L-97-034-PB

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:

22nd - 24th July 1998

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1998

Report date:

1998

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Pentaerythritol mixed esters with 2-methyl butyric acid, n-pentanoic acid, n-heptanoic acid, 3,5,5-trimethylhexanoic acid, n-octanoic acid, n-decanoic acid

Cas Number:

141686-49-9

IUPAC Name:

Pentaerythritol mixed esters with 2-methyl butyric acid, n-pentanoic acid, n-heptanoic acid, 3,5,5-trimethylhexanoic acid, n-octanoic acid, n-decanoic acid

Constituent 2

Reference substance name:

Trimethylol propane mixed esters with 2-methyl butyric acid, n-pentanoic acid, n-heptanoic acid, 3,5,5-trimethylhexanoic acid, n-octanoic acid, n-decanoic acid

Cas Number:

141686-50-2

IUPAC Name:

Trimethylol propane mixed esters with 2-methyl butyric acid, n-pentanoic acid, n-heptanoic acid, 3,5,5-trimethylhexanoic acid, n-octanoic acid, n-decanoic acid

Test material form:

liquid

Details on test material:

Identification: Hatcol ® 1772
Appearance/physical state: Clear colorless liquid
Purity: 100% (no solvent present)
Composition: 70% pentaerythritol esters described by CAS# 141686-49-9; 30% trimethylolpropane esters described by CAS# 141686-50-2

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

Verification of Test Concentrations:
Samples were taken from the control and the 100 mg/l loading rate WAFs (replicates R1 - R2 and R3 - R4 pooled) at 0 and 48 hours for immediate quantitative analysis. Duplicate samples were taken at 0 and 48 hours and stored frozen for further analysis if necessary.

Test solutions

Vehicle:

no

Test organisms

Test organisms (species):

Daphnia magna

Study design

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Test conditions

Hardness:

Not reported

pH:

The pH was measured at the beginning and at the end of the test, for all concentrations and the control. The pH remained consistent at 8.0.

Dissolved oxygen:

The dissolved Oxygen content was measured at the beginning and at the end of the test, for all concentrations and the control. The dissolved oxygen content ranged from 8.1-8.4 mg/l

Salinity:

Not applicable

Conductivity:

Not applicable

Results and discussion

Effect concentrations

Effect concentrations 1

Key result

Duration:

24 h

Dose descriptor:

EL50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other:

Remarks:

There was no immobilisation in 40 daphnids exposed to a 100 mg/l loading rate WAF for a period of 48 hours.

Effect concentrations 2

Key result

Duration:

48 h

Dose descriptor:

EL50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other:

Remarks:

There was no immobilisation in 40 daphnids exposed to a 100 mg/l loading rate WAF for a period of 48 hours.

Effect concentrations 3

Key result

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Any other information on results incl. tables

Range-finding study

The results showed no immobilisation at the 10 and 100 mg/l loading rate WAFs. Preliminary work conducted for the validation of mixing period in ASTM medium (3), indicated there was no significant increase in the Total Organic Carbon (TOC) in the 200 mg/l loading rate WAF (compared to the control) after stirring for 144 hours. Therefore a 24 -hour mixing period with a 1 -hour settlement period was considered appropriate for the test.

Based on this information, a single loading rate, of four replicates, of 100 mg/l loading rate WAF was selected for the definitive study. This experimental design conforms to a 'Limit test' to confirm that the maximum test concentration given in the guidelines, no immobilisation or adverse reactions to exposure were observed.

Definitive study

Immobilisation data: There was no immobilisation in 40 daphnids exposed to a 100 mg/l loading rate WAF for a period of 48 hours. The No Observed Effect Concentration (NOEC) after 24 and 48 hours exposure was equal to 100 mg/l loading rate WAF. The NOEC is based upon zero immobilisation at this concentration.

Physico-chemical measurements: Temperature was maintained at 21 ± 1°C throughout the study, whilst there are no treatment related differences for oxygen or pH.

Vortex depth measurements: The vortex depth was recorded at the start and end of the mixing period and was observed to be 25% of the water column height.

Total Organic Carbon (TOC) analysis: Samples of the WAFs were taken for TOC analysis at 0 hours (fresh media) and 48 hours (old media). Given the background level of carbon in the control vessels and the low level of carbon in the test vessels, it was considered that all the results were around the limit of detection of the analytical method and hence did not provide definitive evidence of the stability of the test preparations.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The acute toxicity of the test item to the freshwater invertebrate Daphnia magna has been investigated and based on the nominal concentration gave a 48 hour EL50 value of greater than 100 mg/l loading rate WAF. Correspondingly the NOEC was equal to 100 mg/l loading rate WAF. The results based on the time-weighted mean measured test concentrations gave a 48-hour EL50 of greater than 0.40 mg/l. Correspondingly the NOEC was equal to 0.40 mg/l.

Executive summary:

Introduction

A study was performed to assess the acute toxicity of the test item to Daphnia magna. The method followed was designed to be compatible with the OECD Guidelines for Testing of Chemicals (1984) No 202, "Daphnia sp., Acute Immobilisation Test" referenced as Method C.2 of Commission Directive 92/69/EEC (which constitutes Annex V of Council Directive 67/548/EEC).

Procedures

Following a preliminary range-finding study, forty daphnids (4 replicates of 10 animals) were exposed to a Water Accommodated Fraction (WAF) of the test material at a nominal loading rate of 100 mg/l for 48 hours under static test conditions. Immobilisation and any adverse reactions to exposure were recorded after 24 and 48 hours.

Results

The 48 -hour EL50 for the test material to Daphnia magna based on nominal test concentrations was greater than 100 mg/l loading rate WAF and correspondingly the No Observed Effect Concentration was equal to 100 mg/l loading rate WAF.

Samples of the WAFs were taken at 0 hours (fresh media) and 48 hours (old media) for Total Organic Carbon (TOC) analysis. Given the background level of carbon in the control vessels and also the low level of carbon in the test vessels, it was considered that all the results were around the limit of detection of the analytical method and hence did not provide definitive evidence of stability of the test  preparations.

The concentrations of the components of the test material being taken into the water by the preparation of a WAF were expected to be low given the low water solubility of the test material. Analysis of the 100 mg/l loading rate WAF by a GC method at 0 hours showed measured concentrations of 0.658 and 0.674 mg/l for replicates R1 - R2 pooled and R3 - R4 pooled respectively. After 48 hours a decline in measured concentrations was observed giving values of less than the limit of quantitation of the analytical method.

These results were in-line with pre-study stability analysis performed on a 100 mg/l loading rate WAF which indicated loss of the test material in the test water after 48 hours as a result of adsorption of the test material to the glassware. The results which showed measured values of below the limit of quantitation were considered to be due to problems associated with analysis of WAFs where the amount of dissolved test material is close to the limit of quantitation of the analytical method employed. The measured concentrations were lower than those determined in the pre-study recovery and stability analyses performed on WAFs. This is considered to be due to variation in WAF preparation.

It was therefore considered justifiable to base the results on the time-weighted mean measured concentrations observed in the WAFs also. The 48 -Hour ELR50 based on the time-weighted mean measured concentrations was greater than 0.40 mg/l and correspondingly the No Observed Effect Concentration was equal to 0.40 mg/l.