Thiophanate-methyl

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:

1991-06-04 to 1991-07-16

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EPA OPP 122-1 (Seed Germination/Root Elongation Toxicity Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPP 123-1 (Seedling Emergence Tier II)

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

Samples of the test and control solutions were collected on the day of foliar application and analyzed to confirm the concentration of 14C-Tets item. Sampling procedures typically include syphoning (using silicone tubing) from the midpoint of the test container into graduated cylinders for volumes greater than 200 mL, and pipetting (using volumetric pipets) from the midpoint of the test container for sample volumes less than or equal to 200 mL.

Vehicle:

yes

Remarks:

Acetone

Details on preparation and application of test substrate:

Five stock solutions were prepared by weighing 0.0050 to 0.0056 g (0.0056, 0.0051, 0.0050, 0.0053 and 0.0050 g for stocks A, B, C, D and E, respectively) of 14C-Thiophanate-methyl into a 10.0 mL volumetric flask (Class A) and diluting to volume with acetonitrile. The stock solutions were sonicated for 10 minutes at room temperature (approximately 22 °C). Subsequent to specific activity determinations the five stocks (A - E) were combined in a 50.0 mL volumetric flask (Class A). The acetonitrile was evaporated under a gentle stream on nitrogen and replaced with acetone (final volume 50.0 mL). Triplicate aliquots (25.0 µL) were removed for analysis by Liquid Scintillation Counting (LSC) resulting in a mean measured concentration of 0.455 mg/mL.

Species:

Brassica oleracea var. capitata

Plant group:

Dicotyledonae (dicots)

Details on test organisms:

- Common name: Cabbage
- Variety: Green Jewel
- Prior seed treatment/sterilization: no prior treatment with fungicide or insecticide
- Percentage germination of seed (date tested): 85 % (1990)
- Seed storage: room temperature at 20 °C

Species:

Raphanus sativus

Plant group:

Dicotyledonae (dicots)

Details on test organisms:

- Common name: Radish
- Variety: Easter Egg Blend II
- Prior seed treatment/sterilization: no prior treatment with fungicide or insecticide
- Percentage germination of seed (date tested): 98 % (12/07/1990)
- Seed storage: room temperature at 20 °C

Species:

Zea mays

Plant group:

Monocotyledonae (monocots)

Details on test organisms:

- Common name: Corn
- Variety: Reed's Yellow Dent O.P.
- Prior seed treatment/sterilization: no prior treatment with fungicide or insecticide
- Percentage germination of seed (date tested): 80 % (07/1990)
- Seed storage: room temperature at 20 °C

Species:

Cucumis sativus

Plant group:

Dicotyledonae (dicots)

Details on test organisms:

- Common name: Cucumber
- Variety: Poinsett 76
- Prior seed treatment/sterilization: no prior treatment with fungicide or insecticide
- Percentage germination of seed (date tested): 80 % (06/1990)
- Seed storage: room temperature at 20 °C

Species:

Lactuca sativa

Plant group:

Dicotyledonae (dicots)

Details on test organisms:

- Common name: Lettuce
- Prior seed treatment/sterilization: no prior treatment with fungicide or insecticide
- Percentage germination of seed (date tested): 85 % (11/1989)
- Seed storage: room temperature at 20 °C

Species:

Avena sativa

Plant group:

Monocotyledonae (monocots)

Details on test organisms:

- Common name: Oats
- Variety: Heritage
- Prior seed treatment/sterilization: no prior treatment with fungicide or insecticide
- Seed storage: room temperature at 20 °C

Species:

Allium cepa

Plant group:

Monocotyledonae (monocots)

Details on test organisms:

- Common name: Onion
- Variety: Sweet Winter
- Prior seed treatment/sterilization: no prior treatment with fungicide or insecticide
- Percentage germination of seed (date tested): 92 % (1991)
- Seed storage: room temperature at 20 °C

Species:

Lolium perenne

Plant group:

Monocotyledonae (monocots)

Details on test organisms:

- Common name: Ryegrass
- Variety: N/A
- Prior seed treatment/sterilization: no prior treatment with fungicide or insecticide
- Percentage germination of seed (date tested): 85 % (01/1989)
- Seed storage: room temperature at 20 °C

Species:

Glycine max (G. soja)

Plant group:

Dicotyledonae (dicots)

Details on test organisms:

- Common name: Soybean
- Variety: Williams 82
- Prior seed treatment/sterilization: no prior treatment with fungicide or insecticide
- Percentage germination of seed (date tested): 80 % (12/1991)
- Seed storage: room temperature at 20 °C

Species:

Lycopersicon esculentum

Plant group:

Dicotyledonae (dicots)

Details on test organisms:

- Common name: Tomato
- Variety: Celebrity
- Prior seed treatment/sterilization: no prior treatment with fungicide or insecticide
- Percentage germination of seed (date tested): 94 % (12/1990)
- Seed storage: room temperature at 20 °C

Test type:

seedling emergence toxicity / vegetative vigour test

Study type:

laboratory study

Substrate type:

filter paper

Limit test:

no

Total exposure duration:

25 d

Test temperature:

30 ± 1 °C

Details on test conditions:

SEED GERMINATION PHASE: Tier 1 definitive tests for seed germination were conducted on all species except lettuce and soybean, for which Tier 2 tests were performed.

TEST SYSTEM
- Test container (type, material, size): sterilized glass Pyrex® Petri dishes (diameter = 150 mm, height = 20 mm ) with glass covers, each containing two sheets of 150 mm diameter filter paper
- Method of seeding: 150 mm diameter filter paper
- No. of seeds per container: 20
- No. of replicates per treatment group: 3
- No. of replicates per control: 3
- No. of replicates per solvent control: 3

GROWTH CONDITIONS
- Day/night temperatures: 22 ± 1 to 30 ± 1 °C

EFFECT PARAMETERS MEASURED: seeds were observed for morphological abnormalities such as discoloration, swelling and lesions. Germinated seeds, defined as having radicles > 5 mm in length, were counted and removed. Radicle length measurements of these seeds were then recorded.

