Registration Dossier

Ecotoxicological information

Short-term toxicity to fish

Currently viewing:

Administrative data

Link to relevant study record(s)

Referenceopen allclose all

Endpoint:
short-term toxicity to fish
Type of information:
experimental study
Adequacy of study:
key study
Study period:
Between 21 February 2001 and 9 march 2001.
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: GLP study conducted in compliance with agreed test protocols following OECD Guidelines without deviations. Acceptable restrictions such as lack of test material analyses are not expected to have a major impact on the test result.
Qualifier:
according to guideline
Guideline:
OECD Guideline 203 (Fish, Acute Toxicity Test)
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Analytical monitoring:
no
Details on sampling:
No data available.
Vehicle:
no
Details on test solutions:
Five water accommodated fractions (WAF) were prepared by direct addition of weighed test substance to 21 L of test water to give nominal concentrations of:  3.2, 5.6, 10, 18 and 32 mg/L.  Each mixture was stirred, by magnetic stirrer, for 24 hours then allowed to settle for 2 hours. The water phase was siphoned through a glass tube containing a glass wool plug (discarding the first 75-100 mL) to produce a WAF with little, or no insoluble residues.  The glass wool was pre-conditioned by soaking overnight in deionized, reverse osmosis water, rinsing 3X and autoclaving.
Test organisms (species):
Oncorhynchus mykiss (previous name: Salmo gairdneri)
Details on test organisms:
TEST ORGANISM
- Common name: Rainbow Trout
- Source: Fish were obtained from Donnington Fish Farm, Upper Swell, Gloucestershire, UK and maintained in-house.
- Age at study initiation (mean and range, SD): Juvenile (no further data available)
- Length at study initiation (length definition, mean, range and SD): 4.2 cm (sd = 0.1) at study end.
- Weight at study initiation (mean and range, SD): 0.70 g (sd = 0.15) at study end.
- Method of breeding: not specified
- Feeding during test: feeding discontinued ca. 24 h prior to start of definitive test.


ACCLIMATION
- Acclimation period: from 19 February 2001 to 5 March 2001.
- Acclimation conditions (same as test or not): as test
- Type and amount of food: commercial trout pellets
- Feeding frequency: ad lib on a daily basis
- Health during acclimation (any mortality observed): zero mortality in the 7 days prior to the start of the test.


QUARANTINE (wild caught): Not applicable.
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
96 h
Post exposure observation period:
Mortalities and sub-lethal effects were recorded at 3, 6, 24, 48, 72 and 96 hours.
Hardness:
Approximately 100 mg/L as CaCO3
Test temperature:
Approximately 14 oC
pH:
7.6-7.7
Dissolved oxygen:
7.8-10.3 mg/L (control) and 7.8-10.2 mg/L (test).
Salinity:
Not applicable, it is a freshwater test.
Nominal and measured concentrations:
Nominal concentrations: 3.2, 5.6, 10, 18 and 32 mg/L were used in the definitive test.
Details on test conditions:
TEST SYSTEM
- Test vessel:
- Type (delete if not applicable): covered
- Material, size, headspace, fill volume: 20Litre
- Aeration: yes, via narrow bore glass tubes
- Type of flow-through (e.g. peristaltic or proportional diluter): not applicable.
- Renewal rate of test solution (frequency/flow rate): not applicable.
- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates):1
- No. of vessels per control (replicates):1
- No. of vessels per vehicle control (replicates):N/A
- Biomass loading rate: Based on the mean weight value this gave a loading rate of 0.35 g bodyweighvlitre.


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Laboratory tap water was dechlorinated by passage through an activated carbon filter (Purite Series 500) and partly softened (Elga Nimbus 1248D Duplex Water Softener) giving water with a total hardness of approximately 140 mg/l as CaCO3. After dechlorination and softening the water was then passed through a series of computer controlled plate heat exchangers to achieve the required temperature.
Typical water quality characteristics for the tap water as supplied, prior to dechlorination and softening
- Total organic carbon: 2 mg C/1
- Particulate matter: 0.2 mg/l.
- Metals: various present, none above prescribed concentration values
- Pesticides: none above prescribed concentration values
- Chlorine: 0.16 mg/l
- Alkalinity: 92 mg/l
- Ca/mg ratio: 5
- Conductivity: 1500 uS/cm
- Culture medium different from test medium: Same
- Intervals of water quality measurement: no data available.


