Poly(oxy-1,2-ethanediyl), α-[2-(dide- cylmethylammonio)ethyl]- .omega.- hydroxy-, propanoate (salt) (Bardap 26)

Toxicity to terrestrial plants

Link to relevant study record(s)

Reference

Endpoint:

toxicity to terrestrial plants: short-term

Type of information:

experimental study

Adequacy of study:

key study

Study period:

11/11/2003 - 28/02/2004

Reliability:

1 (reliable without restriction)

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

Principles of method if other than guideline:

Not applicable.

GLP compliance:

yes

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
No information provided.

Analytical monitoring:

not specified

Details on sampling:

Environmental conditions (temperature, relative humidity and light intensity at soil level) were measured daily throughout the exposure period.

Vehicle:

not specified

Details on preparation and application of test substrate:

The soil used was a 50:50 w/w mix of gem quality garden top soil and fibre sand. The pH was found to be 7.2 and the organic carbon content was 1.3%. The Bardac 22 was prepared in a 100 mL volume of reverse osmosis water for each species at each rate of application. This was then thoroughly mixed into the soil. A further 50 mL of water was then added to produce a soil structure suitable for sowing. A weight equivalent to 5000g dry weight of soil was used for each application rate of each species.
The negative controls were treated with reverse osmosis water. A solvent control was also used containing an equivalent volume of isopropanol to that present in the highest rate application of DDAC.

Species:

Brassica alba

Plant group:

Dicotyledonae (dicots)

Details on test organisms:

- Common name: Mustard
- Plant family: Brassicaceae
- Variety: No information provided.
- Source of seed: Purchased as commercially prepackaged seeds
- Batch: BA0302
- Seed storage: Stored in glass bottles under darkness

Species:

Phaseolus aureus

Plant group:

Dicotyledonae (dicots)

Details on test organisms:

- Common name: Mung beans
- Plant family: Fabaceae
- Variety: No information provided.
- Source of seed: Purchased as commercially prepackaged seeds
- Batch: PA0301
- Seed storage: Stored in glass bottles under darkness

Species:

Triticum aestivum

Plant group:

Monocotyledonae (monocots)

Details on test organisms:

- Common name: Wheat
- Plant family: Poaceae
- Variety: No information provided.
- Source of seed: PBI Cambridge Ltd.
- Batch: TA0302
- Seed storage: Stored in glass bottles under darkness

Test type:

other: Seedling emergence and growth inhibition

Study type:

laboratory study

Substrate type:

other: Garden top soil and fibre sand,

Limit test:

no

Total exposure duration:

20 d

Remarks:

19 - 20 days

Post exposure observation period:

Observations were recorded up to 20 days after the start of exposure to the test substance.

Test temperature:

Mung bean 25-27ºC, mustard 22-30ºC, wheat 19-21ºC

pH:

7.2

Moisture:

No information provided.

Details on test conditions:

TEST SYSTEM
For each species, groups of 40 seeds (eight replicate pots of five seeds) were sown into a mix of garden top soil and fibre sand. Treatment levels for the definitive study were based on the results of a preliminary range finding study.

The Bardac 22 was prepared in a 100 mL volume of reverse osmosis water for each species at each rate of application. This was then thoroughly mixed into the soil. A further 50 mL of water was then added to produce a soil structure suitable for sowing.

After application of the test material and sowing the pots were checked daily and emergence recorded. Plants were harvested 14 - 17 days after germination and the wet weight were measured. The plants were then dried before being re-weighed to obtain a measurement of dry weight.

GROWTH CONDITIONS
- Light intensity and quality: Mung bean 118-2710 lux, mustard 105-5420 lux, wheat 119-3380 lux (levels increased from 105-119 after germination).
- Day/night temperatures: Mung bean 25-27ºC, mustard 22-30ºC, wheat 19-21ºC
- Relative humidity (%): Mung bean 31-82%, mustard 24-75%, wheat 30-88%
- Plants were top-watered daily until germination and then top- and bottom-watered as required.

