O,O',O''-(methylsilylidyne)trioxime 2-pentanone

Endpoint summary

Additional information

Short term fish

One short-term toxicity test on fish, performed according to the OECD Guideline 203, with MPKO, the major hydrolysis product of OS1600, is available. In this study the toxicity of MPKO to Rainbow trout (Oncorhynchus mykiss) was evaluated with a limit test during a 96h, static exposure. Fish were exposed to either the control medium or 100 mg/L MPKO (nominal concentration) or 103 mg/L MPKO (measured concentration at the end of exposure). Overall, no mortalities or other significant adverse affects were observed in any of the fish exposed to 100 mg/L MPKO for 96 hrs.

In conclusion, the 96h LC50 value for rainbow trout for MPKO was > 100 mg/L while the NOEC or “no observed effect concentration” was 100 mg/L and the LOEC was >100 mg/L. Therefore, It can be concluded that the substance is not acutely toxic for fish.

 

Short term invertebrates

One short-term toxicity test on aquatic invertebrates, performed according to OECD Guideline 202, with MPKO, the major hydrolysis product of OS1600, is available. In this study, the toxicity of MPKO toDaphnia magnawas evaluated with a limit test during 48 hour, static exposure.Daphniawere exposed to either a control medium or 100 mg/L MPKO (nominal concentration). The results on cumulative immobilisation indicated that 5% immobilization occurred in the dilution water control at 48 hours and that no immobilisation occurred in the test concentration at 48 hours. The 48h EC50 (immobilisation) value for MPKO withDaphnia magnawas determined to be >100 mg/L MPKO, while theNOECor “no observed effect concentration” was >= 100 mg/L. Therefore, it can be concluded that the substance is not acutely toxic for invertebrates.

Short term algae

One study on the freshwater alga (Pseudokirchneriella subcapitata), performed according to the OECD Guideline 201 is available. This study evaluated the toxicity of MPKO during a 72h exposure. Algae were exposed to a control medium and a medium containing 5.6, 10, 18, 32, 56, and 100 mg/L MPKO (nominal). The EbC50 (biomass) was 50 mg/L MPKO and the ErC50 (growth rate) was 88 mg/L MPKO. The NOEC for both biomass and growth rate was 32 mg/L MPKO.

Toxicity to microorganisms

Microbial toxicity of OS1600 was derived from an available ready biodegradation test, performed according to OECD guideline 301B. In this test, ready biodegradability was tested by monitoring CO2 evolution. Both a positive control and a toxicity control were included in the test setup. In the toxicity control OS1600 was added at a concentration of 21.5 mg/L. Validity criteria of the test were fulfilled. Since in the toxicity control more than 25% degradation occurred within 14 days (32 % based on ThCO2) it can be considered that the test substance does not inhibit microbial activity.