isostearic acid monoisopropanolamide

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From June 14, 1999 to July 06, 1999

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.1 (Acute Toxicity for Fish)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Remarks:

HPLC and UV/VIS-detection

Details on sampling:

Analytical report 726120 (Schreitmijller, 1999)
For the analyses of the test substance concentrations in this semi-static test with a test medium renewal every day, a sample was taken from the freshly prepared stock solution, and duplicate samples from the freshly prepared test media of all concentrations and the control at the start of the test (Day 0) and at the last test media preparation on Day 3. To confirm the maintenance of the test substance concentrations during the test medium renewal periods of one day, additional samples were taken in duplicate out of all test media and the control after one day at the end of the first test medium renewal period and at the end of the last test medium renewal (after 96 hours). All samples were taken from the approximate center of the aquaria without mixing of the test media.
Since in a pre-experiment the concentration of the test substance had slightly decreased after storage at -20 “C, acetonitrile was added immediately after sampling to stabilize the test substance during storage. The samples were then deep frozen (at about -20 “C).
The concentrations of the test substance were analyzed in the stock solution sample and in all duplicate test medium samples from the nominal test concentrations of 22 to 100 mg/L. The test medium samples from the test concentrations of 4.6 and 10 mg/L were not analyzed, because at these test concentrations no biological effects were observed, and thus it was clearly below the 96-hour NOEC. From the control only one of the duplicate samples was analyzed from each sampling date.

Vehicle:

no

Details on test solutions:

A concentrated stock solution of nominal 1.5 g/L was freshly prepared prior to the test start or each test medium renewal. Therefore, an aliquot of the test substance was warmed up by means of a waterbath to about 40“C for 5 minutes to increase the fluidity and to improve the spreading properties. The amount of 2.996 - 3.017 g of the test substance was dispersed homogeneously in 2 I test water by ultrasonic treatment for 30 minutes and stirring for 30 minutes at room temperature. Adequate volumes of this intensively stirred stock solution were added to the test water in the aquaria and afterwards the test media were intensively mixed.
Additionally a control was tested in parallel (test water without addition of the test substance).

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

Source: P. Hohler, trout breeding station Zeiningen, CH-4314 Zeiningen, Switzerland.
Acclimatization: at least one week prior to the test
Water temperature: 14 - 15 “C
Light conditions: a 16-hour light to 8-hour darkness photoperiod
Diet (prior test): HOKOVIT 502
Number: 10 fish
Mean body length at the start of the test: 5.1 +/- 0.4 cm
Mean body wet weight: 1.3 +/- 0.2 g

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Hardness:

2.5 mmol/L (= 250 mg/L) as CaC03

Test temperature:

14-15°C

pH:

7.7-8.1

Dissolved oxygen:

8.8 mg/L or higher (higher than 60% oxygen saturation)

Nominal and measured concentrations:

4.6, 10, 22, 46 and 100 mg/L (nominal)

Details on test conditions:

Test water: reconstituted water: in deionized water

Reference substance (positive control):

no

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

ca. 75 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

other: mortality and symptoms

Remarks on result:

other: 100 mg/L nominal

Key result

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

ca. 14 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

other: mortality and symptoms

Remarks on result:

other: 22 mg/L nominal

Details on results:

- The two lowest test concentrations of nominal 4.6 and 10 mg/L were not analyzed since they were below the 96 h NOEC. In the freshly prepared test media of the test substance concentrations of nominal 22, 46, and 100 mg/L the measured mean test substance concentrations ranged from 88 to 96% of the nominal values. After the 24 h test medium renewal period the test substance concentrations had decreased to 30 - 76% of the nominal values. These losses were obviously caused by a separation of the dispersed test substance at the test medium surfaces, and/or adsorption to the glass surfaces. These analytical results reflect the observations during the test that a part of the test substance had separated to the surface of the test medium after 24 h. The total mean measured test concentrations (calculated as the average over all
measurements per test concentration) varied in the range of 64 to 75% of the nominal values. Therefore, the reported biological results were related to the total mean measured test substance concentrations. These were 14 mg/L (22 mg/L nominal), 34 mg/L (46 mg/L nominal), and 75 mg/L (100 mg/L nominal).
- 96 h LC50: about 75 mg/L
- 96 h LC0: 34 mglL
- 96 h LC100: > 75 mg/L
- 96 h NOEC: 14 mg/L
- 96 h LOEC: 34 mg/L
The EC50 should be taken with caution because the mortality was lower than 50% up to the highest concentration tested. The EC50 was calculated by linear extrapolation between the log concentration and the percent mortality.
- In the control and at the test concentrations up to and including 14 mg/L (22 mg/L nominal) all fish survived until the end of the test and no symptoms of intoxication were observed. At the next higher test concentration of 34 mg/L (nominal 46 mg/L) all test fish showed one or several intoxication symptoms at the observation after the test termination. At the highest test concentration of 75 mg/L (100 mg/L nominal) three of the seven fish had died until the end of the test. All four surviving fish showed heavy intoxication symptoms: the fish lay on the side or back on the bottom of the aquarium and only gill movement was visible after 96 h. Thus, the 96 h NOEC of the test substance to rainbow trout amounted to 14 mg/L. The 96 h LOEC and the LC0 were determined to be 34 mg/L. The 96 h LC50 was calculated to be 75 mg/L by linear extrapolation between the log-concentration and the percent mortality. But this value should be taken with caution because the mortality was lower than 50% up to the highest concentration tested. The 96 h LC100 could not be determined since the mortality was lower than 50% up to and including nominal 100 mg/L, but were higher than 75 mg/L (100 mg/L nominal). However, according to the guidelines no concentrations were tested in excess of nominal 100 mg/L.

