This laboratory study exposed the water flea Daphnia magna to lanthanum or gadolinium for seven days and measured survival, feeding, growth and maturation. Delayed maturity was the most sensitive endpoint, responding at well under 1 µg/L of lanthanum, while lethal concentrations were tens to hundreds of µg/L. Dissolved lanthanum declined markedly during the test.
Key numbers
- Day 7 lethal concentrations for lanthanum: LC10 30.40, LC20 78.96, LC50 403.67 µg/L (abstract; Table 2, p. 4).
- Maturity endpoint for lanthanum: EC20 0.79 µg/L and EC10 0.26 µg/L (abstract).
- Measured lanthanum recovery fell from 133.33% at the start to 32.73% by day 7, showing loss from solution (abstract).
Methods (brief)
Static seven-day tests in medium buffered with MOPS to an initial pH of 6.8, with daily algal food; measured concentrations used to derive lethal and effect concentrations.
Evidence fitness
Supports statements about the sensitivity of a freshwater invertebrate to dissolved lanthanum. It is ecotoxicity evidence and does not bear on human dietary exposure or toxicity.
Limitations
Non-standard seven-day design; lanthanum solubility declined during exposure, complicating dose description; single species.
Related evidence
Update history
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