Registration Dossier

Ecotoxicological information

Endpoint summary

Administrative data

Description of key information

Additional information

SHORT-TERM TOXICITY TESTING

DEGDN proved to be relatively non-toxic to the freshwater organisms tested.

The invertebrate 48-h LC50s ranged from 90.1 to 355.3 mg/L, with the water flea being most sensitive. All the fish species had similar sensitivities (mean 96-h LC50 = 273.5 mg/L), except for the fathead minnows, which were somewhat more tolerant with an LC50 of 491.4 mg/L.

There was a dose-response relationship between Selenastrum capricornutum growth and increased DEGDN concentration, the lowest concentration of DEGDN tested (58.4 mg/L) caused a significant reduction in algal cell density and chlorophyll a when compared to control values (Student's t tests with Bonferroni's correction for simultaneous comparisons, p = 0.0001). The 5-day minimum algistatic concentration based on cell density was 171.6 mg/L (95% asymmetrical confidence limits = 86.9 - 335.5 mg/L). The minimum algicidal concentration was greater than 542.4 mg/L, the highest concentration tested. When algal cultures from this treatment were restarted in clean media, they resumed logarithmic growth. The 5-day EC50 for DEGDN and this alga was 39.1 mg/L based on dry weight (95% asymmetrical confidence limits = 28.8 - 52.9 mg/L). Thus, Selenastrum capricornutum was the most sensitive species tested with this compound.

The information about toxicity of DEGDN to microorganisms are not available. The result of study “Determination of the Inhibition of the Respiration of Activated sludge when exposed to Ethylene Glycol Dinitrate according to OECD 209” was used for read across.

LONG-TERM TOXICITY TESTING

The following chronic tests were conducted with TNG: 7-d cladoceran, 60-d ELS rainbow trout, and 28-d ELS fathead minnow. Results of these studies were used for read across for DEGDN.

The LOEC and NOEC for the cladoceran during a 7-d survival and reproduction test, were 5.48 and 3.23 mg/L,

respectively, based on a reduction in neonate production. The LOEC and NOEC for rainbow trout during a 60-d ELS test were 0.06 and 0.03 mg/L (based on a reduction in dry weight). A 28-d ELS with fathead minnow produced a LOEC and NOEC of 0.20 and 0.12 mg/L (based on a reduction in hatching success).

The Selenestrum capricornutum test is an indicator of chronic toxicity since it measures reproduction over the exposure period. Thus, although not directly comparable to the acute toxicity data, the algal data give an indication of possible chronic effect levels for DEGDN.

HARMONIZED CLASSIFICATION

DEGDN has classification harmonized in Annex VI of CLP as Aquatic Chronic 3. The criteria for classifying and categorising substances as “hazardous to the aquatic environment” for Category Chronic 3 are:

Substances for which adequate chronic toxicity data are not available:

96 hr LC50 (for fish) > 10 to ≤ 100 mg/l and/or

48 hr EC50 (for crustacea) > 10 to ≤ 100 mg/l and/or

72 or 96 hr ErC50 (for algae or other aquatic plants)> 10 to ≤ 100 mg/l

and the substance is not rapidly degradable and/or the experimentally determined BCF≥ 500 (or, if absent, the log Kow≥ 4).

CONCLUSION ON C&L

Acute effect values for all three trophic levels are available. C&L is based on data from short-term tests for fish, invertebrates and algae.

Based on existing studies DEGDN is inherently biodegradable and algae Selenastrum capricornutum is the most sensitive species tested with this compound – EC50(5d) = 39.1 mg/L.

These results are consistent with harmonized classification Aquatic Chronic 3.

 

CONCLUSION ON CSA - PNEC DERIVATION

Results of chronic study (60-d ELS test for rainbow trout) for TNG are used for derivation PNEC. Key value for CSA is NOEC = 0.03 mg/L