Cyanamide

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:

2001-10-19

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EPA OPPTS 850.4025 (Target Area Phytotoxicity)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

no

Details on sampling:

No sampling

Vehicle:

no

Details on preparation and application of test substrate:

The method used in the study: application to soil surface

Species:

Zea mays

Plant group:

other: Corn

Details on test organisms:

Not indicated

Species:

Avena sativa

Plant group:

other: Oat

Details on test organisms:

Not indicated

Species:

Allium cepa

Plant group:

other: Onion

Details on test organisms:

Not indicated

Species:

Lolium perenne

Plant group:

other: Onion

Details on test organisms:

Not indicated

Species:

Lolium perenne

Plant group:

other: Perennial reyegrass

Details on test organisms:

Not indicated

Species:

Brassica oleracea var. capitata

Plant group:

other: Cabbage

Details on test organisms:

Not indicated

Species:

Daucus carota

Plant group:

other: Carrot

Details on test organisms:

Not indicated

Species:

Cucumis sativus

Plant group:

other: Cucumber

Details on test organisms:

Not indicated

Species:

Lactuca sativa

Plant group:

other: Lettuce

Details on test organisms:

Not indicated

Species:

Lycopersicon esculentum

Plant group:

other: Tomato

Details on test organisms:

Not indicated

Test type:

other: seedling emergence and early growth

Study type:

laboratory study

Substrate type:

artificial soil

Limit test:

no

Total exposure duration:

14 d

Post exposure observation period:

No post exposure observation

Test temperature:

Day7night temperatures at 25°C/20°C±3°C

pH:

Not indicated

Moisture:

70±5% during light periods and 90% during dark periods

Nominal and measured concentrations:

0.125, 0.5, 2.0, 8.0 and 32.0 kg Cyanamide L 500/ha, corresponding to 0.063, 0.253, 1.01, 4.05 and 16.19 kg as/ha.

Reference substance (positive control):

no

Key result

Species:

Allium cepa

Duration:

14 d

Dose descriptor:

EC50

Effect conc.:

0.87 kg/ha

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

other: shoot dry weight

Remarks on result:

other: The most sensitive plant was Allium cepa, therefore its result is the one which is presented in the results fields.

Details on results:

The most sensitive endpoint in this study was shoot dry weight. The most sensitive plant was Allium cepa with an EC50 value of 1.722 kg cyanamide L 500/ha when applied directly to the soil. The EC50 value of 1.722 kg Cyanamid L500/ha corresponds to 0.87 kg as/ha.

Results with reference substance (positive control):

No positive control

Reported statistics and error estimates:

Not indicated

Effects of Cyanamide L 500 on seedling emergence following a soil surface application:

 

Plant	Genus (Species)	NOEL (kg/ha)	EC50 (kg/ha)	Most sensitive parameter
Monocotyledone
Corn	Zea mays	> 32a	> 32a	Shoot dry weight as well as shoot height
Oat	Avena sativa	> 32a	> 32a	Shoot dry weight as well as shoot height
Onion	Allium cepa	0.068	1.722	Shoot dry weight
Perennialryegrass	Lolium perenne	79.523	> 32a	Shoot dry weight
Dicotyledone
Cabbage	Brassica oleracea	0.20	6.08	Shoot dry weight
Carrot	Daucus carota	20.28	956.4	Shoot height
Cucumber	Cucumis sativus	14.48	75.85	Shoot height
Lettuce	Lactuca sativa	76.32	76.32	Shoot dry weight
Tomato	Lycopersicon esculentum	5.09	18.42	Shoot dry weight

Validity criteria fulfilled:

yes

Conclusions:

The most sensitive endpoint in this study was shoot dry weight. The most sensitive plant was Allium cepa with an EC50 value of 1.722 kg cyanamide L 500/ha when applied directly to the soil. The EC50 value of 1.722 kg cyanamide L 500/ha corresponds to 0.87 kg as/ha.

