2-Propenoic acid, methyl ester, reaction products with mixed O,O-bis(branched and linear pentyl and iso-Bu) phosphorodithioates

Endpoint summary

Description of key information

Daphnia magna

 

Short-term toxicity - supporting study

 

A study was performed to assess the acute toxicity of the test material to Daphnia magna. The method followed that described in the OECD Guidelines for the Testing of Chemicals (1984) No 202, "Daphnia sp, Acute Immobilisation Test and Reproduction Test" referenced as Method C.2 of Commission Directive 92/69/EEC (9which constitutes Annex V of Council Directive 67/548/EEC).

 

Following a preliminary range-finding test, forty daphnids (4 replicates of 10 animals) were exposed to a Water Accommodated Fraction (WAF) of the material, at a single nominal loading rate of 100 mg/L for 48 hours under static test conditions. Immobilisation and any adverse reactions to exposure were recorded after 24 and 48 hours.

 

The 48 -hour EL50 for the test material to Daphnia magna based on nominal loading rates was greater than 100 mg/L loading rate WAF and correspondingly the No Observed Effect Loading rate was 100 mg/L loading rate WAF. It was considered unnecessary and unrealistic to test at loading rates in excess of 100 mg/L.

 

Short-term toxicity - key study

 

A key study was performed in accordance with OECD Guideline No 202 and EC Method C.2 

Following a preliminary range-finding test, twenty daphnids (2 replicates of 10 animals) were exposed to Water Accommodated Fractions (WAFs) of the test item over a range of nominal loading rates of 10, 18, 32, 56 and 100 mg/L for 48 hours at a temperature of 21 - 22°C under static test conditions. The number of immobilised Daphnia and any adverse reactions to exposure were recorded after 24 and 48 hours.

 

Chemical analysis of the test preparations at 0 hours showed measured test concentrations to range from less than the limit of quantification (LOQ) of the analytical method employed, i.e. 0.34 mg/L, to 1.02 mg/L. Chemical analysis of the test preparations at 48 hours showed measured test concentrations to range from less than LOQ to 0.806 mg/L.

 

Given that toxicity cannot be attributed to a single component or a mixture of components but to the test item as a whole, the dissolved test item was close to or below the quantifiable limit of the analytical method , the results were based on nominal loading rates only.

 

The acute toxicity of the test item to Daphnia magna gave a 48 hour EL 50 value of 41 mg/L loading rate WAF with 95% confidence limits of 36 - 47 mg/L loading rate WAF. The No Observed Effect Loading rate at 48 hours was 18 mg/L loading rate WAF. The Lowest Effect Loading rate was considered to be 32 mg/L loading rate WAF.

 

Long-term toxicity key study

  

A key study was performed to assess the effect of the test material on the reproduction of Daphnia magna over a 21-day period. The method followed that described in the OECD Guidelines for Testing of Chemicals No 211 (1998) "Daphnia magna, Reproduction Test", referenced as Method C.20 of Commission Directive 2001/59/EC (which constitutes Annex V of Council Directive 67/548/EEC).

 

Based on the results of an acute toxicity test, Daphnia magna were exposed (10 replicates of a single daphnid per group) to Water Accommodated Fractions (WAF) of the test material over a range of nominal loading rates of 1.0, 3.2, 10, 32 and 100 mg/L for a period of 21 days. The WAFs were renewed 3 times per week. The numbers of live and dead adult Daphnia and young daphnids (live and dead) were determined daily. The Daphnia were fed daily with an algal suspension.

 

The 14 and 21-Day EL50 (immobilisation) values, based on nominal test concentrations, for the parental Daphnia generation (P1) were calculated to be 25 and 11 mg/L loading rate WAF with 95% confidence limits of 15 - 40 mg/L and 7.9 - 16 mg/L loading rate WAF respectively. The 21-Day EL50 (reproduction) value based on nominal test concentrations was calculated to be 16 mg/L loading rate WAF with 95% confidence limits of 10 - 25 mg/L loading rate WAF.

 

The EL50 for reproduction is greater than the EL50 for immobilisation due to the observation that although some daphnids had died, daphnids remaining alive did produce some young. The "Lowest Observed Effect Loading rate" was considered to be 10 mg/L loading rate WAF on the basis that at this test concentration significantly fewer live young per adult were produced when compared to the control and significant mortalities were observed in the adult (P1) generation.

 

The "No Observed Effect Loading rate" was considered to be 3.2 mg/L loading rate WAF on the basis that at this test concentration there were no significant mortalities (immobilisation) observed in the parental generation (P1), no significant differences (P≥0.05) between the control and the 3.2 mg/L loading rate WAF test group in terms of numbers of live young produced per adult and there were no significant differences in terms of length of the surviving adult daphnids when compared to the controls after 21 days.

