2,6-dibromo-4-cyanophenyl octanoate

Toxicity to terrestrial plants

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to terrestrial plants: short-term

Type of information:

experimental study

Adequacy of study:

key study

Study period:

13 Jun - 16 Aug, 1990

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

EPA OPP 122-1 (Terrestrial Plant Toxicity Tier I (vegetative vigor))

Version / remarks:

1982

Qualifier:

according to guideline

Guideline:

EPA OPP 123-1 (Vegetative Vigor Tier II)

Version / remarks:

1982

Deviations:

yes

Remarks:

missing info on test species, slight deviation of environmental conditions and no analytical verification according to the report. Plant stage at initiation, observation timing, number of plants are slightly different from current OECD 227 requirements.

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

The solution samples were inadvertently not treated prior to analysis and do not provide analytical confirmation of the exposure solutions. Consequently, the results of the vegetative vigor tests are reported as nominal test concentrations.

Vehicle:

yes

Remarks:

acetone

Details on preparation and application of test substrate:

A primary stock solution of 437 mg a.i./L (nominal) was prepared by diluting 0.0899 grams of test substance (0.08738 grams active ingredient) with acetone to volume in a 200 mL volumetric flask. The appropriate amounts of this stock solution were diluted to a 50 mL volume with acetone in graduated cylinders. Each dilution was poured into a separate amber glass bottle, to each of which 450 mL of NANOpure water was added.
Replicate pots (3) were grouped and sprayed with 30 ml_ of the appropriate solution 7 days after the seedlings were planted in untreated sand, except for carrot, which were sprayed 21 days after planting.
The control pots were prepared using the same process as the treatment pots, but were sprayed with 30 mL of distilled water.
Additionally, the solvent control plants were treated in a similar manner with a 1:10 solution of acetone to distilled water. This concentration contains an amount of acetone equivalent to the amount applied during each treatment.

Species:

Avena sativa

Plant group:

Monocotyledonae (monocots)

Details on test organisms:

Supplied by Gries Seed Farm, Inc., Fremont, Ohio.
Lot: S1 289-9

Species:

Lactuca sativa

Plant group:

Dicotyledonae (dicots)

Details on test organisms:

Supplied by Carolina Biological Supply Company, Burlington, North Carolina.
Lot: S1 289-8

Species:

Glycine max (G. soja)

Plant group:

Dicotyledonae (dicots)

Details on test organisms:

Supplied by Carolina Biological Supply Company, Burlington, North Carolina.
Lot: S490-5
Variety: Maryard

Species:

Zea mays

Plant group:

Monocotyledonae (monocots)

Details on test organisms:

Supplied by Carolina Biological Supply Company, Burlington, North Carolina.
Lot: S490-3
Variety: field corn

Species:

Lycopersicon esculentum

Plant group:

Dicotyledonae (dicots)

Details on test organisms:

Supplied by Vermont Bean Seed Company, Fair Haven, Vermont.
Lot: S589-9
Variety: New Yorker

Species:

Lolium perenne

Plant group:

Monocotyledonae (monocots)

Details on test organisms:

Supplied by Carolina Biological Supply Company, Burlington, North Carolina.
Lot: S690-6

Species:

Cucumis sativus

Plant group:

Dicotyledonae (dicots)

Details on test organisms:

Supplied by Carolina Biological Supply Company, Burlington, North Carolina
Lot: 690-5

Species:

Daucus carota

Plant group:

Dicotyledonae (dicots)

Details on test organisms:

Supplied by Vermont Bean Seed Company, Fair Haven, Vermont.
Lot: S589-11
Variety: Scarlet Nantes

Species:

Brassica oleracea var. capitata

Plant group:

Dicotyledonae (dicots)

Details on test organisms:

Supplied by Vermont Bean Seed Company, Fair Haven, Vermont.
Lot: S589-10
Variety: Early Jersey

Species:

Allium cepa

Plant group:

Monocotyledonae (monocots)

Details on test organisms:

Supplied by Vermont Bean Seed Company, Fair Haven, Vermont.
Lot: S589-7
Variety: sweet spanish yellow