Executive summary:

Non-target terrestrial plant response to formulated cyanamide product, a 50.6 % (w/w) aqueous solution of cyanamide, was evaluated on 9 common plant species at the following dose levels: 0.125, 0.5, 2.0, 8.0 and 32.0 kg cyanamide L 500/ha, corresponding to 0.063, 0.253, 1.01, 4.05 and 16.19 kg as/ha. Effects on seedling emergence and early growth following soil surface application were assessed. The study was conducted according to the OPPTS 850.4225 (1996). The most sensitive endpoint in this study was shoot dry weight. The most sensitive plant was Allium cepa with an EC50 value of 1.722 kg cyanamide L 500/ha when applied directly to the soil. The EC50 value of 1.722 kg cyanamide L 500/ha corresponds to 0.87 kg as/ha.

Description of key information

Two studies examined the effect of cyanamide on non-target plants, a seedling emergence Tier 2 (LR50) test and vegetative vigour Tier 2 (LR50) test. In both studies the most sensitive endpoint was shoot dry weight.

The most sensitive species in the seedling emergence test was Allium cepa with a EC50 value of 1.722 kg Cyanamid L500/ha (corresponds to 0.87 kg ai/ha). In the vegetative vigour test the most sensitive species was tomato (Lycopersicon esculentum) with a EC50 of 33.2 kg cyanamide L 500/ha.

In a in a vegetative vigour Tier 2 (LR50) test (performed according to the OPPTS 850.4220) the no observed adverse effect concentration (NOAEC) derived from the chronic plant test is ≥ 100 mg a.s./kg soil dry mass.

Key value for chemical safety assessment

Long-term EC10, LC10 or NOEC for terrestrial plants:

100 mg/kg soil dw

Additional information

Two non-target terrestrial plant studies were conducted with cyanamide (a 50.6 % (w/w) aqueous solution of cyanamide). In a seedling emergence Tier 2 (LR50) test (performed according to the OPPTS 850.4225 (1996)) , 9 common plant specie were evaluated the following applied dose levels: 0.125, 0.5, 2.0, 8.0 and 32.0 kg Cyanamid L500/ha, corresponding to 0.063, 0.253, 1.01, 4.05 and 16.19 kg as/ha. Effects on seedling emergence and early growth following soil surface application were assessed. The most sensitive endpoint in this study was shoot dry weight. The most sensitive plant was Allium cepa with an EC50 value of 1.722 kg Cyanamid L500/ha when applied directly to the soil (corresponds to 0.87 kg as/ha).

 

In a in a vegetative vigour Tier 2 (LR50) test (performed according to the OPPTS 850.4220), the most sensitive endpoint was shoot dry weight for all species. The most sensitive sensitive species tested was tomato (Lycopersicon esculentum). The EC50 value for tomato was determined as 33.2 kg Cyanamid L500/ha.

 

A long-term test according to ISO 22030 (2005): "Soil Quality – Biological methods – Chronic Toxicity in Higher Plants" was performed with Avena sativa (Oat, Monocots) and Brassica rapa (turnip, Dicots). For A. sativa, the lowest NOEC was 50 mg a.s./kg soil dm (increase in shoot fresh mass on day 14 and day 39). The lowest NOEC for B. rapa was 50 mg a.s./kg soil (increase of shoot fresh weight on day 14 and dry weight on day 28). Due to a lack of a dose-response relationship between the test item concentrations and the observed effects on the respective endpoints, ECx values could not be calculated. The EC50, however, can nevertheless to be deduced to be > 100 mg a.s./kg soil dry mass. The test item did not reduce the biomass or number of inflorescences or seed pods at any of the tested concentrations up to and including 100 mg a.s./kg soil dry mass for any of the two test species, B. rapa and A. sativa. Based on the assumption that only a reduction in biomass or number of flowers/seed pods is an ecological adverse effect, the no observed adverse effect concentration (NOAEC) derived from the chronic plant test is ≥ 100 mg a.s./kg soil dry mass.