Dibutyltin dichloride

Toxicity to aquatic algae and cyanobacteria

Description of key information

The following studies have been submitted to address the toxicity to aquatic algae and cyanobacteria endpoint:
Huang G et al (1993). Accumulation and toxic effect of organometallic compounds on algae. Applied Organometallic Chemistry, Vol. 7, 373-380.
Huang G et al (1997). Quantitative Structure-Activity Relationship Study for Toxicity of Organotin Compounds on Algae. Bull. Environ. Contam. Toxicol. (1997) 58:299-304.
Oldersma H et al (2003). Dibutyldichlorostannane (CAS# 683-18-1): Determination of the effect on the growth of the fresh water green alga Scenedesmus subspicatus. Testing laboratory: TNO, Project Organisation, Ecotoxicology, Utrechtseweg 48, P. O. Box 370, 3700 AJ Zeist, The Netherlands. Report no.: 2495/04. Owner company: Organotin Environmental Programme (ORTEP) Association, Stabilizer Task Force. Report date: 2003-10-16.
Walsh et al (1985). EFFECTS OF ORGANOTINS ON GROWTH AND SURVIVAL, OF TWO MARINE DIATOMS, SKELETONEMA COSTATUM AND THALASSIOSIRA PSEUDONANA. Chemosphere, Vol.14, No.3/4, pp 383-392.
Wong et al (1982). Structure-toxicity Relationship of Tin Compounds on Algae. Can. J. Fish. Aquat. Sci. 39: 483-488.
Oldersama et al (2003) has been allocated a Klimisch score of 2 because it is a GLP-performed lab study to accepted guidelines; all other references have been allocated a Klimisch score of 4. Oldersama et al (2003) has been determined to be the key study for this endpoint.

Key value for chemical safety assessment

EC50 for freshwater algae:

8 mg/L

EC10 or NOEC for freshwater algae:

2.8 mg/L

Additional information

Oldersma H et al (2003) was provided as the key study for this data requirement. The study was performed according to the method OECD 201 and the EU Method C.3 and in compliance with GLP. The study was assigned a reliability score of 2 (reliable with restrictions) due to minor (unavoidable) deficiencies present in the analytical methods of the test. In thestudy, the effect on the growth of the fresh water green alga Scenedesmus subspicatus was reported (TNO study number: 2495/04). The test material was found to have an NOEC of 2.8 mg.l^-1. Only, in the cultures containing the two highest test substance concentrations, 5.2 and 8.3 mg.l^-1(average measured), deformed cells were observed.

Five further studies were provided as supporting information. Huang G et al (1993), two studies both referenced as Huang G et al (1997), Wong et al (1982) and Walsh et al (1985). All five studies were assigned reliability scores of 4 (not assignable).

Huang G et al (1993) was assigned a reliability score of 4 (not assignable) as there were some deficiencies in the reporting of the methods. The study (not performed to standard methods) reports toxic effects of DBT on the freshwater alga Scenedesmus Obliquus. For comparison, Chlorella Vulgaris was used. The EC50 for Dibutyltin tested on Scenedesmus Obliquus algae was 16.7 µg/l^-1.

The first two of the Huang 1997 studies were toxicity estimations using quantitative structure-activity relationships. The toxicity of the substance was estimated in two species of algae. In the first, the estimated 96-h EC50 for S. obliquus was reported as 2.64 x 10ˆ-1 µmol/l . In the second study, the estimated 96-h EC50 for Platymonas sp. was reported as 2.53 x 10^-1µmol/l .

Wong et al (1982), was assigned a reliability score of 4 (not assignable) due to deficiencies in the reporting and performance of the study and is performed to a non-standard methods, the reliability of the data was based on dose response and structure activity relationships outlined and discussed by the authors. The authors reported that a volume of <0.05% acetone in the medium had no effect on primary productivity. The IC5 of the test material with Ankistrodesmus falcatus was estimated by graphic interpolation and reported as 6.8 mg/L (as Sn).

Walsh et al (1985), was assigned a reliability score of 4 (not assignable) due to deficiencies in the reporting and the performance of the test. From the results of the algal population growth test the 72-h EC50 was estimated using the three point moving average angle method. The 72-h EC50 was reported as 40µg/L (as Sn) for Skeletonema costatum and 181µg/L (as Sn) for Thalassiosira pseudonana.