OTHER TEST CONDITIONS
- Adjustment of pH: no data available.
- Photoperiod: 16 hours light and 8 hours darkness with 20 minute dawn and dusk transition periods
- Light intensity: no data available.


EFFECT PARAMETERS MEASURED (with observation intervals if applicable): Mortality and sub-lethal effects
Reference substance (positive control):
no
Duration:
96 h
Dose descriptor:
LL50
Effect conc.:
ca. 24 mg/L
Nominal / measured:
nominal
Conc. based on:
other: Water accomodated fraction
Basis for effect:
mortality (fish)
Remarks on result:
other: 18-32mg/L WAF
Duration:
96 h
Dose descriptor:
NOELR
Effect conc.:
ca. 3.2 mg/L
Nominal / measured:
nominal
Conc. based on:
other: Water accomodated fraction
Basis for effect:
mortality (fish)
Remarks on result:
other: 3.2 mg/l loading rate WAF
Details on results:
- Behavioural abnormalities: Sub-lethal effects of exposure were observed at the 5.6 mg/l loading rate WAF and above. These responses were increased pigmentation, loss of equilibrium and swimming at the bottom of the test vessels.
- Observations on body length and weight: details given in “Test species”
- Other biological observations: not applicable.
- Mortality of control: none
- Other adverse effects control: none
- Abnormal responses: none.
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: no data available.
- Effect concentrations exceeding solubility of substance in test medium: not applicable.
Results with reference substance (positive control):
No data available.
Reported statistics and error estimates:
The LL50 values and associated confidence limits at 24 hours were calculated by the trimmed Spearman-Karber method using the ToxCalc computer software
Package, and at 48, 72 and 96 hours the LL50 values were calculated using the geometric mean method as follows:
LL50 value = SQRT (L1 x L2)
Where:
L1 = loading rate showing 0% mortality
L2 = loading rate showing 100 % mortality
When only one partial response is shown the trimmed Spearman-Karber method is appropriate.
If there are no mortalities between 0% and 100% mortality, then the geometric mean of the highest loading rate showing no lethality and the lowest loading rate showing 100% lethality is calculated. The loading rates resulting in 0% and 100% mortality will be the 95% confidence limits.
An estimate of the LL50 values at 3 and 6 hours was given by inspection of the mortality data.
Sublethal observations / clinical signs:

Range-finding Studies

Cumulative mortality data from the exposure of rainbow trout to the test material during the range-finding studies showed no mortalities or sub lethal effects at the 3.2 mg/l loading rate WAF. However, mortalities or sub-lethal effects were observed at the 10,32, 100 and 1000 mg/l loading rate WAFs.

Based on this information loading rates of 3.2, 5.6, 10, 18 and 32 mg/l were prepared for the definitive study employing a single phase separation method. The WAFs were removed by siphon through Tygon tubing containing a glass wool plug (2 - 4 cm length) to remove any micro-dispersions which may have entered the WAF.

Definitive Studies

 

Cumulative Mortality Data

mg/L

WAF

3 hours

6 hours

24 hours

48 hours

72 hours

96 hours

Control

0

0

0

0

0

0

  3.2

0

0

0

0

0

0

  5.6

0

0

0a

0a

0a

0a

10

0

0

0a

0a

0a

0a

18

0a

0a

0ab

0ab

0ab

0ab

32

0a

0a

6bc

10

10

10

aincreased pigmentation

bincreased pigmentation and swimming at bottom

cincreased pigmentation, swimming at bottom and loss of equilibrium

Sub-lethal effects were observed at 5.6mg/L WAF and above.  Sub-lethal responses included increased pigmentation, loss of equilibrium and swimming at the bottom the test vessels.