Test type:

vegetative vigour test

Study type:

laboratory study

Substrate type:

artificial soil

Remarks:

silica sand

Limit test:

no

Total exposure duration:

14 d

Remarks:

Observations performed 14 days after application

Test temperature:

16 - 29 °C

pH:

7.8

Moisture:

48 - 72 %

Details on test conditions:

Each replicate exposure unit consisted of a 13 cm tall polypropylene pot containing approximately 1.5 kg of washed, 20-40 mesh silica sand as support medium, equivalent to a sand depth of 10 cm per pot.
Nutrient solution was provided on a daily basis during the 14-day treatment period by subirrigation.
Three replicate trays were maintained for each test species per concentration. Separate growth chambers of similar design were used.
Germinated seedlings of uniform root and shoot development were impartially selected and randomly transplanted into untreated sand. Seedlings were handled carefully during the transplanting process to prevent damage. Five seedlings were planted in each pot containing support medium, except that one extra carrot and onion seedling was planted per pot. This was done to ensure five healthy seedlings were available for the treatment phase. Each pot was placed in an individual saucer and nutrient medium was added to the saucer. Approximately 250 mL of nutrient solution was added to the surface of the silica sand in each pot prior to planting the seedlings. The carrot and onion seedlings were planted in the same manner as the other species and were thinned to five seedlings per pot on the day of treatment.
Individual seedling shoot lengths were measured and recorded on the day of but prior to the application of Bromoxynil and weekly thereafter. Observations of morphological abnormalities were also made on the same days. At test termination, 14 days post-treatment, shoots were severed from the roots at sand level, measured and collected.

Nominal and measured concentrations:

Nominal concentrations for lettuce: 0.012, 0.024, 0.048, 0.095 and 0.19 Ibs a.i./A
Nominal concentrations for all other species: 0.024, 0.048, 0.095, 0.19 and 0.38 Ibs a.i./A

Key result

Species:

other: Brassica oleracea and Lycopersicon esculentum

Duration:

14 d

Dose descriptor:

NOEC

Effect conc.:

ca. 0.024 lbs/acre

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

growth

Remarks on result:

other: equivalent to 26.90 mg a.i./ha and 0.036 mg a.i./kg dry soil

Key result

Species:

Lycopersicon esculentum

Duration:

14 d

Dose descriptor:

EC50

Effect conc.:

ca. 0.041 lbs/acre

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

growth

Remarks:

Shoot weight

Remarks on result:

other: equivalent to 45.96 g a.i./ha and 0.061 mg a.i./kg dry soil

Details on results:

All control, solvent control and treatment plants were healthy prior to the application of the test material.
At termination, cabbage, carrot, corn, lettuce and tomato exhibited significant concentration-related reductions.

Please refer to "overall remark/ attached background material" field for result tables.

Validity criteria fulfilled:

not specified

Conclusions:

The present guideline study was conducted in compliance with GLP. Under the test conditions used, the overall EC50 (14 d) was 0.041 lbs a.i./A equivalent to 45.96 g a.i./ha or 0.061 mg a.i./kg dws, based on Lycopersicon esculentum shoot length parameter. The overall NOEC (14 d) was 0.024 lbs a.i./A equivalent to 26.9 g a.s./ha or 0.036 mg a.i./kg dws.

Reference 2

Endpoint:

toxicity to terrestrial plants: short-term

Type of information:

experimental study

Adequacy of study:

key study

Study period:

13 Jun - 16 Aug, 1990

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

EPA OPP 122-1 (Terrestrial Plant Toxicity Tier I (seedling emergence))

Version / remarks:

1982

Qualifier:

according to guideline

Guideline:

EPA OPP 123-1 (Seedling Emergence Tier II)

Version / remarks:

1982

Deviations:

yes

Remarks:

missing info on test species according to the report. Seed number, observation timing, control % emergence and survival slightly different from current OECD 208 requirements.

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

The nutrient test solutions used to treat the sand were sampled to confirm the concentration of test substance at test initiation. Three Quality Control samples were prepared and remained with the set of samples from each testing period throughout the analyses.

