Magnesium chloride

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:

1997

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Remarks:

Well documented study which meets basic scientific principles

Qualifier:

according to guideline

Guideline:

other: U.S. Environmental Protection Agency. 1991. Methods for measuring the acute toxicity of effluents to freshwater and marine organisms, 4th ed. EPA/600/4-90/027. Cincinnati, OH.

Deviations:

no

Principles of method if other than guideline:

Followed the general guidance of the USEPA (1991) for conducting acute whole effluent toxicity tests. The study was conducted in order to develop research to develop more comprehensive tools for assessing major ion toxicity. Acute toxicity tests were performed using three freshwater organisms (Ceriodaphnia dubia, Daphnia magna and Pimphales promelas) on solutions enriched with different compounds, and in particular Magnesium Chloride.

GLP compliance:

no

Analytical monitoring:

yes

Vehicle:

no

Details on test solutions:

Test solutions were prepared by dissolving individual ion salts in moderately hard reconstituted water (MHRW). Stock solutions were prepared by dissolving the stock solution mg/L in MHRW.

Test organisms (species):

Pimephales promelas

Details on test organisms:

TEST ORGANISM
- Common name: Fathead minnow
- Source: obtained from in-house cultures (ENSR, Fort Collins, CO, USA)
- Age at study initiation : 1 to 7 days old
- Feeding during test: Larva were fed brine shrimp nauplii twice daily until they were used in testing

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Hardness:

85 mg/L

Test temperature:

25 °C

pH:

7.5-9.0

Dissolved oxygen:

Measured DO concnetrations were always in the acceptable range (> 40% saturation)

Nominal and measured concentrations:

All ion concentrations measured in the 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 considered instead of nominal concentrations.
measured: 55.8, 99.5, 187.1, 362.1, 712.2 and 1412.3 mg Mg/L
measured: 91.8, 171.6, 331.1, 650.3, 1288.5 and 2565.0 mg Mg/L

Details on test conditions:

TEST SYSTEM
- Material, size, headspace, fill volume: 30-mL plastic beakers containing 10 mL of test solution
- No. of organisms per vessel: 5

Reference substance (positive control):

no

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

541 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

element

Basis for effect:

mortality (fish)

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

2 119.3 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Validity criteria fulfilled:

yes

Remarks:

Well documented study which meets basic scientific principles

Conclusions:

The 96h LC50 of magnesium chloride to fathead minnows was 541 mg of Mg/L (i.e 2119.3 mg of MgCl2/L).

Executive summary:

The aquatic toxicity of Magnesium Chloride was tested in a Fish acute toxicity test. The exposure duration was 96 hours, test animals were Pimephales promelas. These biotests were performed following the standard protocols developed by the Environmental Protection Agency (EPA. 1991).

The fishes were exposed to one single concentration of the test item in a Moderately hard reconstituted water during 96h.

After 24, 48, 96 hours of exposure, the mortality of the exposed fishes was recorded.

The 96h LC50 to Pimephales promelas was 541 mg of Mg/L (i.e 2119.3 mg of MgCl2/L).

Reference 2

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

disregarded due to major methodological deficiencies

Study period:

1957

Reliability:

3 (not reliable)

Rationale for reliability incl. deficiencies:

other: Insufficient experimental details, no enough available information to consider it reliable

Qualifier:

no guideline followed

Principles of method if other than guideline:

Data were collected on the toxicity of 86 pure chemicals (including MagnesiumChloride) to the mosquito fish Gambusia affinis.

GLP compliance:

no

Analytical monitoring:

not specified

Vehicle:

not specified

Test organisms (species):

Gambusia affinis

Details on test organisms:

TEST ORGANISM
- Common name: Mosquito fish
- Source: Collected from Stillwater Creek in Payne County Okla where they encountered turbidity in their normal habitat

Test type:

static

Water media type:

freshwater

Total exposure duration:

96 h

Test temperature:

21 - 25°C

pH:

7.5 - 7.7

Details on test conditions:

TEST SYSTEM
- Test vessel: no data
- Material, size, headspace, fill volume: Cylindrical pyrex jars 12 in high and 12 in diameter. Each jar contained 15 L water at the beginning of the test and the water was not replaced.
- Aeration: Artificial aeration from a compressor served to maintain oxygen, to mix the chemicals into the water and to disperse the turbidity-producing soil as long as possible in the mixture
- No. of organisms per vessel: 10 (including a control aquaria)

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Farm pond water

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : Checks were made of survivors at 24, 48, 72 and 96 h intervals.

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

4 212 mg/L

Nominal / measured:

nominal

Conc. based on:

element

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

16 500 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Validity criteria fulfilled:

not specified

Conclusions:

The 96 h LC50 of Magnesium Chloride to Gambusia affinis was 4212 mg/L (or 16500 mg of MgCl2/L).

Description of key information

Two reliable studies are available for the acute toxicity of Magnesium Chloride for freshwater and seawater fishes:

For the freswater, the 96h LC50 of Magnesium Chloride to Pimephales promelas was 2119.5 mg of MgCl2/L (i.e. 541 mg of Mg/L), Mount et al. (1997).

For the seawater, the lowest LC50 obtained for Menidia beryllina was 10968 mg MgCl2/L (i.e. 2800 mg of Mg/L), Pillard et al. (2000)

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

2 119.5 mg/L

Marine water fish

Marine water fish

Effect concentration:

10 968 mg/L

Additional information

 Relevant information is available on the acute toxicity of Magnesium Chloride to fish.

 

In total, 2 studies were judged reliable with restriction (Klimisch 2) :

- Mount et al. (1997) investigated the acute toxicity of Magnesium Chloride to freshwater fathead minnow (Pimephales promelas). The 96h LC50 for Magnesium Chloride was 2119.5 mg/L (i.e 541 mg of Mg/L). This study was performed following the standard protocols developed by the Environmental Protection Agency (EPA, 1991), and thus were judged as reliable with restrictions (No guideline study, but well documented and scientifically acceptable).

- Pillard et al. (2000) investigated the acute toxicity of Magnesium Chloride to saltwater silverside minnows (Menidia beryllina). The 48h LC50 for Magnesium Chloride was 10968 mg of MgCl2/L (i.e 2800 mg of Mg/L). This study was performed following the standard protocols developed by the Environmental Protection Agency (EPA, 1991), and thus were judged as reliable with restrictions (water characteristics measured but not reported)

 

One study was unreliable (Klimisch 3)

Wallen et al.(1957) investigated the acute toxicity of Magnesium Chloride Gambusia affinis. The 96h LC50 for Magnesium Chloride was 16 500 mg of MgCl2/L (i.e 4212 mg of Mg/L). This study was not performed following the standard protocols (e.g. tests were performed using waters collected in a highly turbidity farm pond), and thus were judged not reliable (Relevant methodological deficiencies).

 

=> All reliable LC50 values were higher than 100 mg mg/L, with the lowest LC50 value for Pimephales promelas of 2119.5 mg of MgCl2/L (Mount et al., 1997).