Potassium hydrogencarbonate

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: EPA standard method, but some minor deficiencies in reporting

Qualifier:

according to guideline

Guideline:

other: Standard test method used: USEPA (1991), Methods for measuring the acute  toxicity of effluents to freshwater and marine organisms, 4th ed.  EPA/600/4-90/027, U.S. Environmental Protection Agency, Washington DC

Deviations:

yes

Remarks:

Ceriodaphnia were fed during the test. Preliminary tests with and  without feeding had shown that this would not influence the results.

GLP compliance:

no

Analytical monitoring:

yes

Test organisms (species):

Ceriodaphnia dubia

Details on test organisms:

- Source, supplier, any pretreatment, breeding method: in-house cultures  (ENSR Consulting and Engineering, Ford Collins, Colorado, USA), cultured  in hard reconstituted water or 20% mineral water according to the  mentioned EPA-method at 25 °C
- Feeding: 100 µl of a 1:1 mix of yeast/cerophyl/trout chow and algal  suspension was added to each test chamber at test initiation
- Age at study initiation: less than 24 h

Test type:

static

Limit test:

no

Details on test conditions:

- Stock solutions preparation: Stock solutions were prepared by  dissolving 10,000 mg KHCO3 in one l MHRW. Test solutions were prepared by  serially diluting the 10,000-mg/l stock solution with MHRW to develop a  series of test concentrations spaced on a 0.5 x dilution factor (i.e.  10,000, 5,000, 2,500, 1,250 mg/l). As testing proceeded and effect  thresholds were determined, test concentrations were often spaced much  more closely (e.g. 2,500, 2,000, 1,500, 1,000, 500 mg/l) to better define  responses near the effect threshold.
- Test temperature range: 25°C
- Exposure vessel type: 30-ml plastic beakers containing 10 ml of test  solution and five organisms per chamber
- Dilution water source: not reported - Dilution water chemistry: moderately hard reconstituted water (MHRW)
- Lighting: 16h:8h light:dark photoperiod
- Water chemistry in test: Measured dissolved oxygen concentrations were  always within acceptable range (> 40% saturation). Measured pH varied  according to the components of the solution but was generally between ph  7.5 and 9.0.
- Element (unit) basis: immobilisation
- Test design: 2 to 3 replicates
- Exposure period: 24 and 48 hours

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

630 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

act. ingr.

Basis for effect:

mobility

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

630 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

act. ingr.

Basis for effect:

mobility

Reported statistics and error estimates:

EC50 concentrations were calculated using a computer  program following the trimmed Spearman-Karber method.
Data was entered into a database using Paradox 3.1  software (Borland International, Scotts Valley, CA, USA).

RESULTS - EXPOSED:
- Nominal/measured concentrations: All ions concentrations measured in  stock solutions were compared to nominal values. If the measured  concentrations differed from the nominal value by more than 20%, the  actual measured concentrations were substituted for the nominal  concentrations.
- Effect data (Immobilisation):
-- 48 h EC50 = 630 (580-670) mg/l (arithmetic mean of 43replicates  (range) expressed as total ion concentrations added)
-- 24 h EC50 = 630 (580-670) mg/l (arithmetic mean of 2 replicates  (range) expressed as total ion concentrations added)

Validity criteria fulfilled:

not specified

Conclusions:

In a 48-h acute toxicity study, Ceriodaphnia dubia were exposed to KHOC3. The 48-h EC50 was 630 mg a.i./L.

Executive summary:

The 48 –hr-acute toxicity of KHCO3 to Ceriodaphnia dubia was studied under static conditions.  Daphnids were exposed to at nominal concentrations of 500, 1000, 1500, 2000, 2500 mg a.i./L under static conditions.  The 96-h LC₅₀was 630 mg a.i./L

 

This study is classified as acceptable with restrictions and satisfies the guideline requirements for an acute toxicity study with freshwater invertebrates.

 

Results Synopsis

 

Test Organism Age (e.g. 1^stinstar): <24 hours

Test Type (Static): EPA/600/4-90/027 (USEPA 1991)

 

EC₅₀: 630mg a.i./L

 

Endpoint(s) Effected:  mobility

Reference 2

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: EPA standard method, but some minor deficiencies in reporting

Qualifier:

according to guideline

Guideline:

other: Standard test method used: USEPA (1991), Methods for measuring the acute  toxicity of effluents to freshwater and marine organisms, 4th ed.  EPA/600/4-90/027, U.S. Environmental Protection Agency, Washington DC

Deviations:

yes

Remarks:

Daphnids were fed during the test. Preliminary tests with and without  feeding had shown that this would not influence the results.

