Hydroxyl-2-pyridone

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:

1994-05-31 to 1994-07-14

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1995

Report date:

1995

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Deviations:

no

Test guideline 3

Qualifier:

according to guideline

Guideline:

EPA OPP 72-2 (Aquatic Invertebrate Acute Toxicity Test)

Deviations:

no

Test guideline 4

Qualifier:

according to guideline

Guideline:

other: US EPA Hazard Evaluation Division, Standard Evaluation Procedure: Acute Toxicity test for freshwater invertebrates. EPA-540/9-85-005, june 1985

Deviations:

no

Test guideline 5

Qualifier:

according to guideline

Guideline:

other: Stephan, C.E. (1977) Methods for calculating an LC50. Aquatic toxicology and hazard evaluation, ASTM STP 634

Deviations:

no

Test guideline 6

Qualifier:

according to guideline

Guideline:

other: Stephan, C.E. (1982) a computer program for calculating an LC50. US Envirnmental Protection agency.

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Hydroxyl-2-pyridone

EC Number:

212-506-0

EC Name:

Hydroxyl-2-pyridone

Cas Number:

822-89-9

Molecular formula:

C5H5NO2

IUPAC Name:

1-hydroxy-1,2-dihydropyridin-2-one

Test material form:

solid: particulate/powder

Details on test material:

- Name of test material (as cited in study reports): Oxy PYRION
- Physical state: solid (powder)
- Appearance: white speckled gold powder

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: batch number 93100020

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: at ambient temperature in the original container
- Stability under test conditions: no data

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

- Sampling method: samples for possible analysis were taken form all test concentrations and the control at t=0 and t=48h. 20 mL of volume was taken from the approximate centre of the test vessels. At the end of the exposure period, the replicates were pooled at each concentration before sampling
- Sample storage conditions before analysis: Additionally, reserve samples of 20 mL were taken for possible analysis. The samples of aqueous test media (20 mL) were diluted with HPLC mobile phase and the concentrations of Oxypyrion in these samples were determined by high performance liquid chromatography (HPLC) using a spectrophotometric detector

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: a stock solution nominally containing Oxypyrion at 100 m/L was prepared by adding the test material directly to the dilution water. It was either used directly (at highest test level) or diluted to provide the test media at the five lower concentrations (7.78 - 60 mg/L)
- Evidence of undissolved material (e.g. precipitate, surface film, etc): final test solutions were clear and colourless

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Water-flea
- Strain: Daphnia Magna
- Source: University of Sheffield, daphnia maintained in parthenogenetic culture at the Aquatic Studies Laboratories of Pharmaco LSR since 3 August 1989
- Age at study initiation (mean and range, SD): <24h (from parental daphnids of more than 2 weeks old)
- Culture: kept in temperature controlled laboratory nominally maintained at 20 ± 2 °C. Photoperiod of 16h light and 8 hrs darkness. The water (1.5 L) in each culture vessel was replaced at intervals of two weeks with fresh water of the correct temperature. A max. of 20 adult Daphnia were maintained in each culture vessel and juviniles which were produced were removed at least twice each week.
- Feeding during test: no

ACCLIMATION
- Acclimation period: not reported
- Acclimation conditions (same as test or not): yes
- Type and amount of food: fresh water algae (chlorella vulgaris) and yeast.
- Feeding frequency: 5 times each week
- Health during acclimation (any mortality observed): no

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Test conditions

Hardness:

57 mg/L as CaCO3 (alkalinity 50 mg/L CaCO3)

Test temperature:

20.5 - 21.1 °C

pH:

Control medium: 7.5-8.0
At t= 0h: 6.7-7.5
At t= 48h: 7.5-8.2

pH was not adjusted nor controlled during the test

Dissolved oxygen:

98-100 % Air Saturation Value

Nominal and measured concentrations:

Final test
Nominal concentrations: 0, 7.78, 13.0, 21.6, 36.0, 60.0 and 100 mg/L
Measured concentrations (mg/L)* at t=0h: 6.87, 12.45, 19.90, 35.6, 58.15, 98.65
Measured concentrations (mg/L)* at t=48h: 7.40, 12.9, **, 37.95, 62.9, 104,50

*average of 2 replicates
**samples taken from wrong vessel so results were invalid and not reported

exposure concentrations were achieved between 88% and 99% of their nominal values and adequately maintained

Details on test conditions:

TEST SYSTEM
- Test vessel: beaker
- Material, size, headspace, fill volume: 150 mL, crystallising dish covered with a watch glass
- Aeration: not during the test
- Type of flow-through (e.g. peristaltic or proportional diluter): no flow-through
- Renewal rate of test solution (frequency/flow rate): no renewal, static system
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: treated tap water. Treatment involved blending tap water previously filtered through activated carbon to remove chlorine, with tap water, which has been softened and treated by reverse osmosis. In the holding and test areas this water was further blended with a supply of softened water treated by reverse osmosis to reduce hardness to 40-75 mg/L as CaCO3. The required volume was held in the test area overnight in a glass aspirator to allow it to equilibrate to the test temperature.
- Metals: Cd < 0.005 mg/L; Cu = 0.05 - 0.1 mg/L; Pb < 0.05 mg/L: Mercury < 0.0001 mg/L; Ni < 0.1 mg/L; Tin = 0.003 - 0.1 mg/L; Zn = 0.03 - 0.07 mg/L
- Pesticides: < 0.1 µg/L
- Chlorine: 26-28 mg/L (as chloride)
- Ca/Mg ratio: 87-93 mg/L / 3.7-4.1 mg/L (26:1)
- Salinity: Na = 12-13 mg/L; K = 2.0-2.1 mg/L (6:1)
- Culture medium different from test medium: no

OTHER TEST CONDITIONS
- Photoperiod: 16h light daily

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : Immobility was defined as those organisms which are not able to swim within 15 seconds after gentle agitation of the test container and was monitored after 24 and 48 hours of continuous treatment with the test substance.

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 1.6
- Range finding study
- Test concentrations: 0.1, 1.0, 10 and 100 mg/L
- Results used to determine the conditions for the definitive study: yes

Reference substance (positive control):

not specified

Results and discussion

Effect concentrations

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

78.6 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: CL 95%: 60.5-102 mg/L

Details on results:

- Mortality of control: none
- Other adverse effects control: no
- Abnormal responses: none
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: none
- 48-h EC10 = 60.5 mg/L
- 48-h EC100 = 102 mg/L

Reported statistics and error estimates:

Median effect concentrations were calculated by the computer program of Stephan et. al which used the number of Daphnia exposed and the number immobile at each mean measured Oxypyrion cencentration.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The acute toxicity of Oxypyrion to Daphnia magna was determined in a 48-hour static test according to the OECD guideline 202.
Based on geometric mean measured test concentrations, the 48-h EC50 was determined to be 78.6 mg/L (95% CL 60.5-102 mg/L). The results of the test can be considered reliable without restrictions.