Validity criteria fulfilled:
yes
Remarks:
The criteria for a valid test requiring mortality of the control not to exceed 10% and the maintenance of exposure conditions were met.
Conclusions:
The 96 h LL (Lethal Loading Rate) 50 value of the substance was determined (based on nominal loading rates) to be 24 mg/l loading rate WAF with 95% confidence limits of 18 - 32 mg/l loading rate WAF. The No Observed Effect Loading rate was 3.2 mg/l loading rate WAF.
Executive summary:

Introduction. A study was performed to assess the acute toxicity of the test material to rainbow trout(Oncorhynchusmykiss).The method followed that described in the OECD Guidelines for Testing of Chemicals (1992) No 203, "Fish, Acute Toxicity Test" referenced as Method C.l of Commission Directive 92/69/EEC (which constitutes Annex V of Council Directive 67/548/EEC), US CFR Title 40, Part 797, Section 1400 andUS EPADraft Ecological Effects Test Guideline OPPTS 850.1075.

Methods. Following a preliminary range-finding study, fish were exposed, in groups of ten, to Water Accommodated Fractions (WAFS) of the test material, prepared using a method employing a single phase separation over a range of nominal loading rates of 3.2, 5.6, 10, 18 and 32 mg/l for a period of 96 hours under static test conditions. The number of mortalities and any sub-lethal effects of exposure in each test and control vessel were determined 3 and 6 hours after the start of exposure and then daily throughout the study until termination after 96 hours.

Results. The 96-Hour LL50 based on nominal loading rates was 24 mg/l loading rate WAF with 95% confidence limits of 18 - 32 mg/l loading rate WAF. The No Observed Effect Loading rate was 3.2 mg/l loading rateWAF.

Endpoint:
short-term toxicity to fish
Type of information:
experimental study
Adequacy of study:
supporting study
Study period:
Between Sep 09th, 1992 and April 16th, 1993
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: GLP study conducted in compliance with agreed test protocols following OECD Guidelines without deviations. Acceptable restrictions such as lack of test material analyses are not expected to have a major impact on the test result.
Qualifier:
according to guideline
Guideline:
OECD Guideline 203 (Fish, Acute Toxicity Test)
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Analytical monitoring:
no
Details on sampling:
- Concentrations: nominal concentrations of 2.6, 4.3, 7.2, 12 and 20 mg/L
- Sampling method: nominal concentrations
- Sample storage conditions before analysis: at room temperature
Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: nominal concentration praparation, test material was added directly into the vortex of the mixing cylinders.
- Eluate:
- Differential loading:
- Controls: Negative control
- Chemical name of vehicle (organic solvent, emulsifier or dispersant):
- Concentration of vehicle in test medium (stock solution and final test solution(s) including control(s)): 0, 2.6, 4.3, 7.2, 12 and 20 mg/L
- Evidence of undissolved material (e.g. precipitate, surface film, etc): surface foam and white precipitate were observed in treatment replicates.
Test organisms (species):
Pimephales promelas
Details on test organisms:
TEST ORGANISM
- Common name: Fathead minnow
- Strain: Pimephales promelas
- Source: cultures maintained by Wildlife International Ltd.
- Age at study initiation (mean and range, SD): Juvenile
- Length at study initiation (length definition, mean, range and SD): mean = 30 mm, range: 24 - 35 mm
- Weight at study initiation (mean and range, SD): mean = 0.54 g; range: 0.34 - 0.78 g
- Method of breeding:
- Feeding during test
- Food type: flaked fish food and Artemia nauppli
- Amount:
- Frequency:


ACCLIMATION
- Acclimation period: 51 h
- Acclimation conditions (same as test or not): same
- Type and amount of food: flaked fish food and Artemia nauppli
- Feeding frequency:
- Health during acclimation (any mortality observed): healthy

Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
96 h
Hardness:
140 – 148 mg/L as CaCO3
Test temperature:
The temperature was 21.7-22.50C (control) and 21.7 – 22.70C (test).
pH:
pH levels ranged from 8.0-8.3 (control and 8.1-8.3 (test).
Dissolved oxygen:
84.8-98.5% (control) and 91.6-105.4% (test).
Nominal and measured concentrations:
nominal concentrations of 2.6, 4.3, 7.2, 12 and 20 mg/L.
Details on test conditions:
TEST SYSTEM
- Test vessel:
- Material, size, headspace, fill volume: : Test chambers were 60 L glass aquaria holding 40 L of test water. Each test chamber contained a slotted PVC cylinder
extending from the bottom of the aquarium to the surface of the water. Slits were covered with Nytex screening. An electric mixer with a mixing shaft suspended into the center of the cylinder was used for mixing.
- Aeration:
- Type of flow-through (e.g. peristaltic or proportional diluter): The test material was added directly into the vortex of the mixing cylinders. The test material was slowly dispersed through the nylon screened slits of the mixing chamber and into the exposure section of the vessel.
- Renewal rate of test solution (frequency/flow rate): After 48 hours of exposure, fish were transferred to test chambers containing a freshly prepared renewal test solutions. The exposure continued for an additional 48 hours.
- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 2

