2,2,4(or 2,4,4)-trimethyladipic acid

Long-term toxicity to aquatic invertebrates

Administrative data

Endpoint:

long-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1994-01-12 to 1994-02-03

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1994

Report date:

1994

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: OECD 202, part 2 (1984)

Deviations:

yes

Remarks:

(see below, Overall remarks)

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

2,2,4(or 2,4,4)-trimethyladipic acid

EC Number:

258-556-7

EC Name:

2,2,4(or 2,4,4)-trimethyladipic acid

Cas Number:

53445-37-7

Molecular formula:

C9H16O4

IUPAC Name:

2,2,4-trimethylhexanedioic acid; 2,4,4-trimethylhexanedioic acid

Details on test material:

2,2,4(or 2,4,4)-Trimethyladipic acid of Hüls AG, produced 25 March 1992. Sample from continuous production, storage tank FA 975.
Purity 90 % w/w, sample ID 3630/81389, sample No. 1324/920707

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

MONITORING OF TEST SUBSTANCE CONCENTRATION
- For 25 and 50 mg/l (nominal) on days 0, 9, and 14 (fresh solutions) and 2, 12, and 16 (before renewal). 
- For 100 mg/l (nominal) only on days 0 and 2. Concentrations at 6 and 12 mg/l were below the detection limit.

Test solutions

Vehicle:

no

Details on test solutions:

STOCK AND TEST SOLUTION AND THEIR PREPARATION
- 1.1 g test substance were dissolved in 1 litre of deinized water

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISMS
- Strain: Daphnia magna, clone 5
- Source/supplier: Hüls AG (inhouse)
- Breeding method: In M4 medium (Elendt, 1990), water renewal each 2-3  days, isolation of offspring for further breeding each ca. 4 weeks
- Age: < 24 hours on day 0
- Feeding: Scenedesmus subspicatus, daily as much as consumed
- Pretreatment: Removal of adults 24 h prior to testing

Study design

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

21 d

Test conditions

Test temperature:

21 +- 1 °C

pH:

pH: 7.0-7.6 (0-25 mg/l); 5.9-7.3 (50 mg/l) (6 determinations per concentration, no data reported for 100 mg/l)

Dissolved oxygen:

94-101 % saturation (6 determinations per  concentration, no data reported for 100 mg/l)

Nominal and measured concentrations:

Concentrations: 6; 12; 25; 50; 100 mg/l (nominal)
For measured concentrations see below (Remarks on results)

Details on test conditions:

DILUTION WATER
- Synthetic freshwater according to Elendt (1990)

TEST SYSTEM
- Renewal of test solution: Each Monday, Wednesday, and Friday
- Exposure vessel type: 150 ml beakers with approx. 80 ml test solution
- Number of replicates, individuals per replicate: 10 replicates + 2  spare replicates (to substitute males if required) with 1 individual each
- Controls: as above, but without test substance
- Adjustment of pH: no
- Photoperiod: 16 hours 1000 Lux / 8 hours 100 Lux

FEEDING
- Daily with Scenedesmus subspicatus; days 0-6: 5.0E+06 cells/animal daily; days 7-21: 1.0E+07 cells/animal daily

Reference substance (positive control):

not specified

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

22 d

Dose descriptor:

NOEC

Effect conc.:

50 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

reproduction

Effect concentrations 2

Duration:

22 d

Dose descriptor:

LOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks on result:

other: all parent animals died

Details on results:

At 50 mg/L, 4 % inhibition of the reproduction rate was determined. However, this deviation from the controls proved to be not significant. Hence the NOEC was determined as 50.0 mg/L.

Any other information on results incl. tables

- Nominal/measured concentrations (HPLC/UV): 
  25 / 50 / 100 mg/l nominal
  24 / 49 /  93 mg/l mean of measured (fresh solutions)
  25 / 52 / 103 mg/l measured, day 2, solution with daphnia
  26 / 52 /n.d. mg/l measured, day 12, solution with daphnia
  26 / 52 /n.d. mg/l measured, day 16, solution with daphnia
  20 / 46 / 101 mg/l measured, day 2, solution without daphnia
  24 / 49 /n.d. mg/l measured, day 12, solution without daphnia
  24 / 45 /n.d. mg/l measured, day 16, solution without daphnia
  n.d. = not determined. All analytical values were within +- 20 % of  nominal. 

Thus the evaluation was based on nominal concentrations. 

- Effect data (Immobilisation and reproduction): 
  --------------------------------------------------------
  Concentration   Mortality   Offspring/adult   Inhibition
  --------------------------------------------------------
    0 mg/l             0 %      56 +- 10            0 %
    6 mg/l             0 %      62 +-  9          -10 %
   12 mg/l             0 %      62 +- 12          -11 %
   25 mg/l             0 %      55 +- 13            2 %
   50 mg/l             0 %      54 +- 11            4 %
  100 mg/l           100 %       0 +-  0          100 %
  --------------------------------------------------------
  Inhibition at 25 and 50 mg/l was not significant (t-test, alpha = 0.05)

Applicant's summary and conclusion

Validity criteria fulfilled:

not specified

Conclusions:

The NOEC (reproduction) of 2,2,4(or 2,4,4)-trimethyladipic acid was determined as 50 mg/L indicating a chronic hazard to aquatic invertebrates

Executive summary:

The chronic effects of 2,2,4(or 2,4,4)-trimethyladipic acid on Daphnia magna were investigated by Hüls AG (1994) according to OECD 202, part 2 (1984). Five concentrations ranging from 6 to 100 mg/L were tested over a period of 21 days. Mortality of the parent animals and the reproduction rate were studied. No effects on mortality and reproduction were observed at 50 mg/L. The following endpoints were derived:

NOEC (reproduction): 50 mg/L

The study was assessed as "reliable without restrictions".