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Ecotoxicological information

Short-term toxicity to fish

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Description of key information

Sodium lactate fully dissociates into Na+ ions and lactate. The ecotoxicology of sodium lactate can be understood in terms of the ecotoxicology of sodium chloride and lactic acid.
The 96-hour LC50 value of 5840 mg/L for sodium chloride was determined in a continuous flow-through exposure system with bluegill sunfish (Lepomis macrochirus).
The 96-hour LC50 value of 130 mg/L for lactic acid was determined in a static exposure system with rainbow trout (Oncorhynchus mykiss). However, it should be noted that all observed effects are due to the low pH induced by high concentrations of lactic acid, and will completely disappear at lower concentrations.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish
Effect concentration:
162 mg/L

Additional information

Sodium lactate fully dissociates into Na+ ions and lactate. The ecotoxicology of sodium lactate can be understood in terms of the ecotoxicology of sodium chloride and lactic acid.

Sodium chloride:

Four acute freshwater fish studies using four different fish species (bluegill sunfish, goldfish,tilapia, and fathead minnows) were listed for this endpoint. The study conducted with the bluegill sunfish was assigned a Klimish score of 1 since it followed guideline specifications and reported measured concentrations of the toxicant (NaCl). The acute toxicity test with the bluegill sunfish was conducted in a flow-through system and the 96 hour LC50 was 5,840 mg/L.  Two studies (conducted with nile tilapia and goldfish) were assigned Klimish scores of 2 based on good scientific practices followed in the studies, but without specific adherence to a guideline method. The acute toxicity test with goldfish was performed under semi-static conditions and the 96-hour LC50 for sodium chloride was 7341 mg/L. The acute toxicity test withtilapia fingerlings was performed under static conditions and the 96-hour LC50 for sodium chloride was 11,330 mg/L.  The acute toxicity study with the fathead minnow was assigned a Klimish score of 4 based on a lack of information provided in the report. The acute toxicity test with fathead minnows was performed under static conditions and the 96-hour LC50 for sodium chloride was 10,610 mg/L. Thus, the key parameter for the acute fish studies was the LC50 value of 5,840 mg/L for bluegill sunfish since this was the lowest reported LC50 value for sodium chloride.

Lactic acid:

Three short term toxicity studies with lactic acid with fish are available. The 96-hour LC50 value of 130 mg/L for lactic acid was determined in a static exposure system with rainbow trout (Oncorhynchus mykiss). However, it should be noted that all observed effects are due to the low pH induced by high concentrations of lactic acid, and will completely disappear at lower concentrations. This is also evident from available aquatic toxicity studies with sodium lactate, which has a daphnia LC50 of > 6 g/L and (acute) NOEC of 6 g/L (compare with daphnia LC50 for lactic acid of 130 mg/L).

The molar ratio to convert from lactic acid by weight to sodium lactate by weight is 1.24, which gives an estimate for the 96h-LC50 for fish of 162 mg/L. Given that effects of lactic acid can be attributed to pH effects and the neutral pH of sodium lactate solutions, the derived LC50 should be regarded as an extreme overestimation of the toxicity of sodium lactate.