Vehicle:

yes

Remarks:

acetone

Details on preparation and application of test substrate:

For the definitive tests, a 22.12 mg a.i./mL (nominal) stock solution was prepared by diluting 4.5515 grams of test substance (4.4241 grams active ingredient) with acetone to volume in a 200 mL volumetric flask. The lower four desired nominal stock concentrations were prepared by diluting the appropriate amount of stock solution to volume with 100 mL of acetone. To produce the test solutions, 0.325 mL of the primary and each secondary stock solution were added to separate silanized 4 L glass vessels, each containing 3.25 L of nutrient solution. To prepare the solvent control solution, 0.325 mL of acetone was added to 3.25 L of nutrient solution. Control and solvent control vessels were also silanized prior to use. Each test solution was stirred for approximately five minutes just prior to treatment of the sand to ensure that the test solutions were homogeneous.

Species:

Avena sativa

Plant group:

Monocotyledonae (monocots)

Details on test organisms:

Supplied by Gries Seed Farm, Inc., Fremont, Ohio.
Lot: S1 289-9

Species:

Lactuca sativa

Plant group:

Dicotyledonae (dicots)

Details on test organisms:

Supplied by Carolina Biological Supply Company, Burlington, North Carolina.
Lot: S1 289-8

Species:

Glycine max (G. soja)

Plant group:

Dicotyledonae (dicots)

Details on test organisms:

Supplied by Carolina Biological Supply Company, Burlington, North Carolina.
Lot: S490-5
Variety: Maryard

Species:

Zea mays

Plant group:

Monocotyledonae (monocots)

Details on test organisms:

Supplied by Carolina Biological Supply Company, Burlington, North Carolina.
Lot: S490-3
Variety: field corn

Species:

Lycopersicon esculentum

Plant group:

Dicotyledonae (dicots)

Details on test organisms:

Supplied by Park Seed, Greenwood, South Carolina.
Lot: S490-1
Variety: beefmaster

Species:

Lolium perenne

Plant group:

Monocotyledonae (monocots)

Details on test organisms:

Supplied by Carolina Biological Supply Company, Burlington, North Carolina.
Lot: S589-1

Species:

Cucumis sativus

Plant group:

Dicotyledonae (dicots)

Details on test organisms:

Supplied by Carolina Biological Supply Company, Burlington, North Carolina
Lot: 690-5

Species:

Daucus carota

Plant group:

Dicotyledonae (dicots)

Details on test organisms:

Supplied by Carolina Biological Supply Company, Burlington, North Carolina.
Lot: S490-4
Variety: Danvers Half longs

Species:

Brassica oleracea var. capitata

Plant group:

Dicotyledonae (dicots)

Details on test organisms:

Supplied by Park Seed, Greenwood, South Carolina.
Lot: S490-2
Variety: green jewel

Species:

Allium cepa

Plant group:

Monocotyledonae (monocots)

Details on test organisms:

Supplied by Gries Seed Farm, Inc., Fremont, Ohio.
Lot: S690-6
Variety: sweet winter

Test type:

seedling emergence toxicity test

Study type:

laboratory study

Substrate type:

artificial soil

Remarks:

silica sand

Limit test:

no

Total exposure duration:

14 d

Remarks:

Observations performed 14 days after application

Test temperature:

22 - 28 °C

pH:

7.8

Moisture:

62 - 80 %

Details on test conditions:

Each replicate exposure unit consisted of a 13 cm tall polypropylene pot containing approximately 1.5 kg of washed, 20-40 mesh silica sand as support medium, equivalent to a sand depth of 10 cm per pot.
Nutrient solution was provided on a daily basis during the 14-day treatment period by subirrigation.
Three replicate trays were maintained for each test species per concentration. Separate growth chambers of similar design were used for the emergence and vegetative vigor tests.
Artificial lighting was provided for the emergence tests using a combination of commercial 75 watt fluorescent and 25 watt incandescent bulbs.
Each replicate pot was observed on test days 10 and 14 (test termination) to determine the percent seedling emergence. Morphological abnormalities of the emerged shoots (e.g., scaling, wilting, mildew, chlorosis, leaf blotch, foliar lesions, necrosis) were also recorded at each observation interval. Additionally, the shoot length of each seedling surviving to test termination was measured.

