Calcium acetylide

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:

1999

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

The test samples of the acute toxicity fish test were received in Sarstedt tubes.
The test samples were stored at -18 °C until sample analysis.

Vehicle:

no

Details on test solutions:

Preparation of the test solution:
The test substance Calciumcarbide is soluble in the test water. Therefore, the test solution was prepared with test water and by weighing and transferring of the test substance directly in the test water. The test solutions were prepared corresponding to the required test concentrations in the
following way:
Preparation of the test solution:
- Filling of the aquarium with 30 l test water
- Transfer of the fish into the test aquarium with the test water
- Addition of the test substance weighed per vessel directly into the test water with the fish
The control vessels contained test water only.
For the beginning of the test the test water was prepared the day before and aerated overnight in the same cabinet and at the same temperatures as the fish test was performed.

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

TEST ORGANISM
- Common name: rainbow trout
- Source: purchased from Forellenhof Fredelsloh, Gudrun Müller, D-37186 Moringen; further holding in the test facility
- Length at study initiation (length definition, mean, range and SD): 5.0 ± 1.0 cm
- Feeding during test: no feeding during the test period


ACCLIMATION
- Acclimation period: 13 days (in tap water for 6 days and in test water for 7 days prior to test initiation)
- Acclimation conditions (same as test or not): similar
- Light-dark-cycle: 16 h light : 8 h dark
- Temperature: 13 - 17 °C
- Food type: Tetra Min
- Amount: no data
- Frequency: daily until 24 hours prior to test initiation
- Health during acclimation (any mortality observed): During the acclimatisation period not any fish died.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Post exposure observation period:

not applicable

Hardness:

Hardness of water was equal to 2 mmol/l CaCO3, which is equivalent to a hardness of 200 mg/l CaCO3 (valid: 10 – 250 mg/l).

Test temperature:

16.0-16.5 °C

pH:

7.75

Dissolved oxygen:

9.3 mg/l

Salinity:

not applicable

Nominal and measured concentrations:

Pre-test: 0 (control), 5, 10, 50, 100, 150 mg/L nominal
Main test: 0 (control), 50 mg/L nominal

Details on test conditions:

TEST SYSTEM
- Test vessel: 5 l aquarium (pre-test), 30 l aquarium (60 cm x 30 cm x 30 cm) for main test
- Type (delete if not applicable): open
- Fill volume: 3 L (pre-test), 30 L (main test)
- No. of organisms per vessel: 3 (pre-test), 10 (main test)
- No. of vessels per concentration (replicates): 1 (pre-test), 1 (main test)
- No. of vessels per control (replicates): 1 (pre-test), 1 (main test)
- Biomass loading rate: maximum loading of 1.0 g fish/l

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16 h light : 8 h dark
- Light intensity: no data
- Temperature: 16.0 - 16.5 °C
- Light-dark-cycle: 16 h light : 8 h dark, daily

EFFECT PARAMETERS MEASURED (with observation intervals if applicable): mortality and observation of behavioural anomaliesat at 3, 6, 24, 48, 72 hours as well as 96 hours

Reference substance (positive control):

no

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 50 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Key result

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

50 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

1) Mortality at 3, 6, 24, 48, 72 h and 96 hours after application:
In the pre-test the median lethal concentration (LC50) of Calciumcarbide after 96 hours, i.e. the concentration which proved mortality to 50 % of fish was 70.7 mg/l (nominal concentration). The highest concentration tested which did not show a significant inhibition of the number of
living fish relative to control values is considered the “No Observed Effect Concentration” (NOEC).
At the test concentration 50 mg/l Calciumcarbide no statistically significant mortality of fish could be determined on the assessment after 96 h, so this concentration has to be set as the NOEC in the pre-test.
The lowest concentration tested which showed a significant mortality of fish relative to control values is considered the “Lowest Observed Effect Concentration” (LOEC). At the test concentration 100 mg/l Calciumcarbide a statistically significant inhibition in the number of living fish could be determined on the assessment after 48 h, so this concentration has to be set as the LOEC in the pre-test.

