Iodomethane

Toxicity to terrestrial plants

Link to relevant study record(s)

Reference

Endpoint:

toxicity to terrestrial plants: long-term

Type of information:

experimental study

Adequacy of study:

key study

Study period:

12 July 2006 to 17 October 2006

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 208 (Terrestrial Plants, Growth Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 850.4100 (Terrestrial Plant Toxicity Tier I (seedling emergence))

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 850.4225 (Seedling Emergence Tier II)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

no

Vehicle:

no

Details on preparation and application of test substrate:

- Method of application to soil surface: Planted replicate test pots were exposed to vapours of the test material. Injection containers were dosed wih a known volume of test material which was allowed to volatilise within a contained area for a 48 hour exposure period. Drain holes at the bottom of containers were covered with tape and the soil surface was covered with polyethylene film. Injections were made using HPLC syringes. Upon injection of the test material, the injection pot was immediately placed inside a plastic bag. These bags were sealed to contain vapours that may have volatilised from the soil.
- Controls: Negative and room controls were performed at the same time as the test material treatments.

Species:

Allium cepa

Plant group:

Monocotyledonae (monocots)

Details on test organisms:

- Common name: Onion
- Plant family: Amaryllidaceae
- Variety: WI 609
- Source of seed: Wannermaker Seeds, St Matthews SC USA
- Prior seed treatment/sterilisation: No
- Historical germination of seed (germination of seed lot tested): >80 %

Species:

Avena sativa

Plant group:

Monocotyledonae (monocots)

Details on test organisms:

- Common name: Oat
- Plant family: Poaceae
- Variety: Rodeo
- Source of seed: Johnny's Selected Seeds, Winslow, ME USA
- Prior seed treatment/sterilisation: No
- Historical germination of seed (germination of seed lot tested): 95 %

Species:

Lolium perenne

Plant group:

Monocotyledonae (monocots)

Details on test organisms:

- Common name: Ryegrass
- Plant family: Poaceae
- Variety: Manhattan 4
- Source of seed: The Meyer Seed Co, Baltimore, MD USA
- Prior seed treatment/sterilisation: No
- Historical germination of seed (germination of seed lot tested): 90 %

Species:

Zea mays

Plant group:

Monocotyledonae (monocots)

Details on test organisms:

- Common name: Corn
- Plant family: Poaceae
- Variety: Mandan Bride
- Source of seed: Johnny's Selected Seed Co, Winslow, ME, USA
- Prior seed treatment/sterilisation: No
- Historical germination of seed (germination of seed lot tested):94 %

Species:

Beta vulgaris

Plant group:

Dicotyledonae (dicots)

Details on test organisms:

- Common name: Sugarbeet
- Plant family: Amaranthaceae
- Variety: Beta 5713
- Source of seed: Betaseed Inc., Shakopee MN, USA
- Prior seed treatment/sterilisation: No
- Historical germination of seed (germination of seed lot tested): 74 %

Species:

Brassica oleracea var. capitata

Plant group:

Dicotyledonae (dicots)

Details on test organisms:

- Common name: Cabbage
- Plant family: Brassicaceae
- Variety: Late Flat Dutch
- Source of seed: Meyer Seed Co, Baltimore, MD, USA
- Prior seed treatment/sterilisation: No
- Historical germination of seed (germination of seed lot tested) :85 %

Species:

Glycine max (G. soja)

Plant group:

Dicotyledonae (dicots)

Details on test organisms:

- Common name: Soybean
- Plant family: Fabacaee
- Variety: Williams 82
- Source of seed: Missouri Foundation Seeds, Columbia MO, USA
- Prior seed treatment/sterilisation: No
- Historical germination of seed (germination of seed lot tested): 100 %

Species:

Lactuca sativa

Plant group:

Dicotyledonae (dicots)

Details on test organisms:

- Common name: Lettuce
- Plant family: Asteraceae
- Variety: Buttercrunch
- Source of seed: Johnny's Swlected Seeds, Winslow ME, USA
- Prior seed treatment/sterilisation: No
- Historical germination of seed (germination of seed lot tested): 99 %

