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 algae.

Key value for chemical safety assessment

Additional information

In water, the tetrahydrofuran - boron trifluoride complex rapidly decomposes to form tetrahydrofuran 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 products of hydrolysis.

Bringmann and Kuhn reported a toxic threshold concentration of 3700 mg/L for eight days exposure of Scenedesmus quadricauda to tetrahydrofuran (Bringmann and Kuhn, 1976).

The toxicity of boron trifluoride dihydrate was investigated following the guideline of Directive 92/69/EEC, method C3 and according to GLP. The EC50 value based on growth rate was determined to be greater than 500 mg/L (Arkema, 2005).

The toxicity of boron toSpirodella polyrrhizawas 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 inS. 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 duckweedSpirodella 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 ofSelenastrum capricornutum(Hanstveit and Oldersma 2000) reported a NOEC concentration of 17.5 mg-B/L..

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