The main test was conducted only at the one concentration of 50 mg/l Calciumcarbide (technical product) which resulted in no mortality in the pre test. This highest concentration tested caused no significant mortality of fish, relative to control values, in the main test after 96 hours. No other concentrations were tested in the main test because at the test concentration 50 mg/l Calciumcarbide light cauterisation of the anal, pelvic and pectoral fin edge and a more light colour were already observed on all test fish as a result of the pH increase. Therefore, in the main test only the one concentration of 50 mg/l Calciumcarbide was tested as a limit-test (according to Commission Directive 92/96/EC; C.1.).
At the test concentration 50 mg/l Calciumcarbide no statistically significant mortality of fish could be determined on the assessments 3, 6, 24, 48, 72 and 96 hours after test initiation, so this concentration has to be set as the No Observed Effect Concentration (NOEC).
The lowest concentration tested which showed a significant mortality of fish relative to control values was not determined, i.e. the lowest observed effect concentration (LOEC) was > 50 mg/l Calciumcarbide.
The LC50 of Calciumcarbide after 96 hours was not determined because no mortality was observed at the concentration of 50 mg/l Calciumcarbide.

2) Abnormal responses of the fish
At the inspections after 3 and 6 hours a light cauterisation of the anal, pelvic and pectoral fin edge was observed in the main test at the test concentration of 50 mg/l Calciumcarbide. The fish tested at the concentration of 50 mg/l Calciumcarbide also looked light coloured in comparison to control. The reason for these observed effects was the pH increase up to 10.58 shortly after application of the test substance.
After 96 h the cauterisation of the anal, pelvic and pectoral fin edge was slightly reduced (reversible) compared to the observations after 3 h and 6 h. The reason for this observation was the decline of the pH up to 8.24 after 96 hours.
The more light colour of the fish tested at the concentration of 50 mg/l Calciumcarbide in comparison to control was not reversible at 96 hours after test initiation.

Reported statistics and error estimates:

The determination of the median lethal concentration value (LC50) was carried out by non-linear interpolation (Easy Assay Critical Values, Ver. 3.0, 1998 by RATTE) between 50.0 and 100.0 mg/l Calciumcarbide (technical product).
Regarding the NOEC and LOEC`s, the results were proved by means of multiple comparison procedure for comparing several treatments. This procedure was a variance test (ANOVA /Dunnett’s t-test), testing the significance of the differences between each of the treatments compared to the mean values of each group.

Sublethal observations / clinical signs:

Table 1:

Calcium carbide (technical product)   (mg/L)		3h	6h	24h	48h	72h	96h
		Number of living fish
CaC2	C2H2	pre-test
Control	Control	3	3	3	3	3	3
5	2.03	3	3	3	3	3	3
10	4.06	3	3	3	3	3	3
50	20.30	3*	3	3	3	3	3
100	40.60	0**	0*	0	0	0	0
150	60.92	0**	0	0	0	0	0
		Calciumcarbide (CaC2) mg/L / equivalent to Acetylene (C2H2) mg/L
LC50 [mg/L]		>150.0/60.9	70.7/28.7	70.7/28.7	70.7/28.7	70.7/28.7	70.7/28.7
LOEC [mg/L]		>150.0/60.9	100.0/40.6	100.0/40.6	100.0/40.6	100.0/40.6	100.0/40.6
NOEC [mg/L]		>150.0/60.9	50.0/20.3	50.0/20.3	50.0/20.3	50.0/20.3	50.0/20.3
		Main test
Control		10	10	10	10	10	10
50		10*	10*	10•	10	10	10
LC50 [mg/L]		> 50.0/20.3	> 50.0/20.3	> 50.0/20.3	> 50.0/20.3	> 50.0/20.3	> 50.0/20.3
LOEC [mg/L]		> 50.0/20.3	> 50.0/20.3	> 50.0/20.3	> 50.0/20.3	> 50.0/20.3	> 50.0/20.3
NOEC [mg/L]		> 50.0/20.3	> 50.0/20.3	> 50.0/20.3	> 50.0/20.3	> 50.0/20.3	> 50.0/20.3

*: light cauterisation of the anal, pelvic and pectoral fin edge

**: very strong cauterisation of the sclera and anal, pelvic and pectoral fin

•: the fish looked light coloured in comparison to control

Results of the analytical determination of Calciumcarbide in the test solutions

The method of the analytical determination of the concentrations is described in the related analytical report.