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: filtered well water passed through a sand filter and pumped into a 37,800 L storage tank and aerated.
- Total organic carbon: 1.2 mg/l
- Particulate matter: 260 mg/l
- Metals: Cu, 0.0084 mg/l; Ni, 0.0011 mg/l; K, 6.0 mg/l; Na, 25.3 mg/l; B, 0.16 mg/l
- Pesticides: PCB < 1 ug/L and pesticides < 2ug/L
- Chlorine:
- Alkalinity: 186-190 mg/l
- Ca/mg ratio: 2.3
- Conductivity:
- Culture medium different from test medium: no
- Intervals of water quality measurement:


OTHER TEST CONDITIONS
- Adjustment of pH: 7.6
- Photoperiod: 16 hour light and 8 hour dark
- Light intensity: 1346 lux


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :


TEST CONCENTRATIONS
- Spacing factor for test concentrations: 2.6, 4.3, 7.2, 12 and 20 mg/L
- Justification for using less concentrations than requested by guideline:
- Range finding study
- Test concentrations:
- Results used to determine the conditions for the definitive study:
Duration:
96 h
Dose descriptor:
LC50
Effect conc.:
ca. 19 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mortality (fish)
Remarks on result:
other: 16-26 mg/L WAF
Duration:
96 h
Dose descriptor:
NOELR
Effect conc.:
ca. 7.2 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mortality (fish)
Sublethal observations / clinical signs:

                           Cumulative Mortality Data

Nominal

Cumulative Mortality %

mg/L

0 Hours

24 Hours

48 Hours

72 Hours

96 Hours

0

0

     0

    0C

0

0

2.6

0

     0

    0

0

0

4.3

0

     0

    0

0

0

7.2

0

     0

    0

0

0

12

0

     0

    0

10E

 15AN

20

0

   35N

40CDN

  50CEN

  55EMN

ASurfacing     D Discoloration              M Moribund

CLethargy      E Eraticswimming         N Loss of equilibrium

Signs of toxicity were observed at the 12 and 20 mg/L nominal concentrations and included surfacing, lethargy, loss of equilibrium, erratic swimming and discoloration.

Validity criteria fulfilled:
yes
Remarks:
The criteria for a valid test requiring mortality of the control not to exceed 10% and the maintenance of constant exposure conditions were met.
Conclusions:
The 96-Hour LC50 was 19 mg/L WAF with a 95% confidence interval of 16-26 mg/L WAF. The NOEL was 7.2 mg/L WAF.
Executive summary:

A study was performed to assess the effect of the test substance on the Fathead Minnow/Pimephales promelas over a 96 h period following the method described in OECD 203. Fish was exposed to the test substance at nominal concentrations of 0, 2.6, 4.3, 7.2, 12 and 20 mg/L for a total of 96 hours under static-renewal conditions. The number of mortalities in each test and control vessel was determined until 96 h after initiation of the test. The following results were obtained: the 96-Hour LC50 was 19 mg/L WAF with a 95% confidence interval of 16-26 mg/L WAF. The NOEL was 7.2 mg/L WAF.

