
- Photoperiod: 16/8 light/dark
- Light source: mixture of natural and artificial light
- Light intensity and quality: 226 – 278 µE/(m2·s)
- Day/night temperatures: not specified
- Relative humidity (%): 70 ± 25
- Watering regime and schedules: continuous bottom watering via glass fibre wicks
- Any pest control method/fertilization (if used): amended with fertilizer (COMPO Grünpflanzendünger, COMPO GmbH & Co. KG, P.O. Box 2107, 48008 Münster, Germany), 1mL fertilizer/L water

ACCLIMATION PERIOD: not specified

EFFECT PARAMETERS MEASURED (with observation intervals if applicable): fresh mass, emergence, growth, post-emergence survival

- Phytotoxicity rating system (if used): documentation via photo and/or reported (necrosis, chlorosis, growth aberration, mortality)

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 3 (onion, oat, corn, turnip, tomato), 2 (sunflower, mung bean)
- Range finding study: yes
- Results used to determine the conditions for the definitive study: Allium cepa showed no valid seelding emergence and was abstained from evaluation.

Nominal and measured concentrations:

Nominal concentrations: Onion: 0.12, 0.37, 1.11, 3.33 and 10.0 mg test item/kg dry mass soil;
Oat, Corn, Turnip, Tomato: 1.23, 3.70, 11.1, 33.3 and 100 mg test item/kg dry mass soil;
Sunflower, Mung Bean: 6.25, 12.5, 25.0, 50.0 and 100 mg test item/kg dry mass soil

Reference substance (positive control):

yes

Remarks:

In order to confirm the sensitivity of the test species, previous non-GLP reference toxicity tests with trichloroacetate were performed.

Species:

Allium cepa

Duration:

14 d

Dose descriptor:

NOEC

Basis for effect:

seedling emergence

Remarks:

, post-emergence survival & shoot fresh mass

Remarks on result:

not determinable

Remarks:

Allium cepa (onion) showed no valid emergence rate.

Species:

Avena sativa

Duration:

14 d

Dose descriptor:

NOEC

Effect conc.:

3.7 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth

Remarks:

shoot fresh mass

Species:

Zea mays

Duration:

15 d

Dose descriptor:

NOEC

Effect conc.:

>= 100 mg/kg soil dw

Basis for effect:

seedling emergence

Remarks:

, post-emergence survival & shoot fresh mass

Species:

Brassica rapa

Duration:

16 d

Dose descriptor:

EC10

Effect conc.:

3.27 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth

Remarks:

shoot fresh mass

Key result

Species:

Brassica rapa

Duration:

16 d

Dose descriptor:

EC50

Effect conc.:

28.5 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth

Remarks:

shoot fresh mass

Species:

Phaseolus aureus

Duration:

14 d

Dose descriptor:

EC10

Effect conc.:

40.5 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth

Remarks:

shoot fresh mass

Species:

Helianthus annuus

Duration:

14 d

Dose descriptor:

EC10

Effect conc.:

2.69 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

seedling emergence

Species:

Helianthus annuus

Duration:

14 d

Dose descriptor:

EC10

Effect conc.:

16.1 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth

Remarks:

shoot fresh mass

Species:

other: Solanum lycopersicum

Duration:

15 d

Dose descriptor:

NOEC

Effect conc.:

1.23 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth

Remarks:

shoot fresh mass

Key result

Species:

other: Solanum lycopersicum

Duration:

15 d

Dose descriptor:

EC10

Effect conc.:

1.69 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth

Remarks:

shoot fresh mass

Species:

other: Solanum lycopersicum

Duration:

15 d

Dose descriptor:

EC50

Effect conc.:

29.1 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth

Remarks:

shoot fresh mass

Details on results:

SEED GERMINATION
- Results with reference substance valid? yes
- see table 2

SEEDLING EMERGENCE
- Percent seedling emergence as mean values at highest concentration of test item: 95 (oat), 90 (corn), 0 (turnip), 5 (tomato), 100 (mung bean), 30 (sunflower) and lowest test concentration: 95 (oat), 80 (corn), 75 (turnip), 80 (tomato), 95 (mung bean), 66.7 (sunflower)
- Percent survival post-emergence at highest concentration: 100 (oat), 94,4 (corn), 0 (turnip), 100 (tomato), 100 (mung bean), 100 (sunflower)
- Fresh weight of the shoots as mean values at highest concentration: 0.258 ± 0.043 (oat), 8.785± 2.149 (corn), 0 (turnip), 1.562 (tomato, only 1 seedling), 0.742 ± 0.342 (mung bean), 0.460 ± 0.521 (sunflower)

- Abnormal seed development or appearance: there was no effect on the visual appearance regarding pathological symptoms of any of the species.

