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Ecotoxicological information

Toxicity to microorganisms

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Description of key information

Microibial inhibition:  NOEC 20 mg/L

Key value for chemical safety assessment

EC10 or NOEC for microorganisms:
20 mg/L

Additional information

In accordance with REACH Regulation 1907/2008 Annex VIII Column 2, testing need not be undertaken if microbial toxicity is unlikely (if the substance is insoluble in water or if the substance is readily biodegradable). In a test of ready biodegradability the substance was found to be readily biodegradable. Waiving of the endpoint is thus justified.

A NOEC value has been asssigned based on the concentration used in the ready bidegradability test.

In a review of the aquatic toxicity of eighteen phthalate esters, Staples et.al. (Environmental Toxicology and Chemistry, Vol. 16(5): 875-89l, 1997) summarises published literature on phthalate esters, including diethyl phthalate. No details are available on methodology but the following results are cited:

 

Test species

Fresh/salt

water

Measured/nominal

concentration

Test

duration

Endpoint/

criteria

EC50/LC50

(95%CL)

(mg/L)

NOEC

(LOEC)

(mg/L)

Protozoa

T. pyriformis

F

N

24 hours

Growth inhibition

-

50 (100)

Protozoa

T. pyriformis

F

N

48 hours

Growth inhibition

132

50 (100)

Laboratory digester culture

F

M

5-193 hours

Anaerobic metabolic inhibition

-

100

Protozoa

Entosiphon sulcatum

F

N

72 hours

5% inhibition of reproduction

-

- (19)

Bacteria

P. phosphoreum

S

N

5-30 minutes

Light inhibition

111

-

Bacteria

Pseudomonas putida

F

N

16 hours

3% inhibition of reproduction

-

- (400)

Protozoa

Uronema parduczi

F

N

20 hours

5% inhibition of reproduction

-

- (48)

This supports the view that the substance is not significantly toxic to microorganisms and that the assigned NOEC is conservative.