Concentration of Calciumcarbide (determined by measuring the Ca content) in the vessels after a test period of 96 hours:

Table 2:

Calciumcarbide(technical product)concentration (mg/L)	TheoreticalCa content(mg/L)	measured Ca content (mg/L)   hours after test initiation		measured Ca content (mg/L)(in % to nominal)
		0h	96h	0h	96h
Control	80.15	81	78	101.06	97.31
50	111.41	101	109	90.65	97.83

The analysis showed that the test concentrations (Ca content nominal according the technical product) could be recovered within a deviation below ± 20 % of the nominal Ca content in the test solutions measured after test initiation (0 h). Therefore, the results of this study were calculated on basis of the nominal values.

Oxygen concentrations, pH values and temperatures

During the test period the dissolved oxygen concentrations, pH values and temperature of the control and of the test solution were checked at 24-hour intervals.

Dissolved oxygen concentration (table 3):

Calcium carbide (technical product)concentration (mg/l)	Dissolved oxygen concentration in the test water (mg/l)
	hours after test initiation
	0	24	48	72	96
Control	9.3	9.3	8.9	8.9	8.8
50	9.3	9.3	8.9	8.9	8.9

volumetric instrument: O2-meter OXI 96, WTW Wissenschaftlich-Technische Werkstätten GmbH, D-82362 Weilheim, Germany

pH value (table 4):

Calcium arbide (technical product) concentration (mg/l)	pH value
	hours after test initiation
	0	24	48	72	96
Control	7.75	8.25	8.29	8.35	8.40
50	10.58	8.17	8.30	8.28	8.24

volumetric instrument: pH-meter pH 95, WTW Wissenschaftlich-Technische Werkstätten GmbH, D-82362 Weilheim, Germany

The pH value of the test solution was not adjusted.

Water temperature:

0 h: 16.0 °C

24 h: 16.2 °C

48 h: 16.5 °C

72 h: 16.5 °C

96 h: 16.5 °C

Validity criteria fulfilled:

yes

Remarks:

No mortality in the control; dissolved oxygen concentration >/= 60% of air saturation value; analytical evidence that CaC2concentration (i.e. the Ca content) had been satisfactorily maintained during the test period.

Conclusions:

The 96-h LC50 of the test substance for rainbow trout is > 50 mg/L under the conditions of the test.

Executive summary:

The acute toxicity of calcium carbide to rainbow trout (Oncorhychnus mykiss) was assessed using the methods according to OECD guideline 203 (1992).

Water quality parameters of temperature, dissolved oxygen and pH were measures throughout the test an were within acceptable limits. Culture and acclimation period records indicated the fish were in good condition for testing.

 

The study was conducted at the 0 (control) and 50 mg/L calcium carbide. Ten fish, with a standard length of 5 (± 1) cm, were exposed to each test concentration and control.

 

The results of the four day static fish toxicity study using calcium carbide are summarized below. The 24- and 48-hour LC50 values were also determined.

 

 96-hour LC50 > 50 mg/l

 96-hour LOEC > 50 mg/l

 96-hour NOEC = 50 mg/l

 

Description of key information

The LC50 of calcium carbide to rainbow trout

(Oncorhychnus mykiss) was determined to be > 50 mg/L under the conditions of OECD guidline 203 (1992).
50 mg/L was the highest test concentration in the test.
 

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

50 mg/L

Additional information

The acute toxicity of calcium carbide to rainbow trout (Oncorhychnus mykiss) was assessed using the methods according to OECD guideline 203 (1992).

Water quality parameters of temperature, dissolved oxygen and pH were measures throughout the test and were within acceptable limits. Culture and acclimation period records indicated the fish were in good condition for testing.

The study was conducted at the 0 (control) and 50 mg/L calcium carbide. Ten fish, with a standard length of 5 (± 1) cm, were exposed to each test concentration and control.

The results of the four day static fish toxicity study using calcium carbide are summarized below. The 24- and 48-hour LC50 values were also determined.

 96-hour LC50 > 50 mg/l

 96-hour LOEC > 50 mg/l

 96-hour NOEC = 50 mg/l