Use of this information is subject to copyright laws and may require the permission of the owner of the information, as described in the ECHA Legal Notice.
EC number: 200-543-5
CAS number: 62-56-6
For the assessment of the short-term
toxicity of thiourea to fish five different studies are available.
Species tested werePimephales promelas,Leuciscus idus(L.),
Hong Kong guppy,Danio rerio,andOryzias latipes. In none of
the studies could an LC50value be obtained that would be
close to the regulatory cut-off value of 100 mg/L for classification.
Therefore, classification of thiourea for acute toxicity to fish is not
The 14-d subchronic NOEC of thiourea to fish
was determined to be 5000 mg/L.
The 96-hr effect concentrations of thiourea
to the green algaScenedesmus subspicatusChodat used in the risk
assessment of the substance are as follows: EC10= 0.3 mg/L,
and EC50= 3.8 mg/L.
Conflicting results are available regarding
the short-term toxicity of thiourea to daphnia. Several non-standard
data of low reliability are available that provide information on the
acute toxicity of thiourea towards daphnia. Reported EC50values
were determined after 24 to 96 hours exposure and range between 1.8 mg/L
and 4000-6000 mg/L. However, consistent results are reported with regard
to the long-term toxicity to daphnia. All 21-d NOEC values
(reproduction) are in the range of 0.1 to 1 mg/L. Following the
precautionary principle, the lowest reported result of NOEC (21-d) of
0.1 mg/L is used in the assessment of thiourea.
Regarding the toxicity of thiourea to
microorganisms, it could be demonstrated in several studies that
thiourea is toxic to microorganisms, with nitrification being the most
sensitive process. Toxic effects (75 % nitrification inhibition) were
reported at thiourea concentrations ranging from 0.76 mg/L to 0.076
mg/L. However, acclimatisation to thiourea occurs over time, resulting
in the microorganism's capability of degrading thiourea. In a study
conducted by Tomlinson et al. (1966) incremental increase of thiourea
concentrations up to 76 mg/l correlated with a gradual increase of the
degradation products nitrate and sulphate, indicating complete
mineralisation of thiourea. An EC50of 0.35 mg/l could be
established with respect to the inhibitory effect of thiourea to STP
microorganisms. This value was chosen for the risk assessment as it is
the only result obtained making use of a (modified) standard guideline
For details on the information referenced
above please refer to the individual sections.
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.
Esta web utiliza cookies para mejorar su experiencia de navegación en nuestros sitios web.
Welcome to the ECHA website. This site is not fully supported in Internet Explorer 7 (and earlier versions). Please upgrade your Internet Explorer to a newer version.
Do not show this message again