Nominal and measured concentrations:

Nominal concentrations: 0.024, 0.048, 0.095, 0.19 and 0.38 Ibs a.i./A for all species. Additional concentrations for lettuce only: 0.095, 0.048, 0.024, 0.012 and 0.006 Ibs a.i./A.
Mean measured concentrations for corn, cucumber, lettuce, onion, ryegrass, soybean and tomato: 0.015, 0.048, 0.091, 0.18 and 0.17 lbs a.i./A (ranging from 44.7 to100 % of the nominal)
Mean measured for cabbage, carrot and oat: 0.023, 0.027, 0.11 and 0.47 lbs a.i./A (ranging form 56.7 to 123 %)

Key result

Species:

Brassica oleracea var. capitata

Duration:

14 d

Dose descriptor:

NOEC

Effect conc.:

ca. 0.027 lbs/acre

Nominal / measured:

meas. (initial)

Conc. based on:

act. ingr.

Basis for effect:

growth

Remarks:

Shoot length

Remarks on result:

other: equivalent to 30.26 mg a.i./ha and 0.0403 mg a.i./kg dry soil

Key result

Species:

Lactuca sativa

Duration:

14 d

Dose descriptor:

EC50

Effect conc.:

ca. 0.16 lbs/acre

Nominal / measured:

meas. (initial)

Conc. based on:

act. ingr.

Basis for effect:

growth

Remarks:

length

Remarks on result:

other: equivalent to 179.3 g a.i./ha and 0.239 mg a.i./kg dry soil

Details on results:

At test termination, none of the morphological abnormalities (e.g. chlorosis, necrosis, leaf blotch, wilt) observed during the seedling emergence test for any species were apparently related to the concentration of test substance. All emerged cucumber and onion plants survived until test
termination. Occasional mortalities of corn, ryegrass, soybean and tomato plants were observed but were not believed to be concentration-related.

Please refer to "overall remark/ attached background material" field for result tables.

Validity criteria fulfilled:

not specified

Conclusions:

The present guideline study was conducted in compliance with GLP. Under the test conditions used, the overall EC50 (14 d) was 0.16 lbs a.i./A equivalent to 179.3 g a.i./ha or 0.239 mg a.i./kg dws, based on Lactuca sativa shoot length parameter. The overall NOEC (14 d) was 0.027 lbs a.i./A equivalent to 30.26 g a.i./ha or 0.0403 mg a.i./kg dws, based on Brassica oleracea shoot length parameter.

Description of key information

The overall ER₅₀ and NOER was 0.041 lbs/acre (equivalent to 0.061 mg a.i./kg dws) and 0.024 lbs/acre (equivalent to 0.036 mg a.i./kg dws) for vegetative vigor study.

Key value for chemical safety assessment

Short-term EC50 or LC50 for terrestrial plants:

0.061 mg/kg soil dw

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

0.036 mg/kg soil dw

Additional information

One GLP-study is available for toxicity testing to terrestrial plants and was identified as key study.

 

In the key study (1990), the toxicity to terrestrial plants was investigated in a 14-day test on seedling emergence (application by incorporation with soil substrate), on vegetative vigor (application as spray) and on germination (filter paper dampened) according to US EPA 1222-1 and 123-1 guidelines. Ten species (4 monocotyledonous and 6 dicotyledonous) were exposed to nominal concentrations of 0.006, 0.012, 0.024, 0.048, 0.095, 0.19 and 0.38 Ibs a.i./A, alongside with a control, for seedling emergence and vegetative vigor. Ten species (4 monocotyledonous and 6 dicotyledonous) were exposed to nominal concentrations of 0.069, 0.14, 0.28, 0.55 and 1.1 mg a.i./L for germination test. The lowest ER₅₀and NOER was 0.041 lbs/acre (equivalent to 0.061 mg a.i./kg dws) and 0.024 lbs/acre (equivalent to 0.036 mg a.i./kg dws) for vegetative vigor studyafter 14 days exposure for survival and shoot height and weight.