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Ecotoxicological information

Short-term toxicity to aquatic invertebrates

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Administrative data

Endpoint:
short-term toxicity to aquatic invertebrates
Type of information:
experimental study
Adequacy of study:
key study
Study period:
28 to 30 July 1982
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Well reported, good quality study to GLP; considered adequate for assessment
Cross-reference
Reason / purpose:
reference to same study

Data source

Referenceopen allclose all

Reference Type:
study report
Title:
Unnamed
Year:
1983
Report Date:
1983
Reference Type:
secondary source
Title:
Unnamed
Year:
2000

Materials and methods

Test guideline
Qualifier:
no guideline followed
Principles of method if other than guideline:
Immobilisation of the freshwater crustacean, Daphnia magna, assessed following exposure to Chlorowax 500C (a C10-12 chlorinated paraffin; 58% chlorination) for 48 h.
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): Chlorowax 500C
- Substance type: technical product
- Physical state: liquid
- Analytical purity: "100% chlorinated paraffin"
- Impurities (identity and concentrations): free HCl, 7 ppm; no stabiliser
- Composition of test material, percentage of components: C10-12 chlorinated paraffin (58% chlorination)
- Lot/batch No.: R201-198
- Expiration date of the lot/batch: "dependent on routine analysis"
- Radiochemical purity (if radiolabelling): >98%
- Specific activity (if radiolabelling): 47 mCi/mmol
- Locations of the label (if radiolabelling): chlorinated n-undecane-6-14C
- Expiration date of radiochemical substance (if radiolabelling): no data
- Stability under test conditions: unstable
- Storage condition of test material: -20 degrees C
Specific details on test material used for the study:
Details on properties of test surrogate or analogue material (migrated information):
not relevant

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
Samples (3.0 mL) were taken of each test solution and analysed for C-14 concentration by liquid scintillation counting. At the end of the test, two replicates of each control and treatment were sampled and analysed in the same manner.
[On each occasion, samples were analysed from the control and solvent control to ensure that the count lay within 3 standard deviations of the background count for the scintillation counter].
Parent compound analysis was also conducted. At the start of the test, samples (250 ml) were taken from the control, 18, 100 and 560 ug/L nominal concentrations and extracted with hexane (30 ml) in an upwards displacement liquid/liquid extraction apparatus.

Test solutions

Vehicle:
yes
Details on test solutions:
The chlorinated paraffin was mixed with the 14C-labelled chlorinated n-undecane by dissolving accurately weighed quantities of both compounds in acetone and mixing known volumes together. Individual stock solutions were prepared which, when diluted with water, would give the required total chlorinated paraffin concentration. The radioactivity in the test solutions was proportional to the total concentration of chlorinated paraffin. The minimum nominal activity of the solutions was 0.58 Bq/ml.

Test organisms

Test organisms (species):
Daphnia magna
Details on test organisms:
TEST ORGANISM
- Common name: freshwater flea
- Strain: Daphnia magna Straus
- Source: continuous laboratory cultures
- Age at study initiation (mean and range, SD): <24 h old
- Method of breeding: diploid parthenogenesis
- Feeding during test: no

ACCLIMATION
- Acclimation period: none

Study design

Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
48 h
Remarks on exposure duration:
Assessments carried out after 24 and 48 h
Post exposure observation period:
none

Test conditions

Hardness:
177 mg CaCO3/l
Test temperature:
20+/-1 degree C (range 19.1-20.7 degree C, mean 19.8 degree C); temperature measured daily by thermometer and twice/h by automatic recorder in an additional vessel, identical to and situated amongst the test vessels, but containing only dilution water without Daphnia magna
pH:
control: pH 8.28 at start and pH 8.20-8.28 at the end of the test from 2 replicates
solvent control: pH 8.10 at start and pH 8.25-8.28 at the end of the test from 2 replicates
test solutions: pH 8.00-8.12 at start and pH 8.32-8.35 at the end of the test from 2 replicates
Dissolved oxygen:
control: 8.80-9.15 mg/L at the end of the test from 2 replicates
solvent control: 8.60-8.65 mg/L at the end of the test from 2 replicates
test solutions: 8.60-9.20 mg/L at the end of the test from 2 replicates
Salinity:
no data
Nominal and measured concentrations:
Nominal concentrations: 18, 32, 56, 100, 180, 320, 560 ug/L
Measured concentrations at 0 and replicate 48 h: 11-13, 22-26, 39-47, 68-82, 130-160, 240-270, 370-450 ug/L
Mean of the initial and final (mean of 2 replicates) measured concentrations: 12, 24, 43, 75, 145, 255, 415 ug/L (See Table 1 under "Any other information materials and methods incl. tables" below).
Control, solvent control and 18, 100 and 560 ug/L nominal test concentrations were also used to measure the test concentration by parent compound analysis. It was recognised that the method was relatively inaccurate but was the only available analytical technique specific for chlorinated paraffins. Concentrations of chlorinated paraffin measured as parent compound in the test solutions were <5, <5, 20, 100 and 600 ug/l respectively and by 14C analysis in the final hexane extracts were 13, 85 and 430 ug/l for the 18, 100 and 560 ug/L samples respectively.
Details on test conditions:
TEST SYSTEM
- Test vessel: beakers
- Type (delete if not applicable): closed - loose fitting lids
- Material, size, headspace, fill volume: borosilicate glass beakers, 250 mL nominal capacity
- Aeration: >12 h before use
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4
- No. of vessels per vehicle control (replicates): 4
- Biomass loading rate: no data