VEHICLE CONTROL PERFORMED: yes

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 2
- Range finding study: yes
- Test concentrations: 4.7, 0.47 and 0.047 mg/kg soil equivalent to 1.57, 0.57 and 0.057 mg/kg soil.
- Results used to determine the conditions for the definitive study: yes

SEEDLING EMERGENCE PHASE: A Tier 2 definitive test with cucumber and Tier 1 definitive tests with the remaining nine test species.

TEST SYSTEM
- Test container (type, material, size): polypropylene pots (13 cm tall with a top diameter of 13 cm and a bottom diameter of 9 cm) with interior base fitted with a 15 cm diameter filter paper.
- Amount of soil: 1.5 kg of support medium (The support medium consisted of washed, 20 - 40 mesh silica sand and was characterized as having a pH of 6.2 and contained 0.11 % organic matter.)
- Method of seeding: 15 cm diameter filter paper and mesh silica
- No. of seeds per container: 10
- No. of replicates per treatment group: 3
- No. of replicates per control: 3
- No. of replicates per vehicle control: 3

NUTRIENT MEDIUM: prepared according to US FDA, 1987

GROWTH CONDITIONS
- Photoperiod: 16 hours light: 8 hours dark
- light source: Artificial lighting (fluorescent bulbs and incandescent bulbs)
- Light intensity and quality: Approx. 1100 footcandles
- Day/night temperatures: 21 - 29 °C
- Relative humidity (%): 74 %
- Air exchange rate: controlled thermostatically regulated heater/air conditioner system

EFFECT PARAMETERS MEASURED: Morphological abnormalities of the emerged shoots (e.g., chlorosis, leaf blotch, foliar lesions, necrosis) and mortality were also recorded at each observation interval. In addition, the shoot length of each seedling surviving to test termination (day 14) was measured

VEHICLE CONTROL PERFORMED: yes

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 2
- Range finding study: yes
- Test concentrations: 1.57, 0.78, 0.35, 0.18 and 0.088 mg/kg soil
- Results used to determine the conditions for the definitive study: yes

VEGETATIVE VIGOR PHASE: The test was designed to assess plant response during sensitive plant development, which is characterized by rapid growth and a high level of metabolic activity.

TEST SYSTEM
- Test container (type, material, size): polypropylene pots (13 cm tall with a top diameter of 13 cm and a bottom diameter of 9 cm) with interior base fitted with a 15 cm diameter filter paper.
- Amount of soil: 1.5 kg of support medium (The support medium consisted of washed, 20 - 40 mesh silica sand and was characterized as having a pH of 6.2 and contained 0.11 % organic matter.)
- Method of seeding: 15 cm diameter filter paper and mesh silica
- No. of seeds per container: 10

NUTRIENT MEDIUM: prepared according to US FDA, 1987

GROWTH CONDITIONS
- Photoperiod: 16 hours light: 8 hours dark
- Light source: Artificial lighting (fluorescent bulbs and incandescent bulbs)
- Light intensity and quality: Approx. 1600 footcandles
- Day/night temperatures: 21 - 30 °C
- Carbon dioxide: 430 ppm
- Relative humidity (%): 81 %
- Air exchange rate: controlled thermostatically regulated heater/air conditioner system

EFFECT PARAMETERS MEASURED: Observations of morphological abnormalities were assessed

VEHICLE CONTROL PERFORMED: yes

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 2
- Range finding study: yes
- Test concentrations: 1.57, 0.78, 0.35, 0.18 and 0.088 mg/kg soil
- Results used to determine the conditions for the definitive study: yes

Nominal and measured concentrations:

Details available in the section "Any other information on materials and methods incl. tables"

Reference substance (positive control):

no

Key result

Species:

other: Zea mays and Cucumis sativus

Duration:

6 d

Dose descriptor:

NOEC

Effect conc.:

1.34 kg/ha

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

germination

Remarks on result:

other: Equivalent to 1.79 mg/kg soil

Key result

Species:

other: Avena sativa, Allium cepa, Lolium perenne, Brassica oleracea, Raphanus sativus, Lycopersicon esculentum, Glycine max and Lactuca sativa

Duration:

6 d

Dose descriptor:

NOEC

Effect conc.:

1.46 kg/ha

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

germination

Remarks on result:

other: Equivalent to 1.95 mg/kg soil

Species:

other: Zea mays and Cucumis sativus

Duration:

6 d

Dose descriptor:

EC50

Effect conc.:

> 1.34 kg/ha

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

germination

Species:

other: Avena sativa, Allium cepa, Lolium perenne, Brassica oleracea, Raphanus sativus, Lycopersicon esculentum, Glycine max and Lactuca sativa

Duration:

6 d

Dose descriptor:

EC50

Effect conc.:

> 1.46 kg/ha

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

germination

Species:

other: Zea mays and Cucumis sativus

Duration:

6 d

Dose descriptor:

EC25

Effect conc.:

> 1.34 kg/ha

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

germination

Remarks on result:

other: equivalent to > 1.79 mg/kg

Species:

other: Avena sativa, Allium cepa, Lolium perenne, Brassica oleracea, Raphanus sativus, Lycopersicon esculentum, Glycine max and Lactuca sativa

Duration:

6 d

Dose descriptor:

EC25

Effect conc.:

> 1.46 kg/ha

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

germination

Remarks on result:

other: equivalent to 1.95 mg/kg soil

Species:

Cucumis sativus

Duration:

7 d

Dose descriptor:

EC50

Effect conc.:

2.35 kg/ha

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

seedling emergence

Remarks on result:

other: Based on most sensitive parameter, the percent emergence

Species:

other: Zea mays, Avena sativa, Allium cepa, Lolium perenne, Brassica oleracea, Raphanus sativus, Lycopersicon esculentum, Glycine max and Lactuca sativa

Duration:

7 d

Dose descriptor:

EC50

Effect conc.:

> 1.68 kg/ha

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

seedling emergence

Species:

other: Zea mays, Avena sativa, Allium cepa, Cucumis sativus, Lolium perenne, Brassica oleracea, Raphanus sativus, Lycopersicon esculentum, Glycine max and Lactuca sativa

Duration:

7 d

Dose descriptor:

NOEC

Effect conc.:

1.68 kg/ha

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

seedling emergence

Species:

other: Zea mays, Avena sativa, Allium cepa, Lolium perenne, Brassica oleracea, Raphanus sativus, Lycopersicon esculentum, Glycine max and Lactuca sativa

Duration:

7 d

Dose descriptor:

EC25

Effect conc.:

> 1.68 kg/ha

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

seedling emergence

Remarks on result:

other: 2.24 mg/kg soil

Species:

Cucumis sativus

Duration:

7 d

Dose descriptor:

EC25

Effect conc.:

1.34 kg/ha

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

seedling emergence

Remarks on result:

other: 1.79 mg/kg soil

Species:

Glycine max (G. soja)

Duration:

24 d

Dose descriptor:

EC50

Effect conc.:

2.67 kg/ha

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

growth

Remarks on result:

other: Based on the most sensitive parameter, the shoot weight

Species:

Glycine max (G. soja)

Duration:

24 d

Dose descriptor:

NOEC

Effect conc.:

0.77 kg/ha

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

growth

Remarks on result:

other: Based on most sensitive parameters, shoot length and shoot weight NOEC values.

Species:

other: Zea mays, Avena sativa, Allium cepa, Cucumis sativus, Lolium perenne, Brassica oleracea, Raphanus sativus, Lycopersicon esculentum and Lactuca sativa

Duration:

24 d

Dose descriptor:

EC50

Effect conc.:

> 1.57 kg/ha

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

growth

Species:

Lycopersicon esculentum

Duration:

24 d

Dose descriptor:

NOEC

Effect conc.:

< 1.57 kg/ha

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

growth

Species:

other: Zea mays, Avena sativa, Allium cepa, Cucumis sativus, Lolium perenne, Brassica oleracea, Raphanus sativus and Lactuca sativa

Duration:

24 d

Dose descriptor:

NOEC

Effect conc.:

1.57 kg/ha

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

growth

Species:

other: Glycine max and Lycopersicon esculentum

Duration:

24 d

Dose descriptor:

EC25

Effect conc.:

ca. 1.57 kg/ha

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

growth

Remarks on result:

other: 2.09 mg/kg soil

Species:

Glycine max (G. soja)

Duration:

24 d

Dose descriptor:

EC25

Effect conc.:

11.12 kg/ha

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

growth

Remarks on result:

other: 1.49 mg/kg soil

Species:

other: Brassica oleracea, Zea mays, Cucumis sativus, Lactuca sativa, Allium cepa, Raphanus sativus and Lolium perenne

Duration:

24 d

Dose descriptor:

EC25

Effect conc.:

> 1.57 kg/ha

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

growth

Remarks on result:

other: > 2.09 mg/kg soil

Details on results:

SEED GERMINATION PHASE
At test termination, mold was observed in all replicates of the treatment level and the control during the germination test with corn and in all replicates except one control replicate for onion. For soybean, mold was observed in two control replicates, one solvent control replicate and in at least one replicate from each of the five treatment levels. Mold was not observed in any of the remaining species tested. The presence of mold is believed to have had no effect on the outcome of the corn, onion or soybean tests.

SEEDLING EMERGENCE PHASE
Cabbage - At test termination, all surviving control, solvent control and treatment level plants were observed to be healthy. No mortalities were observed among the control, solvent control or treatment level plants.
Corn - At test termination, all surviving control plants were observed to be healthy. One of the solvent control plants exhibited brown leaf tip at days 10 and 14. For the treatment level plants, two plants were observed to be stunted. No mortality was observed among either the control, solvent control or treatment level plants.
Cucumber - At test termination, all control, solvent control and treatment level plants were observed to be healthy and exhibited no morphological abnormalities.
Lettuce - At test termination, no mortality was observed among the control, solvent control or treatment level plants. All of the plants were observed to be healthy with the exception of one control plant which was observed to be chlorotic and wilted, two solvent control plants which were chlorotic, and one treatment level plant that were observed to be necrotic and one treatment level plant which was chlorotic.
Oats - At test termination, all surviving control, solvent control and treatment level plants were observed to be healthy with the exception of one control plant that was observed to be chlorotic at day 10 and which was observed to be dead at day 14. No other mortality was observed among the control, solvent control or treatment level plants.
Onion - At test termination, all surviving control, solvent control and treatment level plants were observed to be healthy. No mortality was observed among the control, solvent control or treatment level plants.
Radish - At test termination, all surviving control and solvent control plants were observed to be healthy. At the treatment level tested, two surviving plants exhibited brown leaf tip at day 10. No mortalities were observed among the control or solvent control plants, however, one mortality was observed among the treatment level plants at day 14.
Ryegrass - At test termination, all surviving control, solvent control and treatment level plants were observed to be healthy with the exception of one control plant that were observed to be chlorotic at day 10 and was observed to be dead at day 14. No mortality was observed among the solvent control or treatment level plants.
Soybean - At test termination, all surviving control, solvent control and treatment level plants were observed to be healthy with the exception of one treatment level plant which exhibited brown leaf tip. No mortality was observed among either the control or the treatment level plants, however, one mortality was observed among the solvent control plants at day 14.
Tomato - At test termination, all surviving control, solvent control and treatment level plants were observed to be healthy. No mortality was observed among the control, solvent control or treatment level plants.

VEGETATIVE VIGOR PHASE
At test termination of the vegetative vigor tests, no concentration-related mortalities were observed among plants from any of the species tested.

Table 1: Percent germination of cabbage (Brassica oleracea) seeds exposed to Thiophanate-methyl during a seed germination test.

