Potassium hexadecyl hydrogen phosphate

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:

2013-01-14 to 2013-02-27

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

The study was regarded as reliable without restrictions because it was conducted in compliance with GLP regulation and guideline.

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

Details on sampling:

Duplicate samples from the freshly prepared test medium of the only test concentration and the control were taken at the start of the test.
For the determination of the stability of the test item under the test conditions and of the maintenance of the test item concentration during the test period, duplicate samples from the test medium of the only test concentration and the control were collected at the end of the test (after 96 hours) from the approximate centre of the aquaria.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method:
The test item was not well soluble in test water. Therefore, a stock suspension of 100 mg test item/L was prepared by suspending 1.0002 g of test item in 10.0002 L test water for preparing the test concentration. The stock suspension was stirred for 24 hours to dissolve as much test item as possible. Then, the undissolved test item was separated by filtration (0.45 µm cellulose acetate nitrate filter). The test media were prepared just before introduction of the test fish (= start of the test).

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

TEST ORGANISM
- Common name: Rainbow trout
- Source: The test fish were obtained from Forellenzuchtbetrieb Störk, 88348 Bad Saulgau, Germany
- Age at study initiation: Juveniles
- Length at study initiation: 4.83 cm ± 0.30 cm
- Weight at study initiation: 1.12 ± 0.23 g
- Feeding during test: no

ACCLIMATION
- Acclimation period: All fish were obtained and held in the laboratory for at least 12 days before the start of the test.
- Acclimation conditions: same as test conditions
- Feeding frequency: three times per week or daily until 24 hours before the test was started
- Health during acclimation: During the last 7 days prior to the start of the test no fish died in the test fish batch. Therefore, the mortalities in the fish batch were below 5 % and the fish batch was accepted.

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

96 h

Hardness:

2.5 mmol/L (= 250.0 mg/L) as CaCO3

Test temperature:

15 °C

pH:

7.8 to 8.2

Dissolved oxygen:

93 to 98 % of the air saturation value

Nominal and measured concentrations:

A filtrate of a supersaturated stock suspension of nominal 100 mg/L. No measured concentrations are available (below LOD).

Details on test conditions:

TEST SYSTEM
- Test vessel: 12 litre glass aquaria with 10 litre test medium
- Aeration: The test media were slightly aerated during the test.
- No. of organisms per vessel: 7
- No. of vessels per concentration: 1
- No. of vessels per control : 1

TEST MEDIUM / WATER PARAMETERS
- Chlorine: 2.0 mmol/L (= 294.0 mg/L)
- Alkalinity: 0.8 mmol/L
- Ca/mg ratio: 4 : 1 (based on molarity)
- Conductivity: < 10 µS.cm-1
- Culture medium different from test medium: no

OTHER TEST CONDITIONS
- Adjustment of pH:
- Photoperiod: 16 h light : 8 h dark; 30 min dawn/dusk period was provided
- Light intensity: 780 to 810 lux

TEST CONCENTRATIONS
- Test concentrations:
The test item was not well soluble in test water. Therefore, a stock suspension of 100 mg test item/L was prepared by suspending 1.0002 g of test item in 10.0002 L test water for preparing the test concentration. The stock suspension was stirred for 24 hours to dissolve as much test item as possible. Then, the undissolved test item was separated by filtration (0.45 µm cellulose acetate nitrate filter). The test media were prepared just before introduction of the test fish (= start of the test).

Reference substance (positive control):

no

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: up to the water solubility of the test item no mortality of the test animals occurred.

Duration:

96 h

Dose descriptor:

LC0

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: up to the water solubility of the test item no mortality of the test animals occurred.

Details on results:

- Test item group: In the control and the only test concentration of nominal 100 mg test item/L, all fish survived until the end of the experiment and showed no sublethal effects during the exposure time.
- Control: In the control no fish died until the end of the test.