EFFECT PARAMETERS MEASURED: After application and sowing the pots were checked daily and emergence recorded. After emergence was complete, assessment of plant appearance continued daily until the plants were harvested. This assessment was conducted using a uniform scoring system based on plant size and vigour. The numberof dead seedlings in each replicate was also recorded at the same time as visual assessments.

VEHICLE CONTROL PERFORMED: yes

TEST CONCENTRATIONS
- Spacing factor for test concentrations: Factor of 2.
- Range finding study Preliminary reange finding study was conducted to determine test concentrations.
- Test concentrations: 100, 200, 400, 800, 1600 mg/kg dry soil (mustard and wheat)
5, 20, 80, 320, 1280 mg/kg dry soil (mung bean)

Nominal and measured concentrations:

Application rate 100, 200, 400, 800, 1600 mg/kg

Reference substance (positive control):

not specified

Key result

Species:

Brassica alba

Duration:

20 d

Dose descriptor:

EC50

Effect conc.:

283 mg/kg soil dw

Nominal / measured:

meas. (initial)

Conc. based on:

act. ingr.

Basis for effect:

growth

Remarks on result:

other: 95% CL: 213 - 375

Species:

Triticum aestivum

Duration:

20 d

Dose descriptor:

EC50

Effect conc.:

857 mg/kg soil dw

Nominal / measured:

meas. (initial)

Conc. based on:

act. ingr.

Basis for effect:

growth

Remarks on result:

other: 95% CL: 552 -1410

Species:

Phaseolus aureus

Duration:

20 d

Dose descriptor:

EC50

Effect conc.:

1 670 mg/kg soil dw

Nominal / measured:

meas. (initial)

Conc. based on:

act. ingr.

Basis for effect:

growth

Remarks on result:

other: 95% CL: 1240 - 2530

Details on results:

Herbicidal symptoms:
For all plant species there was significant growth inhibition at the higher rates of application. The mean visual assessment scores for mustard were 5.50, 7.75 and 8.50 at 400, 800 and 1600 mg/kg respectively and 4.62 and 6.12 for wheat at 800 and 1600 mg/kg. For mung bean the mean visual assessment was 5.63 at 1280 mg/kg.
(Scoring: 0 = no abnormal effects, to 10 = all plants within a replicate were dead.)

Effect on plant growth:
Growth inhibition was observed for all plants at higher rates of application of the test materials.
For mung bean, DDAc at 1280 mg/kg gave a significant reduction (p<0.001) in dry weight, 38% lower than that of the control.
For mustard the 200, 400, 8000, and 1600 mg/kg concentrations gave 45, 55, 76 an 80% respective reductions in dry weight compared to the control.
For wheat the test substance at 800 and 1600 mg/kg gave dry weights reduced growth of 59 and 63% respectively.

Mortality:
Mustard: 3 and 11% at 800 and 1600 mg/kg respectively.
Wheat: 3% at 1600 mg/kg
Mung bean: None

The test substance had no significant effect on the number of germinated plants for any species.
For mustard, all concentrations of the test substance significantly reduced both wet and dry weight. For wheat, the test substance at 400 mg a.s./kg and higher gave a significant reduction for both dry weight and wet weight. For mung bean, at 320 mg a.s./kg and higher gave a significant reduction for both wet and dry weight.
Mustard: EC50 = 283 mg/kg (dry weight)
Wheat: EC50 = 857 mg/kg (dry weight)
Mung: EC50 = 1670 mg/kg (dry weight)

Results with reference substance (positive control):

No information provided.

Reported statistics and error estimates:

Each parameter for each species was analysed separately.
The number of germinated plants was analysed by comparing water control and each concentration of compound to solvent control by Fisher’s exact test (1973). LC50s could not be estimated because the compound had no significant effect on the number of germinated plants.
For plant dry and wet weight, data were averaged for all plants in each replicate before analysis. These average weights were log transformed. Each concentration of compound was compared to water control by Williams’ test (1971, 1972). Solvent control was compared to water control by t-tests. EC50s were estimated by non-linear regression (logistic curve) and 95% confidence intervals were calculated by the likelihood ratio method (Donaldson and Schnabel, 1985).

