Sodium p-chloro-m-cresolate

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

11 Jan 1993 - 15 Jan 1993

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

The test temperature (11.8-12.7°C) was slightly under the recommended range for Oncorhynchus mykiss (13-17°C).

Qualifier:

according to guideline

Guideline:

EPA OPP 72-1 (Fish Acute Toxicity Test)

Deviations:

yes

Remarks:

The test temperature (11.8-12.7°C) was slightly under the recommended range for Oncorhynchus mykiss (13-17°C).

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

- Concentrations: control, solvent control, 0.259, 0.432, 0.72, 1.2 and 2.0 mg a.i./L
- Sampling method: Analytical measurements were performed at day 0 and at day 2. Samples from the definitive study were extracted within 48 hours of sampling.

Vehicle:

yes

Remarks:

acetone

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: On Day 0 a stock solution was prepared: 4.0011 g test item was dissolved in acetone in a 100 ml volumetric flask (40.0 g a.i./L acetone). The amount of stock solution per 17 L volume used was: 850 μL for 2.0 mg a.i./L; 510 μL for 1.2 mg a.i./L; 306 μL for 0.72 mg a.i./L; 184 μL for 0.432 mg a.i./L; and 110 μL for 0.259 mg a.i./L. All test levels and the solvent control received the same solvent load; 50 μL acetone per liter of water. On day 2 each test solution was siphoned down to a low volume while minimizing stress to the fish. The appropriate amount of stock solution and solvent was added to a separate stainless steel aquarium and filled to 17 L volume with water. This new test solution was gently poured into the test aquaria to renew each tank.
- Differential loading: no
- Controls: yes, water and solvent control
- Chemical name of vehicle (organic solvent): acetone
- Concentration of vehicle in test medium (stock solution and final test solution(s) or suspension(s) including control(s)): 50 µL acetone/L water for all test levels and solvent control

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

TEST ORGANISM
- Common name: Rainbow trout
- Source: Mount LassenTrout Farm of Red Bluff, California, USA
- Age at study initiation (mean and range, SD): 20 days
- Length at study initiation (length definition, mean, range and SD): 2.91 (± 0.22) cm
- Weight at study initiation (mean and range, SD): 0.29 (± 0.08) g

ACCLIMATION
- Acclimation conditions (same as test or not): During 48 hours immediately prior to test initiation fish were held under test conditions (temperature 12.1 °C, 16 h photoperiod, no food).
- Feeding frequency during acclimation: During the acclimation period fish were fed daily with newly hatched brine shrimp and/or a commercial fish food.

FEEDING DURING TEST
- None

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Test temperature:

11.8 – 12.7 °C

pH:

7.1 – 7.6

Dissolved oxygen:

7.1 - 10.2 mg/L (71 - 95 % saturation)

Conductivity:

132 µmhos

Nominal and measured concentrations:

Nominal concentrations: control, solvent control, 0.259, 0.432, 0.72, 1.2 and 2.0 mg a.i./L
Measured concentrations (mean values):

Details on test conditions:

TEST SYSTEM
- Test vessel: 20 L stainless steel aquaria
- Type (delete if not applicable): open
- Material, size, headspace, fill volume: stainless steel, 20 L, headspace: 3 L, fill vokume: 17 L
- Aeration: none
- Renewal rate of test solution (frequency/flow rate): Renewal of the test solution on day 2
- No. of organisms per vessel: 20
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 1
- No. of vessels per vehicle control (replicates): 1
- Biomass loading rate: 0.34 g fish/L

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Process water (spring water blended with treated city water)
- Hardness: 52 mg/L (as CaCO3)
- Alkalinity: 47 mg/L (as CaCO3)

OTHER TEST CONDITIONS
- Photoperiod: 16 hours light and 8 hours dark, (with 30 min transition period, simulating dawn and dusk)
- Light intensity: 50 - 70 foot-candles, combination of cool white and Agro-Lite fluorescent bulbs

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Mortality was recorded after 24, 48, 72 and 96 h
- Behaviour of fish was observed after 24, 48, 72 and 96 h

TEST CONCENTRATIONS
- Spacing factor for test concentrations: approx. 1.6
- Range finding study : yes
- Test concentrations: 0.5, 1, 5 and 10 mg/L
- Results used to determine the conditions for the definitive study: At test termination there was 100 % mortality in the 1, 5, and 10 mg/L test levels. Sublethal effects were observed in all test concentrations on day 0; however, all survivors were normal on day 2 to 4.

Reference substance (positive control):

no

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

0.917 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks:

95% CI: 0.64 - 1.11 mg/L

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

0.366 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

- Behavioural abnormalities: Behavioural or sublethal effects were observed during the exposure period. All fish at 0.644 mg/L were observed to be hyperreactive. Survivors in the 1.11 mg/L level showed a loss of equilibrium and vertical orientation.
- Mortality of control: no

Reported statistics and error estimates:

The 24, 48, 72 and 96 h LC50 values and their corresponding 95% confidence limits were calculated by a computerized program developed by Stephan, C.E. (1977) using one of three statistical techniques: moving average angle, binomial probability.

