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

Toxicological Summary

Workers - Hazard via inhalation route

Systemic effects

Long term exposure

Hazard assessment conclusion:

DNEL (Derived No Effect Level)

Value:

1.12 mg/m³

Most sensitive endpoint:

repeated dose toxicity

Route of original study:

By inhalation

DNEL related information

Overall assessment factor (AF):

6

Modified dose descriptor starting point:

NOAEC

Acute/short term exposure

Hazard assessment conclusion:

DNEL (Derived No Effect Level)

Value:

2.45 mg/m³

Most sensitive endpoint:

irritation (respiratory tract)

DNEL related information

Local effects

Long term exposure

Hazard assessment conclusion:

DNEL (Derived No Effect Level)

Value:

1.12 mg/m³

Most sensitive endpoint:

repeated dose toxicity

DNEL related information

Overall assessment factor (AF):

6

Dose descriptor:

NOAEC

Acute/short term exposure

Hazard assessment conclusion:

DNEL (Derived No Effect Level)

Value:

2.45 mg/m³

Most sensitive endpoint:

irritation (respiratory tract)

DNEL related information

Workers - Hazard via dermal route

Systemic effects

Acute/short term exposure

DNEL related information

Workers - Hazard for the eyes

Local effects

Hazard assessment conclusion:

high hazard (no threshold derived)

Additional information - workers

Long term, inhalation DNEL (workers)

The toxicological effects of Trihydrogen trifluoro[phosphato(3-)-O]borate(3-) are basically driven by the toxicological properties of BF₃which is released from hydrolysis of this adduct in aqueous media. Hence, for the DNEL it is proposed to overwrite the DNEL of BF₃or rather BF₃dihydrate on a molar ratio.

The subchronic study performed by Rusch et al. (1986) was considered as the study in which exposure was probably best reflecting occupational exposure conditions. In this study (Rusch et al., 1986), rats were exposed to aerosols of BF₃dihydrate for 13 weeks, the NOAEC was set at 6 mg/m3 based on the occurring kidney effects. Clinical signs of respiratory irritation were seen at all dose levels, but without abnormal histological findings. In addition, necrosis of the renal tubular epithelium could be detected.

For the derivation of the long-term DNEL, the starting point had to be modified according to Chapter R.8 of the REACH Guidance. Here, a correction for activity driven differences of respiratory volumes in workers compared to workers in rest was added to receive a starting point of 4.02 mg/m³. Additionally, an overall assessment factor of 6 was established: 2 for time extrapolation and 3 for intraspecies variability. The latter factor is lower than the default factor of 5 since the effects were considered to be mainly due to unspecific chemical reactivity of BF₃and hydolysis to degradation products. No enzyme polymorphism is expected to be involved. No interspecies factor was used since the exposure route of the experimental study was inhalation. Thus, applying these assessment factors, a health-based occupational exposure limit of 0.7 mg/m³was recommended for BF₃dihydrate. Based on the molar ratio of 1:1.6, an exposure limit of 1.12 mg/m³was calculated for Trihydrogen trifluoro[phosphato(3-)-O]borate(3-) which is supposed to cover both local and systemic effects.

Description	Value	Remark
Step 1) Relevant dose-descriptor	NOAEC: 6 mg/m3
Step 2) Modification of starting point	× 6.7 m3/10 m3	According to Chapter R.8 of REACH Guidance, correction for activity driven differences of respiratory volumes in workers compared to workers in rest.
Modified dose-descriptor	6 * 0.67 =4.02 mg/m3
Step 3) Assessment factors
Interspecies	1	No allometric scaling has to be applied in case of inhalation to inhalation route to route extrapolation.
Intraspecies	3	Default assessment factor for workers decreased from 5 to 3 because no differences will be expected (no enzyme polymorphisms exist)
Exposure duration	2	Default assessment factor, extrapolation from sub-chronic to chronic
Dose response	1	Starting point=NOAEC
Quality of database	1
DNEL BF32*H2O	4.02 / (1 × 3 × 2 × 1 × 1) =0.7 mg/m^3
DNELTrihydrogen trifluoro[phosphato(3-)-O]borate(3-)	0.7 * 1.6 =1.12 mg/m^3(Mol: BF3 2*H2O=103,Trihydrogen trifluoro[phosphato(3-)-O]borate(3-)= 165.81 --> ratio 1:1.6)

 

Short term inhalation DNEL (workers)

For the short-term DNEL of BF₃the German OEL of 1 mg/m³has been employed with the following rationale: the ECHA guidance authorizes a registrant to use a national OEL instead of deriving a DNEL in case where toxicological information and evaluations of health effects used for setting the national OEL are documented and available. Therefore, it is proposed to use the German OEL (1 mg/m³for BF₃, equivalent to 1.5 mg/m³for BF₃dihydrate) (http://www.baua.de/cae/servlet/contentblob/664358/publicationFile/47955/900-bortrifluorid-dihydrat.pdf) in place of the derivation of the DNEL. This OEL value is the lowest occupational exposure level in Europe, and is based on available and relevant toxicological data at present.

ForTrihydrogen trifluoro[phosphato(3-)-O]borate(3-) an equimolar DNEL of 2.45 mg/m³is proposed.

 

General Population - Hazard via inhalation route

Systemic effects

Acute/short term exposure

DNEL related information

Local effects

Acute/short term exposure

DNEL related information

General Population - Hazard via dermal route

Systemic effects

Acute/short term exposure

DNEL related information

General Population - Hazard via oral route

Systemic effects

Acute/short term exposure

DNEL related information

Additional information - General Population

There are only industrial uses for boron trifluoride phosphate. The rejects of the substance in the environment (water, air) is extremely low. General population is not exposed via inhalation, dermal or oral route. Therefore no DNEL is calculated for the general population.