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Read across to structural analogue. All members of this category of esters have a hydrophobic nature. Based on structural similarities of the substance of interest and the members of the category it was concluded that it was justified to applyread across for this endpoint.

 

96-Hour Acute Toxicity Study in Carp with HATCOL 3331.

 

A limit test was performed exposing seven carp to a filtered (ca. 5 μm) HATCOL 3331 solution prepared at a loading rate of 100 mg/l and to a blank-control. The total test period was 96 hours.

 

HATCOL 3331 induced no visible effects in carp at the concentration obtained in a filtered solution prepared at a loading rate of 100 mg/l, corresponding to an average exposure concentration approaching the solubility limit, i.e. 0.22-0.27 mg/l.

 

In conclusion: Due to the very low solubility of HATCOL 3331 in water, concentration levels that might be toxic for carp could not be reached. Therefore, the 96h-LC50 exceeded the maximum solubility of HATCOL 3331 in test medium.

 

Acute Toxicity Study in Daphnia magna with HATCOL 3331.

 

All solutions at loading rates of 1.0 mg/l and higher were prepared separately. These supersaturated solutions were magnetically stirred for two days to ensure maximum solubility in test medium. The resulting solution was colourless, but contained a floating layer and test substance particles. Collection of the water phase by siphoning or centrifugation was not an option considering the specific gravity of the test substance. After the stirring period the mixture was therefore filtered through a paper filter (ca. >5 μm). The filtrate was clear and colourless.

 

 The project was started with a limit test, exposing daphnia to a filtrate (ca. >5 μm) prepared at a loading rate of 100 mg/l and a blank-control. The test was performed in duplicate with 5 daphnids per vessel and samples for analysis were taken at the start and the end of the test.

 

The analytical results showed that the average exposure concentration was higher than the solubility limit of HATCOL 3331 (i.e. <0.2 mg/l). At the end of the test, 45% of the daphnids exposed to the filtrate were immobilized. Since concentrations were all below 1.0 mg/l, a final test was performed using a range of concentrations nominally spaced by a factor of 10.

 

A final test was performed exposing daphnia to filtrates (ca. >5 μm) prepared at loading rates of 1.0, 10 and 100 mg/l and a 10-foid dilution of the filtrate at 1.0 mg/l. Samples for analysis taken at the start and the end of the test showed that the average exposure concentration in the 1.0 mg/l filtrate approximated the water solubility (i.e. <0.2 mg/l), while average exposure concentrations in the 10 and 100 mg/l filtrates were maintained above the water solubility of HATCOL 3331.

 

HATCOL 3331 did not induce acute immobilisation of Daphnia magna at the concentration obtained in a filtered solution prepared at a loading rate of 100 mg/l, corresponding to an average exposure concentration above the water solubility, i.e. 1.1-1.4 mg/l after 48 hours of exposure (NOEC). Also, no immobilisation was observed at concentrations approximating the water solubility.

 

In conclusion: Due to the very low solubility of HATCOL 3331 in water, concentration levels that might be toxic for daphnia could not be reached. Therefore, the 48h-EC50 exceeded the maximum solubility of HATCOL 3331 in test medium.

 

Selenastrum capricornutum, Fresh Water Algal Growth Inhibition Test with HATCOL 3331.

 

A limit test was performed exposing exponentially growing algal cultures to a filtered (ca. 5 μm) HATCOL 3331 solution prepared at a loading rate of 100 mg/I and a blank-control. The initial cell density was 104cells/mL. The total test period was 72 hours. Samples for determination of actual exposure concentrations were taken at the start, after 24 hours of exposure and at the end of the test period.

 

Analysis of the samples showed that average exposure concentrations were at or above the solubility limit of HATCOL 3331 (i.e. <0.2 mg/I).

 

HATCOL 3331 induced no inhibition of cell growth or reduction of growth rate in Selenastrum capricornutum at the concentration obtained in a filtered solution prepared at a loading rate of 100 mg/l, corresponding to an average exposure concentration of 0.22-0.79 mg/I (NOEC).

 

Due to the very low solubility of HATCOL 3331 in water, concentration levels that might be toxic for algae could not be reached.

 

Toxicity to microorganisms - HATCOL 3331

 

 

The influence of HATCOL 3331 on the respiration rate of activated sludge was investigated after a contact time of 30 minutes.

 

Since HATCOL 3331 was hardly soluble in water, the test substance was quantitatively added to the test vessels. A nominal concentration of 100 mg/L was tested in duplicate. The concentration was approved by the study director in the study files.

 

No significant inhibition of respiration rate of the sludge was recorded at 100 mg HA TCOL 3331 per litre. The duplicate measurement confirmed the result of the first measurement. Therefore no further testing was needed.

The respiration rates of the controls were within 15% of each other.

The EC50 of the reference substance, 3,5-dichlorophenol, was 11 mg/L.

Therefore, the test was considered to be valid.

 

In conclusion, under the conditions of this present test, HATCOL 3331 was not toxic to waste water (activated sludge) bacteria at a concentration of 100 mg/L.