Sodium hydrogencarbonate

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:

1993

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

In the OECD SIDS on sodium bicarbonate (2002) a similar reliability was assigned.

Qualifier:

according to guideline

Guideline:

EPA OPP 72-1 (Fish Acute Toxicity Test)

Deviations:

yes

Remarks:

Fish were fed in the 48 hours prior to the study

GLP compliance:

yes

Analytical monitoring:

yes

Vehicle:

not specified

Test organisms (species):

Lepomis macrochirus

Test type:

flow-through

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Reference substance (positive control):

no

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

5 200 mg/L

Nominal / measured:

meas. (not specified)

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

7 100 mg/L

Nominal / measured:

meas. (not specified)

Basis for effect:

mortality (fish)

Reported statistics and error estimates:

Moving average angle analysis, probit analysis and nonlinear interpolation with 95% confidence intervals calculated by binominal probability. METHOD OF CALCULATION: the 24-, 48-, 72- and 96-hour median LC50 values were estimated from derived mortality data at the measured concentrations using the described statistical methods which were available in a computer programme. If two or more statistical methods produced acceptable results, then the method which yielded the smallest 95% confidence interval was selected.

Sublethal observations / clinical signs:

RESULTS: EXPOSED
- Nominal/ measured concentrations in mg A.I./ L
Nominal: 780 Mean Measured (SD):740 (190)
Nominal: 1300 Mean Measured (SD):1200 (49)
Nominal: 2200 Mean Measured (SD):2700 (550)
Nominal: 3600 Mean Measured (SD):5200 (2200)
Nominal: 6000 Mean Measured (SD):6300 (390)
Nominal: 10000 Mean Measured (SD):9400 (1100)

- Concentration / response curve:
Mean percentage mortality (of vessel A and B) after 96 hours:
Control: 5 %
740 mg A.I./L: 0 %
1200 mg A.I./L: 10 %
2700 mg A.I./L: 5 %
5200 mg A.I./L: 0 %
6300 mg A.I./L: 20 %
9400 mg A.I./L: 100 %

- Other effects: At 6000 mg A.I./L all of the surviving fish
were observed lethargic, two of the surviving fish were
observed to be dark

RESULTS: CONTROL
- Number/percentage of animals showing adverse effects:
5 % mortality in the control.

Validity criteria fulfilled:

yes

Conclusions:

96-hr acute flow-through test with bluegill sunfish (Lepomis macrochirus) a NOEC of 5,200 mg/l and a LC50 of 7,100 mg/l were determined

Executive summary:

A study was conducted exposing for 96-hr in flow-through system, bluegill sunfish (Lepomis macrochirus) to NaHCO3 at concentration ranging from 740 to 9400 mg/L, following the EPA OPP 72-1 “Fish Acute Toxicity Test’ guideline performed by GLP standard. Results showed a NOEC of 5,200 mg/L (measured concentration) and a LC50 of 7,100 mg/L (measured concentration).

Description of key information

Only one study was performed by GLP standard (Machado, 1993) is available and so it was chosen as key study. Machado (1993) exposed, in a 96-hr acute flow-through test, bluegill sunfish (Lepomis macrochirus) to NaHCO₃ at concentration ranging from 740 to 9,400 mg/L, following the EPA OPP 72-1 “Fish Acute Toxicity Test’ guideline. Results showed a NOEC of 5,200 mg/L (measured concentration) and a LC50 of 7,100 mg/L (measured concentration).

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

7 100 mg/L

Additional information

Two further reliable (K 2) studies (Harper et al., 2014 and Farag et al., 2014) were available reporting data from laboratory (Harper et al. 2014) and field (Farag et al., 2014) testing with overall seven different species of fish, resulting in 9 different endpoint study records.

Harper et al. (2014) exposed for 96h, in separated experiments, juveniles or embryos of the following fish: white sucker (Catostomus commersoni, 22dph); pallid sturgeon, (Scaphirhynchus albus, 4 dph); shovelnose sturgeon (Scaphirhynchus platorynchus, 4 dph); fathead minnow (Pimephaphales promelas, 2dph); rainbow trout (Oncorhynchus mykiss, 2dph); walleye (Sander vitreus, 1dph) and northern pike (Esox lucius,1dph).

Test were conducted following the EPA guideline 821/R-02/012 “Methods for measuring the acute toxicity of effluents and receiving waters to freshwater and marine organisms, 5th ed”. The test medium used, which differed depending on the species, were: reconstituted Tongue river water (C. commersoni, S. albus, P. promelas, O. mykiss); reconstituted Powder river water (C. commersoni, S. albus, P. promelas) and Yellowstone river water (S. platorynchus,S. vitreus, E. lucius). Results showed a LC50 ranging from 1,295 to 8,070 mg/L NaHCO₃, depending on the species and the medium used.

Differently, Farag et al. (2014) exposed 2 species of fish, fathead minnows (Pimephales promelas, 2dph) and pallid sturgeon (Scaphirhynchus albus, 4 and 6dph), for 96h in a field study. Experiment with fathead minnows were conducted in 4 different experimental sites with NaHCO₃ concentrations ranging from 1,850 to 3,318 mg/L and two references sites with NaHCO₃ concentrations of 856 and 260 mg/L. Results showed that 6phd fish survival was not significantly affected compared with the control, determining a NOEC of 3,318 mg/L (higher concentration tested), while 2 dph fish were more sensitive to NaHCO₃exposure. Indeed, a significant difference in survival compared with the references sites was recorder at all the experimental site, determining a LOEC of 1,850 mg/L (lowest concentration tested).

Experiments with pallid sturgeon were, instead, performed in3 different experimental sites with NaHCO₃ concentrations ranging from 2,194 to 3,504 mg/L and a references sites with NaHCO₃ concentration of 228 mg/L. 4 dph were also exposed in a static-renewal laboratory experiment using water collected from the field study. Initial field experiments with 2 dph fish showed a high mortality also at the reference site, hence it was stopped at 24 h. Results showed that 4-6 dph fish survival was significantly affected compared with the control in either field or laboratory experiments, determining a LOEC of 2,194 mg/L (lower concentration tested).