Registration Dossier

Administrative data

Endpoint:
toxicity to terrestrial plants: long-term
Type of information:
experimental study
Adequacy of study:
supporting study
Study period:
4th August - 1st September 1997
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Guideline study to GLP

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1992

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 208 (Terrestrial Plants Test: Seedling Emergence and Seedling Growth Test)
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): L-2-Chloropropionic acid, assigned Brixham test substance number AD0381
- Physical state: Liquid
- Analytical purity: 97.2 %w/w
- Purity test date: 23rd May 1997
- Lot/batch No.: Bx 19
- Expiration date of the lot/batch: Not specified
- Storage condition of test material: Refrigerated in it's original container

Test organisms

open allclose all
Species:
Avena sativa
Plant group:
Monocotyledonae (monocots)
Details on test organisms:
- Common name: Oat
- Plant family: Avena sativa
- Variety: Dula
- Source of seed: Twyford Seeds,Scotts Farm, King Sutton, Banbury, Oxon, UK
- Prior seed treatment/sterilization: Not specified
- Historical germination of seed (germination of seed lot tested): Not specified
- Seed storage: Not specified
Species:
Helianthus annuus
Plant group:
Dicotyledonae (dicots)
Details on test organisms:
- Common name: Sunflower
- Plant family: Helianthus annuus
- Variety: Sungold
- Source of seed:E W King and Co Limited, Monks Farm, Coggeshall Road, Levedon, Essex, CO5 9PG, UK
- Prior seed treatment/sterilization: Not specified
- Historical germination of seed (germination of seed lot tested): Not specfied
- Seed storage: Not specifid
Species:
Phaseolus aureus
Plant group:
Dicotyledonae (dicots)
Details on test organisms:
- Common name: Mung Bean
- Plant family: Phaseolus aureus
- Variety: Not specified
- Source of seed: Suttons Seeds, Torquay, UK
- Prior seed treatment/sterilization: Not specified
- Historical germination of seed (germination of seed lot tested): Not specified
- Seed storage: Not specified

Study design

Test type:
other: Seedling emergence and early plant growth
Study type:
extended laboratory study
Substrate type:
natural soil
Limit test:
no
Total exposure duration:
28 d

Results and discussion

Effect concentrationsopen allclose all
Species:
Avena sativa
Duration:
7 d
Dose descriptor:
LC50
Effect conc.:
> 1 000 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
germination
Species:
Helianthus annuus
Duration:
7 d
Dose descriptor:
LC50
Effect conc.:
500 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
germination
Species:
Phaseolus aureus
Duration:
7 d
Dose descriptor:
LC50
Effect conc.:
78 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
germination
Species:
Avena sativa
Duration:
21 d
Dose descriptor:
LC50
Effect conc.:
420 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth
Species:
Helianthus annuus
Duration:
21 d
Dose descriptor:
LC50
Effect conc.:
380 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth
Species:
Phaseolus aureus
Duration:
21 d
Dose descriptor:
LC50
Effect conc.:
41 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth

Any other information on results incl. tables

A results summary for the germination and growth data is given in Table 1.

Table 1.

 

 

Concentration of L-2-Chloropropionic acid mg kg-1(dry soil)

 

 

Control 1

Control 2

1.0

10

100

1000

Avena sativa

Total seeds emerged

32

35

34

35

35

21*

Pooled control (emergence)

34

 

% of pooled control

-

100

103

103

62*

% reduction in emergence

-

a

a

a

38*

Total shoot weight

37.2

39.7

36.5

51.1

35.7

8.44

Helianthus annuus

Total seeds emerged

33

34

34

31

34

10*

Pooled control (emergence)

34

 

% of pooled control

-

100

91

100

29*

% reduction in emergence

-

a

a

a

71*

Total shoot weight

99.4

103.8

102.3

97.0

127.8

23.0*

Phaseolus aureus

Total seeds emerged

31

31

31

35

18*

0*

Pooled control (emergence)

31

 

% of pooled control

-

100

113

58*

0*

% reduction in emergence

-

a

a

42*

100*

Total shoot weight

30.9

29.9

30.5

36.2

7.71*

0.36*

 

a             No significant decrease compared to pooled control

*             Significant decrease compared to pooled control

A summary of the glasshouse temperatures recorded is presented in Table 2.

Table2.