Measured Concentration (lb A.I./A)	Treatment Results
	Mean Percent Germination	Standard Deviation	95 % Confidence Interval
			Lower		Upper
Control	81.7	10.4	55.8	107.5
Solvent Control	85.0	5.0	72.6	97.4
1.3	88.3	2.9	81.2	95.5

 

Table 2: Radicle length of cabbage {Brassica olerácea) seeds exposed to Thiophanate-methyl during a seed germination test.

Measured Concentration (lb A.I./A)	Radicle Length (mm)
	Individual Replicate Results						Treatment Level Results
	Replicate		Replicate		Replicate				95 % CI. ^a
	#1		#2		#3		Mean	S.D. ^b	Lower	Upper
Control	29.8	(16.1)^c	23.1	(18.7)	33.6	(23.2)	28.8	5.3	15.6	42.0
Solvent Control	33.0	(22.8)	38.1	(22.2)	23.5	(16.0)	31.5	7.4	13.0	50.0
1.3	31.0	(18.4)	31.8	(18.2)	31.6	(21.2)	31.4	0.4	30.4	32.5

 

a C.I. = Confidence Interval

b S.D. = Standard Deviation

c The standard deviation is presented in parentheses.

Table 3: Percent germination of corn (Zea mays) seeds exposed to Thiophanate-methyl during a seed germination test.

Measured Concentration (lb A.I./A)	Treatment Results
	Mean Percent Germination	Standard Deviation	95 % Confidence Interval
			Lower		Upper
Control	85.0	13.2	52.1	117.9
Solvent Control	93.3	5.8	79.0	107.7
1.3	95.0	5.0	82.6	107.4

 

Table 4: Radicle length of corn (Zea mays) seeds exposed to Thiophanate-methyl during a seed germination test.

Measured Concentration (lb A.I./A)	Radicle Length (mm)
	Individual Replicate Results						Treatment Level Results
	Replicate		Replicate		Replicate				95 % CI. ^a
	#1		#2		#3		Mean	S.D. ^b	Lower	Upper
Control	41.1	(18.9)^c	35.4	(30.9)	53.2	(29.6)	43.3	9.0	20.9	65.7
Solvent Control	52.3	(26.3)	58.7	(42.8)	60.3	(39.7)	57.1	4.2	46.6	67.6
1.3	71.1	(33.9)	82.4	(63.8)	48.9	(33.6)	67.5	17.1	25.0	110

 

a C.I. = Confidence Interval

b S.D. = Standard Deviation

c The standard deviation is presented in parentheses.

Table 5: Percent germination of cucumber (Cucumis sativus) seeds exposed to Thiophanate-methyl during a seed germination test.

Measured Concentration (lb A.I./A)	Treatment Results
	Mean Percent Germination	Standard Deviation	95 % Confidence Interval
			Lower		Upper
Control	83.3	5.8	69.0	57.7
Solvent Control	88.3	12.6	57.1	119.6
1.3	86.7	12.6	55.4	117.9

 

Table 6: Radicle length of cucumber (Cucumis sativus) seeds exposed to Thiophanate-methyl during a seed germination test.

Measured Concentration (lb A.I./A)	Radicle Length (mm)
	Individual Replicate Results						Treatment Level Results
	Replicate		Replicate		Replicate				95 % CI. ^a
	#1		#2		#3		Mean	S.D. ^b	Lower	Upper
Control	33.1	(25.4)^c	39.4	(29.9)	34.2	(23.0)	35.5	3.4	27.1	44.0
Solvent Control	49.8	(36.7)	67.7	(46.4)	35.6	(19.5)	51.0	16.1	11.0	91.0
1.3	25.6	(26.1)	57.8	(38.3)	58.5	(35.5)	47.3	18.8	0.6	94.0

a C.I. = Confidence Interval

b S.D. = Standard Deviation

c The standard deviation is presented in parentheses.

 

Table 7: Percent germination of lettuce (Lactuca sativa) seeds exposed to Thiophanate-methyl during a seed germination test.

Measured Concentration (lb A.I./A)	Treatment Results
	Mean Percent Germination	Standard Deviation	95 % Confidence Interval
			Lower		Upper
Control	90.0	0.0	90.0	90.0
Solvent Control	85.0	5.0	72.6	97.4
0.078	86.7	2.9	79.5	93.8
0.16	95.0	5.0	82.6	104.7
0.31	93.3	5.8	79.0	107.7
0.69	90.0	5.0	77.6	102.4
1.3	90.0	8.7	68.5	111.5

 

Table 8: Radicle length of lettuce (Lactuca sativa) seeds exposed to Thiophanate-methyl during a seed germination test.

Measured Concentration (lb A.I./A)	Radicle Length (mm)
	Individual Replicate Results						Treatment Level Results
	Replicate		Replicate		Replicate				95 % CI. ^a
	#1		#2		#3		Mean	S.D. ^b	Lower	Upper
Control	14.5	(6.7)^c	16.7	(9.0)	18.6	(9.2)	16.6	2.1	11.5	21.7
Solvent Control	19.2	(10.2)	18.4	(10.8)	20.0	(10.6)	19.2	0.8	17.1	21.2
0.078	18.7	(10.0)	19.5	(12.1)	20.7	(10.0)	19.6	1.0	17.1	22.1
0.16	19.1	(6.7)	20.3	(12.3)	21.3	(6.9)	20.2	1.1	17.5	23.0
0.31	20.6	(8.1)	20.5	(9.3)	22.1	(9.5)	21.1	0.9	18.8	23.3
0.69	18.0	(10.2)	17.3	(9.8)	22.2	(8.8)	19.1	2.6	12.6	25.7
1.3	16.4	(6.1)	18.8	(7.2)	20.8	(13.2)	18.6	2.2	13.2	24.0

a C.I. = Confidence Interval

b S.D. = Standard Deviation

c The standard deviation is presented in parentheses.

 

Table 9: Percent germination of oat (Avena sativa) seeds exposed to Thiophanate-methyl during a seed germination test.