Species:

Lycopersicon esculentum

Plant group:

Dicotyledonae (dicots)

Details on test organisms:

- Common name: Tomato
- Plant family: Solanaceae
- Variety: Rutgers
- Source of seed: Meyer Seed Co, Baltimore, MD, USA
- Prior seed treatment/sterilisation: No
- Historical germination of seed (germination of seed lot tested): 90 %

Species:

Raphanus sativus

Plant group:

Dicotyledonae (dicots)

Details on test organisms:

- Common name: Radish
- Plant family: Brassicaceae
- Variety: Cherry Belle
- Source of seed: Meyer Seed Co., Baltimore, MD, USA
- Prior seed treatment/sterilisation: No
- Historical germination of seed (germination of seed lot tested): 85 %

Test type:

seedling emergence toxicity test

Study type:

laboratory study

Substrate type:

artificial soil

Limit test:

no

Total exposure duration:

48 h

Post exposure observation period:

- After approximately 48 hours, bags containing treatment group pots were taken outside of the greenhouse facility where the bags were opened and replicate pots were removed in order to prevent contamination of the control group. After removal from their bags, test pots were placed in subirrigation trays on greenhouse benches.
- Seedlings were observed for 21 days following exposure.

Test temperature:

16.4 - 40.4 ° C

Moisture:

13.6 - 94.2 %

Details on test conditions:

TEST SYSTEM
- Testing facility: Greenhouse Facility at Wildlife International
- Test container :Plastic pots approximately 16 cm in diameter and 12 cm deep
- Amount of soil: A. cepa, R. sativus, L. esculentum, B. oleracea , B. vulgaris and L. sativa were planted at a depth of 6 mm while Z. mays, G. max and A. sativa were planted at a depth of 20 mm
- Method of seeding: A template was used to gently compact the soil and leave 10 uniform holes for planting. One indiscriminately selected seed was then planted in each hole.
- No. of seeds per container: 10 seeds per container
- No. of replicates per treatment group: 4 replicates per treatment group
- No. of replicates per control: 4 replicates per control

SOURCE AND PROPERTIES OF SUBSTRATE (if soil)
- Artificial soil made from a mixture of kaolinite clay, industrial quartz sand and peat with limestome added to buffer the pH. Soil consisted of 65 % sand, 18 % silt, 17 % clay with and organic matted content of 2.2 %.
- Soil taxonomic classification: Sandy loam soil
- Organic carbon (%): 2.2

NUTRIENT MEDIUM
- Description: A slow release fertiliser was added to provide nutrients for plant growth.

GROWTH CONDITIONS
- During the 48 hour exposure period all supplemental lighing in the test rooms was turned off and shadecloth remained closed inorder to prevent over heating of the seedlings whlile they were sealed in plastic bags.Following removal of the test pots from the bags, control of the shadecloth and lighting level reteurned to the wadsworth envionmental control system.
- Photoperiod: 16 hours light and 8 hours dark
- Light intensity: 4.9 to 19.6 moles photosynthetically active radiation (PAR)
- Watering regime and schedules: Seedlings were subirrigated to minimise the potential for leaching of the test material through the soil. Watering occured every 2-3 days.

EFFECT PARAMETERS MEASURED (with observation intervals if applicable):
- Observations were made on days 7 and 14 to document seedling emergence.Observations on day 21 were made to document seedling emergence, survival, and growth and to determine the general condition of the seedlings.
- Seedling condition was described noting the presence or absence of signs of phytotoxicity such as necrosis, leaf wrinkle, chlorosis plant lodging or plant stunting.
- Growth of emerged seedlings was evaluated by assessing the height and dry weight at test termination.
- Phytotoxicity rating system (if used): Rating system adapted from Robert & Talbert (1977) Design of field experiments and the measurement and analysis of plant responses.

VEHICLE CONTROL PERFORMED: yes

Nominal and measured concentrations:

Nominal concentrations: 2.4, 7.3, 21.7, 65.3 and 196 kg/ha.