Period

Temperature,oC

Maximum

Minimum

Average

04 Aug – 11 Aug 1997

38.7

15.5

23.6

11 Aug – 18 Aug 1997

36.2

15.1

24.5

18 Aug – 24 Aug 1997

34.0

17.2

24.2

24 Aug – 31 Aug 1997

28.0**

13.0**

21.3**

 

Maximum, minimum and average temperatures calculated from hourly recordings during each period.

Wide variations from the nominal temperatures of 12oC at night and 18oC at day are not unusual in glasshouses and were considered acceptable.

 

**Thermohydrograph failed due to power cut. Readings taken from a max/min mercury thermometer at 0900h and 1630h daily.

 

 

The pH of the soils in water are summarised in Table 3 below.

 

Table 3.

Day

pH of soil in water

Nominal concentration of L-2-chloropropionic acid (mg kg-1dry soil)

Control 1

Control 2

1

10

100

1000

-8

7.2

7.1

7.1

7.1

7.1

7.0

21

6.4

6.4

6.5

6.5

6.5

6.3

The pH of the soil was not significantly altered by the addition of the test substance.

 

 

Applicant's summary and conclusion

Conclusions:
Soil treated with L-2-chloropropionic acid had a detrimental effect on the emergence of oat and sunflower at test concentrations of 1000 mg kg -1 (dry soil) and for mung bean at 100mg kg -1(dry soil).
Soil treated with L-2-Chloropropionic acid had a detrimental effect on the early plant growth of oat and sunflower at concentrations of 1000mg kg-1 (dry soil) and for mung bean at 100mg kg -1(dry soil).
Based on the results the LC50 and EC50 were determined:

Oat Sunflower Mung bean
LC50 (germination) mg kg-1 >1000 500 78
EC50(growth) mg kg-1 420 380 41

Executive summary:

 

The pH of the soil was not significantly altered by the addition of the test substance.

The effect of L-2-Chloropropionic acid on germination and early plant growth was assessed on oat (Avena sativa), sunflower (Helianthus annuus) and mung bean (Phaseolus aureus) using a study in accordance with OECD 204. The study was conducted at nominal test substance concentrations of 1.0, 10, 100 and 1000 mg kg-1(dry soil). Two control tests were prepared for each test species. Four replicate pots were prepared at each concentration. Each pot contained 9 seeds, which was later thinned to 4 seedlings. The soil used was ‘WC-B’, a soil mix prepared containing sterilized Mendip loam and Cornish grit, with the addition of Osmocote and superphosphate. The test substance was dried onto prepared silver sand and then subsequently incorporated into the soil mix.

The seeds were planted on day -7, seven days later a preliminary assessment of germination was made. This was designated ‘Day 0’.

After a further seven days (Day 7) a definitive assessment of germination was made and the seedlings thinned to 4 per pot by removal of the weakest plants.

On day 21, the plants were cropped at soil level and the total fresh weight of the cropped tissue for each pot determined.

Visual assessments of the condition of the plants were made on Day 7 and 21.

The temperature of the glasshouse was recorded hourly throughout the study. The pH of the soil was measured in a control sample on days -8 and day 21. 

 The pots were contained in individual trays containing capillary matting. This allowed watering of the pots whilst ensuring any leachate was retained and available for re-absorption into the pots.

 

The germination and seedling growth data figures for the controls were compared using the Students t-test. All species showed no significant difference between the control values, therefore controls 1 and 2 were pooled for subsequent statistical analysis on emergence.

The test substance treatments for all test species were compared with the pooled controls using Dunnett's procedure.

 

There was a significant decrease in the germination figures for oat and sunflower at 1000mg kg-1. (dry soil). A decrease of 38% was observed for oat and 71% compared for sunflower when compared to the controls.

 

A significant decrease in emergence of mung beans was observed at 100mg kg-1(dry sol) to 42% of the controls. By day 7, no emergence was yet observed at1000mg kg-1. At the end of the test period, 4 seedlings had emerged in the 1000mg kg-1test concentration.

 

There was significant decrease in the total fresh weight of shoots for oat and sunflower at 1000mg kg-1when compared to the pooled controls. The mung bean showed a significant decrease in the total weight of fresh shoots at 100 mg kg-1when compared to the controls. These were in excess of the expected for the reduced seeds emerging, indicating that the growth form the emerging seeds was detrimentally affected by the test substance.

 

Based on the results the LC50 and EC50 were determined:

 

 

Avena sativa

Helianthus annuus

Phaseolus aureus

LC50 (germination) mg kg-1

>1000

500

78

EC50 (growth) mg kg-1

420

380

41