Z-85

Endpoint summary

Additional information

Fish

A key study to assess theacute toxicity study of test substance to zebra fish (Brachydanio rerio) was conductedin accordance withOECD Guideline 203 and SEPA Guideline 203. Based on the results of the preliminary test, a definitive study was conducted using a limit test concentration of 1,000 mg/L (nominal concentration). A concurrent water control group was performed in parallel. The study was performed with a semi-static water renewal system and the water used was reconstituted water. Dissolved oxygen and pH value were determined at the beginning of the test and at 24 hour intervals during the 96 hour exposure period.The measured concentrations of total organic carbon (TOC) were determined in the samples of test media. Samples were taken from each test vessel and analyzed at the beginning and the end of the first and the third 24 hours of the test.

During the 96 hour exposure period, no toxic signs and deaths were observed in either the control or exposure fish. TOC measurements show that there was no significant difference comparing fresh solution with the expired. Because of adding test substance at 1,000 mg/L to the test water the measured concentration of TOC was 0.993 mg/L (i.e. mean of TOC TS-Control). 

The No Observed Effect Concentration (NOEC) and 96 hour LC50 were both greater than 1,000 mg/L loading rate WAF.

Aquatic invertebrate

A key study study to OECD Guideline 202 and EC Method C.2 was performed to assess the acute toxicity of the test material to Daphnia magna.Following a preliminary range-finding test, twenty daphnids (2 replicates of 10 animals) were exposed to Water Accommodated Fractions (WAFs) of the test material over a range of nominal loading rates of 10, 18, 32, 56, and 100 mg/L for 48 hours at a temperature of 21 to 22 degrees C under static test conditions. The number of immobilised Daphnia were recorded after 24 and 48 hours.

The 48 hour EL50 for the test material to Daphnia magna based on nominal loading rates was 82 mg/L loading rate WAF with 95% confidence limits of 68 to 110 mg/L loading rate WAF. The No Observed Effect Loading rate was 32 mg/L loading rate WAF. 

Analysis of samples taken at 0 hours showed results of less than the limit of quantitation (LOQ) of the analytical method which was assessed to be 0.0047 mg/L. Given that the 0-hour samples were less than the LOQ, analysis of samples at 48 hours was not conducted as it would provide no additional information on exposure concentrations. Therefore, given that toxicity cannot be attributed to a single component or a mixture of components but to the test material as a whole, and the dissolved test material was below the quantifiable limit of the analytical method, the results were based on nominal loading rates only.

Algae

A key study to assess the effect of the test material on the growth of the green alga Desmodesmus subspicatus was performed in accordance with OECD Guideline No 201 and EC Method C.3.Following a preliminary range-finding test, Desmodesmus subspicatus was exposed to a Water Accommodated Fraction (WAF) of the test material, at a single nominal loading rate of 100 mg/L (six replicate flasks) 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. A positive control conducted approximately every six months used potassium dichromate as the reference material. Desmodesmus subspicatus was exposed to an aqueous solution of the reference material at concentrations of 0.0625, 0.125, 0.25, 0.5, and 1.0 mg/L (three replicate flasks per concentration) for 72 hours.

Exposure of Desmodesmus subspicatus to the test material gave EL50 values of greater than 100 mg/l loading rate WAF and correspondingly the No Observed Effect Loading Rate was 100 mg/l loading rate WAF. Analysis of samples taken at 0 hours showed results of less than the limit of quantitation (LOQ) of the analytical method which was assessed to be 0.0051 mg/l. Given that the 0-hour samples were less than the LOQ, analysis of samples at 72 hours was not conducted as it would provide no additional information on exposure concentrations. Therefore given that toxicity cannot be attributed to a single component or a mixture of components but to the test material as a whole, and the dissolved test material was below the quantifiable limit of the analytical method, the results were based on nominal loading rates only.Exposure ofDesmodesmus subspicatusto the reference material, potassium dichromate, gave an ErC50 (0-72h) of 0.57 mg/L; 95% confidence limits 0.48 to 0.66 mg/L, an EyC50 (0-72h) of 0.32 mg/L; 95% confidence limits 0.29 to 0.35 mg/L, and an EbC50 (0-72) of 0.31 mg/L; 95% confidence limits 0.28 to 0.35 mg/L. The Lowest Observed Effect Concentration based on inhibition of growth rate, yield and biomass integral were 0.50, 0.125, and 0.125 mg/l respectively and the No Observed Effect Concentrations were 0.25, 0.0625, 0.0625 mg/l respectively.

Micro-organisms

Read-across to an analog substance, see Section 13 for read-across justification.

A 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 (2010) No 209 "Activated Sludge, Respiration Inhibition Test" and US EPA OPPTS 850.6800.

Following a preliminary range-finding test activated sewage sludge was exposed to an aqueous dispersion of the test item at a concentration of1000mg/l (3 replicates) for a period of 3 hours at a temperature of 21°C with the addition of a synthetic sewage as a respiratory substrate.

The rate of respiration was determined after 30 minutes and 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 EC₅₀value of greater than 1000 mg/L. The No Observed Effect Concentration (NOEC) after 3 hours exposure was 1000 mg/L. 

The reference item gave a 3-Hour EC₅₀value of 7.0 mg/L, 95% confidence limits5.4 - 9.0 mg/L.