Hydroxyl-2-pyridone

Short-term toxicity to fish

Administrative data

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

1994-05-20 to 1994-06-09

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 203 (Fish, Acute Toxicity Test)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.1 (Acute Toxicity for Fish)

Deviations:

no

Test guideline 3

Qualifier:

according to guideline

Guideline:

EPA OPP 72-1 (Fish Acute Toxicity Test)

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: 93100020

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: at ambient temperature in the original container until required.
- Stability under test conditions: not specified

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

- Sampling method: 4 samples for possible analysis were taken from all test concentrations and the control at t=0 and t=96h. 20 mL of volume was taken from the approximate centre of the test vessels. On each occasion, two of the samples were analysed immediately and the other two were stored in a a refrigerator in case further analysis was required. Dilution water, either fresh or taken from the control vessels, served as blanks during analysis
- Sample storage conditions before analysis: two of the samples were analysed immediately and the other two were stored in a a refrigerator in case further analysis was required. The samples of aqueous test media (20 mL) were diluted with HPLC mobile phase and the concentrations of Oxypyrion in these solutions determined by high performance liquid chromatoraphy (HPLC) with a spectrophotometric detector

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: The test medium was prepared in duplicate. Each batch was prepared from a concentrated aqueous dispersion (2L) in which Oxypyrion (nominally 5 g) had been added to water; this was diluted in a test vessel to a final volume of fifty litres.
- Evidence of undissolved material (e.g. precipitate, surface film, etc.): All aqueous solutions were clear and colourless

Test organisms

Test organisms (species):

Lepomis macrochirus

Details on test organisms:

TEST ORGANISM
- Common name: Bluegill Sunfish
- Source: Aquatic Research Organisms, New Hampshire, USA. The fish were reared at Osage Catfisheries Inc., Missouri, USA.
- Length at study initiation (length definition, mean, range and SD): mean length 4.6 cm
- Weight at study initiation (mean and range, SD): mean weight 1.6 g
- Feeding during test: no. The fish were last fed ~ 20 hours before the start of the definitive test.

ACCLIMATION
- Acclimation period: at least 14 days after delivery in an aerated supply of dilution water under flow-through conditions
- Acclimation conditions (same as test or not): yes
- Monitored water quality during the 14 day holding period:
* Temperature: 21.1 - 21.4 °C
* pH values: 7.5 - 7.7
* DO (% ASV): 88-100%
* water hardness: 58 - 67 mg/L CaCO3

- Type and amount of food: pelleted fish food, supplemented with live Daphnia magna when available
- Feeding frequency: daily
- Health during acclimation (any mortality observed): mortality less than 1%, 14 days before test

Study design

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

96 h

Test conditions

Hardness:

54-56 mg/L as CaCO3

Test temperature:

20.9-22.2 °C

pH:

At t= 0h: 7.4-7.7
At t= 96h: 6.2-7.2

Dissolved oxygen:

85-100 % Air Saturation Value

Salinity:

not relevant

Nominal and measured concentrations:

Final test
Nominal concentrations: 0 and 100 mg/L
Measured concentrations (mg/L)* at t=0h: n.d., 96.12
Measured concentrations (mg/L)* at t=96h: n.d., 99.50

* average of 2 replicates

Details on test conditions:

TEST SYSTEM
- Test vessel: all-glass aquaria
- Material, size, headspace, fill volume: 80L, all-glass filled with 50 litres
- Aeration: gently aerated during the test
- No. of organisms per vessel: 15
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 2

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. This water was held in an intyermediate tank were it was equilibrated to the test temperature and gently aerated before being supplied to the holding and test areas.
- 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
- Adjustment of pH: no adjustment
- Photoperiod: 16h light daily

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : Fish were considered to be dead when no reaction was observed after touching the caudal peduncle and visible breathing movements were absent. In addition, fish that were convulsing or showing other severe forms of distress not considered transient in nature and likely to become more severe before the exposure is terminated, will be sacrificed for humane reasons. These fish will be treated as having died in the test, based on OECD guideline on humane endpoint (ENV/JM/MONO/(2000)7).

TEST CONCENTRATIONS
- Range finding study: combined/range finding study was performed
- Test concentrations: 0.10, 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

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 97.8 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

- Other biological observations:
* rangefinding test: no effects were observed
* limit test: one fish died between 24 and 48 hrs, no other mortalities occured. From 48 hrs onwards, seven fish (23%) exhibited minor sublethal effects which comprised darkened pigmentation. One fish exhibited lethargy but thatwas not sustained.
- Mortality of control: none
- Other adverse effects control: none

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The acute toxicity of Oxypyrion to Bluegill Sunfish was determined in a 96-hour static test according to the OECD guideline 203.
Under the conditions of the present study, the 96-h LC50 was greater than 97.8 mg/L based on mean measured concentrations (95% confidence interval not determined). The results of the test can be considered reliable without restriction.