Registration Dossier

Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

Currently viewing:

Administrative data

Link to relevant study record(s)

Description of key information

With high probability acutely not harmful to aquatic algae.

Key value for chemical safety assessment

Additional information

In water, diethyl ether - boron trifluoride rapidly decomposes to form diethyl ether and boron trifluoride dihydrate. The latter reacts further to boric acid and fluoroboric acid, which finally hydrolyses to yield hydrofluoric acid/ fluoride ions (BUA, 2005). The assessment of fish toxicity was therefore based on studies on the substance itself as well as on the products of hydrolysis.

The acute toxicity of diethyl ether – boron trifluoride on algae was investigated, using Scenedesmus subspicatusas test organism. The test was conducted according to the EC Directive 79/831/EEC (C) and GLP. No effects were observed at 10 mg/L, the highest concentration tested (BASF AG, 1993). In a newer guideline study (Directive 92/69/EEC, method C3) with the hydrolysis product boron trifluoride dihydrate, the EC50 value based on growth rate was determined to be greater than 500 mg/L (Arkema, 2005).

 

The toxicity of boron to Spirodella polyrrhiza was determined by Davis et al. 2002 using standard methods. Frond production is apparently a more sensitive endpoint than either growth rate or the presence of abnormal fronds. Frond production in S. polyrrhizawas significantly reduced at 3.55 mg B/L. Significant reductions in growth rate and the percentage of abnormal (chlorotic, necrotic, and dead) fronds were observed at 18.9 and 22.4 mg B/L, respectively. The EC50for frond production, frond growth rate, and abnormal fronds were 14.3, 11.7, and 17.7 mg B/L, respectively. Davis et al. (2002) reported a NOEC value of 6.1 mg- B/L for the duckweed Spirodella polyrhiza. They reported endogenous boron level of 0.9 mg- B/L from the various nutrient media used.

Another non published data, an OECD 201 study of Selenastrum capricornutum (Hanstveit and Oldersma 2000) reported a NOEC concentration of 17.5 mg-B/L..

Other studies reported NOEC values were obatined for Chlorella pyrenoidosa (10 mg-B/L), Scenedesmus subspicatus (24 mg-B/L), Anacystis nidulans (50 mg-B/L) and Lemna minor (60 mg-B/L) are also available.