A table with all effect concentrations can be found in the attached documents.

Results with reference substance (positive control):

see Table 2

Reported statistics and error estimates:

The percent inhibition of seedling emergence for each plant species was calculated as an absolute value and in comparison to the control.
Post-emergence survival was calculated as an absolute value and in comparison to the control.
The percent inhibition of fresh weight was calculated in comparison to the control.
All statistical tests – depending on normal distribution (after Shapiro-Wilk’s test) and homogeneity of variances (after Levene test) the (Qualitative) Trend Analysis by Contrasts, Fisher`s Exact Binomial Test with Bonferroni Correction Williams Multiple Sequential t-test Procedure, or Dunnett`s Multiple t-test Procedure for the NOEC calculation; ECx calculation – were performed with the computer software ToxRat Professional by ToxRat® Solutions GmbH [6].
For ECx calculations probit-analysis assuming log-normal distribution of values was applied.

Table 2: non-GLP Terrestrial plants growth tests with trichloroacetate to confirm reproducibility and germination capacity and sensitivity of the test species.

Species	Emergence Control [%]	Test concentration [mg TCA/kg]	Emergence Test [%]	EC50 for growth [mg/kg (fresh mass per plant)]
Allium cepa	88	100	55	20
Avena sativa	93	80	100	12
Zea mays	100	400	25	21
Brassica rapa	60	1000	0	147
Helianthus annuus	85	200	100	384
Phaseoulus aureus	90	400	47	31
Solanum lycopersicum	92	1000	35	>1000

Validity criteria fulfilled:

yes

Remarks:

further information are provided in attached document

Conclusions:

In a valid, reliable and conclusive study following the OECD 208, the effects of the test item Benzotriazole on seedling emergence and early growth of emerged plants were tested. Benzotriazole has concentration depending effects on all of the plant species tested under the chosen test conditions. The most sensitive endpoint in all species was shoot fresh mass. The most sensitive species overall was Solanum lycopersicum, the most sensitive acute species was Brassica rapa.

Executive summary:

The effect of Benzotriazole on the emergence and growth of terrestrial plant seedlings in seven species was investigated according to the OECD guideline 208 [5]. The following test species were used: Avena sativa (oat), Allium cepa (onion), Zea mays (corn), Brassica rapa (turnip), Helianthus annuus (sunflower), Solanum lycopersicum (tomato) and Phaseolus aureus (mung bean).

The plant seeds were placed in a natural sandy soil containing the test item at nominal concentrations of 0.12, 0.37, 1.11, 3.33 and 10.0 mg test item per kg dry mass soil (onion), 1.23, 3.70, 11.1, 33.3 and 100 mg test item per kg dry mass soil (oat, corn, turnip and tomato) or 6.25, 12.5, 25.0, 50.0 and 100 mg test item per kg dry mass soil (sunflower and mung bean). The test item was incorporated into the test soil at the beginning of the experiment.

The effects on seedling emergence and growth were determined 14 days (onion, oat, sunflower and mung bean), 15 days (tomato and corn) and 16 days (turnip) after emergence of 50 % of the control seedlings.

According to the OECD guideline 208 [5], effect values are calculated based on concentrations initially applied to the soil at the start of the incubation period. For this, measured concentration of the highest application solution should be considered. With a recovery rate of 83.9 - 93.9 % in the highest application solution, recovery was within 80 – 120 % of nominal. Therefore, evaluation was based on nominal concentrations.

Allium cepa showed no valid seedling emergence in neither the range finding test nor the GLP test and therefore was abstained from evaluation. Even though Zea mays and Avena sativa are both from Poaceae, they were considered as if from different families because the former is a type C4 plant and the latter a type C3 plant.

