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Description of key information

This substance is a reaction mass of dipropylene glycol dibenzoate (DPGDB) and diethylene glycol dibenzoate (DEGDB). No testing has been performed on the reaction mass itself but data are available for DPGDB and DEGDB individually. All the studies were performed according to international test guidelines and in compliance with GLP. They are presented below, by component.

The acute toxicity studies were carried out on freshwater fish species (rainbow trout and fathead minnow) and Daphnia magna. The algal growth inhibition studies were performed on Selenastrum capricornutum (Pseudokirchnerella subcapitata). The substance was introduced using a water accommodated fraction (WAF) and also in the case of DPGDB with fish, by flow through. Many of the original studies conducted using a WAF had endpoints reported based upon nominal loading rates. These studies did include analytical measurments of the exposure solutions and the results were re-evalauted based upon mean measured concentrations and the robust study summaires have been revised.

 

For each component an ASRIT study was performed to determine the effect on sewage micro-organisms. A second study on each component was also conducted to assess the effect on the growth of the bacteriaPseudomonas putida.These latter studies followed the method described in the German Water Hazard Classification Scheme, Bewertung Wassergefahrdender Stoffe LTWS Nr 10 and ISO 10712.

DEGDB:

Short-term toxicity to fish:

- Key study, reliability 1, OECD 203, rainbow trout - LC50 (96h) = 1.12 mg/L

- Supporting study, reliability 1, OECD 203, fathead minnow - LC50 (96h) = 1.85 mg/L

Short-term toxicity to aquatic invertebrates:

- Key study, reliability 1, OECD 202, Daphnia magna - EC50 = 3.05 mg/L

Toxicity to aquatic algae and cyanobacteria:

- Study in progress

- Disregarded study, reliability 3,OECD 201, Pseudokirchneriella subcapitata - The test substance was not anaytically detected at the end of the study and therefore it was determined that the geometric mean of the exposure concentrations was unreliable and the study should be repeated.

Toxicity to microorganisms:

- Key study, reliabiltiy 1, OECD 209, activated sludge of a predominantly domestic sewage - EC50 (3 h) > 100 mg/L and NOEC (3 h) >= 100 mg/L

- Supporting study, reliability 2, ISO 10712 Determination of the inhibitory effect of water constituents on bacteria Pseudomonas cell multiplication inhibition test, Pseudomonas putida - EC10 and EC50 > 10 mg/L, NOEC >= 10 mg/L

DPGDB:

Short-term toxicity to fish:

- Key study, reliability 1, OECD 203, fathead minnow - LC50 (96h) = 3.7 mg/L

- Supporting study, reliability 1, OECD 203, rainbow trout - LC50 (96h) > 3.0 mg/L

- Supporting study, reliability 2, QSAR calculation (EPIWIN-ECOSAR v1.00) - LC50 = 3.94 mg/L

- Disregarded study, reliability 3, OECD 203, fathead minnow - LL50 > 100 mg/L, NOELR = 0.8 mg/L, poor correlation of nominal levels with measured concentrations

- Disregarded study, reliability 3, OECD 203, rainbow trout - LL50 = 0.25 mg/L, NOELR = 0.06 mg/L, poor correlation of nominal levels with measured concentrations

Short-term toxicity to aquatic invertebrates:

- Key study, reliability 1, OECD 202, Daphnia magna - EC50 = 5.0 mg/L

Long-term toxicity to aquatic invertebrates

- Key Study, reliability 1, OECD 211, Daphnia magna: LOEC (reproduction & length) = 5.6 mg/L, NOEC (reproduction & length) = 2.2 mg/L, EC10 (reproduction) = 2.5 mg/L, EC10 (length) = >5.6 mg/L

Toxicity to aquatic algae and cyanobacteria:

- Key study, reliability 1, OECD 201, Pseudokirchneriella subcapitata - The EbC50 (biomass 72 h) was 0.70 mg/L and the ErC50 (Growth rate 0 - 72 h) was 3.2 mg/L. The EbC50 (biommass 96 h) was 0.62 mg/L and the EbC50 (Growth rate 0 - 96 h) was 2.5 mg/L.

The 72 and 96 hour "no-observed effect concentrations" (NOEC) for growth rate were 0.68 and 0.27 mg/L, respectively.

Toxicity to microorganisms:

- Key study, reliabiltiy 1, OECD 209, activated sludge of a predominantly domestic sewage - EC50 (3 h) > 100 mg/L and NOEC (3 h) >= 100 mg/L

- Supporting study, reliability 1, ISO 10712 Determination of the inhibitory effect of water constituents on bacteria Pseudomonas cell multiplication inhibition test, Pseudomonas putida - EC10 and EC50 > 10 mg/L, NOEC >= 10 mg/L

These data demonstrate that DPDGB and DEGDB have similar environmental profiles with all short-term EC50 values in the range of >1.0 mg/L and <10 mg/L. A toxicity to aquatic algae and cyanobactor tests with DEGDB is in progress to complete that endpoint for the reaction mass, and a long-term toxicity to fish study with DEGDB is proposed to further refine the key values used in the chemical safety assessment. The most sensitive endpoint result currently available for these components has been used as the key value to evaluate hazard and is highlighted below.

The current key values used in the chemical safety assessment are:

Short-term aquatic toxicity EC/LC50 = 1.12 mg/L (DEGDB rainbow trout)

Long-term aquatic toxicity NOEC = 0.68 mg/L (DPGDB, 72 hour algal growth rate)

Toxicity to micro-organisms = 100 mg/L

Additional information