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Long-term toxicity to fish

Link to relevant study record(s)

Reference

Endpoint:

long-term toxicity to fish

Type of information:

read-across based on grouping of substances (category approach)

Adequacy of study:

key study

Study period:

From April 14, 1991 to May 28, 1991

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

KL2 due to RA

Justification for type of information:

Refer to the Quaternary ammonium salts (QAS) category or section 13 of IUCLID for details on the category justification. The study with the read across substance is considered sufficient to fulfil the information requirements as further explained in the provided endpoint summary.

Reason / purpose for cross-reference:

read-across source

Qualifier:

according to guideline

Guideline:

other: U.S. EPA FIFRA 72-4(a)

Deviations:

yes

Remarks:

the slight deviations from the protocol (such as hardness level, renewal of test solutions, temperature) did not have any impact on the test results

GLP compliance:

yes

Remarks:

US EPA GLP

Analytical monitoring:

yes

Details on sampling:

See below under 'Details on test solutions'

Vehicle:

yes

Details on test solutions:

- The test solutions used in this study were prepared from a single primary stock solution. The primary stock was prepared by mixing appropriate amounts of 14C-a.s. test substance and non-radiolabelled a.s. test substance in de-ionized water to yield a nominal concentration of 3.93 mg/mL 14C-a.s. test substance/a.s. test substance. The concentration of the radiolabelled a.s. test substance in the stock solution was verified by liquid scintillation counting (LSC).
- Test solutions were prepared by adding measure aliquots of the primary stock solution to dilution water. All test solutions were re-newed daily and prepared immediately before use. The 24h old test solutions were siphoned remained in the vessel. To complete the renewal process, newly prepared test solution or control water was gently poured along the side of the appropriate vessel.
- Triplicate one mL samples were collected and counted for all LSC analyses.

Test organisms (species):

Pimephales promelas

Details on test organisms:

Test organism:
- Common name: Fathead minnow
- Source: The U. S. EPA-Environmental Monitoring and Support Laboratory (Newtown, OH)
- Age at study initiation: <24 h

Method for preparation and collection of fertilized eggs:
- Method of collection of fertilised eggs: Eggs were obtained from in-house culture
- Subsequent handling of eggs: Fertilized eggs ≤24 h old were exposed in prepared test containers. They were examined daily to monitor hatching. For 5-7 d after test initiation, fry were observed for development, hatching and survival on a daily basis.

Post-hatch feeding:
- Type/source of feed: Newly hatched brine shrimp (Artemia salina) nauplii was used as food source
- Frequency of feeding: At least twice per day (second feeding prior to test water renewal)

Test type:

other: Daily static-renewal without aeration

Water media type:

freshwater

Total exposure duration:

34 d

Remarks on exposure duration:

(6d pre-hatch + 28d post-hatch)

Hardness:

75 mg/L CaCO3

Test temperature:

24.2 to 26.3°C

pH:

6.7 to 7.6

Dissolved oxygen:

5.0 to 9.2 mg/L (61 to 111% air saturation) at 25°C

Nominal and measured concentrations:

Nominal concentrations: 0, 27, 74, 135, 180, 270 and 490 µg/L
Measured concentrations: 0, 32.2, 75.9, 134.2, 186.8, 273.2 and 488.7 µg a.i./L

Details on test conditions:

Test sytem:
- Test vessel: 1 L glass beakers containing 0.5 L of test solution with an approx. depth of 65 cm.
- Type: Closed - to minimise evaporation and keep out foreign matter
- Aeration: No aeration
- Renewal rate of test solution (frequency/flow rate): Daily
- No. of fertilized eggs/embryos per vessel: 20 eggs per replicate. After 7 d of exposure, surviving fry from two replicates were thinned to 10 animals per replicate for each test concentration and control.
- No. of vessels per concentration (replicates): 4 replicates per group

Test medium / water parameters:
- Source/preparation of dilution water: Dilution water consisted of water from two deep wells. Water was treated to remove iron and organic impurities, passed through reverse-osmosis purifiers, and treated to obtain a hardness of approximately 75 mg/L as CaCO3.
- Alkalinity: 80-84 mg/L
- Conductivity: 206-211 umhos

Other test conditions:
- Photoperiod: 16 h light : 8 h dark
- Light intensity: Fluorescent light of 76.4 to 80.5 fc intensity

Effect parameters measured (with observation intervals if applicable) : Toxicity, mortality, effects on hatchability and growth

Vehicle control: Yes

Range-fingind study:
- Test concentrations: 100, 300, 600 and 900 µg/L
- Duration of exposure: 10d
- Number of eggs/vessel: 30 eggs for each test concentration, transferred using a wide-bore pipette
- Results used to determine the conditions for the definitive study: Yes; fry mortality was ≤10% in the control and 100 ug/L; 80% in 300 µg/L and 100% in the 600 and 900 µg/L nominal test concentrations during the 10-d exposure.

Post-hatching details:
- Begin of post-hatch period: After 6d

Reference substance (positive control):

no

Duration:

7 d

Dose descriptor:

NOEC

Effect conc.:

273.7 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

act. ingr.

Basis for effect:

number hatched

Key result

Duration:

28 d

Dose descriptor:

LC50

Effect conc.:

94 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

act. ingr.

Basis for effect:

mortality

Remarks on result:

other: 64-126 ug/L

Key result

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

32.2 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

act. ingr.

Basis for effect:

mortality

Key result

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

> 32.2 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

act. ingr.

