5,7-di-tert-butyl-3-[4-(2-hydroxyethoxy)phenyl]-1-heteropolycycl-2(3H)-one

Ecotoxicological Summary

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:

PNEC aqua (freshwater)

PNEC value:

0.1 mg/L

Assessment factor:

1 000

Extrapolation method:

assessment factor

PNEC freshwater (intermittent releases):

1 mg/L

Marine water

Hazard assessment conclusion:

PNEC aqua (marine water)

PNEC value:

0.01 mg/L

Assessment factor:

10 000

Extrapolation method:

assessment factor

STP

Hazard assessment conclusion:

PNEC STP

PNEC value:

100 mg/L

Assessment factor:

10

Extrapolation method:

assessment factor

Sediment (freshwater)

Hazard assessment conclusion:

PNEC sediment (freshwater)

PNEC value:

146.36 mg/kg sediment dw

Extrapolation method:

equilibrium partitioning method

Sediment (marine water)

Hazard assessment conclusion:

PNEC sediment (marine water)

PNEC value:

14.636 mg/kg sediment dw

Extrapolation method:

equilibrium partitioning method

Hazard for air

Air

Hazard assessment conclusion:

no hazard identified

Hazard for terrestrial organisms

Soil

Hazard assessment conclusion:

PNEC soil

PNEC value:

29.205 mg/kg soil dw

Extrapolation method:

equilibrium partitioning method

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:

PNEC oral

PNEC value:

0.667 mg/kg food

Additional information

The acute toxicity of the test material to fish was determined using rainbow Trout (Oncorhynchus mykiss) in a study performed under GLP conditions and in accordance with the standardised guidelines OECD 203 and EU Method C.1.

Seven fish were exposed the hydrolysis solution for 96 hours under semi-static conditions and observed for any mortalities and sub-lethal effects.

 

Under the conditions of the test, fish exposed to the hydrolysis product of the test material in a 100 % v/v saturated solution displayed no mortality or signs of sub-lethal effects. Accordingly the LC50 was determined to be > 100 % v/v saturated solution, and the NOEC 100 % v/v saturated solution. This study showed that there were no toxic effects at the limit of water solubility.

 

 

The acute toxicity of the test material to the freshwater invertebrate was determined usingDaphnia magnain a study performed under GLP conditions and in accordance with the standardised guidelines OECD 202 and EU Method C.2.

Four replicates each containing five daphnids were exposed the hydrolysis product of the test material in a 100 % v/v saturated solution and a blank control for 48 hours. Daphnids were observed for immobilisation and adverse reactions at 24 and 48 hours.

Under the conditions of the test, no immobilisation or signs of toxicity were observed at 100% saturation of the hydrolysis product of the test material. The EC50 was > 100 % v/v saturated solution and the NOEC was 100 % v/v saturated solution.This study showed that there were no toxic effects at the limit of water solubility.

 

The acute toxicity of the test material to the algae was determined usingPseudokirchnerella subcapitatain a study performed under GLP conditions and in accordance with the standardised guidelines OECD 201 and EU Method C.3.

Six replicates each containing the algal cultures at an initial cell density of 4.57 x 10^5 cells per mL were exposed the hydrolysis product of the test material in a 100 % v/v saturated solution and a blank control for 72 hours. Cultures were observed effects on growth rate and cell number.

Under the conditions of the test, no effects were observed at saturation of the hydrolysis product. Therefore the ErC50 was determined to be > 100 % v/v saturation solutions and the NOEC 100 % v/v saturation solution.This study showed that there were no toxic effects at the limit of water solubility.

The toxicity of the test material to microorganisms was determined in an activated sludge respiration inhibition test (carbon and ammonium oxidation) test performed under GLP conditions and in accordance with the standardised guidelines OECD 209.

Activated sewage sludge was exposed to an aqueous dispersion of the test material at concentrations of 10, 100 and 1000 mg/L (3 replicates of the 1000 mg/L test concentration) for a period of 3 hours at a temperature of 20 ± 2 °C with the addition of a synthetic sewage as a respiratory substrate. The rate of respiration was determined after 3 hours contact time and compared to data for the control and a reference item, 3,5-dichlorophenol.

 

Under the conditions of the test, oxygen consumption was not significantly inhibited at any of the concentrations tested. Since no significant toxic effects were shown the 3 hour EC50 is > 1000 mg/L and the NOEC is 1000 mg/L.

 

 

These key studies were all performed in line with GLP and accepted standardised guidelines with a high standard of reporting. They were assigned a reliability score of 1 in accordance with the criteria outlined by Klimisch (1997) and are considered suitable for assessment as an accurate reflection of the test material and test results are based on nominal concentrations.

 

No signs of toxicity were seen in any of the tests at the maximum concentrations tested and as such no acute environmental effects are noted.

Conclusion on classification

The substance exhibited no signs of toxicity to the environment based on the studies conducted, however the physico-chemical properties of the substance (low water solubility and high log P_ow) in conjunction with its lack of ready biodegradability indicates that the substance requires classification as Chronic Category 4 with regards to its effects on the environment.