There was no significant effect on seedling emergence of Avena sativa, Zea mays and Phaseolus aureus (NOEC ≥ 100 mg TI/kg DM; EC₁₀ and EC₅₀ > 100 mg/kg DM) due to the test item up to and including the highest concentration tested. For Solanum lycopersicum no concentration-depending effect was observed (EC₁₀ and EC₅₀ > 100 mg TI/kg DM). However, the NOEC value was 33.3 for mg/kg DM. With an EC₁₀ of 33.1 mg test item dry mass content per kg dry mass soil (NOEC = 33.3 mg TI/kg DM and EC₅₀ = 51.8 mg TI/kg DM) and 2.69 mg TI/kg DM (NOEC = 12.5 mg TI/kg DM and EC₅₀ = 42.2 mg TI/kg DM), respectively, emergence inhibition of Brassica rapa and Helianthus annuus showed a concentration dependent effect by Benzotriazole.

There was no impairment on post-emergence survival of Avena sativa, Zea mays, Helianthus annuus, Solanum lycopersicum and Phaseolus aureus (NOEC ≥ 100 mg TI/kg DM; EC₁₀ and EC₅₀ > 100 mg TI/kg DM) due to the test item up to and including the highest concentration tested. With an EC₁₀ value of 28.5 mg TI/kg DM (EC₅₀ > 100 mg TI/kg DM), post-emergence of Brassica rapa was slightly affected by Benzotriazole. However, the NOEC value was ≥ 100 mg TI/kg DM.

The most sensitive endpoint in all species was shoot fresh mass. There was a concentration dependent effect on shoot fresh weight in all species tested. The sensitivity in increasing series was: Zea mays (NOEC: ≥ 100 mg TI/kg DM; EC₁₀: > 100 mg TI/kg DM; EC₅₀: > 100 mg TI/kg DM), Phaseolus aureus, Helianthus annuus, Avena sativa, Brassica rapa and the most sensitive species Solanum lycopersicum (NOEC: 1.23 mg TI/kg DM; EC₁₀: 1.69 mg TI/kg DM (95 % CL: 0.28 – 3.35); EC₅₀: 28.5 mg TI/kg DM).

The most sensitive acute species was Brassica rapa with an EC₅₀ of 28.5 mg TI/kg DM (95 % CL: 19.2 – 58.6).

Reference 2

Endpoint:

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

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

See read-across justification in Section 13.2 titled "140704_NaBZT_rationale_RA 8.4.16".

Reason / purpose for cross-reference:

read-across source

Species:

Allium cepa

Duration:

14 d

Dose descriptor:

NOEC

Basis for effect:

seedling emergence

Remarks:

, post-emergence survival & shoot fresh mass

Remarks on result:

not determinable

Remarks:

Allium cepa (onion) showed no valid emergence rate.

Species:

Avena sativa

Duration:

14 d

Dose descriptor:

NOEC

Effect conc.:

4.4 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth

Remarks:

shoot fresh mass

Species:

Zea mays

Duration:

15 d

Dose descriptor:

NOEC

Effect conc.:

>= 119 mg/kg soil dw

Basis for effect:

seedling emergence

Remarks:

, post-emergence survival & shoot fresh mass

Species:

Brassica rapa

Duration:

16 d

Dose descriptor:

EC10

Effect conc.:

3.87 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth

Remarks:

shoot fresh mass

Key result

Species:

Brassica rapa

Duration:

16 d

Dose descriptor:

EC50

Effect conc.:

33.8 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth

Remarks:

shoot fresh mass

Species:

Phaseolus aureus

Duration:

14 d

Dose descriptor:

EC10

Effect conc.:

48 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth

Remarks:

shoot fresh mass

Species:

Helianthus annuus

Duration:

14 d

Dose descriptor:

EC10

Effect conc.:

3.19 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

seedling emergence

Species:

Helianthus annuus

Duration:

14 d

Dose descriptor:

EC10

Effect conc.:

19.1 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth

Remarks:

shoot fresh mass

Species:

other: Solanum lycopersicum

Duration:

15 d

Dose descriptor:

NOEC

Effect conc.:

1.46 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth

Remarks:

shoot fresh mass

Key result

Species:

other: Solanum lycopersicum

Duration:

15 d

Dose descriptor:

EC10

Effect conc.:

2 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth

Remarks:

shoot fresh mass

Species:

other: Solanum lycopersicum

Duration:

15 d

Dose descriptor:

EC50

Effect conc.:

34.5 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth

Remarks:

shoot fresh mass

Details on results:

SEED GERMINATION
- Results with reference substance valid? yes
- see table 2

SEEDLING EMERGENCE
- Percent seedling emergence as mean values at highest concentration of test item: 95 (oat), 90 (corn), 0 (turnip), 5 (tomato), 100 (mung bean), 30 (sunflower) and lowest test concentration: 95 (oat), 80 (corn), 75 (turnip), 80 (tomato), 95 (mung bean), 66.7 (sunflower)
- Percent survival post-emergence at highest concentration: 100 (oat), 94,4 (corn), 0 (turnip), 100 (tomato), 100 (mung bean), 100 (sunflower)
- Fresh weight of the shoots as mean values at highest concentration: 0.258 ± 0.043 (oat), 8.785± 2.149 (corn), 0 (turnip), 1.562 (tomato, only 1 seedling), 0.742 ± 0.342 (mung bean), 0.460 ± 0.521 (sunflower)

- Abnormal seed development or appearance: there was no effect on the visual appearance regarding pathological symptoms of any of the species.

A table with all effect concentrations can be found in the attached documents.

Results with reference substance (positive control):

see Table 2

Reported statistics and error estimates:

The percent inhibition of seedling emergence for each plant species was calculated as an absolute value and in comparison to the control.
Post-emergence survival was calculated as an absolute value and in comparison to the control.
The percent inhibition of fresh weight was calculated in comparison to the control.
All statistical tests – depending on normal distribution (after Shapiro-Wilk’s test) and homogeneity of variances (after Levene test) the (Qualitative) Trend Analysis by Contrasts, Fisher`s Exact Binomial Test with Bonferroni Correction Williams Multiple Sequential t-test Procedure, or Dunnett`s Multiple t-test Procedure for the NOEC calculation; ECx calculation – were performed with the computer software ToxRat Professional by ToxRat® Solutions GmbH [6].
For ECx calculations probit-analysis assuming log-normal distribution of values was applied.

Table 2: non-GLP Terrestrial plants growth tests with trichloroacetate to confirm reproducibility and germination capacity and sensitivity of the test species.

Species	Emergence Control [%]	Test concentration [mg TCA/kg]	Emergence Test [%]	EC50 for growth [mg/kg (fresh mass per plant)]
Allium cepa	88	100	55	20
Avena sativa	93	80	100	12
Zea mays	100	400	25	21
Brassica rapa	60	1000	0	147
Helianthus annuus	85	200	100	384
Phaseoulus aureus	90	400	47	31
Solanum lycopersicum	92	1000	35	>1000

Validity criteria fulfilled:

yes

Remarks:

further information are provided in attached document

Conclusions:

In a valid, reliable and conclusive study on the source substance, following the OECD 208, the effects on seedling emergence and early growth of emerged plants were tested. The source substance has concentration dependent effects on all of the plant species tested under the chosen test conditions. The most sensitive endpoint in all species was shoot fresh mass. The most sensitive species overall was Solanum lycopersicum (EC10growth: 1.69 mg/kg soil dw), the most sensitive acute species was Brassica rapa (EC50growth: 28.5 mg/kg soil dw).

As read-across has been shown to be applicable (IUCLID Section 13.2), but there are differences in molecular weight between the source and target substance the endpoint has been corrected for this difference. After molecular weight correction this is equal to an Solanum lycopersicum EC10growth of 2 mg/kg soil dw and a Brassica rapa EC50growth of 33.8 mg/kg soil dw.

Executive summary:

A one-to-one read-across approach with correction for molecular weight has been used to derive endpoints for the target substance. The read-across was from benzotriazole (EC No.: 202-394-1) to sodium 1H-benzotriazolide (EC No. 239-269-6).  In line with ECHA guidance the reported endpoint values are those relevant to the target substance and have been corrected for molecular weight (ECHA How to prepare registration and PPORD dossiers, v10.0, 2021). The only differences between the substances is the addition of a sodium salt in the target substance.  However, at relevant environmental pH ca. 6-9, protonation will occur yielding the neutral form of the target substance (See Section 13.2 for more information).

The effect of Benzotriazole on the emergence and growth of terrestrial plant seedlings in seven species was investigated according to the OECD guideline 208. The following test species were used: Avena sativa (oat), Allium cepa (onion), Zea mays (corn), Brassica rapa (turnip), Helianthus annuus (sunflower), Solanum lycopersicum (tomato) and Phaseolus aureus (mung bean).

