diisopentylphthalate

Short-term toxicity to aquatic invertebrates

Administrative data

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

16 November 2010 - 29 March 2011

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: The study was conducted according to official EC and OECD test guidelines, and in compliance with GLP.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2011

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Test guideline 2

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Diisoamyl phthalate

IUPAC Name:

Diisoamyl phthalate

Details on test material:

- Name of test material (as cited in study report): Diisoamyl phthalate
- Substance type: Organic
- Physical state: Colourless to yellow liquid

- Analytical purity: 100%
- Lot/batch No.: 7920-1-1
- Expiration date of the lot/batch: 12 August 2012
- Storage condition of test material: room temperature in the dark

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

- Concentrations: first range finding test concentrations 0.1, 1.0 and 10 mg/L
- Concentrations: second range finding test concentrations 0.01, 0.1 and 1.0 mg/L
- Concentrations: definitive nominal concentration 1.0 mg/L, control group
- Sampling method: four replicates of five animals per vessel, were exposed in each control and test group, placed at random into glass vials containing 100 mL of medium, to give a loading of 20 mL medium per organism,.

Test solutions

Details on test solutions:

The test medium was prepared in Elendt M4 medium by the direct addition of the test substance to the dilution medium; to aid dissolution, vigorous stirring was employed.
At the start of the test, the mean measured concentration of diisoamyl phthalate in the test medium approximated 20% of its nominal concentration; this level was maintained over the duration of the test, with a mean measured concentration of 83% of the starting value at 48 hours. The overall mean measured level of diisoamyl phthalate was 0.163 mg/L

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: daphnia magna
- Age at study initiation (mean and range, SD): less than 24 hours old
- Method of breeding: cultured in house (parthenogenesis)
- Feeding: daily with a suspension of the unicellular green algae

Study design

Test type:

static

Limit test:

yes

Total exposure duration:

48 h

Post exposure observation period:

The numbers of mobile, immobile and floating Daphnia were counted approximately 24 and 48 hours after the start of the study

Test conditions

Hardness:

250 mg/L

Test temperature:

20.4 - 21.0 ºC

pH:

7.89 - 8.11

Dissolved oxygen:

100-95 % of air saturation value

Salinity:

N/A

Nominal and measured concentrations:

1.0 mg/L nominal,
0.482 mg/L measurd (range finding test)
0.163 mg/L measured (definitive test)

Details on test conditions:

Test area was maintained at 20 +/- 2ºC during the definitive test. The temperature of the test area was continuously monitored in an additional vessel containing the same volume of dilution medium. A photoperiod of 16 hours light : 8 hours dark was maintained, with periods of subdued lighting at the beginning and end of each light phase. No supplementary aeration was employed and no feed was given during the exposure period.

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 0.482 mg/L

Nominal / measured:

meas. (arithm. mean)

Basis for effect:

mobility

Effect concentrations 2

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

ca. 0.482 mg/L

Nominal / measured:

meas. (arithm. mean)

Basis for effect:

mobility

Details on results:

No immobilisation or adverse effects on the Daphnia were noted.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

Diisoamyl phthalate was not found to be acutely toxic to Daphnia magna at measured concentrations up to 0.482 mg/L, which was considered to reflect the maximum achievable concentrations within the limit of solubility of the test substance.
Consequently, the 48-hour EC50 could not be calculated but must be >0.482 mg/L and the “no-observed effect concentration” was 0.482 mg/L.

Executive summary:

The acute toxicity of diisoamyl phthalate to Daphnia magna was assessed under static exposure conditions. The definitive test was conducted under sealed conditions without a headspace due to the volatile nature of the test substance.

The study was conducted in accordance with EC Methods for Determination of Ecotoxicity, Annex to Commission Regulation (EC) No 440/2008 (O.J. No. L142/456, 2008) Part C, Method 2 “Daphnia sp.Acute Immobilization Test” and the OECD Guideline for Testing of Chemicals No. 202, “Daphnia Acute Immobilization Test” (2004). 

A group of twenty Daphnia, less than 24 hours old, was exposed for 48 hours to diisoamyl phthalate at a nominal concentration of 1.0 mg/L, which approximated the limit of aqueous solubility of the substance under test conditions. The test medium was prepared in Elendt M4 medium by the direct addition of the test substance to the dilution medium; to aid dissolution, vigorous stirring was employed.

At the start of the test, the mean measured concentration of diisoamyl phthalate in the test medium approximated 20% of its nominal concentration; this level was maintained over the duration of the test, with a mean measured concentration of 83% of the starting value at
48 hours. The overall mean measured level of diisoamyl phthalate was 0.163 mg/L. As these concentrations were lower than expected, based on the measured levels achieved during a range finding test conducted under sealed conditions,the results of both phases of the study are reported to indicate the effects of diisoamyl phthalate on Daphnia magna at the maximum achievable concentration within the limit of its aqueous solubility.

Observations of the Daphnia in each control and test vessel were made after 24 and 48 hours. 

No immobilisation or adverse effects on the Daphnia were noted in either test.