GLP compliance:

no

Analytical monitoring:

yes

Test organisms (species):

Daphnia magna

Details on test organisms:

- Source, supplier, any pretreatment, breeding method: in-house cultures  (ENSR Consulting and Engineering, Ford Collins, Colorado, USA), cultured  in hard reconstituted water according to the mentioned EPA-method at 20 °C
- Feeding: 100 µl of a 1:1 mix of yeast/cerophyl/trout chow and algal  suspension was added to each test chamber at test initiation
- Age at study initiation: less than 24 h

Test type:

static

Limit test:

no

Details on test conditions:

- Stock solutions preparation: Stock solutions were prepared by  dissolving 10,000 mg KHCO3 in one l MHRW. Test solutions were prepared by  serially diluting the 10,000-mg/l stock solution with MHRW to develop a  series of test concentrations spaced on a 0.5 x dilution factor (i.e.  10,000, 5,000, 2,500, 1,250 mg/l). As testing proceeded and effect  thresholds were determined, test concentrations were often spaced much  more closely (e.g. 2,500, 2,000, 1,500, 1,000, 500 mg/l) to better define  responses near the effect threshold.
- Test temperature range: 20 °C
- Exposure vessel type: 30-ml plastic beakers containing 10 ml of test  solution and five organisms per chamber
- Dilution water source: not reported
- Dilution water chemistry: moderately hard reconstituted water (MHRW)
- Lighting: 16h:8h light:dark photoperiod
- Water chemistry in test: Measured dissolved oxygen concentrations were  always within acceptable range (> 40% saturation). Measured pH varied  according to the components of the solution but was generally between ph  7.5 and 9.0.
- Element (unit) basis: immobilisation
- Test design: 4 replicates
- Exposure period: 24 and 48 hours

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

650 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

act. ingr.

Basis for effect:

mobility

Remarks on result:

other: IUCLID4 note: "m" (measured/nominal)

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

670 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

act. ingr.

Basis for effect:

mortality

Remarks on result:

other: IUCLID4 note: "m" (measured/nominal)

Reported statistics and error estimates:

EC50 concentrations were calculated using a computer  program following the trimmed Spearman-Karber method. Data was entered into a database using Paradox 3.1  software (Borland International, Scotts Valley, CA, USA).

RESULTS - EXPOSED:
- Nominal/measured concentrations: All ions concentrations measured in  stock solutions were compared to nominal values. If the measured  concentrations differed from the nominal value by more than 20%, the  actual measured concentrations were substituted for the nominal  concentrations.
- Effect data (Immobilisation):
-- 48 h EC50 = 650 (380-820) mg/l (arithmetic mean of 4 replicates  (range) expressed as total ion concentrations added)
-- 24 h EC50 = 670 (440-880) mg/l (arithmetic mean of 4 replicates  (range) expressed as total ion concentrations added)

Validity criteria fulfilled:

not specified

Conclusions:

In a 48-h acute toxicity study, water fleas (Daphnia magna) were exposed to KHOC3. The 48-h EC50 was 650 mg a.i./L.

Executive summary:

The 48 –hr-acute toxicity of KHCO3 to water flea Daphnia magna was studied under static conditions.  Daphnids were exposed to nominal concentrations of 500, 1000, 1500, 2000, 25000 mg a.i./L under static conditions.  The 48-h LC₅₀was 650 mg a.i./L

 

This study is classified as acceptable with restrictions and satisfies the guideline requirements for an acute toxicity study with freshwater invertebrates.

 

Results Synopsis

 

Test Organism Age (e.g. 1^stinstar): <24 hours

Test Type (Static): EPA/600/4-90/027 (USEPA 1991)

 

EC₅₀: 650mg a.i./L

 

Endpoint(s) Effected:  mobility

Description of key information

The 48-h EC50 for Ceriodaphnia dubia is 630 mg a.i./L.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

630 mg/L

Additional information

In a 48-h acute toxicity study, water fleas (Daphnia magna) and Ceriodaphnia dubia were exposed to KHCO3. The 48-h EC50 were 650 mg a.i./L. and 630 mg a.i./L, respectively. The 48h EC 50 of Ceriodaphnia dubia was somewhat lower. Therefore this value is used for the assessment.