Diisononyl adipate

Long-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

long-term toxicity to aquatic invertebrates

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

22 May - 12 Jun 1996

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

REPORTING FORMAT FOR THE ANALOGUE APPROACH
See explainations in the endpoint study summary and the analogue justification document attached in chapter 12.

Reason / purpose for cross-reference:

read-across source

GLP compliance:

yes

Analytical monitoring:

yes

Key result

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

>= 0.77 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

other: reproduction and survival

Duration:

21 d

Dose descriptor:

LOEC

Effect conc.:

> 0.77 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

other: reproduction and survival

Reference 2

Endpoint:

long-term toxicity to aquatic invertebrates

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

supporting study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

REPORTING FORMAT FOR THE ANALOGUE APPROACH
See explainations in the endpoint study summary and the analogue justification document attached in chapter 12.

Reason / purpose for cross-reference:

read-across source

Qualifier:

according to guideline

Guideline:

OECD Guideline 211 (Daphnia magna Reproduction Test)

Deviations:

no

Key result

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

>= 4.4 µg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

other: reproduction, growth, mortality

Remarks on result:

other: saturated test solution tested

Description of key information

With high probability diisononyl adipate is chronically not harmful to aquatic invertebrates.

Additional information

Since no study assessing the long-term toxicity of DINA to aquatic invertebrates is available, in accordance to Regulation (EC) No. 1907/2006 Annex XI, 1.5 Grouping of substances, a read-across to structurally very similar Bis(2-ethylhexyl) adipate (CAS 103-23-1, DEHA) was conducted. The read across is justified due to the similarity of structure and functional groups and accordingly similar physico-chemical properties which result in similar environmental behavior and fate (see table below).

Substance	Diisononyl adipate (DINA)	Bis(2-ethylhexyl) adipate (DEHA)
CAS number	33703-08-1	103-23-1
Structure	see attachment	see attachment
Molecular formula	C24H46O4	C22H42O4
Molecular weight	398.63 g/mole	370.58 g/mole
PC parameter
Water solubility	RA to 103-23-1	0.0032 mg/L (EU A.6)
Partition coefficient	9.54 (OECD 117)	8.94 (OECD 117)
Vapour pressure	0.00000002 hPa at 20 °C (calculation)	0.0000003 hPa at 20 °C (calculation)
Environmental fate
Biodegradability	> 90% in 28 days (OECD 301F)	>90% in 28 days (OECD 301F)
Adsorption [log KOC]	5.15 (calculation)	4.56 (calculation)
Hydrolysis	not relevant
Ecotoxicology
Short-term toxicity to fish [96h-LC50]	No toxicity within the limit of water solubility	No toxicity within the limit of water solubility
Long-term toxicity to aquatic invertebrates [NOEC]	-	-
Short-term toxicity to aquatic invertebrates [48h-EC50]	No toxicity within the limit of water solubility	No toxicity within the limit of water solubility
Long-term toxicity to aquatic invertebrates [21d-NOEC]	RA drom 103 -23 -1	No toxicity within the limit of water solubility
Short-term toxicity to algae [72h-EC50]	No toxicity within the limit of water solubility	No toxicity within the limit of water solubility
Long-term toxicity to algae [72h-NOEC/EC10]	No toxicity within the limit of water solubility	No toxicity within the limit of water solubility
Toxicity to microorganisms [NOEC]	The inhibition of the degradation activity of activated sludge is not anticipated when DINA is introduced in appropriate low concentrations.	The inhibition of the degradation activity of activated sludge is not anticipated when DEHA is introduced in appropriate low concentrations.

Three studies investigating the long-term toxicity of Di(2-ethylhexyl) adipate (CAS 103-23-1, DEHA) to aquatic invertebrates are available. The key study was performed according to GLP and OECD guideline 202, part 2 using Daphnia magna as test organism (Huels 1996). Test concentrations from 0.5 to 2 mg/L were tested using Marlowet R40 as vehicle (2 mg/L). The stability of the highest test concentration (2 mg/L) was analytically examined. A geometric mean value of 0.77 mg/L was measured, which considerably exceeded the intrinsic water solubility of the substance (approx. 0.0032 mg/L). Nevertheless, no significant adverse effects on reproduction rate or survival of the parent animals were observed at any of the concentrations tested. Thus, the 21d-NOEC value is determined to be ≥ 0.77 mg/L (measured concentration) and > the solubility in water, respectively.

This result is confirmed by supporting studies: Robillard et al. (2008) conducted a long-term toxicity test with Daphnia magna at the saturation limit, which was measured to be an average exposure concentration of 4.4 μg/L (water solubility = 5.5 µg/Lmeasured using the slow stir method). The test concentration was chosen to avoid insoluble test material and physical entrapment. One hundred percent of the DEHA-treated organisms survived compared to 90% survival in both the control and solvent control. Mean neonate reproduction was 152, 137, and 148 and mean dry weight per surviving female was 0.804, 0.779, and 0.742 mg in the treatment, control and solvent control, respectively. No adverse effects were observed. Thus, the 21d-NOEC value is determined to be ≥ 4.4 µg/L (measured concentration) and > the solubility in water, respectively.

The data indicate that DEHA does not adversely affect aquatic invertebrates at long-term exposure in the range of its water solubility. Based on the mentioned structural similarities between the source and the target substance resulting in a similar efate and ecotoxicological profile this efferct value can also considered to be true for Diisononyl adipate (CAS 33703-08-1) and thus adequately covers this endpoint for the hazard assessment of DINA.