Lanthanum chloride, anhydrous

Endpoint summary

Additional information

The following information were available for terrestrial toxicity to Lanthanum chloride, anhydrous, in which also information from Lanthanum nitrate and mixtures of rare earth chlorides were taken into account for the toxicological assessment of this endpoint.

A summary of the information about the analogue source substances is given in the data matrix of the justification for the analogue source substances approach, which can be found either in the CSR or as an attachment in IUCLID section 13.

 

1. Toxicity to soil macroorganisms except arthropods:

There is one publication available which determined the effects of Lanthanum chloride, anhydrous on Caenorhabditis elegans (Zhang et al. 2010), but with regard to the test design the results could not be taken into account for the assessment of the toxicity to soil macroorganisms. Furthermore information is available for the toxicity to Eisenia fetida with a mixture of rare earth elements (Wen et al. 2006). No mortality of earthworms (Eisenia fetida) was observed in nine natural chinese soils within 6 weeks. The total content of Lanthanum, Yttrium, Cerium, Praseodymium and Neodymium in these soils was 18.61 - 162.28 mg/kg dw, the concentration of Lanthanum was in a range of 4.6 - 71.9 mg La/kg dw. So generally, a LC0 > 71.9 mg La/kg could be stated. Although the total content of the rare earth elements can not be recalculated to Lanthanum, the more than two fold higher value of the total content of rare earth elements compared to the content of La as element showed, that the LC0 for Lanthanum is clearly underestimated.

 

2. Toxicity to soil macroorganisms

No information is available on the toxicity to terrestrial arthropods with Lanthanum chloride, anhydrous, but data are available for this endpoint with a mixture of rare earth chloride hexahydrate (Li et al. 2006). The mixture was composed mainly of Cerium, Lanthanum and Praseodymium, a concentration of individual rare earth elements was not given.

The short-term toxicity of a mixture of rare earth chloride hexahydrate on Holotrichia parallela (Coleoptera, larvae in the third stage) was tested in a filter paper contact test, yielding a LC50 > 3000 mg/L.

In a prolonged soil test groups of larvae (Holotrichia parallela) at the third larval stage were kept in the soil, spiked with mixed rare earth chloride hexahydrate. The exposure lasted until adult eclosion. Mortality, pupation and emergence were assessed after the exposure and revealed a NOEC value of > 3000 mg/kg soil.

Although the test substance was a mixed rare earth chloride hexahydrate with Cerium, Lanthanum and Praseodymium as rare earth elements, the high concentration without effects on mortality, emergence or pupation could be used for the assessment of Lanthanum chloride, anhydrous on terrestrial arthropods.

 

3. Toxicity to terrestrial plants:

No information is available for the toxicity to terrestrial plants with Lanthanum chloride, anhydrous, but one study was available with a plant soil system, using Lanthanum nitrate as test substance. Seedlings of Zea mays were grown in a red loamy soil, spiked with up to 2.5 g La/kg. Primary root elongation and dry weight of roots and shoots were measured after 14 d of application. The NOEC and LOEC for primary root elongation and root dry weight were 250 and 500 mg La/kg dw, respectively.

 

4. Toxicity to microorganisms:

The potential long term effect of Lanthanum chloride hexahydrate on carbon transformation activity of soil microorganisms was investigated according to OECD 217 under GLP- conditions. The test substance caused a maximum inhibition of 19.6% at the highest test concentration. Therefore the EC50 could not be calculated, but it can be concluded that the EC50 is higher than 1514.2 mg test item/kg soil dry weight (1051.0 mg LaCl3/kg soil dw), the highest concentration tested. The NOEC of the test item was calculated to be 757.10 mg/kg soil dry weight (525.5 mg LaCl3/kg soil dw) after 28 days of exposure.

Furthermore, the potential long term effect of Lanthanum chloride hexahydrate on nitrogen transformation activity of soil microorganisms was tested according to OECD 216 under GLP-conditions. The test substance caused a maximum inhibition of 18.5% at the highest test concentration. Hence the EC50 could not be calculated, but it can be concluded that the EC50 is higher than 1441 mg LaCl3*6H20/kg soil dw (1000 mg LaCl3/kg soil dw), the highest concentration tested. The NOEC of the test item derived from the variance analysis was 500 mg LaCl3/kg soil dw (720 mg LaCl3*6H20)/kg soil dw after 28 days of exposure.

 

Taken into account all available data, the most sensitive data for terrestrial toxicity were available for earthworms with an EC0 greater than 162 mg REE/kg dw and for plants with a NOEC of 250 mg La/kg dw.