Measured Concentration (lb A.I./A)	Treatment Results
	Mean Percent Germination	Standard Deviation	95 % Confidence Interval
			Lower		Upper
Control	88.3	7.6	69.4	107.3
Solvent Control	91.7	7.6	72.7	110.6
1.3	80.0	5.0	67.6	92.4

 

Table 10: Radicle length of oat (Avena sativa) seeds exposed to Thiophanate-methyl during a seed germination test.

Measured Concentration (lb A.I./A)	Radicle Length (mm)
	Individual Replicate Results						Treatment Level Results
	Replicate		Replicate		Replicate				95 % CI. ^a
	#1		#2		#3		Mean	S.D. ^b	Lower	Upper
Control	37.6	(26.3)^c	41.6	(26.4)	26.4	(14.6)	35.2	7.9	15.7	54.7
Solvent Control	40.8	(24.6)	50.8	(29.2)	36.1	(22.7)	42.6	7.5	23.9	61.2
1.3	32.0	(22.9)	28.5	(26.0)	34.9	(24.8)	31.8	3.2	23.9	39.7

a C.I. = Confidence Interval

b S.D. = Standard Deviation

c The standard deviation is presented in parentheses.

 

Table 11: Percent germination of onion (Allium cepa) seeds exposed to Thiophanate-methyl during a seed germination test.

Measured Concentration (lb A.I./A)	Treatment Results
	Mean Percent Germination	Standard Deviation	95 % Confidence Interval
			Lower		Upper
Control	48.3	17.6	4.7	92.0
Solvent Control	58.3	15.3	20.4	96.3
1.3	58.3	10.4	32.5	84.2

 

Table 12: Radicle length of onion (Allium cepa) seeds exposed to Thiophanate-methyl during a seed germination test.

Measured Concentration (lb A.I./A)	Radicle Length (mm)
	Individual Replicate Results						Treatment Level Results
	Replicate		Replicate		Replicate				95 % CI. ^a
	#1		#2		#3		Mean	S.D. ^b	Lower	Upper
Control	6.1	(7.2)^c	2.8	(4.7)	9.3	(9.4)	6.1	3.3	-2.0	14.1
Solvent Control	9.4	(7.7)	6.6	(6.9)	7.0	(9.4)	7.6	1.5	3.9	11.4
1.3	3.9	(5.3)	10.0	(8.4)	5.7	(5.7)	6.5	3.1	-1.3	14.3

a C.I. = Confidence Interval

b S.D. = Standard Deviation

c The standard deviation is presented in parentheses.

 

Table 13: Percent germination of radish (Raphanus sativus) seeds exposed to Thiophanate-methyl during a seed germination test.

Measured Concentration (lb A.I./A)	Treatment Results
	Mean Percent Germination	Standard Deviation	95 % Confidence Interval
			Lower		Upper
Control	93.3	2.9	86.2	100.5
Solvent Control	86.7	11.5	58.0	115.4
1.3	95.0	5.0	82.6	107.4

 

Table 14: Radicle length of radish (Raphanus sativus) seeds exposed to Thiophanate-methyl during a seed germination test.

Measured Concentration (lb A.I./A)	Radicle Length (mm)
	Individual Replicate Results						Treatment Level Results
	Replicate		Replicate		Replicate				95 % CI. ^a
	#1		#2		#3		Mean	S.D. ^b	Lower	Upper
Control	42.4	(18.3)^c	39.7	(23.0)	58.0	(34.5)	46.7	9.9	22.2	71.2
Solvent Control	42.5	(23.9)	39.0	(35.3)	31.6	(33.9)	37.7	5.6	23.8	51.5
1.3	42.2	(25.9)	43.1	(25.1)	35.1	(25.2)	40.1	4.4	29.2	51.0

a C.I. = Confidence Interval

b S.D. = Standard Deviation

c The standard deviation is presented in parentheses.

 

Table 15: Percent germination of ryegrass (Lolium perenne) seeds exposed to Thiophanate-methyl during a seed germination test.

Measured Concentration (lb A.I./A)	Treatment Results
	Mean Percent Germination	Standard Deviation	95 % Confidence Interval
			Lower		Upper
Control	88.3	2.9	81.2	95.5
Solvent Control	85.0	5.0	72.6	97.4
1.3	90.0	8.7	68.5	111.5

 

Table 16: Radicle length of ryegrass (Lolium perenne) seeds exposed to Thiophanate-methyl during a seed germination test.

Measured Concentration (lb A.I./A)	Radicle Length (mm)
	Individual Replicate Results						Treatment Level Results
	Replicate		Replicate		Replicate				95 % CI. ^a
	#1		#2		#3		Mean	S.D. ^b	Lower	Upper
Control	44.4	(19.4)^c	45.0	(19.1)	36.9	(19.8)	42.1	4.5	30.8	53.3
Solvent Control	36.4	(21.7)	40.2	(21.8)	28.3	(18.7)	35.0	6.1	19.9	50.0
1.3	46.3	(14.5)	30.2	(16.6)	35.8	(22.6)	37.4	8.2	17.1	57.8

a C.I. = Confidence Interval

b S.D. = Standard Deviation

c The standard deviation is presented in parentheses.

 

Table 17: Percent germination of soybean (Glycine max) seeds exposed to Thiophanate-methyl during a seed germination test.

Measured Concentration (lb A.I./A)	Treatment Results
	Mean Percent Germination	Standard Deviation	95 % Confidence Interval
			Lower		Upper
Control	71.7	11.5	43.0	100.4
Solvent Control	63.3	7.6	44.4	82.3
0.078	53.3	7.6	34.4	72.3
0.16	63.3	5.8	49.0	77.7
0.31	61.7	20.2	11.5	111.9
0.69	68.3	2.9	61.2	75.5
1.3	53.3	16.1	13.4	93.3

 

Table 18: Radicle length of soybean (Glycine max) seeds exposed to Thiophanate-methyl during a seed germination test.

