2-Propenoic acid, 2-hydroxyethyl ester, reaction products with O,O-bis(dialkyalkyl) hydrogen phosphorodithioate and dimethyl phosphonate

Endpoint summary

Description of key information

Fish: Based on mean measured concentrations, the LL50 (96 h) value for fathead minnow (Pimephales promelas) was determined to be 14 mg/L (OECD 203 and OCSPP 850.1075).

 

Aquatic invertebrates: Based on mean measured loading rates, the EL50 (48 h) value for Daphnia magna was determined to be 0.56 mg/L (OECD 202 and OCSPP 850.1010).

Algae: Based on nominal WAF loading rate, the EL50 (96 h) value for Raphidocelis subcapitata was determined to be > 100 mg/L based on growth rate. The NOELR (96 h) value was reported as 10 mg/L based on growth rate (OECD 201 and OCSPP 850.4500).

 

Microorganisms: The EC50 of the test item was determined to be greater than the highest concentration tested based on the available experimental data and 1000 mg/L can be taken as No Observed Effect Concentration (NOEC) (OECD 209).

Additional information

Fish

The key study protocol was based on was procedures in the OECD Guidelines for Testing of Chemicals, Guideline 203: Fish, Acute Toxicity Test; the U.S. EPA Series 850 - Ecological Effects Test Guidelines, OCSPP 850.1075: Freshwater and Saltwater Fish Acute Toxicity Test; and ASTM Standard E 729-96: Standard Guide for Conducting Acute Toxicity Tests on Test Materials with Fishes, Macroinvertebrates, and Amphibians.

 

Fathead minnows (Pimephales promelas) were exposed for 96 hours under static conditions to five WAF loading rates of 1.0, 3.0, 10, 30 and 100 mg/L plus a negative control consisting of dilution water.

 

Test solutions in the test chambers at these nominal concentrations appeared clear and colourless during the test, with no evidence of precipitation observed, and also when viewed under a microscope. Measured loading rates of the samples ranged from approximately < LOD to 69 % of nominal. When measured concentrations of the samples were averaged, the mean measured loading rates for the study were < LOD, 1.0, 4.1, 8.7, and 31 mg/L, representing 0, 33, 41, 29, and 31 % of nominal concentrations, respectively.

Based on the mean measured concentrations, the 96-hour LL50 value was 14 mg/L, with a 95% confidence interval of 8.7 to 31 mg/L. The no-mortality loading rate was 4.1 mg/L, the 100% mortality loading rate was 31 mg/L and the NOELR was 1.0 mg/L. Based on the nominal WAF loading rates, the 96-hour LL50 value was 48 mg/L, with a 95% confidence interval of 30 to 100 mg/L. The no-mortality loading rate was 10 mg/L, the 100% mortality loading rate was 100 mg/L and the NOELR was 3.0 mg/L.

Daphnia magna

The key study protocol was based on procedures outlined in the OECD Guidelines for Testing of Chemicals, Guideline 202: Daphnia sp., Acute Immobilization Test; U.S. Environmental Protection Agency Series 850 – Ecological Effects Test Guidelines, OCSPP Number 850.1010: Aquatic Invertebrate Acute Toxicity Test, Freshwater Daphnids; and ASTM Standard E 729-96: Standard Guide for Conducting Acute Toxicity Tests on Test Materials with Fishes, Macroinvertebrates and Amphibians.

 

Due to the low aqueous solubility and complex nature of the test item, the investigation was performed using a water accommodated fraction (WAF). Daphnia were exposed to five nominal WAF loading rates of 0.3, 1.0, 3.0, 10 and 30 mg test item and a negative control (dilution water) for 48 hours under static-renewal conditions. Test concentrations were measured in samples of test water collected from the batches of test solution prepared for each treatment and control group at the beginning of the test, at the 24-hour renewal (± 1 hour) and from two of four replicate test chambers at 24 hours (old solutions) and 48 hours (± 1 hour) to determine concentrations of the test substance. Results of the analyses were used to calculate mean measured test concentrations.

