Heptanoic anhydride

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2002

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

no

GLP compliance:

not specified

Analytical monitoring:

yes

Details on sampling:

Sampling schedule: Control at 72 hours and test concentration at 0, 24, 48 and 72 hours

Vehicle:

no

Test organisms (species):

Raphidocelis subcapitata (previous names: Pseudokirchneriella subcapitata, Selenastrum capricornutum)

Details on test organisms:

- Common name: Unicellular green algae
- Strain: ATCC22662
- Source: American Type Culture Collection
- Date of receipt: June 20, 1996
- Maintenance of obtained algae: Algae have been maintained by period subculture using Gorham medium and were kept under sterile condition; sterile test has been performed periodically, every six months, to confirm that the algae are not contaminated
- Conditions of preculture: Preculture period (August 30 to November 3, 2002); the algae were precultured under the same conditions as the test culture; neither modified nor unusual cells were confirmed

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Hardness:

No data

Test temperature:

23.4 - 24-2°C

pH:

5.7 - 9.8

Dissolved oxygen:

No data

Salinity:

n.a.

Nominal and measured concentrations:

Test concentration after 0 hrs (nominal): 10, 15, 22, 32, 46, 68 and 100 mg/L
Test concentration after 72 hrs: 7.9, 13.5, 19.2, 27.5, 39.9, 62.6 and 86.6 mg/L

Details on test conditions:

TEST CONDITIONS:
- Exposure procedure: static and shaking (100 rpm)
- Volume of test solutions: 100 mL/vessel
- Number of vessels: 3 vessels/test group
- Temperature: 23 ± 2 °C
- Initial biomass: 1 X 10E+4 cells/mL
- pH: not adjusted
- Light: 4000 lux, continuous illumination

APPARATUS AND INSTRUMENTS:
- Test Vessel: 300 mL capacity glass triangle plus (with the air permeability of the silicon plug).
- Culturing apparatus: AGP-150RL, Itoh Seisakusho, Ltd.
- Microscope: ECLIPSE TE300, Nikon Co., Ltd.
- Electronic particle counter: CDA-500, Sysmex Co., Ltd.
- Thermometer: TascoJapan made TNA-120 type
- Luminometer: Topcon made IM-2D type
- pH meter: HM-40V, Toa Electronics Corporation
- Electrobalance: AG204, Mettler K.K., AB204-S, Mettler K.K., PB3002, Mettler K.K., MS3002S, Mettler-Toledo K.K.

ANALYSIS (GC):
- Gas chromatograph: Hewlett Packard HP G1800A GCD (No.1)
- Auto sampler: 7673A
- Detector: EID (Electron Ionization Detector)
- Work station: HP GCD Chemstation
- Data analysis software: G1034C MS ChemStation

Reference substance (positive control):

yes

Remarks:

Potassium dichromate, reagent grade

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

32 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

56.4 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: 95% confidence limit: 36.9 - 86.4 mg/L

Results with reference substance (positive control):

- The latest value of 72 hours EbC50: 0.473 mg/L (95% confidence limit 0.163-1.37mg/L)
- This value is below EbC50 value in the Institute shown (since November 1996)
- The average values of EbC50 0.440±0.0784 mg/L, n=10 (Minimum-maximum: 0.285-0.543 mg/L)

The EC50 values and associated 95% confidence limits were determined by least squares linear regression analysis of the logarithm of test concentration against percent growth inhibition relative to the control. The NOEC values were determined by ananalysis of variance (ANOVA), Dunnett test subsequent to Bartlett test for homogeneity of variances.

Validity criteria fulfilled:

yes

Conclusions:

The toxicity of heptanoic acid (CAS 111-14-8) to algae was tested according to OECD guideline 201 'Alga, Growth Inhibition Test'. Heptanoic acid is the hydrolysis product of heptonoic anhydride. During 72 hours exposure an EC50(growth rate) of 56.4 mg/L and a NOEC of 32.0 mg/L were determined.

Executive summary:

The study was conducted in accordance with the OECD Guidelines for the Testing of Chemicals No.201 "Freshwater Alga and Cyanobacteria, Growth Inhibition Test" (2006). Test concentrations in the range between 10 and 100 mg/L were used to exposure heptanoic acid to the test species. During 72 hours an EC50(growth rate) of 56.4 mg/L and a NOEC of 32.0 mg/L were determined. This toxicity study is classified as acceptable and satisfies the guideline requirements for the Algae study.

Reference 2

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

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

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Justification for type of information:

Heptanoic acid was used as the read across source, as heptanoic anhydride hydrolyses in aqueos media.

Reason / purpose for cross-reference:

read-across source

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

32 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

56.4 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: 95% confidence limit: 36.9 - 86.4 mg/L

Description of key information

The toxicity of heptanoic acid (CAS 111-14-8) to algae was tested according to OECD guideline 201 'Alga, Growth Inhibition Test'. Heptanoic acid is the hydrolysis product of heptonoic anhydride. During 72 hours exposure an EC50 (growth rate) of 56.4 mg/L and a NOEC of 32.0 mg/L were determined.

Key value for chemical safety assessment

EC50 for freshwater algae:

56.4 mg/L

EC10 or NOEC for freshwater algae:

32 mg/L

Additional information

Heptanoic anhydride can be considered as hydrolytically instable in the pH range 2-10, which is of relevance for biological systems.

The half-life of 1.5 h was measured at pH 7.