Hexachlorocyclopentadiene

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1977

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

yes

Remarks:

Limited number of animals per concentration; low hardness

GLP compliance:

no

Specific details on test material used for the study:

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- Treatment of test material prior to testing: test compound dissolved in acetone

Analytical monitoring:

not specified

Details on sampling:

- Concentrations: 0.24 mg/L; 0.16 mg/L; 0.10 mg/L; 0.065 mg/L; 0.042 mg/L; 0.028 mg/L; 0.018 mg/L; 0.012 mg/L.

Vehicle:

yes

Remarks:

acetone

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: For each test concentration, the appropriate amount of test compound, dissolved in acetone, was pipetted into 500 ml of diluent water and mixed with a magnetic stirrer. The remaining 50 ml were used for 0-hour pH and DO determinations.
- Controls: Negative controls (same dilution water and conditions but with no test substance or acetone) and positive controls (containing greatest amount of acetone introduced into any one test vessel).
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): Acetone

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Water flea
- Source: Laboratory stocks cultured at Bionomics
- Age of parental stock: <= 24 hours

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

35 mg/L CaCO3

Test temperature:

21 ± 1 °C

pH:

7.1

Dissolved oxygen:

> 60% saturation

Nominal and measured concentrations:

Nominal concentrations (mg/L): 0.24; 0.16, 0.10; 0.065; 0.042; 0.028; 0.018; 0.012.

Details on test conditions:

TEST SYSTEM
- Test vessel: 250 ml beaker
- Material, size, headspace, fill volume: 250 ml beaker containing 150 ml test solution
- Aeration: Test solutions were not aerated during the tests
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 3

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Well water was used to culture the water fleas. Prior to the test, diluent water was filtered through polyester fiber and sterilized with an ultraviolet light to remove any microorganisms.
- Intervals of water quality measurement: Dissolved oxygen concentration, pH and temperature of test solutions were checked at 0 and 48 hours in the highest, middle and lowest test concentrations, at a minimum.

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : percentage mortality at 24 and 48 hours

VEHICLE CONTROL PERFORMED: yes

RANGE-FINDING STUDY
- Test concentrations: The preliminary test defined a narrower range of concentrations to be used in the definitive test which would then assess the dose-response relationship and permit calculation of an LC50 and its 95% confidence interval from the mortality data produced.

Reference substance (positive control):

no

Duration:

24 h

Dose descriptor:

LC50

Effect conc.:

0.13 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Key result

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

0.039 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

0.018 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Details on results:

- Other biological observations: All dead water flea observed during this exposure were carrying a partially attached carapace, suggesting the organisms died while attempting to moult.
- Mortality of control: No mortality
- Other adverse effects control: No effects

Reported statistics and error estimates:

LC50 (24hr) = 0.068 - 0.26 mg/L (95% confidence interval)
LC50 (48hr) = 0.030 - 0.052 mg/L (95% confidence interval)

Table showing concentrations tested and corresponding average observed percentage mortalities for the water flea (Daphnia magna) exposed to hexachlorocyclopentadiene:

Nominal concentration (mg/L)	Average percentage mortality
	24 hr	48 hr
0.24	87	100
0.16	33	100
0.10	33	100
0.065	40	93
0.042	7	57
0.028	0	20
0.018	0	0
0.012	0	0
control (acetone)	0	0
control	0	0

Validity criteria fulfilled:

yes

Conclusions:

The 48 hr LC50 of hexachlorocyclopentadiene for Daphnia magna was 0.039 mg/L.

Executive summary:

The short-term toxicity of hexachlorocyclopentadiene to the freshwater invertebrate species Daphnia magna was determined using a procedure equivalent to the OECD Guideline for Testing of Chemicals 202, with acceptable restrictions. The study determined the average percent mortality over a range of concentrations between 0.012 - 0.24 mg/L. It was determined that the 48 hr LC50 of the registered substance was 0.039 mg/L.

Description of key information

Two non-GLP short-term toxicity studies were performed according to a method similar to the OECD Testing Guideline 202 on Daphnia magna. The lowest 48-hour EC50 was 0.039 mg/l. It was selected as the key value as it represents a worst-case scenario.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

0.039 mg/L

Additional information

The short-term toxicity of the registered substance to marine invertebrates was not investigated as part of this REACH Registration. It was not considered as relevant taking into account the uses of the substance.