The mean measured loading rate was < LOD in the 0.3 mg/L test item treatment group due to the difficult nature of the test material and analytical method limitations. Over the course of the study, percent recoveries ranged from < LOD to 134% of nominal WAF loading rates. Measured loading rates in the remaining treatment group means ranged from 24 to 52 % of nominal. When measured loading rates of the samples collected during the test were averaged, the mean measured test loading rates for this study were < LOD, 0.36 0.75, 2.4, and 16 mg/L. For results > LOD, percent recoveries of nominal WAF loading rates were 36, 25, 24, and 52 %, respectively.

Based on mean measured loading rates, the 48-hour EL50 was determined to be 0.56 mg/L. The concentration causing no immobility at test end was 0.36 mg/L and the concentration causing 100 % immobility was 2.4 mg/L. The NOELR was 0.36 mg/L. Based on nominal WAF loading rates and immobility data, the 48-hour EL50 determined to be 2.0 mg/L with a 95 % confidence interval of 1.0 to 3.0 mg/L. The highest loading rate causing no immobility at test end was 1.0 mg/L, the lowest loading rate causing 100% immobility at test end was 10 mg/L, and the no-observed effect loading rate was 1.0 mg/L.

Algae

Thekeystudy protocol was based on procedures outlined in the OECD Guideline for Testing of Chemicals, 201: Freshwater Alga and Cyanobacteria, Growth Inhibition Test; the Official Journal of the European Communities No. L 383 A, Method C.3. Algal Inhibition Test (2); and in the ASTM Standard E1218-04(2012) Standard Guide for Conducting Static Toxicity Tests with Microalgae.

 

Due to the low aqueous solubility and complex nature of the test item, the investigation was performed using a water accommodated fraction (WAF). The alga was exposed to nominal WAF loading rates of 1.0, 3.0, 10, 30 and 100 mg test item and a control (culture medium) for 96 hours under static renewal conditions. Samples were analysed for total organic carbon since chromatographic methods for analysis were unobtainable due to the contributions in the test matrix.

 

Toxicity of the test item was assessed based on effects on area under the growth curve, growth rate and yield. All control validity criteria specified in the study protocol were achieved.

The 72-hour values were determined to be 37 mg/L (EbL50), > 100 mg/L (ErL50) and 33 mg/L (EyL50). The 96-hour values were determined to be 39 mg/L (EbL50), > 100 mg/L (ErL50) and 41 mg/L (EyL50). The 72-hour NOELR values were reported as 10 mg/L based on biomass, growth rate and yield. The 96-hour NOELR value was reported as 3.0 mg/L based on biomass. The 96-hour NOELR value was reported as 10 mg/L based on growth rate. The 96-hour NOELR value was reported as < 1.0 mg/L based on yield.

Inhibition of sewage sludge micro-organisms

A key study was performed based on procedures in the OECD Guideline for the Testing of Chemicals, Guideline 209: Activated Sludge, Respiration Inhibition Test (Carbon and Ammonium Oxidation).

 

The test contained control, reference, and treatment groups. The control replicates were used to determine the background respiration rate of the sludge and were not exposed to the test or reference substances. The reference group was dosed with 3, 5-dichlorophenol, a known inhibitor of respiration, at concentrations of 3, 15, and 50 mg/L. The test substance was tested at nominal dose levels of 10, 100, and 1000 mg/L. The 1000 mg/L treatment was tested in triplicate. An abiotic control was treated with the test item at a dose level of 1000 mg/L to examine the potential for abiotic reactions of the test substance to consume or release oxygen under the tested conditions.

 

Under the test conditions, of the test item did not inhibit activated sludge respiration at dose levels of 10, 100 mg/L, and 1000 mg/L. The EC50 of the test item was determined to be greater than the highest concentration tested based on the available experimental data and 1000 mg/L can be taken as No Observed Effect Concentration (NOEC).