Endpoint:
short-term toxicity to fish
Type of information:
experimental study
Adequacy of study:
supporting study
Study period:
Between Dec 22nd, 1997 and Jan. 06th, 1998.
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
GLP study conducted in compliance with agreed test protocols following OECD (Method 203) Guidelines. Acceptable restrictions such as lack of test material analyses and minor deviation from the standard guidance are not expected to have a major impact on the test result.
Qualifier:
according to guideline
Guideline:
OECD Guideline 203 (Fish, Acute Toxicity Test)
Deviations:
yes
Remarks:
Dissolved oxygen concentrations exceeded 105% saturation at 96 h duringt he definitive toxicity test. This deviation did not affect the outcome of the toxicity test.
GLP compliance:
yes (incl. QA statement)
Analytical monitoring:
no
Vehicle:
no
Details on test solutions:
An appropriate amount of test substance was added directly to separate test vessels containing 15 L of test water to give nominal concentrations of: 6.0, 10, 17, 28 and 47 mg/L. Two replicate test vessels for each concentration of test substance were prepared. Mixtures were stirred continuously throughout testing.
Test organisms (species):
Pimephales promelas
Details on test organisms:
TEST ORGANISM
- Common name: Fathead minnow
- Strain: Pimephales promelas
- Source: The test organisms were from a single source and were procured from a commercial supplier.
- Age at study initiation (mean and range, SD): Juvenile
- Length at study initiation (length definition, mean, range and SD): 35.1 mm
- Weight at study initiation (mean and range, SD): 0.34 g
- Method of breeding:
- Feeding during test
- Food type: Dry commercial food
- Amount:
- Frequency: every day


ACCLIMATION
- Acclimation period: 14 days
- Acclimation conditions (same as test or not): same
- Type and amount of food: Dry commercial food
- Feeding frequency: every day
- Health during acclimation (any mortality observed): The mortality rate was 3% during the 48 hours prior to testing
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
96 h
Post exposure observation period:
Mortalities and sub-lethal effects were recorded initially and at 24, 48, 72 and 96 h. .
Test temperature:
21.5 – 21.70C
pH:
7.9-8.9
Dissolved oxygen:
minimum of 8.2 mg/L (equivalent to 94.3% air saturation)
Salinity:
Not applicable.
Nominal and measured concentrations:
Nominal concentrations of: 6.0, 10, 17, 28 and 47 mg/L
Details on test conditions:
TEST SYSTEM
- Test vessel:
- Material, size, headspace, fill volume: 20 L glass aquaria each containing a cylinder approx. 8 cm in diameter with screened openings at the water surface and at 2 cm from the bottom.
- Aeration:
- Type of flow-through (e.g. peristaltic or proportional diluter): The test material was added directly into the vortex of the mixing cylinders. The test material was slowly dispersed through the nylon screened slits of the mixing chamber and into the exposure section of the vessel.
- Renewal rate of test solution (frequency/flow rate): no
- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 2

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Deionized tap water
- Total organic carbon: <1.0 mg/L
- Particulate matter:
- Metals:Calcium = 0.2 mg/l; Magnesium = 22.6 mg/l; Potassium = 5.64 mg/l; sodium = 47.9 mg/l
- Pesticides:
- Chlorine: 4.8 mg/l
- Alkalinity:
- Ca/mg ratio:
- Conductivity: 610-640 umhos/cm
- Culture medium different from test medium:
- Intervals of water quality measurement:


OTHER TEST CONDITIONS
- Adjustment of pH: 8.4-8.9
- Photoperiod: 16 hour light and 8 hour dark
- Light intensity: 6μEin/m2sec


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :


TEST CONCENTRATIONS
- Spacing factor for test concentrations:
- Justification for using less concentrations than requested by guideline:
- Range finding study
- Test concentrations: 0, 0.5, 5.0, 50, and 500 mg/l
- Results used to determine the conditions for the definitive study: After 96 h there was 1005 survival at 0, 0.5, 5.0 mg/l, and 0% survival at 50 and 500 mg/l.
Duration:
96 h
Dose descriptor:
LC50
Effect conc.:
ca. 8.5 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mortality (fish)
Remarks on result:
other: 6.0–10 mg/L
Sublethal observations / clinical signs:

                          Survival and Sublethal Effect Data    

Number Alive

Number Unaffected

Nominal

mg/L

Rep

0 hrs

24 hrs

48 hrs

72 hrs

96 hrs

0 hrs

24 hrs

48 hrs

72 hrs

96 hrs

0

1

10

10

10

10

10

10

10

10

10

10

2

10

10

10

10

10

10

10

10

10

10

6

1

10

10

10

10

10

10

10

10

10

10

2

10

10

10

10

10

10

10

10

10

10

10

1

10

10

9

4

4

10

9

9

4

4

2

10

9

0

0

0

10

4

0

0

0

17

1

10

0

0

0

0

10

0

0

0

0

2

10

0

0

0

0

10

0

0

0

0

28

1

10

0

0

0

0

10

0

0

0

0

2

10

0

0

0

0

10

0

0

0

0

47

1

10

0

0

0

0

10

0

0

0

0

2

10

0

0

0

0

10

0

0

0

0

 Sub-lethal effects were initially observed at a nominal test substance concentration of 10 mg/L at 24 hours.  Responses included lethargy and loss of equilibrium.

