Boron, (acetonitrile)trifluoro-, (T-4)-

Toxicity to aquatic algae and cyanobacteria

Additional information

No study data is available for the test substance. Similar to all coordination complexes of boron trifluoride with organic and inorganic species (like alcohols, ethers, amines, sulfuric acid, sulfuric dioxide, etc) the complex of boron trifluoride and acetonitrile is extremely water sensitive and reacts even with moist air. In the instantaneous reaction with water as a first step acetonitrile and boron trifluoride dihydrates are formed. The latter undergoes further rapid hydrolysis to boric acid, fluoboric acid and tetrafluoroborate. Effects on aquatic algae were studied using the read across substances boric acid (CAS No 10043-35-3), tetrafluoroborate, and acetonitrile (CAS No 75-05-8).

 

WoE (public references I and II from 1965 to 1990 and from 1980 to 2002; focus on boron)

NOEC(4d) values, obtained for the fresh water algae Chlorella pyrenoidosa (10 mg B/L), Anacystis nidulans (50 mg B/L) and EC10(3d) values obtained from fresh water algae Selenastrum capricornutum (24.5 mg B/L, biomass; 35 mg B/L; growth rate) are reported and applicable assessing the read across substance boric acid (CAS No 10043-35-3). Another non published data according to OECD 201 with Selenastrum capricornutum (Hanstveit and Oldersma 2000) reported a NOEC concentration of 17.5 mg B/L. The lowest NOEC value was found in the fresh water algae Chlorella pyrenoidosa (0.4 mg B/L) after 14 days study duration which does not meet the standard procedure. Finally, the EC50(4d) value obtained for the fresh water algae Selenastrum capricornutum of 3.3 mg B/L (growth rate) is regarded as worst case result.

 

WoE (tetrafluoroborate)

In the present study, the toxic effects of imidazolium-based ILs (1-butyl-3-methylimidazolium cation associated with bromide [BMiM][Br] and tetrafluoroborate [BMIM][BF4]) to the freshwater green alga Selenastrum capricornutum were investigated. Two approaches were followed to quantify toxicity of these compounds: Analyses of photosynthetic activity and cell proliferation. The obtained data showed that the relative declines of growth rates generally were more pronounced than those of photosynthetic activity. The ecotoxicity of a range of common organic solvents also was examined. It was revealed that both imidazolium-based ILs studied were some orders of magnitude more toxic than methanol, isopropanol, and dimethylformamide ([BMIM][BF4] EC50 was estimated 3467μM). In addition, with respect to incorporating perfluorinated anion, EC50 values of the previously prepared stock solution were significantly lower compared to those of the freshly made one. This might be due to hydrolytic effects of [BMIM][BF4] leading to fluoride formation, which was confirmed by ion chromatography analysis.

WoE (acetonitrile; study report 2010)

In a guideline and GLP study (INEOS Nitriles, 2010) the effect of the read across substance (acetonitrile) on the unicellular marine algae Phaeodactylum tricornutum was assessed over 72 hours using a static, sealed test system with no headspace. The test was conducted using a static sealed test system, without headspace to avoid loss of the test substance by volatilisation from the test system. Algal cultures with an initial cell density of 1 x 104 cells/mL were exposed to nominal concentrations of 100, 400, 1600, 6400 and 25600 mg/L. Determination of the acetonitrile concentration was carried out using samples taken at 0 and 72 hours. Concentrations of acetonitrile were achieved and maintained between 90 and 108% of nominal throughout the test giving overall mean measured concentrations of 94.1, 387, 1647, 5920 and 25313 mg/L. As the measured concentrations were within 80-120% of nominal, endpoints have been reported based on nominal concentrations. Cell densities were determined at 24, 48 and 72 hours to monitor growth throughout the test period. Results were expressed as average specific growth rate and yield over the 72 hour test period in terms of nominal concentration of acetonitrile.

After 72 hours the following effect concentrations were calculated:

ErC50 (growth rate) = 696 (95% CI: 7484 - 17597) mg/L

EyC50 (yield) = 3560 (95% CI: 1604 - 7017) mg/L

The "no observed effect concentration" (NOEC) and "lowest observed effect concentration" (LOEC) for both growth rate and yield where statistically derived as 400 and 1600 mg/L respectively.

Other study reported NOEC (growth rate, 72h) value was 700 mg/L.

The NOEC and EC50 values based on algae growth were 100 mg/L and > 100 mg/L.

 

Conclusion:
The EC50(4d) value with boric acid obtained for the fresh water algae Selenastrum capricornutum of 3.3 mg B/L (growth rate) is regarded as worst case result  but would not trigger classification and labelling for boric acid as all (chronic) NOEC values are > 1 mg/L and the substance has no potential to bioaccumulate.
Based on the results of the acute ecotoxicity tests using freshwater algae, the EC50(96h) of > 100 mg/L for acetonitrile does not indicate toxicity triggering classification and labelling.
In conclusion, the substance boron trifluoride acetonitrile complex needs not to be classified and labelled for acute toxicity in algae under Regulation (EC) No 1272/2008, as amended for the sixth time in Regulation EC No 605/2014.