BoraxUpdated a year ago
Toxicological Information
Information on the likely routes of exposure (inhalation, ingestion, skin and eye contact)
Inhalation is the most significant route of exposure in occupational and other settings. Dermal exposure is not usually a concern because product is poorly absorbed through intact skin. Product is not intended for ingestion.
(a) Acute toxicity
Method: Acute Oral Toxicity Study – U.S. EPA FIFRA Guidelines
Species: Rat
Dose: 3,200 - 3,400 mg/kg of body weight
Routes of Exposure: Oral
Results: Low acute oral toxicity. LD50 in rats is 3,305 mg/kg of body weight.
Classification: Acute Toxicity (Oral) Category 5 (Hazard statement: H303: May be harmful if swallowed)
Method: Acute Dermal Toxicity Study – U.S. EPA FIFRA Guidelines
Species: Rabbit
Dose: 2,000 mg/kg bw
Routes of Exposure: Dermal
Results: Low acute dermal toxicity; LD50 in rabbits is > 2,000 mg/kg of body weight. Poorly absorbed through intact skin.
Based on the available data, the classification criteria are not met.
Method: Acute Inhalation Toxicity Study – OECD Guideline 403
Species: Rat
Dose: 2.12 mg/L
Routes of Exposure: Inhalation
Results: Low acute inhalation toxicity; LC50 in rats is > 2.0 mg/l (or g/m3). Based on the available data, the classification criteria are not met.
(b) Skin corrosion / irritation:
Method: Primary Dermal Irritation Study – U.S. EPA FIFRA Guidelines
Species: New Zealand White Rabbit
Dose: 0.5 g moistened with saline
Routes of Exposure: Dermal
Results: No skin irritation. Mean Primary Irritation Score: 0. Based on the available data, the classification criteria are not met.
(c) Serious eye damage / irritation:
Method: Eye Irritation Study – similar to OECD Guideline 405
Species: New Zealand White Rabbit
Dose: 0.08 ml equivalent
Routes of Exposure: Eye
Results: Irritating, fully reversible in 14 days.
Classification: Eye Irritation Category 2A (Hazard statement: H319: Causes serious eye irritation.)
Many years of occupational exposure indicate no adverse effects on human eye.
(d) Respiratory or skin sensitisation:
Method: Buehler Test – OECD Guideline 406
Species: Guinea Pig
Dose: 0.4 g
Routes of Exposure: Dermal
Results: Not a skin sensitiser. No respiratory sensitisation studies have been conducted. There are no data to suggest that disodium tetraborates are respiratory sensitisers. Based on the available data, the classification criteria are not met.
(e) Germ cell mutagenicity:
Method: Several in vitro mutagenicity studies have been carried out on boric acid including gene mutation in mammalian cells, unscheduled DNA synthesis, chromosomal aberration and sister chromatid exchange in mammalian cells.
Species: L5178Y mouse lymphoma, V79 Chinese hamster cells, C3H/10T1/2 cells, hepatocytes, Chinese hamster ovary (CHO cells).
Dose: 1.0 - 10.0 mg/ml (1000 -10000 ppm) boric acid
Routes of Exposure: in vitro
Results: Not mutagenic (based on boric acid). Based on the available data, the classification criteria are not met.
(f) Carcinogenicity:
Method: OECD 451 equivalent.
Species: B6C3F1 mice
Dose: 446 ; 1150 mg boric acid/kg bw/day
Routes of Exposure: Oral feeding study
Results: No evidence of carcinogenicity (based on boric acid). Based on the available data, the classification criteria are not met.
(g) Reproductive toxicity:
Method: Three-generation feeding study, similar to OECD 416 Two-Generation Study
Species: Rat
Dose: 0; 34 (5.9); 100 (17.5); and 336 (58.5) mg boric acid (mg B)/kg bw/day; and 0; 50 (5.9); 155 (17.5); and 518 (58.5) mg borax (mg B)/kg bw/day
Routes of Exposure: Oral feeding study
Results: NOAEL in rats for effects on fertility in males is 100 mg boric acid/kg bw and 155 mg sodium tetraborate decahydrate/kg bw; equivalent to 17.5 mg B/kg bw.
