Registration Dossier

Ecotoxicological information

Endpoint summary

Administrative data

Description of key information

Additional information

Given that the toxicity cannot be attributed to any one or more of the components in the WAF, but to the mixture as a whole, the results are based on nominal loading rates only.

Acute

Fish

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.l of Commission Directive 92/69/EEC (which constitutes Annex V of Council Directive 67/548/EEC), US CFR Title 40, Part 797, Section 1400 and US EPA Draft Ecological Effects Test Guideline OPPTS 850.1075.

Following a preliminary range-finding study 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 1000 mg/L for a period of 96 hours under 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 study until termination after 96 hours.

The 96-Hour LL50 based on nominal loading rates was greater than 1000 mg/L loading rate WAF and correspondingly the No Observed Effect Loading rate was 1000 mg/L loading rate WAF.

Daphnia

A study was performed to assess the acute toxicity of the test material toDaphnia magna. The method followed that described in the OECD Guidelines for 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 (which constitutes Annex V of Council Directive 67/548/EEC).

Following a preliminary range-finding study, twenty daphnids (2 replicates of 10 animals) were exposed to filtered Water Accommodated Fractions (WAFS) of the test material at nominal loading rates of 10, 18, 32, 56, 100, 180, 320, 560 and 1000 mg/L for 48 hours 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 150 mg/L loading rate filtered WAF with 95% confidence limits of 130 - 160 mg/L loading rate filtered WAF. The No Observed Effect Loading rate was 100 mg/L loading rate filtered WAF.

Algae

A study was performed to assess the effect of the test material on the growth of the green alga Scenedesmus subspicatus. The method followed that described in the OECD Guidelines for Testing of Chemicals (1984) No 201, "Alga, Growth Inhibition Test" referenced as Method C.3 of Commission Directive 92169/EEC (which constitutes Annex V of Council Directive 67/548/EEC).

 

Following a preliminary range-finding study, Scenedesmus subspicatus was exposed to Water Soluble Fraction (WSF) of the test material at loading rates of 6.25, 12.5, 25, 50 and 100 mg/L for 72 hours, under constant illumination and shaking at a temperature of 24 ± 1 Deg C. Samples of the algal populations were removed daily and cell concentrations determined for each control and treatment group using a Coulter® Multisizer II Particle Counter.

 

Exposure of Scenedesmus subspicatus to the test material gave an EbLR50 (72 h) value of 14 mg/l loading rate WSF: 95% confidence limits 13 - 15 mg/l loading rate WSF and an ErLR50 (0-72 h) value of 16 mg/l loading rate WSF: 95% confidence limits 15 - 17 mg/l loading rate WSF. The No Observed Effect Loading Rate was found to be 6.25 mg/l loading rate WSF.

 

Chronic

Daphnia

A study was performed to assess the effect of the test material on the reproduction ofDaphnia magnaover a 21 day period. The method followed that described in the OECD Guidelines No 211 "Daphnia magna, Reproduction test".

Based on the results of an acute toxicity study,Daphnia magnawere exposed (10 replicates of a single daphnid per group) to filtered WAF of the test material over a range of nominal loading rates of 1.5, 4.8, 15, 48, 150 mg/L for a period of 21 days. The test solutions were renewed 3 times per week. The numbers of live and dead adult Daphnia and young daphnids were determined daily. TheDaphniawere fed daily with an algal suspension.

The 14 and 21 -day EL50 (immobilisation) values, based on the nominal loading rates, for the parentalDaphniageneration were calculated to be 48 and 27 mg/L loading rate filtered WAF with 95% confidence limits of 33 -69 mg/L loading rate filtered WAF and 15 -48 mg/L loading rate filtered WAF respectively.

The 21 -day EL50 (reproduction) was calculated to be 31 mg/L loading rate filtered WAF with 95% confidence limits of 37 -37 mg/L. The LOEC is considered to be 48 mg/L loading rate filtered WAF on the basis that at this loading there were significant mortalities (immobilisation) observed in the parental generation. The NOEC is considered to be 15 mg/L loading rate filtered WAF on the basis that at this loading rate there were no mortalities (immobilisation) observed in the parental generation and that there were no significant differences between the control and the 15 mg/L loading rate filtered WAF test group in terms of the number of live young produced per adult by day 21.

STP Microorganisms

The potential impact of test item on microbial metabolism, as represented by the consumption of oxygen, was investigated using the "Activated Sludge, Respiration Inhibition Test" as prescribed by OECD (1984). The test duration was a 3 -h exposure period to the test material followed by up to 10 minutes for the measurement of oxygen consumption. The study design was comprised of 5 nominal exposure concentrations: 1, 10, 100, 1000, and 10000 ppm; a duplicated control group; and an assessment of the sensitivity of the inoculum used in the test to a reference toxicant (3,5 -dichlorophenol).

The EC50 calculated for the reference toxicant was 16.2 mg/L, within the acceptable range of 5 to 30 mg/L. The 2 control replicates produced oxygen consumption rates within the required 15% of each other, 33.4 and 33.0 mg O2/L x hour. The respiration rates of the sludge-associated microbes exposed to the 5 nominal concentrations of the substance were 36.9, 31.7, 31.8, 29.5, and 20.2 mg O2/Lxhr respectively. The EC50 was calculated to be greater than 10000 mg/L.