Reference substance (positive control):

no

Key result

Species:

Allium cepa

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

65.3 kg/ha

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth

Key result

Species:

Allium cepa

Duration:

21 d

Dose descriptor:

EC50

Effect conc.:

131 kg/ha

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth

Key result

Species:

Avena sativa

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

21.7 kg/ha

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth

Key result

Species:

Avena sativa

Duration:

21 d

Dose descriptor:

EC50

Effect conc.:

168 kg/ha

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth

Key result

Species:

Lolium perenne

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

65.3 kg/ha

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth

Key result

Species:

Lolium perenne

Duration:

21 d

Dose descriptor:

EC50

Effect conc.:

143.4 kg/ha

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth

Key result

Species:

Zea mays

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

196 kg/ha

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth

Key result

Species:

Zea mays

Duration:

21 d

Dose descriptor:

EC50

Effect conc.:

196 kg/ha

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth

Key result

Species:

Beta vulgaris

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

21.7 kg/ha

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth

Key result

Species:

Beta vulgaris

Duration:

21 d

Dose descriptor:

EC50

Effect conc.:

61.7 kg/ha

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth

Key result

Species:

Brassica oleracea var. capitata

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

65.3 kg/ha

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth

Key result

Species:

Brassica oleracea var. capitata

Duration:

21 d

Dose descriptor:

EC50

Effect conc.:

196 kg/ha

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth

Key result

Species:

Glycine max (G. soja)

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

7.3 kg/ha

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth

Key result

Species:

Glycine max (G. soja)

Duration:

21 d

Dose descriptor:

EC50

Effect conc.:

65.3 kg/ha

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth

Key result

Species:

Lactuca sativa

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

21.7 kg/ha

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth

Remarks on result:

other: l

Key result

Species:

Lactuca sativa

Duration:

21 d

Dose descriptor:

EC50

Effect conc.:

100.6 kg/ha

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth

Key result

Species:

Lycopersicon esculentum

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

2.4 kg/ha

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth

Key result

Species:

Lycopersicon esculentum

Duration:

21 d

Dose descriptor:

EC50

Effect conc.:

184.8 kg/ha

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth

Key result

Species:

Raphanus sativus

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

196 kg/ha

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth

Key result

Species:

Raphanus sativus

Duration:

21 d

Dose descriptor:

EC50

Effect conc.:

196 kg/ha

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth

Details on results:

SEEDLING EMERGENCE
There were no apparent effects on the emergece ad survival of B. oleracea, L. sativa and L. esculentum. Apparent treatment related reductions in emergence were observed in the remaining 6 species. No diverse effects on seedling emergence, survival, growth or condition were seen in R,. sativus (radish). There were no apparent effects on height or dry weight resulting from the application of the test material to Z. mays. Treatment related effects were observed in the other test species. The dry weight of A. sativa was reduced by 20 and 55 % in the 65.296 and 196 kg/ha test rates respectively. There was also a 23 % reduction in the dry weight of B. oleracera in the 196 kg/ha test group relative to the room control The mean dry weight of L. esculentum seedlings in the 7.25, 21.73 and 65.29 kg/ha groups were all reduced by approximately 32 % relative to the room control mean. Effects on the dry weight and height of A. cepa and L. perenne were only seen at the 196 kg/ha application rate and on B.vulgaris and L. sativa at the 65.296 and 196 kg/ha application rates.

Table 1: Summary of NOEC and EC₅₀values for the four measured parameters

Species	21 day assessments (kg/ha)
	Emergence		Survival		Height		Biomass
	NOEC	EC50	NOEC	EC50	NOEC	EC50	NOEC	EC50
Monocots
Alium cepa	65.3	181.4	65.3	181.4	65.3	196.0	65.3	131.0
Avena sativa	65.3	187.0	65.3	187.0	65.3	196.0	21.7	168.0
Lolium perenne	65.3	196.0	65.3	196.0	65.3	196.0	65.3	143.4
Zea mays	65.3	196.0	65.3	196.0	196.0	196.0	196.0	196.0
Dicots
Beta vulgaris	21.7	88.3	21.7	92.5	21.7	136.6	21.7	61.7
Brassica oleracea	196.0	196.0	196.0	196.0	196.0	196.0	65.3	196.0
Glycine max	65.3	103.5	65.3	77.8	65.3	65.3	7.3	65.3
Lactuca sativa	196.0	196.0	196.0	196.0	21.7	196.0	21.7	100.6
Lycopersicon esculentum	196.0	196.0	196.0	196.0	7.3	196.0	2.4	184.8
Raphanus sativus	196.0	196.0	196.0	196.0	196.0	196.0	196.0	196.0

