Tin bis(2-ethylhexanoate)

Endpoint summary

Description of key information

The 96-hour LC50 value of >116 mg/L for tin bis(2-ethylhexanoate) was taken from a valid exposure study with rainbow trout (Oncorhynchus mykiss). In an acute, static, toxicity study with Daphnia magna,the 48-hour EC₅₀ value for tin bis (2-ethylhexanoate) was > 100 mg/L based on nominal concentrations. The 72-hour NOEC and ErC₅₀ for Pseudokirchneriella subcapitata exposed to tin bis(2-ethylhexanoate) was 0.54 and 6.9 mg/L, respectively. The acute toxicity value of 6.9 mg/L was the lowest acute value among the three trophic levels of examined aquatic organisms.

An OECD 212 Guideline study with Tin dichloride has been identified and the results will be used for risk characterisation.
Read-across with source SnCl2, OECD 212, static, Danio rerio, NOEC is calculated as 10,1 mg/L.

Read-across with sodium bis(2-ethylhexanoate), OECD 211, Daphnia magna, semi-static, NOEC(21d) 18.0 mg/L.
Read-across with SnCl2, LOEC 350 µg/L Sn, Referred to the target substance the LOEC is 1.194 mg/L.

The 72-hour NOEC for Pseudokirchneriella subcapitata exposed to tin bis(2-ethylhexanoate) was 0.54 mg/L, respectively. The chronic toxicity value of 0.54 mg/L was the lowest chronic value among the three trophic levels of examined aquatic organisms. This value is taken for risk assessment.

Additional information

One acute freshwater fish study with rainbow trout (Oncorhynchus mykiss) was assessed for this endpoint. This study was determined to be acceptable for use in risk assessment (Klimisch score = 2). Rainbow trout were exposed to a geometric series of five test concentrations and a negative (dilution water) control for 96 hours in a semi-static exposure system. Test solutions were renewed every 24 hours. Observations of mortality and other signs of toxicity were made approximately 3.5, 24, 48, 72 and 96 hours after test initiation. The 24, 48, 72, and 96 hour LC₅₀ values were >116 mg/L tin bis(2-ethylhexanoate).

A study with SnCl2 has been conducted accoring to OECD Guideline 212 at concentrations of 10, 25, 50,100 and 250 µM in a static freshwater design. Validity criteria were fulfilled. The results of the current study show that the tested compound induced early life stage toxicity in zebrafish embryos and larvae when embryos were exposed from 6 to 120 h. It was revealed that exposure to low doses of SnCl2 (10, 25 µM) did not significantly affect the embryos’ survival or cause obvious malformation during the embryonic stages (6–120 hpf). However, exposure to higher concentrations of SnCl2 (50, 100, and 250 µM) reduced survival and caused changes in embryonic development, including tail deformation, reduced body growth, smaller head and eyes, bent trunk, mild pericardial edema, and smaller caudal fin. These data enriched our knowledge of the influence of SnCl2 on embryonic development. These results were in good agreement with those reported in previous studies related to zebrafish and other fish species.
Results clearly indicate a significant dose-dependent increase of developmental and genetic toxicity due to exposure to SnCl2. The NOEC was determined to be 25 µM/L SnCl_2 (=4,7 mg SnCl_2 / L), higher concentrations than 50µM/L (9,4 mg SnCl_2/ L) cause malformations in embryonic state. If referred to the Sn content in the target substance, the NOEC is calculated as 10,1 mg/L. 

 

One static acute toxicity test with Daphnia magna conducted according to OECD 202 under GLP is available for tin bis (2-ethylhexanoate). This study was determined to be acceptable for use in risk assessment (Klimisch score = 1). The study was conducted as a limit test, with four replicate vessels of five daphnids per test level, exposed to nominal test concentrations of 0 (water control) and 100 mg/L tin bis (2-ethylhexanoate). Measured concentrations of the exposures ranged from 95.9 to 97.4% of the nominal concentration over the course of the exposure period. Observations were made at 24 and 48 hours for daphnid immobility and any changes in behavior or appearance. The 48-hour EC₅₀ value was reported as > 100 mg/L based on nominal concentrations. The 48-hour NOEC value was reported as 100 mg/L based on nominal concentrations.

 

Study reporting on short term and long term toxicity of tin to Daphnia magna. Tests not done according to standard protocol, but of sufficient quality and considered useful for setting the PNEC freshwater. Study used for that purpose in the EU risk assessment process on tin (ECB 2008). Culture medium, test water conditions well described. Referred to the target substance the LOEC is 1.194 mg/L.

 

Reproductive Inhibition Test of Sodium 2-Ethylhexanoate against Daphnia magna study is done under GLP condition. Animals were exposed total 21days in semi-static water flow system for concentrations: 10.0, 18.0, 32.0, 56.0, 100 mg/L. Half lethal concentration (LC₅₀) of parent Daphnia magna exposed for 21 days is not be determined(LC₅₀: >100 mg/L (95% confidence interval: not calculated). The 50% reproductive inhibitory concentration (EC₅₀) of the exposure for 21 days is: 43.3 mg/L (95% confidence interval: 39.4-48.0 mg/L). The maximum no effect concentration (N0EC) and minimum no effect concentration (LOEC) of 21-day exposure on the cumulative number of litters per parent Daphnia magna is as follow: NOEC: 18.0 mg/L. LOEC: 32.0 mg/L

 

In a valid toxicity study with Pseudokirchneriella subcapitata (Klimisch score = 2), algal cells were exposed to nominal test concentrations of 0, 0.25, 0.55, 1.2, 2.7 and 6.0 mg/L tin bis(2-ethylhexanoate). Measured test concentrations were determined from samples of test medium collected from each treatment and control group at the beginning and end of the test. Samples were collected from each replicate test chamber at approximately 24-hour intervals during the test to determine cell densities. Areas under the growth curve and growth rates were used to calculate percent inhibition values relative to the control over the 72 -hour exposure period. The 72-hour NOEC and EC₅₀ based on growth rate were 0.54 and 6.9 mg/L, respectively. The 72-hour NOEC and EC50 based on biomass were 0.22 and 1.0 mg/L, respectively. Since the use of the average specific growth rate for estimating toxicity is scientifically preferred (OECD 201), this toxicity value was selected as key for this endpoint.