Dibutyltin maleate

Toxicity to aquatic algae and cyanobacteria

Description of key information

The following study was submited as the key study to address the toxicity of dibutyltin maleate to aquatic algae:
Oldersma H, Hanstveit AO & de Wolf JM (2003) 1,3,2-Dioxastannepin-4,7-dione, 2,2-dibutyl-(DBTM) (CAS # 78-04-6): Determination of the effect on the growth of the fresh water green algae Scenedesmus subspicatus. Testing laboratory: TNO, Project Organisation, Ecotoxicology, Utrechtseweg 48, P.O. Box 360, 3700 AJ Zeist, The Netherlands. Owner company: Organotin Environmental Programme (ORTEP) Association, Stabilizer Task Force. Report No.: V4017/05. Report date: 2003-10-16
In a determination of the effect on the growth of the fresh water green algae Scenedesmus subspicatus study, the 72h ErC50 for the test material was 4.1 mg/L and the estimated 72h NOEC was 0.88 mg/L based on the growth rate. The analytical data demonstrated stable test substance concentrations during the test. The effect values were based on the average of the measured concentrations of 1,3,2-dioxastannepin-4,7-dione, 2,2-dibutyl- (DBTM). The toxicity estimates derived from the statistical model demonstrated that 1,3,2-dioxastannepin-4,7-dione, 2,2-dibutyl- (DBTM) had a significant adverse effect on the growth rate (ErC50). The lower EbC50 value is therefore considered to have no toxicological relevance. The study was conducted to the OECD Guideline no. 201 and the EU Guideline no. C.3, and in compliance with the OECD Principles of Good Laboratory Practice.
A further study performed on dibutyltin oxide was provided as supporting information. In this study, a saturated solution of di-n-butyltin (oxide (1.6 mg/L) was not toxic to the green algae Scenedesmus subspicatus.

Key value for chemical safety assessment

EC50 for freshwater algae:

4.1 mg/L

EC10 or NOEC for freshwater algae:

0.88 mg/L

Additional information

The following studies have been submitted to address the toxicity to aquatic algae and cyanobacteria endpoint:

Oldersma H, Hanstveit AO & de Wolf JM (2003). 1,3,2-Dioxastannepin-4,7-dione, 2,2-dibutyl-(DBTM) (CAS # 78-04-6): Determination of the effect on the growth of the fresh water green algae Scenedesmus subspicatus. Testing laboratory: TNO, Project Organisation, Ecotoxicology, Utrechtseweg 48, P. O. Box 360, 3700 AJ Zeist, The Netherlands. Report no.: V4017/05. Owner company: Organotin Environmental Programme (ORTEP) Association, Stabilizer Task Force. Report date: 2003-10-16.

Steger-Hartmann T (1999). Growth inhibition test of di-n-butyltin oxide (ZK 26385) on the green algae Scenedesmus subspicatus. Testing laboratory: Schering AG, Experimentelle Toxikologie, D-13342 Berlin, Germany. Report no.: IC28. Owner company: Schering AG, Experimentelle Toxikologie, Berlin, Germany. Study number: TXST19980234. Report date: 1999-02-17.

Oldersama et al (2003) has been performed in line with the appropriate guideline and to GLP and has been allocated a Klimsich score of 1. This study is considered to be the key study for this endpoint. The 72h ErC50 for the test material was 4.1 mg/L and the estimated 72h NOEC was 0.88 mg/L based on the growth rate.

Steger-Hartmann (1999) has been performed in line with the appropriate guideline but using dibutyltin oxide as the test material. The study has been allocated a Klimisch score of 2 and so is considered to be a supporting study due to the fact that it is known that organotin ligand will hydrolyse to this form. A saturated solution of di-n-butyltin oxide (1.6 mg/L) was not toxic to the green algaeScenedesmus subspicatus.