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Ecotoxicological information

Endpoint summary

Administrative data

Description of key information

Additional information

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

 

*LL = Lethal Loading rate

 

Fish

The key study was performed in accordance with OECD Guidelines for Testing of Chemicals (1992) No 203, "Fish, Acute Toxicity Test" referenced as Method C.1 of Commission Regulation (EC) No. 440/2008.

Following a preliminary range-finding test, fish (Rainbow trout) were exposed, in groups of seven, 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 a period of 96 hours at a temperature of approximately 14°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 LL*50based on nominal loading rates was 26 mg/L loading rate WAF with 95% confidence limits of 22 - 30 mg/L loading rate WAF. The Lowest Observed Effect Loading rate was 32 mg/L loading rate WAF. The No Observed Effect Loading rate was 18 mg/L loading rate WAF.

Total Organic Carbon (TOC) analysis of the test preparations at 0 (fresh media), 24 and 96 hours (old media) showed measured concentrations below the limit of quantification (assessed as 1.0 mg Carbon/L).

 

Daphnia

The key study was performed to US EPA Draft Ecological Effects Test Guidelines OPPTS 850.1010 and the OECD Guidelines for Testing of Chemicals (April 2004) No 202, "Daphniasp, Acute Immobilisation Test" referenced as Method C.2 of Commission Regulation (EC) No. 440/2008.

Following a preliminary range-finding test and an initial experiment, twenty daphnids (4 replicates of 5 animals) were exposed to Water Accommodated Fractions (WAFs) of the test item over a range of nominal loading rates of 1.0, 1.8, 3.2, 5.6, 10, 18, 32, 56 and 100 mg/L for 48 hours at a temperature of 21°C to 22 ºC under static test conditions. The number of immobilizedDaphniaand any adverse reactions to exposure were recorded after 24 and 48 hours.

The 48-Hour EL*50for the test item toDaphnia magnabased on nominal loading rates was 75 mg/L with 95% confidence limits of 56 - 100 mg/L loading rate WAF. The Lowest Observed Effect Loading rate was considered to be 100 mg/L loading rate WAF. The No Observed Effect Loading rate was 56 mg/L loading rate WAF.

 

Algae

The acute 96h toxicity of the water accommodated fraction (WAF) of the test material to freshwater alga, Selenastrum capricornutum, was determined in a study performed to OECD Guideline 201.

The test was performed at 24 ± 1°C under static conditions with a control (0 mg/L) and five concentrations of WAF (8.1, 16,32,64, and 110 mg/L). The dilution water was sterile enriched media adjusted to a pH of 7.5 ± 0.1.

Exposure of the algae to the test substance resulted in the following growth after 96 hours:

control - 3010000 avg. cells/ml

8.1 mg/l - 2853000 avg. cells/ml (95% of control)

16 mg/l - 2640000 avg. cells/ml (88% of control)

32 mg/l - 878000 avg. cells/ml (29% of control)

64 mg/l - 377000 avg. cells/ml (13% of control)

110 mg/l - 69000 avg. cells/ml (2% of control)

The 96 hour median effective concentration (EC50) was 25 mg/L when calculated using cells/mL, and 79 mg/L when determined using the average specific growth rate. The 96 hour no observed effect concentration (NOEC) is 8.1 mgIL when determined using the number of cells/mL and 16 mg/L when determined using the average specific growth rate.

 

Micro-organisms

The potential impact of the test material on microbial metabolism, as represented by the consumption of oxygen, was investigated using the "Activated Sludge, Respiration Inhibition Test" as prescribed by OECD Guideline 209. The test duration was a three-hour exposure period to the test material followed by up to ten minutes for the measurement of oxygen consumption. The study design was comprised of five nominal exposure concentrations: 1, 10, 100, 1,000 and 10,000 ppm; a duplicate 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 11.2 mg/L, within the acceptable range of 5 to 30 mg/L. The two control replicates produced oxygen consumption rates within the required 95% of each other, 51.8 and 60.7 mg O2/L*hr. The respiration rates of the sludge-associated microbes exposed to the five nominal concentrations of the test material were 37.2, 49.2, 36.0, 42.0 and 17.2 mg O2/L*hr respectively. The EC50 is 4550 mg/L.