 

Algae

 

A key study was performed in accordance with OECD Guideline No 201 and EC Method C.3 in which, due to the low aqueous solubility and complex nature of the test item, the test item was prepared as a Water Accommodated Fraction (WAF).

 

Following a preliminary range-finding test, Pseudokirchneiella subcapitata was exposed to WAFs of the test item over a range of nominal loadinfrates of 1.0, 3.2, 10, 32 and 100 mg/L (three replicate flasks per concentration) for 72 hours, under constant illumination and shaking at a temperature of 24 ± 1°C. Samples of the algal populations were removed daily and cell concentrations determined for each control and treatment group, using a Coulter Multisizer Particle Counter.

 

Chemical analysis of the test preparations at 0 hours showed measured test concentrations to range from less than the limit of quantification (LOQ) of the analytical method employed, i.e. 0.34 mg/L, at 1.0 mg/L loading rate WAF to 1.3 mg/L at 100 mg/L loading rate WAF. A decline in measured test concentration was observed at 72 hours in the range of less than the LOQ at 1.0 mg/L loading rate WAF to 0.72 mg/L at 100 mg/L loading rate WAF.

 

Given that toxicity cannot be attributed to a single component or a mixture of components but to the test item as a whole the results were based on nominal loading rates only. The EL50 (72h) based on inhibition of growth rate was > 100 mg/L loading rate WAF. The No Observed Effect Loading Rate based on growth rate was 10 mg/L loading rate WAF. Correspondingly the Lowest Observed Effect Loading Rate based on growth rate was 32 mg/L loading rate WAF.

 

Fish

 

Short-term toxicity – supporting study

 

A study was performed to assess the acute toxicity of the test material to rainbow trout (Oncorhynchus mykiss). The method followed that described in the OECD Guidelines for Testing of Chemicals (1992) No 203, "Fish, Acute Toxicity Test" referenced as Method C.1 of Commission Directive 92/69/EEC (which constitutes Annex V of Council Directive 67/548/EEC).

 

Following a preliminary range-finding test fish were exposed, in two groups of ten, to a Water Accommodated Fraction (WAF) of the test material, at a single nominal loading rate of 100 mg/L for a period of 96 hours at a temperature of 14.0°C under semi-static test conditions. The number of mortalities and any sub-lethal effects of exposure in each test and control vessel were determined 3 and 6 hours after the start of exposure and then daily throughout the test until termination after 96 hours.

 

The 96-Hour LL50 based on nominal loading rates was greater than 100 mg/L loading rate WAF and correspondingly the No Observed Effect Loading rate was 100 mg/L loading rate WAF. It was considered unnecessary and unrealistic to test at loading rates in excess of 100 mg/L.

 

Short-term toxicity – key study

 

A key study was performed in accordance with OECD Guideline No. 203 and EC Method C.1.

 

Following a preliminary range-finding test, seen fish were exposed to a Water Accommodated Fraction (WAF) of the test item, at a single nominal loading rate of 100 mg/L for a period of 96 hours at a temperature of approximately 14°C under semi-static conditions. The number of mortalities and any sub-lethal effects of exposure in each test and control vessel were determined 3 and 6 hours after the start of exposure and then daily throughout the test until termination after 96 hours.

 

Analysis of test preparations at 0 (fresh media, 24 and 96 hours (old media) showed measured concentrations to range from less than the limit of quantification (LOQ) of the analytical method (assessed as 0.34 mg/L) to 0.547 mg/L.

 

Given that toxicity cannot be attributed to a single component or a mixture of components but to the test item as a whole, the dissolved test item was close to or below the quantifiable limit of the analytical method, the results were based on nominal loading rates only.

 

The 96 h LL50 based on nominal loading rates was greater than or equal to 100 mg/L loading rate WAF. The No Observed Effect Loading Rate (NOEL) was 100 mg/L loading rate WAF. It was considered unnecessary and unrealistic to test at loading rates in excess of 100 mg/L.

 

Inhibition of sewage sludge micro-organisms

 

A key study was performed to assess the effect of the test item on the respiration of activated sewage sludge. The method followed was designed to be compatible with the OECD Guidelines for Testing of Chemicals No. 209 "Activated Sludge, Respiration Inhibition Test".

 

Activated sewage sludge was exposed to an aqueous dispersion of the test item at a concentration of 1000 mg/L for a period of 3 hours at a temperature of 20 ± 2 deg. C with the addition of a synthetic sewage as a respiratory substrate. The rate of respiration was determined after 3 hours contact time and compared to data for the control and a reference item, 3,5-dichlorophenol.

 

The effect of the test item on the respiration of activated sewage sludge gave a 3-Hour EC50 value of greater than 1000 mg/L and a No Observed Effect Concentration (NOEC) of 1000 mg/L. The reference item gave a 3-Hour EC50 value of 18.0 mg/L.