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Ecotoxicological information

Short-term toxicity to fish

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Description of key information

A key study (Hefner, 2014a) is available that investigated lanthanum toxicity to juvenile rainbow trout (Oncorhynchus mykiss). Lanthanum was supplied as La(NO3)3. This key study was assigned a Klimisch 2 score (highest possible score when used for read across purposes). The 96-h LC50 reported in this study is 1.01 mg La(NO3)3/L or 0.42 mg La/L. This 96-h LC50 is considered as the key value for this endpoint and will be taken forward to PNEC derivation and for classification purposes. This LC50 corresponds to 0.96 mg/L, when expressed as lanthanum triacetate, indicating that the substance is very toxic to fish.

Key value for chemical safety assessment

LC50 for freshwater fish:
0.42 mg/L

Additional information

There are three studies included in this dossier on acute lanthanum toxicity to fish (Bazin, 1996; Peterson et al., 1974; Hefner, 2014a).

The key study was the study of Hefner (2014a). In this study, juvenile rainbow trout (Oncorhynchus mykiss) were exposed to lanthanum (added as La(NO3)3) for 96 h in a semi-static test. Dissolved lanthanum concentrations were monitored in fresh as well as old test media at the start and end of each renewal period, respectively. A 96-h LC50 of 1.01 mg La(NO3)3/L, corresponding to 0.42 mg La/L was obtained. This value should be considered as a key value and will be taken forward to PNEC derivation and for classification purposes. When expressed as lanthanum triacetate, this LC50 is equal to 0.96 mg/L, indicating that lanthanum triacetate should be considered as very toxic to fish.

The study of Peterson et al. (1974) reported a 96-h LC50 value of 0.47 mg La/L for Coho salmon (Oncorhynchus kisutch) from a test in which LaCl3 was used to add lanthanum to the test media. Lanthanum concentrations were however not measured, hence the results of this study may also have been underestimated. The study was not considered reliable but can be considered as a supporting study.

The study of Bazin (1996) exposed juvenile rainbow trout (Oncorhynchus mykiss) to lanthanum (added as La(NO3)3) for 96 h and concluded that the LC50 was higher than 100 mg/L (as La(NO3)3). However, since the lanthanum concentration in the water column had decreased below 1 mg La/L after 24 h, toxicity may have been substantially underestimated in this test, which is also confirmed by the results of the other two available studies (see above). Therefore, the results of this study were disregarded.