Trihydrogen trifluoro[phosphato(3-)-O]borate(3-)

Short-term toxicity to fish

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 phosphoric acid is extremely water sensitive and reacts even with moist air. In the instantaneous reaction with water as a first step phosphoric acid and boron trifluoride dihydrates are formed. The latter undergoes further rapid hydrolysis to boric acid, fluoboric acid and tetrafluoroborate. Therefore aquatic toxicity was assessed with adequate read across substances like boric acid. The most reliable tests with this read across substance of acute effects on fish (4-day duration) show mortality effects (LC50) in the range of 125 to 600 mg B/L and were performed in salmonids (Oncorhynchus kisutch, O. tshawtscha) and several endangered species (Gila elegans, Ptychocheilus lucia, Xyrauchen texanus, and Catostomas latipinnis). A study performed with ammonium

tetrafluoroborate resulted in a LC50 of 600 mg substance/L. LD50 values > 100 mg/L are also the results of test with phosphate and calcium hydrogenorthophosphate.

key (publications; boric acid)

The purpose of the study conducted by Hamilton and Buhl (1997) was to determine the acute toxicity of arsenate, boron, copper, molybdenum, selenate, selenite, uranium, vanadium, and zinc singly, and of five environmental inorganic mixtures to larval flannelmouth sucker in water simulating the San Juan River. The tests were performed according the following national standards:

- ASTM (1989). Standard guide for conducting acute toxicity tests with fish; macroinvertebrates, and amphibians.

- APHA, AWWA, WPCF (1989). Standard Methods for the Examination of Water and Wastewater

The acute toxicity values of the different test substances were then compared with environmental concentrations of their inorganics found in various waters in the San Juan River to assess their potential hazard to flannelmouth sucker.

Groups of 10 fish were exposed to a geometric series of six to eight nominal concentrations of boric acid (CAS No 10043-35-3) and a control treatment under static conditions. The acute toxicity value for boron for flannelmouth sucker was estimated at 125 mg B/L and was on the lower end of the wide range reported in the published literature.

In another publication Hamilton (1995) reported 96 h LC50s for boron of 233 mg/L for razorback sucker and 279 mg/L for Colorado squawfish, both tested in reconstituted Green River water. Others have reported LC50 values for boron within this range that encompass those in the present study (Tumbull et al.,1954; Taylor et al.,1985; Hamilton and Buhl, 1990). The wide range of values reported may be due in part to the different boron compounds and fish species tested and to the dilution water used.

supporting (publication; phosphates)

In a 96 -hour acute toxicity study, Japanese rice fish (Oryzias latipes) were exposed to the read across substances tricalcium phosphate (CAS No 7758-87-4) and calcium hydrogenorthophosphate (CAS No 7757-93-9) at concentrations of 0 (control) and 100 mg/L under static conditions. The test concentrations were based a range finding test, where the fish were exposed to test substance concentrations of 0, 0.1, 1, 10 and 100 mg/L. No mortality or any adverse effects were observed, therefore the main test was only conducted with a limit concentration of 100 mg/L. The 96 -h LC50 was above 100 mg/L, because no mortality or adverse effects were observed during the main study.

supporting (public references 1954 -1998; focus on boron)

A few studies reported endpoints in the 5 to 15 mg B/L range, but these were judged not reliable, or did not have sufficient information to permit data quality review. For example, Turnbull et al. (1954) reported a 24-hour median tolerance limit (TLm) to bluegill of 4.6 mg B/L in response to the read across substance sodium tetraborate decahydrate (CAS No 1303-96-4). However, they also reported a 24-hour TLm of 2389 mg B/L in response to the read across substance boron trifluoride (CAS No 7637-07-2). Their procedure used relatively large fish (ca. 5 g, 7 cm). No information was provided on replication, intervals between test concentrations, or similar operational details. Guhl (1992a) reported 96-hour LC50 for zebrafish of 14.2 mg B/L, but cited an unpublished study from Henkel KGaA. Terhaar et al. (1976) reported median lethal times for boric acid (CAS No 10043-35-3) of 10 hours, exposed to 1750 mg B/L which was extrapolated to an acute toxicity estimate of 17.5 to 175 mg B/L. These studies cannot be adequately reviewed or compared to standard protocols, thus they cannot be judged reliable.
This compilation of public references also include more reliabe LC50 values of about 600 mg B/L in Oncorhynchus kisutch and O. tshawtscha.

supporting (publication; ammonium tetrafluoroborate)
Static 96-hr toxicity tests were conducted with 40 such chemicals to provide basic toxicity data for regulatory decision making (Curtis and Ward, 1981). Thirty-two of the 40 chemicals tested were hazardous to aquatic life as determined by 96-hr LC50 values less than or equal to 500 mg/L. All 40 chemicals were tested with the fresh water fathead minnow (Pimephales promelas). With regards to the read across substance ammonium tetrafluoroborate (EC No 237-531-4) no mortality was observed below 600 mg/L.

Based on the results of the acute ecotoxicity tests using fish, LC50 values were above 100 mg/L, indicating no toxicity triggering classification and labelling.