Table 1 Wet weight results

Species	Treatment	Application rate (mg a.s./kg)	Geometric mean wet weight (mg)	Percent reduction	p
Mustard	Water control		708	0
(Brassica	Solvent control		669	6	0.600^T
alba)	DDAC	100	467	34	<0.001***^W
	DDAC	200	310	56	<0.001***^W
	DDAC	400	232	67	<0.001***^W
	DDAC	800	119	83	<0.001***^W
	DDAC	1600	85	88	<0.001***^W
Wheat	Water control		312	0
(Triticum	Solvent control		299	4	0.820^T
aestivum)	DDAC	100	254	19	0.409^W
	DDAC	200	268	14	0.409^W
	DDAC	400	163	48	0.001**^W
	DDAC	800	82	74	<0.001***^W
	DDAC	1600	65	79	<0.001***^W
Mung bean	Water control		758	0
(Phaseolus	Solvent control		830	0^a	0.056^T
aureus)	DDAC	5	853	0^a	>0.999^W
	DDAC	20	818	0^a	>0.999^W
	DDAC	80	787	0^a	>0.999^W
	DDAC	320	608	20	<0.001***^W
	DDAC	1280	426	44	<0.001***^W

               pvalues are for the comparison with Water control using Williams' test (W) and thet-test (T)

               **p< 0.01,  ***p< 0.001,       0^aNo reduction

 

Table 2 Dry weight results

Species	Treatment	Application rate (mg a.s./kg)	Geometric mean dry weight (mg)	Percent reduction	p
Mustard	Water control		35.6	0
(Brassica	Solvent control		34.1	4	0.684^T
alba)	DDAC	100	26.9	24	0.009**^W
	DDAC	200	19.7	45	<0.001***^W
	DDAC	400	16.2	55	<0.001***^W
	DDAC	800	8.7	76	<0.001***^W
	DDAC	1600	7.2	80	<0.001***^W
Wheat	Water control		28.3	0
(Triticum	Solvent control		26.7	6	0.742^T
aestivum)	DDAC	100	24.1	15	0.725^W
	DDAC	200	27.7	2	0.725^W
	DDAC	400	19.0	33	0.035*^W
	DDAC	800	11.6	59	<0.001***^W
	DDAC	1600	10.6	63	<0.001***^W
Mung bean	Water control		54.1	0
(Phaseolus	Solvent control		59.0	0^a	0.099^T
aureus)	DDAC	5	62.7	0^a	>0.999^W
	DDAC	20	59.7	0^a	>0.999^W
	DDAC	80	56.6	0^a	>0.999^W
	DDAC	320	46.6	14	0.006**^W
	DDAC	1280	33.7	38	<0.001***^W

               pvalues are for the comparison with Water control using Williams' test (W) and thet-test (T)

               *p< 0.05,  **p< 0.01,  ***p< 0.001

               0^aNo reduction

 

 

Table 3 Estimates and 95% confidence intervals for point of 50% inhibition

Species	Variable	EC50(mg a.s./kg)	95% Confidence interval
Mustard (Brassica alba)	Dry weight	283	213 - 375
Wheat (Triticum aestivum)	Dry weight	857	552 - 1410
Mung bean (Phaseolus aureus)	Dry weight	1670	1240 - 2530

Validity criteria fulfilled:

yes

Conclusions:

The results of the study indicate that Didecyldimethylammonium Chloride is slightly toxic to terrestrial plants, under the conditions of this study. The EC50 for mung bean was found to be 1670 mg/kg, the EC50 for mustard was 283 mg/kg, and the EC50 for wheat was 857 mg/l.

Executive summary:

In a study conducted in accordance with OECD Guideline 208, Mustard (Brassica alba), Mung bean (Phaseolus aureus) and Wheat (Triticum aestivum) were exposed to the test susbtance, Bardac 22 at concentrations of 100, 200, 400, 800 and 1600 mg/kg for a period of 19 - 20 days. Groups of 40 seeds (eight replicate pots of five seeds) were sown into mixture of garden top soil and fibre sand, with controls also included. The Bardac 22 was prepared in a 100 mL volume of reverse osmosis water for each species at each rate of application. This was then thoroughly mixed into the soil. A further 50 mL of water was then added to produce a soil structure suitable for sowing.

