Oxalonitrile

Toxicity to terrestrial plants

Link to relevant study record(s)

Reference

Endpoint:

toxicity to terrestrial plants, other

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 227 (Terrestrial Plant Test: Vegetative Vigour Test)

GLP compliance:

yes

Species:

other: beans, lettuce, cabbage, carrot, perennial rye grass wheat, strawberry

Duration:

24 h

Dose descriptor:

LC50

Effect conc.:

>= 0.1 - <= 6.1 other: mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth

Conclusions:

Based on physical and chemical properties of ethanedinitrile and modelling of the environmental fate of ethanedinitrile, the exposure of the environment has been shown to be negligible. Therefore, it is not necessary to conduct environmental risk assessment towards this biota. This biota is also not expected to be present at the fumigation site.
The substance will stay in the air based on its physical and chemical properties and will not transfer to other environmental compartments such as soil and water as confirmed by models in the environmental fate part of dossier.

Logistic dose-response curves were used to estimate ethanedinitrile concentration required to achieve a plant mortality of 50% (LC50) using SAS probit procedure (SAS Institute Inc., Cary, NC, USA). For 24-hour exposure, the estimated LC50for the various crops were: 0.6 mg ethanedinitrile L-1air for Bean, 5.5 mg ethanedinitrile L-1air for Bell Pepper, 6.0 mg ethanedinitrile L-1air for Cabbage, 0.9 mg ethanedinitrile L-1air for Carrot, 0.9 mg ethanedinitrile L-1air for Corn, 0.1 mg ethanedinitrile L-1air for Cucumber, 0.6 mg ethanedinitrile L-1air for Lettuce, 5.5 mg ethanedinitrile L-1air for Onion, 6.0 mg ethanedinitrile L-1air for Ryegrass, 6.1 mg ethanedinitrile L-1air for Spinach, 0.6 mg ethanedinitrile L-1air for Strawberry, 0.6 mg ethanedinitrile L-1air for Tomato, and 5.9 mg ethanedinitrile L-1air for Wheat.
There was no negative effect of 0.1 mg ethanedinitrile L-1air concentrations or lower on plant health. It seems that the vigor of some crops (for example, cabbage shoot fresh weight and dry weight) at low concentrations were slightly better than untreated control. However, all plants died at 10 mg ethanedinitrile L-124 hours following ethanedinitrile application at higher rates. Over the 21-day observation period, no seedlings (except cucumber) were affected below the exposure level of 0.1 mg ethanedinitrile L-1air.

Executive summary:

Terrestrial plant test: vegetative vigor test for cyanogen using OECD 227 test method

This study was performed to determine the effects of ethanedinitrile on terrestrial plants to comply with the requirements for an ecotoxicology study on plant protection products ‘vegetative vigor test’. The study was conducted according to the OECD Guidelines for the testing of chemicals, Terrestrial plant test: vegetative vigor test, Guideline 227.

Ethanedinitrile was applied at seven application rates (0, 0.01, 0.1, 1.0, 10, 100, and 1,000 mg C2N2 L^-1air). The test plants lettuce, cabbage, carrot, perennial ryegrass, onion, tomato, cucumber, bean, wheat, bell pepper, spinach, strawberry and corn were selected for this study.

Transplants in pots were exposed to ethanedinitrile in glass fumigation chambers. The chambers were completely sealed and covered with Totally Impermeable Film. All chambers were analyzed for the C₂N₂concentrations before ventilation to confirm that the concentrations were within 10% of the initial target concentrations. After ventilation, the plants were transferred to the greenhouse. Greenhouse temperature and humidity were recorded and standard nutrition solution and water was provided during the growth period at different time intervals.

Plants were harvested 21 days following the application of ethanedinitrile. Fresh and dry weights of plant shoots were measured at the end of the experiment. Plant samples were dried at 60 °C in the oven for 24 hours.

Logistic dose-response curves were used to estimate ethanedinitrile concentration required to achieve a plant mortality of 50% (LC₅₀) using SAS probit procedure (SAS Institute Inc., Cary, NC, USA). For 24-hour exposure, the estimated LC₅₀for the various crops were: 0.6 mg ethanedinitrile L^-1air for Bean, 5.5 mg ethanedinitrile L^-1air for Bell Pepper, 6.0 mg ethanedinitrile L^-1air for Cabbage, 0.9 mg ethanedinitrile L^-1air for Carrot, 0.9 mg ethanedinitrile L^-1air for Corn, 0.1 mg ethanedinitrile L^-1air for Cucumber, 0.6 mg ethanedinitrile L^-1air for Lettuce, 5.5 mg ethanedinitrile L^-1air for Onion, 6.0 mg ethanedinitrile L^-1air for Ryegrass, 6.1 mg ethanedinitrile L^-1air for Spinach, 0.6 mg ethanedinitrile L^-1air for Strawberry, 0.6 mg ethanedinitrile L^-1air for Tomato, and 5.9 mg ethanedinitrile L^-1air for Wheat.

There was no negative effect of 0.1 mg ethanedinitrile L^-1air concentrations or lower on plant health. It seems that the vigor of some crops (for example, cabbage shoot fresh weight and dry weight) at low concentrations were slightly better than untreated control. However, all plants died at 10 mg ethanedinitrile L^-124 hours following ethanedinitrile application at higher rates. Over the 21-day observation period, no seedlings (except cucumber) were affected below the exposure level of 0.1 mg ethanedinitrile L^-1air.

Logistic dose-response curves were used to estimate the ethanedinitrile concentration required to achieve a plant mortality of 50 (LC₅₀) percent using SAS probit procedure (SAS Institute Inc., Cary, NC, USA).

 

Table 8.6.2. – 1. Ethanedinitrile LC₅₀calculated from the dose-response curves for the various crops

Plant	LC50(mg ethanedinitrileL^-1for 24 hours)
	Fresh Weight	Dry Weight
Bean	0.6	0.6
Bell Pepper	5.5	5.5
Cabbage	6.1	6.0
Carrot	0.9	0.9
Corn	0.9	0.9
Cucumber	0.1	0.1
Lettuce	0.6	0.6
Onion	5.7	5.5
Ryegrass	6.1	6.0
Spinach	5.9	6.1
Strawberry	0.6	0.6
Tomato	0.2	0.6
Wheat	5.8	5.9

 

LC₅₀for the tested plants ranged between 0.1 and 6.1mg ethanedinitrile L^-1air (Table 8.6.2. – 1.).

Description of key information

LC₅₀for the tested plants ranged between 0.1 and 6.1mg ethanedinitrile L^-1air