The plant seeds were placed in a natural sandy soil containing the test item at nominal concentrations of 0.12, 0.37, 1.11, 3.33 and 10.0 mg test item per kg dry mass soil (onion), 1.23, 3.70, 11.1, 33.3 and 100 mg test item per kg dry mass soil (oat, corn, turnip and tomato) or 6.25, 12.5, 25.0, 50.0 and 100 mg test item per kg dry mass soil (sunflower and mung bean). The test item was incorporated into the test soil at the beginning of the experiment.

The effects on seedling emergence and growth were determined 14 days (onion, oat, sunflower and mung bean), 15 days (tomato and corn) and 16 days (turnip) after emergence of 50 % of the control seedlings.

According to the OECD guideline 208, effect values are calculated based on concentrations initially applied to the soil at the start of the incubation period. For this, measured concentration of the highest application solution should be considered. With a recovery rate of 83.9 - 93.9 % in the highest application solution, recovery was within 80 – 120 % of nominal. Therefore, evaluation was based on nominal concentrations.

Allium cepa showed no valid seedling emergence in either the range finding test or the GLP test and therefore was abstained from evaluation. However, this did not effect the validity of the results as it pertains to long-term toxicity assessment s 6 species (2 monocot and 4 dicot) were still tested. This number of species, as well as the split between monocot and dicots are consdiered acceptable for long-term hazard assessment. 

Even though Zea mays and Avena sativa are both from Poaceae, they were considered as if from different families because the former is a type C4 plant and the latter a type C3 plant.

There was no significant effect on seedling emergence of Avena sativa, Zea mays and Phaseolus aureus (NOEC ≥ 100 mg TI/kg DM; EC₁₀ and EC₅₀ > 100 mg/kg DM) due to the test item up to and including the highest concentration tested.  After correction for molecular weight this equates to a NOEC/EC₁₀/EC₅₀ for the target substance of > 119 mg/kg soil dw.

For Solanum lycopersicum no concentration-dependent effects were observed on seedling emergence (EC₁₀ and EC₅₀ > 100 mg TI/kg DM).  After correction for molecular weight this is equal to an EC₁₀/EC₅₀ of > 119 mg/kg soil dw. 

Brassica rapa and Helianthus annuus showed concentration dependent effects. The NOEC value was 33.3 for mg/kg DM, EC₁₀ of 33.1 mg/k soil dw and EC₅₀ = 51.8 mg/kg soil dw) for Brassica rapa.  Correcting for molceular weight this is a NOEC of 39.5 mg/kg soil dw, EC₁₀ of 39.2 mg/kg soil dw and EC₅₀ of 61.4 mg/kg soil dw for the target substance.  For Helianthus annuus for emergence inhibiton the EC₁₀ = 2.69 mg/kg soil dw, the NOEC = 12.5 mg/kg soil dw and the EC₅₀ = 42.2 mg/kg soil dw after.  After molecular weight correction this leads to effect levels of EC10 = 3.19 mg/kg soil dw, NOEC = 14.8 and an EC50 = 50.0 mg/kg soil dw, for the target substance. 

There was no impairment on post-emergence survival of Avena sativa, Zea mays, Helianthus annuus, Solanum lycopersicum and Phaseolus aureus (NOEC ≥ 100 mg TI/kg DM; EC₁₀ and EC₅₀ > 100 mg TI/kg DM) due to the test item up to and including the highest concentration tested.  This leads to a NOEC, EC₁₀ and EC₅₀ of ≥ 119 mg/kg soil dw, for the target substance for this end point and these species. 

With an EC₁₀ value of 28.5 mg TI/kg DM (EC₅₀ > 100 mg TI/kg DM), post-emergence of Brassica rapa was slightly affected by Benzotriazole. However, the NOEC value was ≥ 100 mg TI/kg DM.  The EC₁₀ and NOEC/EC₅₀ for the target susbtance after molecular weight correction are 33.8 mg/kg soil dw and 119 mg/kg soil dw. 