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: reconstituted water medium
- Total organic carbon: 0.9 mg/l
- Metals: cadmium 0.2 ug/l, copper 1.0 ug/l, cobalt <1.0 ug/l, iron 4.0 ug/l, lead <0.5 ug/l, manganese 0.8 ug/l, nickel <0.5 ug/l, zinc 2.0 ug/l
- Alkalinity: 122 mg/l
- Conductivity: 500 uS/cm
- Culture medium different from test medium: No
- Intervals of water quality measurement: No data

OTHER TEST CONDITIONS
- Photoperiod: 16 h light/8 h dark

EFFECT PARAMETERS MEASURED (with observation intervals if applicable): Immobilisation after 24 and 48 h (Each Daphnia magna was viewed by eye and was defined as immobile if showing no whole body movement relative to the water within a period of 10 seconds, even if movement of individual appendages was visible).

TEST CONCENTRATIONS
- Test concentrations (nominal): 0, 18, 32, 56, 100, 180, 320 and 560 ug/L
- Results used to determine the conditions for the definitive study: no data
Reference substance (positive control):
no

Results and discussion

Effect concentrations
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
530 µg/L
Nominal / measured:
estimated
Conc. based on:
test mat.
Basis for effect:
mobility
Remarks on result:
other: 95% cCL 355-1540 ug/L
Details on results:
Flotation of Daphnia magna (either just below or on the surface) was observed in certain of the solutions containing the test substance and was most pronounced at nominal concentrations of 100 ug/L and above. After 24 h, no Daphnia were immobilised and all those floating were resubmerged with drops of the test solution. After 48 h, significant flotation had re-occurred at a nominal concentration of 180 ug/L and above and concentration related immobilisation was observed. Those Daphnia neither floating nor immobilised were observed to display somewhat erratic and reduced swimming activity at all concentrations except 18 ug/L (see Table 2 below for details)

Results with reference substance (positive control):
not applicable
Reported statistics and error estimates:
The values obtained for the 48 h EC50 for immobilisation were calculated by probit analysis and based on the mean measured concentrations of the test substance.

Any other information on results incl. tables

It was noted that the EC50 value was greater than the maximum measured concentration tested since the test substance caused the Daphnia magna to float, on or near the surface of the solution, at measured concentrations of approximately 75 ug/L and above.

Table 2. Percentage of immobolised and floating Daphnia at 24 and 48 h

Time (hours)

Nominal concentration (ug/l)

Total number tested

% Immobilised

% Floating

24

control

20

0

0

solvent control

20

0

0

18

20

0

5

32

20

0

0

56

20

0

15

100

20

0

35

180

20

0

65

320

20

0

100

560

20

0

90

48

Control

20

0

0

Solvent control

20

0

0

18

20

0

0

32

20

0

0

56

20

0

0

100

20

5

5

180

20

5

45

320

20

25

20

560

20

40

5

Applicant's summary and conclusion

Validity criteria fulfilled:
not applicable
Conclusions:
The 48 h EC50 for immobilisation of Chlorowax 500C (a C10-12 chlorinated paraffin; 58% chlorination) to the freshwater crustacean, Daphnia magna, was estimated to be 530 µg/L, based on measured concentrations.
Executive summary:

In a well reported, good quality study to GLP, the acute toxicity of Chlorowax 500C (a C10-12 chlorinated paraffin; 58% chlorination) to the freshwater crustacean, Daphnia magna, was determined in a static system. Groups of 20 Daphnia, aged <24 h, were exposed to nominal concentrations of 0, 18, 32, 56, 100, 180, 320 or 560 µg/L for up to 48 h. The Daphnia were not fed during the course of the test and immobilisation was assessed after 24 and 48 h.

The 48 h EC50 for immobilisation to Daphnia magna was estimated, based on measured concentrations, to be 530 µg/L (95% CL 355-1540 µg/L). This value was in excess of the maximum measured concentration tested of 415 µg/L, since the test substance caused the Daphnia to float, on or near the surface of the solution, at measured concentrations of approximately 75 µg/L and above.