Guanidinium chloride

Toxicity to terrestrial plants

Link to relevant study record(s)

Reference

Endpoint:

toxicity to terrestrial plants: short-term

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Reason / purpose for cross-reference:

read-across source

Key result

Species:

Triticum aestivum

Duration:

14 d

Dose descriptor:

NOEC

Effect conc.:

435 mg/kg soil ww

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: wheat germination, seedling groth

Conclusions:

Available data from Guanidine nitrate were used to evaluate the toxicity to terrestrial plants of Guanidine hydrochloride.
The effect of Guanidine nitrate on germination and growth of wheat seedlings was tested for 14 days. At a Guanidine nitrate concentration of 200 µg N/g soil, (GuNi 45.9%N; 435mgGuNi/Kg soil) there was no adverse affect in wheat germination. The response of wheat dry matter production was the same as with urea.

Description of key information

The NOEC of the read-across substance Gunanidine nitrate on terrestrial plants is 435mg/kg soil.

Key value for chemical safety assessment

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

435 mg/kg soil dw

Additional information

The effect of the read-across substance Guanidine nitrate on germination and growth of wheat seedlings was tested for 14 days. At a Guanidine nitrate concentration: 200 µg N/g soil, GuNi 45.9%N; 435mgGuNi/Kg soil) there was no adverse affect in wheat growth and germination. The response of wheat dry matter production was the same as with urea.

This test was used for NOEC derivation according to Guidance R7c, p. 112 (2008).

(Remark: key value for chemical safety assesment NOEC 435 mg/kg is wet weight; pick list doesn't allow to choose ww but dw)

Justification for read-across:

Guanidine hydrochloride and guanidine nitrate dissociate in aqueous media to yield the guanidine ion and the respective anion. Therefore it is reasonable to discuss the effects of the ions separately. The chloride ion is a naturally occurring essential ion in human beings with well-known metabolism and mechanisms of action as described in standard textbooks on pharmacology and physiology. As well it is found as salt in the Earth´s crust and is dissolved in seawater. Effects of guanidine hydrochloride are expected to be based primarily on the guanidine ion. The physiological processing of the guanidine ion is expected to be independent of the individual source. Therefore read-across from guanidine nitrate for effects of guanidine dissociated from guanidine hydrochloride is considered valid. This strategy is supported by a quite similar toxicological profile of both substances, as shown in acute toxicity, irritation, sensitization and genotoxic studies.

A more detailed justification for read-across is attached in IUCLID chapter 13.