The most sensitive endpoint in all species was shoot fresh mass (growth). There was a concentration dependent effect on shoot fresh weight in all species tested. The sensitivity in increasing series was: Zea mays (NOEC: ≥ 100 mg/kg soil dw; EC₁₀: > 100 mg/kg soil dw; EC₅₀: > 100 mg/kg soil dw (corrected for target substance NOEC/EC₁₀/EC₅₀ ≥ 100 mg/kg soil dw)). Phaseolus aureus EC_10growth = 40.5 mg/kg soil dw, corrected for molecular weight the EC_10growth of the target substance = 48.0 mg/kg soil dw. Helianthus annuus has an EC10 growth of 16.1 mg/kg soil dw, corrected for molecular weight this is an EC10 of 19.1 mg/kg soil dw for the target substance. Avena sativa has a NOEC_grwoth of 3.7 mg/kg soil dw, a NOEC_growth of 4.38 mg/kg soil dw after molcular weight correction for the target substance.  Brassica rapa had an EC_10growth of 3.27 mg/kg soil dw and an EC_50growth of 28.5 mg/kg soil dw. For the target substance, after molecular wieght correction this was 3.87 mg/kg soil dw and 33.8 mg/kg soil dw for the EC_10growth and EC_50growth respectively.  Brassica rapa was the most acutely sensitive species. For Solanum lycopersicum  the results were NOEC_growth = 1.23 mg/kg soil dw,  EC_10growth, 1.69 mg/kg soil dw and the EC_50growth = 29.1 mg/kg soil dw.  The corresponding values for the target substance after molecular weight correction were 1.46 mg/kg soil dw, 2.00 mg/kg soil dw and 34.5 mg/kg soil dw, respectively.  Solanum lycopersicum was the most sensitive species chronically. 

Description of key information

Most sensitive acute endpoint: Brassica rapa (turnip) EC_50growth = 34.5 mg/kg soil dw, OECD 208. Simon, 2021. 

Most sensitive chronic endpoint: Solanum lycopersicum (tomato) EC_10growth = 2.00 mg/kg soil dw, OECD 208. Simon, 2021.

Key value for chemical safety assessment

Short-term EC50 or LC50 for terrestrial plants:

34.5 mg/kg soil dw

Long-term EC10, LC10 or NOEC for terrestrial plants:

2 mg/kg soil dw

Additional information

A one-to-one read-across approach with correction for molecular weight has been used to derive endpoints for the target substance. The read-across was from benzotriazole (EC No.: 202-394-1) to sodium 1H-benzotriazolide (EC No. 239-269-6).  In line with ECHA guidance the reported endpoint values are those relevant to the target substance and have been corrected for molecular weight. The only differences between the substances is the addition of a sodium salt in the target substance.  However, at relevant environmental pH ca. 6-9, protonation will occur yielding the neutral form of the target substance (See Section 13.2 for more information). 

The effect of Benzotriazole on the emergence and growth of terrestrial plant seedlings in seven species was investigated according to the OECD guideline 208. The following test species were used: Avena sativa (oat), Allium cepa (onion), Zea mays (corn), Brassica rapa (turnip), Helianthus annuus (sunflower), Solanum lycopersicum (tomato) and Phaseolus aureus (mung bean).

The plant seeds were placed in a natural sandy soil containing the test item at nominal concentrations of 0.12, 0.37, 1.11, 3.33 and 10.0 mg test item per kg dry mass soil (onion), 1.23, 3.70, 11.1, 33.3 and 100 mg test item per kg dry mass soil (oat, corn, turnip and tomato) or 6.25, 12.5, 25.0, 50.0 and 100 mg test item per kg dry mass soil (sunflower and mung bean). The test item was incorporated into the test soil at the beginning of the experiment.

The effects on seedling emergence and growth were determined 14 days (onion, oat, sunflower and mung bean), 15 days (tomato and corn) and 16 days (turnip) after emergence of 50 % of the control seedlings.

According to the OECD guideline 208, effect values are calculated based on concentrations initially applied to the soil at the start of the incubation period. For this, measured concentration of the highest application solution should be considered. With a recovery rate of 83.9 - 93.9 % in the highest application solution, recovery was within 80 – 120 % of nominal. Therefore, evaluation was based on nominal concentrations.

Allium cepa showed no valid seedling emergence in either the range finding test or the GLP test and therefore was abstained from evaluation. However, this did not effect the validity of the results as it pertains to long-term toxicity assessment 6 species (2 monocot and 4 dicot) were still tested. This number of species, as well as the split between monocot and dicots are consdiered acceptable for long-term hazard assessment. 