Measured Concentration (lb A.I./A)	Radicle Length (mm)
	Individual Replicate Results						Treatment Level Results
	Replicate		Replicate		Replicate				95 % CI. ^a
	#1		#2		#3		Mean	S.D. ^b	Lower	Upper
Control	20.8	(18.4)^c	4.7	(3.8)	13.0	(16.9)	12.8	8.1	-7.2	32.8
Solvent Control	18.9	(26.3)	15.7	(18.2)	7.8	(9.4)	14.1	5.7	-0.1	28.3.
0.078	12.6	(13.5)	5.5	(7.3)	14.8	(16.5)	10.9	4.9	-1.2	23.0
0.16	20.5	(18.8)	14.9	(14.7)	11.8	(12.7)	15.7	4.4	4.8	26.7
0.31	17.8	(13.4)	12.6	(15.8)	12.2	(15.7)	14.2	3.1	6.4	22.0
0.69	16.9	(17.7)	23.0	(20.7)	15.9	(15.5)	18.6	3.9	8.9	28.2
1.3	2.4	(3.5)	18.1	(17.2)	16.4	(16.5)	12.3	8.6	-9.2	33.7

a C.I. = Confidence Interval

b S.D. = Standard Deviation

c The standard deviation is presented in parentheses.

 

Table 19: Percent germination of tomato (Lycopersicon esculentum) seeds exposed to Thiophanate-methyl during a seed germination test.

Measured Concentration (lb A.I./A)	Treatment Results
	Mean Percent Germination	Standard Deviation	95 % Confidence Interval
			Lower		Upper
Control	90.0	5.0	77.6	102.4
Solvent Control	88.3	7.6	69.4	107.3
1.3	90.0	0.0	90.0	90.0

 

Table 20: Radicle length of tomato (Lycopersicon esculentum) seeds exposed to Thiophanate-methyl during a seed germination test.

Measured Concentration (lb A.I./A)	Radicle Length (mm)
	Individual Replicate Results						Treatment Level Results
	Replicate		Replicate		Replicate				95 % CI. ^a
	#1		#2		#3		Mean	S.D. ^b	Lower	Upper
Control	24.4	(9.2)^c	29.8	(13.1)	21.6	(11.0)	25.2	4.2	14.9	35.6
Solvent Control	22.9	(7.9)	26.3	(10.9)	21.2	(13.1)	23.5	2.6	17.1	29.8
1.3	23.4	(11.2)	27.3	(15.5)	25.5	(12.0)	25.4	1.9	20.6	30.2

a C.I. = Confidence Interval

b S.D. = Standard Deviation

c The standard deviation is presented in parentheses.

 

Table 21: Summary of EC25, EC50 and NOEC values determined during a seed germination test exposing ten plant species to Thiophanate-methyl.

Species	Parameter	EC25^a (lb A.I./A)	EC50^a (lb A.I./A9	r^2	NOEC^ab (lb A.I./A)
Cabbage	Percent germination	> 1.3	> 1.3	NA	1.3
	Radicle length	> 1.3	> 1.3	NA	1.3
Corn	Percent germination	> 1.2	> 1.2	NA	1.2
	Radicle length	> 1.2	> 1.2	NA	1.2
Cucumber	Percent germination	> 1.2	> 1.2	NA	1.2
	Radicle length	> 1.2	> 1.2	NA	1.2
Lettuce	Percent germination	> 1.3	> 1.3	NA	1.3
	Radicle length	> 1.3	> 1.3	NA	1.3
Oat	Percent germination	> 1.3	> 1.3	NA	1.3
	Radicle length	> 1.3	> 1.3	NA	1.3
Onion	Percent germination	> 1.3	> 1.3	NA	1.3
	Radicle length	> 1.3	> 1.3	NA	1.3
Radish	Percent germination	> 1.3	> 1.3	NA	1.3
	Radicle length	> 1.3	> 1.3	NA	1.3
Ryegrass	Percent germination	> 1.3	> 1.3	NA	1.3
	Radicle length	> 1.3	> 1.3	NA	1.3
Soybean	Percent germination	> 1.3	> 1.3	NA	1.3
	Radicle length	> 1.3	> 1.3	NA	1.3
Tomato	Percent germination	> 1.3	> 1.3	NA	1.3
	Radicle length	> 1.3	> 1.3	NA	1.3

 

NOTE: 1.4 lb A.I./A = Maximum application rate NA = Not applicable

^a Based on measured concentration (See Tables 2a and 2b in the "Attached background material”)

^b NOEC = No Observed Effect Concentration

 

More tables can be found in the table attached to the section Attached background material. Original data in the study were measured in lb/ha, thus, all values in the attachements have not ben converted to kg/ha or mg/kg soil.

Validity criteria fulfilled:

yes

Conclusions:

The toxicity of the test item to ten plant species during three critical phases of development (seed germination, seedling emergence and plant growth) was investigated according to EPA OPP 122-1 and EPA OPP 123-1 under GLP. The exposure concentrations were analytically verified during the tests. The NOEC based on germination for corn and cucumber was determined to be 1.34 kg/ha (equivalent to 1.79 mg/kg soil) and the NOEC based on germination for the remaining plant species was determined to be 1.46 kg/ha (equivalent to 1.95 mg/kg soil). In conclusion, the test material demonstrated either no toxicity or an insignificant impact on the test species at or below the recommended application rate.

Executive summary:

The effects of the test item on the seed germination, seedling emergence and vegetative vigor of ten representative and economically important terrestrial plant species were evaluatedaccording to EPA OPP 122-1 and EPA OPP 123-1 under GLP. Each species was incubated and treated with the test item, at or below the maximum application rate (1.57 kg/ha equivalent to 2.09 mg/kg soil) for this material, via water (germination), silica sand (emergence) and foliar (vegetative vigor) routes of administration. Concentrations of the test item were analytically confirmed for each of the three phases (i.e., seed germination, seedling emergence and vegetative vigor) of the study.