After application and sowing the pots were checked daily and emergence recorded. Growth inhibition, mortality and other symptoms were recorded daily. Plants were harvested 14 - 17 days after germination by cutting each stem at soil level. The wet weight of each plant was then recorded. The plants were then dried before being re-weighed to obtain a measurement of dry weight.

The test substance had no significant effect on the number of germinated plants for any species.

For mustard, all concentrations of the test substance significantly reduced both wet and dry weight. For wheat, the test substance at 400 mg/kg and higher gave a significant reduction for both dry weight and wet weight. For mung bean, at 320 mg/kg and higher gave a significant reduction for both wet and dry weight. 

The EC₅₀for mustard seeds was determined to be 283 mg/kg (dry weight), for wheat, the EC₅₀was determined to be 857 mg/kg (dry weight) and for mung beans, the EC₅₀was determined to be 1670 mg/kg (dry weight). The results of the study indicate that Didecyldimethylammonium Chloride is slightly toxic to terrestrial plants.

Description of key information

One key study to assess the toxicity to terrestrial plants. The study was conducted in accordance with OECD Guideline 208 and was GLP compliant. The study was conducted on 3 species of plants - Brassica alba, Phaseolus aureus and Triticum aestivum which were exposed to the test material for a period of 20 days. The test substance had no significant effect on the number of germinated plants for any species.
For mustard, all concentrations of the test substance significantly reduced both wet and dry weight. For wheat, the test substance at 400 mg/kg and higher gave a significant reduction for both dry weight and wet weight. For mung bean, at 320 mg/kg and higher gave a significant reduction for both wet and dry weight. The LC50 for mustard seeds was determined to be 283 mg/kg (dry weight), for wheat, the LC50 was determined to be 857 mg/kg (dry weight) and for mung beans, the LC50 was determined to be 1670 mg/kg (dry weight).

The results of the study indicate that Didecyldimethylammonium Chloride is slightly toxic to terrestrial plants.

Key value for chemical safety assessment

Short-term EC50 or LC50 for terrestrial plants:

283 mg/kg soil dw

Additional information

In a study conducted in accordance with OECD Guideline 208, Mustard (Brassica alba), Mung bean (Phaseolus aureus) and Wheat (Triticum aestivum) were exposed to the test substance, Bardac 22 at concentrations of 100, 200, 400, 800 and 1600 mg/kg for a period of 19 - 20 days. Groups of 40 seeds (eight replicate pots of five seeds) were sown into a mix of garden top soil and fibre sand. The Bardac 22 was prepared in a 100 mL volume of reverse osmosis water for each species at each rate of application. This was then thoroughly mixed into the soil. A further 50 mL of water was then added to produce a soil structure suitable for sowing.

After application and sowing the pots were checked daily and emergence recorded. Growth inhibition, mortality and other symptoms were recorded at least every other day following 50% emergence in the control pots. Plants were harvested 14 - 16 days after germination by cutting each stem at soil level. The wet weight of each plant was then recorded. The plants were then dried before being re-weighed to obtain a measurement of dry weight.

The test substance had no significant effect on the number of germinated plants for any species.

For mustard, all concentrations of the test substance significantly reduced both wet and dry weight. For wheat, the test substance at 400 mg/kg and higher gave a significant reduction for both dry weight and wet weight. For mung bean, at 320 mg/kg and higher gave a significant reduction for both wet and dry weight. 

The LC₅₀for mustard seeds was determined to be 283 mg/kg (dry weight), for wheat, the LC₅₀was determined to be 857 mg/kg (dry weight) and for mung beans, the LC₅₀was determined to be 1670 mg/kg (dry weight). The results of the study indicate that Didecyldimethylammonium Chloride is slightly toxic to terrestrial plants.