1-(2,6-dimethylphenoxy)acetone

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:

15.11.1999 - 06.12.1999

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: The study was conducted in GLP compliance and in accordance with internationally acknowledged guidelines for testing of chemicals.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1999

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)

Test guideline 3

Qualifier:

according to guideline

Guideline:

EPA OPPTS 850.1010 (Aquatic Invertebrate Acute Toxicity Test, Freshwater Daphnids)

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

1-(2,6-dimethylphenoxy)acetone

EC Number:

258-292-2

EC Name:

1-(2,6-dimethylphenoxy)acetone

Cas Number:

53012-41-2

Molecular formula:

C11H14O2

IUPAC Name:

1-(2,6-dimethylphenoxy)propan-2-one

Sampling and analysis

Analytical monitoring:

no

Test solutions

Vehicle:

no

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Strain: Daphnia magna (Straus ), clone 5
- Sex: female
- Source: supplied 1997 by the Umweltbundesamt, Institut für Wasser-, Boden- und Lufthygiene, Berlin, Germany
- Age at study initiation (mean and range, SD): 6.5 - 22 hours
- Method of breeding: The Daphnia were bred in the laboratories of IBACON under similar temperature and light conditions as in the test, and in reconstituted water of a similar quality regarding to pH, components of the main ions and total hardness as the test water used in the test (see below). The test organisms were not first brood progeny.


ACCLIMATION
- Acclimation period: for 6.5 hours under test conditions

Study design

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Post exposure observation period:

none

Test conditions

Hardness:

2.5 mmol/L (= 250.0 mg/L) as CaC03

Test temperature:

21°C

pH:

pH 7.7 to 7.8

Dissolved oxygen:

at least 8.1 mg/L or higher

Nominal and measured concentrations:

4.6, 10, 21, 46 and 100 mg test substance/L (nominal)

Details on test conditions:

TEST SYSTEM
- Test vessel: glass beakers of 100 mL volume with 50 mL testmedium

- Aeration:
- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 2


TEST MEDIUM / WATER PARAMETERS
In deionized water (conductivity < 5 µScm-1 ) analytical grade salts were added to following nominal concentrations:
CaCl2 x 2H20 2.0 mmol/L (= 294.0 mg/L)
MgS04 x 7H20 0.5 mmol/L (= 123.0 mg!L)
NaHC03 0.75 mmol/L (= 65.0 mg/L)
KCl 0.075 mmol/L (= 5.8 mg!L)
Water Hardness: 2.5 mmol/L (= 250.0 mg/L) as CaC03
Alkalinity: 0.8 mmol/L
ratio of Ca : Mg = 4: 1 (based on molarity)
Na : K = 10: 1 (based on molarity)

OTHER TEST CONDITIONS
- Photoperiod: 16 h light: 8 h dark
- Light intensity: approximately 600 lux
- Surrounding Type: controlled environment room

TEST CONCENTRATIONS
- Range finding study: yes
- Test concentrations: 4.6, 10, 21, 46 and 100 mg test substance/L

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

10 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: immobility or mortality

Remarks on result:

other: Those animals not able to swim within 15 seconds after gentle agitation of the test beaker were considered to be immobile.

Effect concentrations 2

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

53.4 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: immobility or mortality

Remarks on result:

other: with 95 % eonfidence limits from 35.9 to 79.4 mg/L. Those animals not able to swim within 15 seconds after gentle agitation of the test beaker were considered to be immobile

Effect concentrations 3

Duration:

48 h

Dose descriptor:

EC100

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: mortality or immobilization

Remarks on result:

other: Those animals not able to swim within 15 seconds after gentle agitation of the test beaker were considered to be immobile

Effect concentrations 4

Duration:

48 h

Dose descriptor:

EC0

Effect conc.:

10 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: mortality or immobilization

Remarks on result:

other: Those animals not able to swim within 15 seconds after gentle agitation of the test beaker were considered to be immobile

Details on results:

Results after 24 hours: The 24-hour EC 50 and EC 100 of the test substanee were higher than 100 mg test substanee/L.
The 24-hour EC 0 was determined to be 46 mg test substanee/L.

Results with reference substance (positive control):

For the evaluation of the quality of the Daphnia clone and the experimental conditions the substance potassium dichromate p.A. (E. Merck, Darmstadt, Germany) is tested at least twice a year to demonstrate satisfactory test conditions.

Reported statistics and error estimates:

The 24-hour EC 50 and the 95 % confidence value could not be calculated due to the low toxic effect after 24 hours test duration. The 48-hour EC 50 was calculated by the Moving average interpolation. The NOEC, EC 0 and EC 100 were determined directly from the raw data.

Any other information on results incl. tables

Influence of 2,6-DMPA on the mobility of Daphnia magna

Concentration of the test substance	No. of Daphnia tested	No. of immobilized Daphnia after		% of immobilized Daphnia after
[mg/L]		24h	48 h	24h	48h
control	20	0	0	0	0
4.6	20	0	0	0	0
10	20	0	0	0	0
21	20	0	1	0	5
46	20	0*	9**	0	45
100	20	14*	17**	70	85

* a1l surviving Daphnia looked pale

** a1l surviving Daphnia showed mobilization only after gentle agitation of the test beakers

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The 48-hour EC 50 was calculated tobe 53.4 mg test substance/L with 95 % eonfidence limits from 35.9 to 79.4 mg/L. The 48-hour EC 0 and the 48-hour NOEC (highest eoneentration tested without toxie effects after 48 hours) of 2,6-DMPA were deterrrrined tobe 10 mg test substance/L, since no significant immobilization rate and no other signs of intoxication were observed at the test animals up to and including this test coneentration. The 48- hour EC 100 was high er than 100 mg test substance/L.