7a-ethyldihydro-1H,3H,5H-oxazolo[3,4-c]oxazole

Ecotoxicological Summary

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:

PNEC aqua (freshwater)

PNEC value:

0.051 mg/L

Assessment factor:

10

Extrapolation method:

assessment factor

PNEC freshwater (intermittent releases):

0.011 mg/L

Marine water

Hazard assessment conclusion:

PNEC aqua (marine water)

PNEC value:

0.005 mg/L

Assessment factor:

100

Extrapolation method:

assessment factor

STP

Hazard assessment conclusion:

PNEC STP

PNEC value:

1.66 mg/L

Assessment factor:

100

Extrapolation method:

assessment factor

Sediment (freshwater)

Hazard assessment conclusion:

no exposure of sediment expected

PNEC value:

0.236 mg/kg sediment dw

Extrapolation method:

equilibrium partitioning method

Sediment (marine water)

Hazard assessment conclusion:

no exposure of sediment expected

PNEC value:

0.024 mg/kg sediment dw

Extrapolation method:

equilibrium partitioning method

Hazard for terrestrial organisms

Soil

Hazard assessment conclusion:

no hazard identified

PNEC value:

0.017 mg/kg soil dw

Extrapolation method:

equilibrium partitioning method

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:

no potential for bioaccumulation

Additional information

From a fugacity model (McKay Level III) based on key physical and chemical property parameters, it can be concluded that the ultimate compartment for distribution of EDHO is the aquatic compartment (100%). Therefore, direct and indirect exposure to the soil compartment is unlikely. EHDO is inherently biodegradable and thus has low potential for bioaccumulation. Secondary poisoning is therefore not considered as relevant route of exposure for consumers and workers. Therefore, no PNEC was calculated for oral derivation.

Based on a Koc value of 10, the mobility of EDHO in soil would be classified as very high and, in addition would not be expected to bind to sediments. Therefore, no sediment PNECs were derived.

Conclusion on classification

Data relevant for classification:

Bioaccumulation potential is expected to be minimal based on a reported log Kow of -0.32.

 

Degradation

EDHO is rapidly hydrolyzed to AEPD and formaldehyde, with half-lives of less than 4 hours at pH 4, 7, and 9 at 25 ºC. As a result of rapid hydrolysis and low potential for continuous input in the aquatic environment based on use patterns, potential for chronic exposure to EDHO is expected to be low. 

 

Bioaccumulation

log Kow: -0.32. (EC method A8)

 

Aquatic acute toxicity

For fish:                             96 h, LC50 (Rainbow trout): 130 mg/L

For aquatic invertebrates:    48 h, EC50 (Daphnia magna): 16.9 mg/L

For algae/aquatic plants:     72 h, ErC50 (Pseudokirchneriella subcapitata): 1.08 TWA mg/L

 

Aquatic chronic toxicity

For fish:                             not available

For aquatic invertebrates:    21d NOEC (Daphnia magna): 5 mg/L

For algae/aquatic plant:       72 h NOECr (Pseudokirchneriella subcapitata): 0.513 TWA mg/L

 

Conclusion:

 

CLP (2ATP):

Based on a review of the ecotoxicity values from the acute fish, daphnid, and algal studies, the key studies indicated that EDHO exhibited acute toxicity (LC/EC50) values ranging from 1.08 to 244 mg/L.  Freshwater green algae were the most sensitive of the three trophic levels to EDHO. The 72-hour ErC50 based on the growth rate endpoint was 1.08 mg/L and the NOEC was 0.513 mg /L.

 

EDHO is classified for environmental hazards as Chronic 3 and labeled as  H412: Harmful to aquatic life with long lasting effects according to the 2ndATP of the Regulation (EC) No.1272/2008 (CLP).