At the termination of each test, statistical analyses were performed on the data obtained to determine treatment effects. Percent germination and radicle length were analyzed for the germination test, percent emergence and shoot length were analyzed for the seedling emergence test, and shoot length, shoot weight and root weight were analyzed for the vegetative vigor test. Results for all three phases of the study are reported as the EC25, EC50 and No Observed Effect Concentration (NOEC), all of which are based on kilograms of test item (as active ingredient) per hectare (kg A.l./ha) (i.e., mg/kg soil).

 

Seed Germination - Based on the results of a preliminary test, Tier 1 definitive tests for seed germination were conducted on all species, except lettuce and soybean for which Tier 2 tests were performed. Tier 1 tests were conducted at a single measured concentration of either 1.34 or 1.46 kg/ha (equivalent to 1.79 or 1.95 mg/kg soil). Tier 2 tests were conducted at measured concentrations of 1.46, 0.77, 0.35, 0.18 and 0.087 kg/ha (equivalent to 1.95, 1.27, 0.47, 0.24 and 0.116 mg/kg soil). Samples of the stock solutions used to treat each test were collected prior to initiation of the test for analysis of the test item concentration. At the termination of the germination tests, no statistically significant effects were established for percent germination or radicle length for any of the ten plant species tested. Additionally, the EC₂₅  and EC₅₀  values for all 10 species were empirically estimated to be > 1.34 kg/ha (equivalent to 1.79 mg/kg soil) for corn and cucumber and > 1.46 kg/ha (equivalent to 01.95 mg/kg soil) for the remaining eight species. The No Observed Effect Concentration established for corn and cucumber was > 1.34 kg/ha (equivalent to 1.79 mg/kg soil) and for the remaining eight species was > 1.46 kg/ha (equivalent to 01.95 mg/kg soil).

 

Seedling Emergence - Based on the results of the preliminary exposure, Tier 1 tests at a nominal concentration of 1.57 kg/ha (c.a. 2.09 mg/kg soil) were performed on all ten plant species, except cucumber in which a Tier 2 test was performed (nominal concentrations: 1.57, 0.78, 0.39, 0.20 and 0.099 kg/ha (equivalent to 2.09, 1.04, 0.52, 0.27 and 0.132 mg/kg soil). Samples of the test solutions were collected prior to test initiation and analyzed for the test item concentration. The results of these analyses established measured concentrations of 1.68, 0.83 0.43, 0.21 and 0.11 kg/ha (c.a. 2.24, 1.11, 0.57, 0.28 and 0.15 mg/kg soil). At the termination of the emergence tests, less than 25 % reduction was observed for both seedling emergence and shoot length for all plant species tested except percent emergence of cucumber. Based on these results, the EC₂₅  and EC₅₀  values for each species except cucumber were empirically estimated to be > 1.68 kg/ha (2.24 mg/kg soil). Based on the observed effect on percent emergence for cucumber, EC₂₅ and EC₅₀ values of 1.34 kg/ha (equivalent to 1.79 mg/kg soil) and 2.35 kg/ha (equivalent to 3.13 mg/kg soil), respectively, were established. The No Observed Effect Concentrations established for the seedling emergence tests was 1.68 kg/ha (equivalent to 2.24 mg/kg soil). The effect observed in cucumber emergence was determined not to be statistically different from the pooled control data.

 

Vegetative Vigor - Based on the results of the preliminary tests, Tier 1 vegetative vigor tests were conducted on the corn, cucumber, oats, onion, radish and tomato species. Tier 2 tests were performed on the cabbage, lettuce, ryegrass and soybean species. Test solutions were sampled on the day of foliar application and analyzed for the test item concentration. The results of these analyses established a measured concentration of 1.57 kg/ha (equivalent to 2.09 mg/kg soil) for the Tier 1 tests. Measured concentrations of 1.57, 0.77, 0.39, 0.22 and 0.10 kg/ha (equivalent to 2.09, 1.03, 0.52, 0.29 and 0.133 mg/kg soil) were established for the Tier 2 tests. At the termination of the Tier 1 vegetative vigor tests, less than 25 % reductions were observed in all growth parameters (i.e., shoot length, shoot and root weight) for each species with the exception of oat root weight (28 % reduction) and tomato shoot weight (29 % reduction). Statistical analyses performed on these parameters demonstrated a significant (p < 0.05) reduction for tomato shoot weight at the 1.57 kg/ha (equivalent to 2.09 mg/kg soil) treatment level. Based on the results for the vegetative vigor tests, EC₂₅ and EC₅₀ values for cabbage, corn, cucumber, lettuce, onion, radish and ryegrass were empirically estimated as being greater than the highest measured concentration tested, 1.57 kg/ha (equivalent to 2.09 mg/kg soil). For oat root weight, > 25 % reduction (28 %) was observed but the reduction was not found to be significantly different from the pooled control data, based on a t-test, and the EC₂₅ was estimated to be approximately 1.57 kg/ha (equivalent to 2.09 mg/kg soil). The minimum EC₂₅ and EC₅₀ values established for soybean were based on effects observed on shoot weight and were estimated to be 1.12 and 2.69 kg/ha (equivalent to 1.49 and 3.59 mg/kg soil), respectively. Tomato shoot weight was reduced by 29 % at 1.57 kg/ha (equivalent to 2.09 mg/kg soil) as compared to the pooled control data. Statistical analyses (t-test) established that the reduction was significant when compared to the pooled control results.

Description of key information

The toxicity of the test item to ten plant species during three critical phases of development (seed germination, seedling emergence and plant growth) was investigated according to EPA OPP 122-1 and EPA OPP 123-1 under GLP. The exposure concentrations were analytically verified during the tests. The NOEC based on germination for corn and cucumber was determined to be 1.34 kg/ha (equivalent to 1.79 mg/kg soil) and the NOEC based on germination for the remaining plant species was determined to be 1.46 kg/ha (equivalent to 1.95 mg/kg soil). In conclusion, the test material demonstrated either no toxicity or an insignificant impact on the test species at or below the recommended application rate.