Sublethal observations / clinical signs:

Table 1: Cumulative mortality and behavioural observations

Concentration (mg a.i./L)	Exposure time
	24 h		48 h		72 h		96 h
	Dead	Obs.	Dead	Obs.	Dead	Obs.	Dead	Obs.
Control	0	20 N	0	20 N	0	20 N	0	20 N
Solvent control	0	20 N	0	20 N	0	20 N	0	20 N
0.218	0	20 N	0	20 N	0	20 N	0	20 N
0.366	0	20 N	0	20 N	0	20 N	0	20 N
0.644	0	20 H	0	20 H	0	20 H	0	20 H
1.110	17	1 N 2 LE	17	3 E, LE	17	1 OB 1 VO 1 E, LE	17	2 LE,VO 1 VO
2.039	20	0 N	20	0 N	20	0 N	20	0 N

Abbreviations of behavioural observations

N       Normal

H       Hyperreactive

E       Erratic behaviour

VO   Vertical orientation

LE     Loss of equilibrium

OB    On bottom

Table 2: Measured test concentrations

Nominal concentraiont (µg/L; ppm)	Measured concentration (µg/L)
	0 h	48 h (old)	48 h (renewal)	Mean (SD)	Percent of nominal
Control	ND <100	ND <100	ND <100	---	---
Solvent control	ND <100	ND <100	ND <100	---	---
259	275	153	225	218 (61)	84
432	440	254	404	366 (99)	85
720	795	437	701	644 (186)	89
1200	1244	1012	1012	1110(120)	93
2000	2039	*	*		102

SD = Standard Deviation

* All organisms were dead after 24 hours

Table 3: Validity criteria

Criterion from the guideline	Outcome	Validity criterion fulfilled
The mortality in the control(s) should not exceed 10% (or one fish if less than ten are used) at the end of the test	0	yes

 

Validity criteria fulfilled:

yes

Remarks:

For further details please refer to “Any other information on results incl. tables”.

Conclusions:

96 h LC50 = 0.917 mg/L
96 h NOEC = 0.366 mg/L

Executive summary:

A 96-hour static-renewal study was conducted by Gagliano & Bowers (1993) in accordance with U.S.-EPA FIFRA Guideline § 72-1 in order to estimate the acute toxicity of p-chloro-m-cresol to rainbow trout (Oncorhynchus mykiss). No mortalities or any symptoms of intoxication occurred in the control groups (dilution water and solvent control). Behavioural or sublethal effects were observed during the exposure period. All fish at 0.644 mg/L were observed to be hyperreactive. Survivors in the 1.11 mg/L level showed a loss of equilibrium and vertical orientation. The No Observed Effect Concentration (NOEC) was 0.366 mg/L based upon the lack of mortality and sublethal effects at this concentration. Mean measured concentration ranged between 84% and 102% of nominal. All results are based on the mean measured test concentrations of the test substance. The validity criteria of the test can be considered as fulfilled and the result will be used in the risk assessment.

Reference 2

Endpoint:

short-term toxicity to fish

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

Refer to analogue justification document provided in IUCLID section 13.

Reason / purpose for cross-reference:

read-across source

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

0.917 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks:

95% CI: 0.64 - 1.11 mg/L

Remarks on result:

other:

Remarks:

source, CAS 59-50-7, key rel 2, Gagliano & Bowers 1993

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

0.366 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other:

Remarks:

source, CAS 59-50-7, key rel 2, Gagliano & Bowers 1993

Description of key information

LC50 (96 h): 0.92 mg/L (meas. arithmetic mean, Oncorhynchus mykiss), read-across

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

0.92 mg/L

Additional information

No study investigating the toxicity ofsodium p-chloro-m-cresolate (CAS 15733-22-9) to acute fish is available. Therefore, in accordance to Regulation (EC) No. 1907/2006 Annex XI, 1.5 a read-across to the source substance (p-chloro-m-cresol, CAS 59-50-7) which is the main transformation product of the target substancesodium p-chloro-m-cresolate (CAS 15733-22-9) is applied.

The source substancep-chloro-m-cresol is the common compound in this analogue approach and is solely responsible for the (absence of) effects.Thus, the source substance is considered a suitable representative for the evaluation of the toxicity of the target substance to aquatic organisms. The read-across approach is justified in detail within the analogue justification in IUCLID section 13.

One experimental study is available investigating the short-term effects of the source substance p-chloro-m-cresol (CAS 59-50-7) to freshwater fish (Gagliano & Bowers 1993). The 96 - hour static-renewal study was conducted in accordance with U.S.-EPA FIFRA Guideline § 72-1 in order to estimate the acute toxicity of the test item to rainbow trout (Oncorhynchus mykiss). Fish were exposed to nominal concentrations of 0.259, 0.432, 0.72, 1.2 and 2.0 mg/L including control and solvent control. Analytical measurements resulted in measured concentrations of 0.218, 0.366, 0.644, 1.110 and 2.039 mg/L (84% and 102% of nominal). No mortalities or any symptoms of intoxication occurred in the control groups (dilution water and solvent control). Behavioural or sublethal effects were observed during the exposure period. All fish at 0.644 mg/L were observed to be hyperreactive. Survivors in the 1.11 mg/L level showed a loss of equilibrium and vertical orientation. The No Observed Effect Concentration (NOEC) was 0.366 mg/L based upon the lack of mortality and sublethal effects at this concentration. The LC50 (96 h) was calculated to be 0.92 mg/L. All results are based on the mean measured test concentrations of the test substance. The validity criteria of the test can be considered as fulfilled and the result will be used in the risk assessment.

Based on the available results from a structurally similar source substance (in accordance to Regulation (EC) No 1907/2006 Annex XI, 1.5) which is the main transformation product of the target substance and is characterized by a similar ecotoxicological profile and comparable structure, it can be concluded thatsodium p-chloro-m-cresolatehas effects in the same range as the target substance.