Even though Zea mays and Avena sativa are both from Poaceae, they were considered as if from different families because the former is a type C4 plant and the latter a type C3 plant.

There was no significant effect on seedling emergence of Avena sativa, Zea mays and Phaseolus aureus (NOEC ≥ 100 mg TI/kg DM; EC₁₀ and EC₅₀ > 100 mg/kg DM) due to the test item up to and including the highest concentration tested.  After correction for molecular weight this equates to a NOEC/EC₁₀/EC₅₀ for the target substance of > 119 mg/kg soil dw.

For Solanum lycopersicum no concentration-dependent effects were observed on seedling emergence (EC₁₀ and EC₅₀ > 100 mg TI/kg DM).  After correction for molecular weight this is equal to an EC₁₀/EC₅₀ of > 119 mg/kg soil dw. 

Brassica rapa and Helianthus annuus showed concentration dependent effects. The NOEC value was 33.3 for mg/kg DM, EC₁₀ of 33.1 mg/k soil dw and EC₅₀ = 51.8 mg/kg soil dw) for Brassica rapa.  Correcting for molceular weight this is a NOEC of 39.5 mg/kg soil dw, EC₁₀ of 39.2 mg/kg soil dw and EC₅₀ of 61.4 mg/kg soil dw for the target substance.  For Helianthus annuus for emergence inhibiton the EC₁₀ = 2.69 mg/kg soil dw, the NOEC = 12.5 mg/kg soil dw and the EC₅₀ = 42.2 mg/kg soil dw after.  After molecular weight correction this leads to effect levels of EC10 = 3.19 mg/kg soil dw, NOEC = 14.8 and an EC50 = 50.0 mg/kg soil dw, for the target substance. 

There was no impairment on post-emergence survival of Avena sativa, Zea mays, Helianthus annuus, Solanum lycopersicum and Phaseolus aureus (NOEC ≥ 100 mg TI/kg DM; EC₁₀ and EC₅₀ > 100 mg TI/kg DM) due to the test item up to and including the highest concentration tested.  This leads to a NOEC, EC₁₀ and EC₅₀ of ≥ 119 mg/kg soil dw, for the target substance for this end point and these species. 

With an EC₁₀ value of 28.5 mg TI/kg DM (EC₅₀ > 100 mg TI/kg DM), post-emergence of Brassica rapa was slightly affected by Benzotriazole. However, the NOEC value was ≥ 100 mg TI/kg DM.  The EC₁₀ and NOEC/EC₅₀ for the target susbtance after molecular wieght correction are 33.8 mg/kg soil dw and 119 mg/kg soil dw. 

The most sensitive endpoint in all species was shoot fresh mass (growth). There was a concentration dependent effect on shoot fresh weight in all species tested. The sensitivity in increasing series was: Zea mays (NOEC: ≥ 100 mg/kg soil dw; EC₁₀: > 100 mg/kg soil dw; EC₅₀: > 100 mg/kg soil dw (corrected for target substance NOEC/EC₁₀/EC₅₀ ≥ 100 mg/kg soil dw)). Phaseolus aureus EC_10growth = 40.5 mg/kg soil dw, corrected for molecular weight the EC_10growth of the target substance = 48.0 mg/kg soil dw. Helianthus annuus has an EC10 growth of 16.1 mg/kg soil dw, corrected for molecular weight this is an EC10 of 19.1 mg/kg soil dw for the target substance. Avena sativa has a NOEC_growth of 3.7 mg/kg soil dw, a NOEC_growth of 4.38 mg/kg soil dw after molcular weight correction for the target substance.  Brassica rapa had an EC_10growth of 3.27 mg/kg soil dw and an EC_50growth of 28.5 mg/kg soil dw. For the target substance, after molecular wieght correction this was 3.87 mg/kg soil dw and 33.8 mg/kg soil dw for the EC_10growth and EC_50growth respectively.  Brassica rapa was the most acutely sensitive species. For Solanum lycopersicum  the results were NOEC_growth = 1.23 mg/kg soil dw,  EC_10growth, 1.69 mg/kg soil dw and the EC_50growth = 29.1 mg/kg soil dw.  The corresponding values for the target substance after molecular weight correction were 1.46 mg/kg soil dw, 2.00 mg/kg soil dw and 34.5 mg/kg soil dw, respectively.  Solanum lycopersicum was the most sensitive species chronically.