Basis for effect:

growth rate

Details on results:

Hatchability:
- Hatchability in the mean measure test concentrations 32.2 through 273.2 µg/L ranged from 78 to 91 percent. None of these differences were significantly (P>0.05) different from the control (89% hatchability).
- Percent hatchability in the 488.7 µg/L was 68 percent which was significantly (P <0.05) lower than the control.
- The NOEC for hatchability, therefore was 273.2 µg/L.

Mortality:
- The 28-d LC50 value was calculated to be 94 ug/L with a 95% confidence interval of 64 to 126 µg/L.. See below Table 1 under ány other information on results incl. tables'
- 10% mortality occured in the dilution water control during the 28-d post-hatch exposure period.
- The survival after 28 d post-hatch in the mean measure test concentration 32.2 µg/L (74%) was not significantly lower (P>0.05) when compared to control survival (90%); however survival in all other test concentrations was significantly lower (P<0.05) than the control.

Growth:
- The average dry weight of the surviving fish generally increased as the concentration of the test substance increased (range, 0.972 mg/fish to 1.908 mg/fish), and in each case was higher than the control (0.800 mg/fish). The trend of increased growth also correlated with the decreased numbers of fish present in each test concentration suggesting food and space may have been the reason for the increased weights in the higher concentrations which were lethal to the less tolerant or weaker fish.
- Since no reduction in growth was observed at any of the test concentrations, th IC50 and LOEC values were not determined.
- The NOEC for gowth was determined to be >32.2 ug/L, the lowest concentration tested without significant decrease in survival.

Results with reference substance (positive control):

-

Reported statistics and error estimates:

Estimate of LC50 values were obtained using version 2 of the computer program TOXSTAT (Peltier and Weber). IC50calculated using monotonic regression analysis. The 28-d post-hatch survival data were analyzed using Fisher’s Exact Test. Analysis of variance (ANOVA) and Dunnett’s multiple comparison tests were used (SAS-Version 6.03) for comparing hatchability and weight data.

Table 1. LC50

LC50 (µg/L)	7-d post hatch	14-d post hatch	21 -d post hatch	28-d post hatch
	198	104	98	94
95% confidence limits (µg/L)	(164-231)	(72-138)	(68-130)	(64-126)

Table 2. NOECs LOECs values

LOEC (µg/L) hatchability	488.7
NOEC (µg/L) hatchability	273.2
NOEC(µg/L) survival	32.2
NOEC (µg/L) growth	>32.2

Validity criteria fulfilled:

not specified

Conclusions:

Based on the results of the read across study, the 34 d NOEC values for hatchability, survivial and growth can be considered to be 273.7 µg a.i./L, 32.2 µg a.i./Land > 32.2 µg a.i./L respectively.

Executive summary:

A study was conducted to determine the long-term toxicity to Fathead minnow (Pimephales promelas) of the read-across substance, C12-16 ADBAC (purity: 30%), according to U.S. EPA FIFRA 72-4(a), in compliance with GLP. Mortality, hatchability and growth were evaluated. Fish eggs (80 per concentration) were exposed for 34 d to mean measured concentrations of 0, 32.3, 75.9, 134.2, 186.8, 273.2 and 488.7 mg a.i./L of the radiolabelled test substance. Analytical determination was performed and the sample concentrations were verified by liquid scintillation counting. After 7 d, surviving fry from two replicates were thinned to 10 animals per replicate for each exposure group (total of 20 animals per concentration) and exposed to the same concentrations for a 28 d post-hatch static renewal toxicity test. Observations of symptoms and mortality were conducted daily. Under the conditions of the study, the 34 d NOEC for hatchability was 0.274 mg/L, the 34d NOEC and LC50 for survival were 0.032 and 0.094 mg a.i./L, respectively, and the 34 d NOEC for growth was > 0.032 mg a.i./L (McIntyre, 1992). Based on the results of the read across study, similar the 34 d NOEC values can also be considered for the test substance, C12-14 TMAC, for long-term toxicity to fish.

Description of key information

Based on the results of the read across study, the 34 d NOEC values of the test substance, C12-14 TMAC, for hatchability of eggs, survivial and growth can be considered to be 273.7 µg a.i./L, 32.2 µg a.i./Land > 32.2 µg a.i./L respectively (measured).

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

0.032 mg/L

Additional information

A study was conducted to determine the long-term toxicity to Fathead minnow (Pimephales promelas) of the read-across substance, C12-16 ADBAC (purity: 30%), according to U.S. EPA FIFRA 72-4(a), in compliance with GLP. Mortality, hatchability and growth were evaluated. Fish eggs (80 per concentration) were exposed for 34 d to mean measured concentrations of 0, 32.3, 75.9, 134.2, 186.8, 273.2 and 488.7 mg a.i./L of the radiolabelled test substance. Analytical determination was performed and the sample concentrations were verified by liquid scintillation counting. After 7 d, surviving fry from two replicates were thinned to 10 animals per replicate for each exposure group (total of 20 animals per concentration) and exposed to the same concentrations for a 28 d post-hatch static renewal toxicity test. Observations of symptoms and mortality were conducted daily. Under the conditions of the study, the 34 d NOEC for hatchability was 0.274 mg/L, the 34d NOEC and LC50 for survival were 0.032 and 0.094 mg a.i./L, respectively, and the 34 d NOEC for growth was > 0.032 mg a.i./L (McIntyre, 1992). Based on the results of the read across study, similar the 34 d NOEC values can also be considered for the test substance, C12-14 TMAC, for long-term toxicity to fish.