Additional information

The effects of the test item on the seed germination, seedling emergence and vegetative vigor of ten representative and economically important terrestrial plant species were evaluatedaccording to EPA OPP 122-1 and EPA OPP 123-1 under GLP. Each species was incubated and treated with the test item, at or below the maximum application rate (1.57 kg/ha equivalent to 2.09 mg/kg soil) for this material, via water (germination), silica sand (emergence) and foliar (vegetative vigor) routes of administration. Concentrations of the test item were analytically confirmed for each of the three phases (i.e., seed germination, seedling emergence and vegetative vigor) of the study.

At the termination of each test, statistical analyses were performed on the data obtained to determine treatment effects. Percent germination and radicle length were analyzed for the germination test, percent emergence and shoot length were analyzed for the seedling emergence test, and shoot length, shoot weight and root weight were analyzed for the vegetative vigor test. Results for all three phases of the study are reported as the EC25, EC50 and No Observed Effect Concentration (NOEC), all of which are based on kilograms of test item (as active ingredient) per hectare (kg A.l./ha) (i.e., mg/kg soil).

 

Seed Germination - Based on the results of a preliminary test, Tier 1 definitive tests for seed germination were conducted on all species, except lettuce and soybean for which Tier 2 tests were performed. Tier 1 tests were conducted at a single measured concentration of either 1.34 or 1.46 kg/ha (equivalent to 1.79 or 1.95 mg/kg soil). Tier 2 tests were conducted at measured concentrations of 1.46, 0.77, 0.35, 0.18 and 0.087 kg/ha (equivalent to 1.95, 1.27, 0.47, 0.24 and 0.116 mg/kg soil). Samples of the stock solutions used to treat each test were collected prior to initiation of the test for analysis of the test item concentration. At the termination of the germination tests, no statistically significant effects were established for percent germination or radicle length for any of the ten plant species tested. Additionally, the EC₂₅  and EC₅₀  values for all 10 species were empirically estimated to be > 1.34 kg/ha (equivalent to 1.79 mg/kg soil) for corn and cucumber and > 1.46 kg/ha (equivalent to 01.95 mg/kg soil) for the remaining eight species. The No Observed Effect Concentration established for corn and cucumber was > 1.34 kg/ha (equivalent to 1.79 mg/kg soil) and for the remaining eight species was > 1.46 kg/ha (equivalent to 01.95 mg/kg soil).

 

Seedling Emergence - Based on the results of the preliminary exposure, Tier 1 tests at a nominal concentration of 1.57 kg/ha (c.a. 2.09 mg/kg soil) were performed on all ten plant species, except cucumber in which a Tier 2 test was performed (nominal concentrations: 1.57, 0.78, 0.39, 0.20 and 0.099 kg/ha (equivalent to 2.09, 1.04, 0.52, 0.27 and 0.132 mg/kg soil). Samples of the test solutions were collected prior to test initiation and analyzed for the test item concentration. The results of these analyses established measured concentrations of 1.68, 0.83 0.43, 0.21 and 0.11 kg/ha (c.a. 2.24, 1.11, 0.57, 0.28 and 0.15 mg/kg soil). At the termination of the emergence tests, less than 25 % reduction was observed for both seedling emergence and shoot length for all plant species tested except percent emergence of cucumber. Based on these results, the EC₂₅  and EC₅₀  values for each species except cucumber were empirically estimated to be > 1.68 kg/ha (2.24 mg/kg soil). Based on the observed effect on percent emergence for cucumber, EC₂₅ and EC₅₀ values of 1.34 kg/ha (equivalent to 1.79 mg/kg soil) and 2.35 kg/ha (equivalent to 3.13 mg/kg soil), respectively, were established. The No Observed Effect Concentrations established for the seedling emergence tests was 1.68 kg/ha (equivalent to 2.24 mg/kg soil). The effect observed in cucumber emergence was determined not to be statistically different from the pooled control data.

 

Vegetative Vigor - Based on the results of the preliminary tests, Tier 1 vegetative vigor tests were conducted on the corn, cucumber, oats, onion, radish and tomato species. Tier 2 tests were performed on the cabbage, lettuce, ryegrass and soybean species. Test solutions were sampled on the day of foliar application and analyzed for the test item concentration. The results of these analyses established a measured concentration of 1.57 kg/ha (equivalent to 2.09 mg/kg soil) for the Tier 1 tests. Measured concentrations of 1.57, 0.77, 0.39, 0.22 and 0.10 kg/ha (equivalent to 2.09, 1.03, 0.52, 0.29 and 0.133 mg/kg soil) were established for the Tier 2 tests. At the termination of the Tier 1 vegetative vigor tests, less than 25 % reductions were observed in all growth parameters (i.e., shoot length, shoot and root weight) for each species with the exception of oat root weight (28 % reduction) and tomato shoot weight (29 % reduction). Statistical analyses performed on these parameters demonstrated a significant (p < 0.05) reduction for tomato shoot weight at the 1.57 kg/ha (equivalent to 2.09 mg/kg soil) treatment level. Based on the results for the vegetative vigor tests, EC₂₅ and EC₅₀ values for cabbage, corn, cucumber, lettuce, onion, radish and ryegrass were empirically estimated as being greater than the highest measured concentration tested, 1.57 kg/ha (equivalent to 2.09 mg/kg soil). For oat root weight, > 25 % reduction (28 %) was observed but the reduction was not found to be significantly different from the pooled control data, based on a t-test, and the EC₂₅ was estimated to be approximately 1.57 kg/ha (equivalent to 2.09 mg/kg soil). The minimum EC₂₅ and EC₅₀ values established for soybean were based on effects observed on shoot weight and were estimated to be 1.12 and 2.69 kg/ha (equivalent to 1.49 and 3.59 mg/kg soil), respectively. Tomato shoot weight was reduced by 29 % at 1.57 kg/ha (equivalent to 2.09 mg/kg soil) as compared to the pooled control data. Statistical analyses (t-test) established that the reduction was significant when compared to the pooled control results.