Sublethal observations / clinical signs:

Table 1 Mortality and Sublethal Effects 

		Nominal conc. [mg/L]
Exposure Time [h]		Control	100
0 h	# mort	0	0
	# symp	0	0
	symp	-	-
2 h	#mort	0	0
	# symp	0	0
	symp	-	-
24 h	#mort	0	0
	# symp	0	0
	symp	-	-
48 h	#mort	0	0
	# symp	0	0
	symp	-	-
72 h	#mort	0	0
	# symp	0	0
	symp	-	-
96 h	#mort	0	0
	# symp	0	0
	symp	-	-

# mort: Number of dead fish

# symp: Number of fish with sublethal effects

 

Table 2 Results for the Determination of the Test Item in the Test Samples

sample description	age		test item found [µg/L]	D.F.	calculated test item [µg/L]
	day	[h]
control	0	0	<LOD	1000	n.a.
control	4	96	<LOD	1000	n.a.
Filtrate of 100 mg test item/L	0	0	<LOD	1000	n.a.
Filtrate of 100 mg test item/L	0	0	<LOD	1000	n.a.
Filtrate of 100 mg test item/L	4	96	<LOD	1000	n.a.
Filtrate of 100 mg test item/L	4	96	<LOD	1000	n.a.

LOD: Limit of Detection = 1.6 µg test item/L
n.a.: not applicable
D.F.: Dilution factor 

Validity criteria fulfilled:

yes

Conclusions:

Based on the test results the 96-hour LC50 of potassium hexadecyl hydrogen phosphate for rainbow trout (Oncorhynchus mykiss) was determined to be higher than 100 mg test item/L (nominal). The LC0 was determined to be 100 mg test item/L (nominal).

Executive summary:

The study was performed in order to evaluate the toxic potential of potassium hexadecyl hydrogen phosphate towards freshwater fish. The study was conducted as limit test in accordance with OECD TG 203 and Regulation (EC) No 440/2008 method C.1. Seven juvenile rainbow trout were exposed in a static test for 96 hours to test water containing the test item at the concentration of nominal 100 mg test item/L. As the test item is poorly water soluble, the “water-accommodated fraction” (WAF) was tested. Therefore, a stock suspension of 100 mg test item/L was prepared. The stock suspension was stirred for 24 hours to dissolve as much test item as possible. Then, the undissolved test item was separated by filtration. The test media were prepared just before introduction of the test fish. In the control and the only test concentration of nominal 100 mg test item/L, all fish survived until the end of the experiment and showed no sublethal effects during the exposure time. The pH and the oxygen values were in normal ranges. The 96-h LC50 was determined at greater than 100 mg/L and the 96-h LC0 was 100 mg/L.

Description of key information

Based on the test results the 96-hour LC50 of Potassium hexadecyl hydrogen phosphate for rainbow trout (Oncorhynchus mykiss) was determined to be higher than 100 mg test item/L (nominal). The LC0 was determined to be 100 mg test item/L (nominal).

Additional information

The study was performed in order to evaluate the toxic potential of potassium hexadecyl hydrogen phosphate towards freshwater fish. The study was conducted as limit test in accordance with OECD TG 203 and Regulation (EC) No 440/2008 method C.1. Seven juvenile rainbow trout were exposed in a static test for 96 hours to test water containing the test item at the concentration of nominal 100 mg test item/L. As the test item is poorly water soluble, the “water-accommodated fraction” (WAF) was tested. Therefore, a stock suspension of 100 mg test item/L was prepared. The stock suspension was stirred for 24 hours to dissolve as much test item as possible. Then, the undissolved test item was separated by filtration. The test media were prepared just before introduction of the test fish. In the control and the only test concentration of nominal 100 mg test item/L, all fish survived until the end of the experiment and showed no sublethal effects during the exposure time. The pH and the oxygen values were in normal ranges. The 96-h LC50 was determined at greater than 100 mg/L and the 96-h LC0 was 100 mg/L.