Registration Dossier

Administrative data

Workers - Hazard via inhalation route

Systemic effects

Long term exposure
Hazard assessment conclusion:
DNEL (Derived No Effect Level)
Value:
8.3 mg/m³
Most sensitive endpoint:
developmental toxicity / teratogenicity
DNEL related information
Overall assessment factor (AF):
12.5
Modified dose descriptor starting point:
NOAEC
Acute/short term exposure
Hazard assessment conclusion:
no hazard identified
DNEL related information

Local effects

Long term exposure
Hazard assessment conclusion:
no hazard identified
Acute/short term exposure
Hazard assessment conclusion:
no hazard identified
DNEL related information

Workers - Hazard via dermal route

Systemic effects

Long term exposure
Hazard assessment conclusion:
DNEL (Derived No Effect Level)
Value:
392 mg/kg bw/day
Most sensitive endpoint:
developmental toxicity / teratogenicity
DNEL related information
Overall assessment factor (AF):
30
Modified dose descriptor starting point:
BMDL05
Acute/short term exposure
Hazard assessment conclusion:
no DNEL required: short term exposure controlled by conditions for long-term
DNEL related information

Local effects

Long term exposure
Hazard assessment conclusion:
no hazard identified
Acute/short term exposure
Hazard assessment conclusion:
no hazard identified

Workers - Hazard for the eyes

Local effects

Hazard assessment conclusion:
medium hazard (no threshold derived)

Additional information - workers

ECHA Guidance on information requirements and chemical safety assessment Chapter R.8: Characterisation of dose [concentration]-response for human health, Appendix R.8 -13 (Deriving DNELs, when a community/national occupational exposure limit (OEL) is available) provides for use of EU member state Indicative OELs (IOEL) as an approach to the derivation of DNELs for a substance.

Chapter R.8 guidance provides for use of the IOEL directly unless significant new data are available. In the case of Boron substances, no significant new data bearing on the estimation of an OEL have become available since 2006.

In March 2007, the FRG Committee for Dangerous Materials- AGS Management- BAuA developed IOEL(s) for Boron substances. This evaluation formally considered all data available and relevant to the establishment of safe worker exposure limits and is fully of the scope anticipated by REACH guidance in calculating worker DNELs.

For the derivation of the worker long-term inhalation DNEL, two aspects were considered based on the German expert committee’s derivation of the worker exposure limits (AGW) for boric acid and sodium tetraborate:

• Local effects: With inhalation exposure to boric acid, boron oxide and sodium tetraborate, irritation to the respiratory tract and to the eyes was described in occupational reports.

• Systemic effects: After oral administration of boric acid or sodium tetraborate to animals, reproductive effects (effects to offspring, fertility effects) were observed. In humans, effects on fertility are suspected.

 

The derivation of the worker exposure limit for boric acid and sodium tetraborate on the basis of the local irritation effects in humans, described in occupational studies, results in a limit for boric acid and sodium tetraborate of 0.5 mg B/m ³ (rounded from 0.45 mg B/m3). In contrast to this, calculation of an extrapolated value expected to be protective against reproductive effects results in an exposure limit of 11 mg Bor/m ³ .

 

Irritative effects on the nose and the throat, coughing, breathlessness, and eye irritation were observed, in a dose-dependent manner, with exposures between approx. 1 mg/m3and15 mg/m3(Hu et al., 1992; Wegman et al., 1994). At the lowest group of exposures (1-4 mg/m3) these effects were minimal, so an acceptable NOAEL is approx. 1-2 mg/m3. As discussed by Culver et al. (1994), as well as after personal communication of Culver (2006), the Wegman et al. study was concluded to underestimate exposure by a factor of 1.76. From these data, they derived a NOAEL for irritation of 3 mg/m3(sodium borate). These values are supported by the study of Garabrant et al. (1985), however, due to instrumentation uncertainties and resulting uncertainties in the administration, this study is considered not relevant for the evaluation.

 

Since the derivation is based on a NOAEL from occupational studies, the extrapolation factors for allometric scaling and species variability, used during the derivation of the AGW on the basis of animal experiments, are not relevant. Regarding the extrapolation from acute to subchronic exposure, an extrapolation factor of 1 is used since no chronic changes were observed after multiyear exposure in occupational studies. On the basis of local irritation effects in humans, a concentration of 0.5 mg B/m3is proposed to be the AGW value for boric acid and sodium tetraborate.

General Population - Hazard via inhalation route

Systemic effects

Long term exposure
Hazard assessment conclusion:
no hazard identified
Acute/short term exposure
Hazard assessment conclusion:
no hazard identified
DNEL related information

Local effects

Long term exposure
Hazard assessment conclusion:
no hazard identified
Acute/short term exposure
Hazard assessment conclusion:
no hazard identified
DNEL related information

General Population - Hazard via dermal route

Systemic effects

Long term exposure
Hazard assessment conclusion:
no hazard identified
Acute/short term exposure
Hazard assessment conclusion:
no hazard identified
DNEL related information

Local effects

Long term exposure
Hazard assessment conclusion:
no hazard identified
Acute/short term exposure
Hazard assessment conclusion:
no hazard identified

General Population - Hazard via oral route

Systemic effects

Long term exposure
Hazard assessment conclusion:
no hazard identified
Acute/short term exposure
Hazard assessment conclusion:
no hazard identified
DNEL related information

General Population - Hazard for the eyes

Additional information - General Population

There is no opportunity for exposure to trimethyl borate. Therefore, setting DNELs for the general population is not appropriate.