A surface film was observed at 0 hours in all non-control test vessels, except, 6 mg/L, and in all non-control test vessels at 96 hours.

Validity criteria fulfilled:
yes
Remarks:
The criteria for a valid test requiring mortality of the control not to exceed 10% and maintenance of constant exposure conditions were met.
Conclusions:
96-Hour LC50 = 8.5 mg/L WAF (95% confidence interval = 6.0–10 mg/L). NOEL = 6.0 mg/L WAF
Executive summary:

A study was performed to assess the effect of the test substance on the Fathead Minnow/Pimephales promelasover a 96 h period following the method described in OECD 203. Following a preliminary range-finding study, fish was exposed to the test substance at nominal concentrations of 0, 6.0, 10, 17, 28 and 47 mg/L for a total of 96 hours under static conditions. The number of mortalities in each test and control vessel was determined until 96 h after initiation of the test. The following results were obtained: the 96-h LC50 value was 8.5 mg/L WAF (95% confidence interval of 6.0–10 mg/L). NOEL value was 6.0 mg/L WAF.

Description of key information

The 96-Hour LL50 based on nominal loading rates in the key study was 24 mg/l loading rate WAF with 95% confidence limits of 18 - 32 mg/l loading rate WAF. The No Observed Effect Loading rate was 3.2 mg/l loading rate WAF (OECD 203).

Key value for chemical safety assessment

Fresh water fish

Fresh water fish
Effect concentration:
24 mg/L

Additional information

A key study was performed to assess the acute toxicity of the test material to rainbow trout (Oncorhynchusmykiss).The method followed that described in the OECD Guidelines for Testing of Chemicals (1992) No 203, "Fish, Acute Toxicity Test" referenced as Method C.1 of Commission Directive 92/69/EEC (which constitutes Annex V of Council Directive 67/548/EEC), US CFR Title 40, Part 797, Section 1400 andUS EPADraft Ecological Effects Test Guideline OPPTS 850.1075. Following a preliminary range-finding study, fish were exposed, in groups of ten, to Water Accommodated Fractions (WAFS) of the test material, prepared using a method employing a single phase separation over a range of nominal loading rates of 3.2, 5.6, 10, 18 and 32 mg/l for a period of 96 hours under static test conditions. The number of mortalities and any sub-lethal effects of exposure in each test and control vessel were determined 3 and 6 hours after the start of exposure and then daily throughout the study until termination after 96 hours. The 96-Hour LL50 based on nominal loading rates was 24 mg/l loading rate WAF with 95% confidence limits of 18 - 32 mg/l loading rate WAF. The No Observed Effect Loading rate was 3.2 mg/l loading rate WAF.

 

A supporting study was performed to assess the effect of the test substance on the Fathead Minnow/Pimephales promelasover a 96 h period following the method described in OECD 203. Following a preliminary range-finding study, fish was exposed to the test substance at nominal concentrations of 0, 6.0, 10, 17, 28 and 47 mg/L for a total of 96 hours under static conditions. The number of mortalities in each test and control vessel was determined until 96 h after initiation of the test. The following results were obtained: the 96-h LC50 value was 8.5 mg/L WAF (95% confidence interval of 6.0–10 mg/L). NOEL value was 6.0 mg/L WAF.

 

A second supporting study was performed to assess the effect of the test substance on the Fathead Minnow/Pimephales promelas over a 96 h period following the method described in OECD 203. Fish was exposed to the test substance at nominal concentrations of 0, 2.6, 4.3, 7.2, 12 and 20 mg/L for a total of 96 hours under static-renewal conditions. The number of mortalities in each test and control vessel was determined until 96 h after initiation of the test. The following results were obtained: the 96-Hour LC50 was 19 mg/L WAF with a 95% confidence interval of 16-26 mg/L WAF. The NOEL was 7.2 mg/L WAF.