Method: Prenatal Developmental Toxicity Study - OECD Guideline 414
Species: Rat
Dose: 0; 19 (3.3); 36 (6.3); 55 (9.6); 76 (13.3) and 143 (25) mg boric acid (mg B)/kg bw.
Routes of Exposure: Oral feeding study
Results: NOAEL in rats for developmental effects on the foetus including foetal weight loss and minor skeletal variations is 55 mg boric acid/kg bw or 9.6 mg B/kg; equivalent to 64.7 mg disodium tetraborate pentahydrate/kg bw.
Classification: Reproductive Toxicity Category 2 (Hazard statement: H361: Suspected of damaging fertility or the unborn child.)
Method: Occupational studies of evaluating sensitive sperm parameters in highly exposed borate workers. Epidemiological studies evaluating high environmental exposures to boron and developmental effects in humans have been conducted.
Species: Human
Dose: A subset of workers was exposed to 125 mg B/day.
Routes of Exposure: Combined oral ingestion and inhalation
Results: No adverse fertility effects in male workers. Epidemiological studies of human developmental effects have shown an absence of effects in exposed borate workers and populations living in areas with high environmental levels of boron.
(h) STOT-single exposure:
Method: Standard Test Method for Estimating Sensory Irritancy of Airborne Chemicals - ASTM E981-04 (2004)
Species: Mouse
Dose: 186 – 1704 mg/m3
Routes of Exposure: Inhalation
Results: The maximum exposure of 1704 mg/m3 resulted in a reduced respiratory rate of 33%, graded as moderate irritation. The lowest exposure tested of 186 mg/m3 sodium tetraborate pentahydrate resulted in a reduced respiration rate of 11%, graded as no irritation. Based on the available data, the classification criteria are not met.
Method: Sensory irritation in human volunteers
Species: Human
Dose: 5 - 40 mg/m3
Routes of Exposure: Inhalation
Results: A NOAEL for irritation from sodium tetraborate pentahydrate of 10 mg/m3 among male and female human volunteers under controlled laboratory conditions. At 10 mg/m3 increased nasal secretion was observed, but occurred in the absence of other irritating effects at a concentration below that considered irritating by volunteers and was not seen in a subsequent study.
(i) STOT-repeated exposure:
Method: Chronic toxicity study of boric acid and disodium tetraborate decahydrate, similar to OECD 452
Species: Rat
Dose: 0; 33 (5.9); 100 (17.5); 334 (58.5) mg boric acid (B)/kg bw per day (nominal in diet); and 0; 52 (5.9); 155 (17.5); 516 (58.5) mg borax (B)/kg/day (nominal in diet)
Routes of Exposure: Oral feeding study
Results: A NOAEL of 17.5 mg B/kg bw/day equivalent to 118 mg sodium tetraborate pentahydrate/kg bw/day was determined in a chronic feeding study (2 years) in rats and is based on testes effects. Other effects (kidney, haemopoietic system) are regarded only at even higher dose levels. Based on the available data, the classification criteria are not met.
(j) Aspiration hazard: Physical form of solid powder indicates no aspiration hazard potential.
11.2
Symptoms related to the physical, and chemical and toxicological characteristics:
At high concentrations irritation of nose, throat and eye may be observed. Products are not intended for ingestion. Small amounts (e.g. a teaspoonful) swallowed accidentally are not likely to cause effects. Symptoms of accidental over-exposure to high doses of inorganic borate salts have been associated with ingestion or absorption through large areas of severely damaged skin. These may include nausea, vomiting, and diarrhoea, with delayed effects of skin redness and peeling.
11.3
Delayed and immediate effects as well as chronic effects from short and long-term exposure:
Human epidemiological studies show no increase in pulmonary disease in occupational populations with chronic exposures to boric acid and sodium borate dust. Human epidemiological studies indicate no effect on fertility in occupational populations with chronic exposures to borate dust and indicate no effect to a general population with high exposures to borates in the environment.