Validity criteria fulfilled:

yes

Conclusions:

Under the conditions of this study, the lowest EC50 obtained was 61.7 kg/ha for biomass of sugar beet (Beta vulgaris). The lowest NOEC was 2.4 kg/ha for biomass of tomato (Lycopersicon esculentum).

Executive summary:

The potential of the test material to cause toxicity to terrestrial plants was investigated in accordance with the standardised guideline OECD 208, under GLP conditions.

Testing was conducted with ten species of non-target plant including seven test groups. These included a room control, a negative control and five rates of the test substance (2.4, 7.3, 21.7, 65.3 and 196 kg/ha). Within each test group there were four replicate pots each containing ten seeds. The species tested were Alium cepa, Avena sativa, Lolium perenne, Zea mays, Beta vulgaris, Brassica oleracea, Glycine max, Lactuca sativa, Lycopersicon esculentum and Raphanus sativus.

Planted replicate pots were exposed to vapours of the test material. Injection containers were dosed with a known volume of the test substance which was allowed to volatilise within a contained area. Test pots were maintained within a sealed plastic bag during a 48 hour exposure period, after which the test pots were removed from the bag a placed on greenhouse benches for the remainder of the 21 day period.  

The total number of seeds emerged were recorded on Days 7 and 14. Observations were made on Day 21 to document seedling emergence, survival and growth, and to determine general condition of the seedlings. The growth of emerged seedlings was evaluated by evaluating the height and dry weight of seedlings at test termination.

Under the conditions of this study, the lowest EC50 obtained was 61.7 kg/ha for biomass of sugar beet (Beta vulgaris). The lowest NOEC was 2.4 kg/ha for biomass of tomato (Lycopersicon esculentum).

Description of key information

Under the conditions of this study, the lowest EC50 obtained was 61.7 kg/ha for biomass of sugar beet (Beta vulgaris). The lowest NOEC was 2.4 kg/ha for biomass of tomato (Lycopersicon esculentum).

Additional information

The potential of the test material to cause toxicity to terrestrial plants was investigated in accordance with the standardised guideline OECD 208, under GLP conditions. The study was awarded a reliability score of 1 in accordance with the criteria set forth by Klimisch et al. (1997).

Testing was conducted with ten species of non-target plant including seven test groups. These included a room control, a negative control and five rates of the test substance (2.4, 7.3, 21.7, 65.3 and 196 kg/ha). Within each test group there were four replicate pots each containing ten seeds. The species tested were Alium cepa, Avena sativa, Lolium perenne, Zea mays, Beta vulgaris, Brassica oleracea, Glycine max, Lactuca sativa, Lycopersicon esculentum and Raphanus sativus.

Planted replicate pots were exposed to vapours of the test material. Injection containers were dosed with a known volume of the test substance which was allowed to volatilise within a contained area. Test pots were maintained within a sealed plastic bag during a 48 hour exposure period, after which the test pots were removed from the bag a placed on greenhouse benches for the remainder of the 21 day period.  

The total number of seeds emerged were recorded on Days 7 and 14. Observations were made on Day 21 to document seedling emergence, survival and growth, and to determine general condition of the seedlings. The growth of emerged seedlings was evaluated by evaluating the height and dry weight of seedlings at test termination.

Under the conditions of this study, the lowest EC50 obtained was 61.7 kg/ha for biomass of sugar beet (Beta vulgaris). The lowest NOEC was 2.4 kg/ha for biomass of tomato (Lycopersicon esculentum).