Sublethal observations / clinical signs:

None.

Validity criteria fulfilled:

yes

Conclusions:

Under the study conditions, the 96 h LC50 and NOEC of the test substance in Rainbow trout were determined to be 75 and 14 mg/L (measured), respectively.

Executive summary:

A study was conducted to determine the short-term toxicity of the test substance, IsoC18 MIPA (94.1% active), to fish according to OECD Guideline 203 and EU Method C.1, in compliance with GLP. Rainbow trout (Oncorhynchus mykiss) were exposed to the test substance (dispersed in test medium by ultrasonication and stirring) at nominal concentrations of 0, 4.6, 10, 22, 46 and 100 mg/L for 96 h under semi-static conditions. Samples for analytical confirmation were taken from the freshly prepared solutions at the start of the test and after 96 h. Mortality and other effects were observed at 3, 24, 48, 72 and 96 h following the start of exposure. Analysis of the samples showed that measured mean concentrations ranged from 88 to 96% of the nominal values. After the 24 h test medium renewal period the test substance concentrations had decreased to 30 - 76% of the nominal values. These losses were obviously caused by a separation of the dispersed test substance at the test medium surfaces and/or adsorption to the glass surfaces. These analytical results reflect the observations during the test that a part of the test substance had separated to the surface of the test medium after 24 h. The total mean measured test concentrations (calculated as the average of all measurements per test concentration) varied in the range of 64 to 75% of the nominal values. Therefore, the reported biological values were related to the total mean measured test substance concentrations (i.e. 14, 34 and 75 mg/L). In the control and at the test concentrations up to and including 14 mg/L (22 mg/L nominal) all fish survived until the end of the test and no symptoms of intoxication were observed. At the next higher test concentration of 34 mg/L (nominal 46 mg/L) all test fish showed one or several intoxication symptoms at the observation after the test termination. At the highest test concentration of 75 mg/L (100 mg/L nominal) three of the seven fish died. All four surviving fish showed symptoms of high intoxication after 96 h. The EC50 should be taken with caution because the mortality was lower than 50% up to the highest concentration tested. Therefore, the EC50 was calculated by linear extrapolation between the log concentration and the percent mortality. Under the study conditions, the 96 h LC50 and NOEC of the test substance in Rainbow trout were determined to be 75 and 14 mg/L (measured), respectively (Batscher, 1999).

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

75 mg/L

Additional information

A study was conducted to determine the short-term toxicity of the test substance, isoC18 MIPA (94.1% active), to fish according to OECD Guideline 203 and EU Method C.1, in compliance with GLP. Rainbow trout (Oncorhynchus mykiss) were exposed to the test substance (dispersed in test medium by ultrasonication and stirring) at nominal concentrations of 0, 4.6, 10, 22, 46 and 100 mg/L for 96 h under semi-static conditions. Samples for analytical confirmation were taken from the freshly prepared solutions at the start of the test and after 96 h. Mortality and other effects were observed at 3, 24, 48, 72 and 96 h following the start of exposure. Analysis of the samples showed that measured mean concentrations ranged from 88 to 96% of the nominal values. After the 24 h test medium renewal period the test substance concentrations had decreased to 30 - 76% of the nominal values. These losses were obviously caused by a separation of the dispersed test substance at the test medium surfaces and/or adsorption to the glass surfaces. These analytical results reflect the observations during the test that a part of the test substance had separated to the surface of the test medium after 24 h. The total mean measured test concentrations (calculated as the average of all measurements per test concentration) varied in the range of 64 to 75% of the nominal values. Therefore, the reported biological values were related to the total mean measured test substance concentrations (i.e. 14, 34 and 75 mg/L). In the control and at the test concentrations up to and including 14 mg/L (22 mg/L nominal) all fish survived until the end of the test and no symptoms of intoxication were observed. At the next higher test concentration of 34 mg/L (nominal 46 mg/L) all test fish showed one or several intoxication symptoms at the observation after the test termination. At the highest test concentration of 75 mg/L (100 mg/L nominal) three of the seven fish died. All four surviving fish showed symptoms of high intoxication after 96 h. The EC50 should be taken with caution because the mortality was lower than 50% up to the highest concentration tested. Therefore, the EC50 was calculated by linear extrapolation between the log concentration and the percent mortality. Under the study conditions, the 96 h LC50 and NOEC of the test substance in Rainbow trout were determined to be 75 and 14 mg/L (measured), respectively (Batscher, 1999).