Aluminum, dross

Endpoint summary

Description of key information

Aluminium dross is not expected to be absorbed via the gastrointestinal tract after oral administration. This is inferred by the study of acute toxicity via oral route (conducted as limit test) where no sign of systemic toxicity was found. Acute toxicity via inhalation route was not feasible since it was not possible to generate an appropriate inhalation atmosphere. Read-across to aluminium metal revealed an acute inhalation LC50 of more than 1000 mg/m3. No other constituents of Al dross present a significant toxicological profile on acute inhalation. Studies on dermal exposure were disregarded since dermal contact in the production and/or use is unlikely and inhalation is likely

Key value for chemical safety assessment

Acute toxicity: via oral route

Endpoint conclusion

Dose descriptor:

LD50

Value:

2 000 mg/kg bw

Acute toxicity: via inhalation route

Endpoint conclusion

Dose descriptor:

LC50

Value:

11 180 000 mg/m³

Acute toxicity: via dermal route

Endpoint conclusion

Value:

mg/kg bw

Additional information

Aluminium dross is not expected to be absorbed via the gastrointestinal tract after oral administration. This is inferred by the study of acute toxicity via oral route (conducted as limit test) where no sign of systemic toxicity was found.

Acute toxicity via inhalation route was not feasible since it was not possible to generate an appropriate inhalation atmosphere. Read-across to aluminium metal revealed an acute inhalation LC50 of more than 1000 mg/m3. No other constituents of Al dross present a significant toxicological profile on acute inhalation.Studies on dermal exposure were disregarded since dermal contact in the production and/or use is unlikely and inhalation is likely.

A study on acute toxicity of aluminium metal inhalation which may be used for derivation of LC50_inhfor aluminium dross shows that aluminium metal powder is not acutely toxic. Furthermore, aluminium (CAS: 91728-14-2) has been characterized as a non-hazardous nuisance dust; the higher the concentration of dust the greater the risk of irritation to the respiratory system and mechanical irritation to the eyes. As a result aluminium should be addressed as a benign dust (poorly soluble dust with low toxicity).

No studies on acute toxicity of aluminium oxide inhalation are available in literature. Chronic toxicity studies show that inhalation of up to 75 mg/m³ for 6 months did not produce adverse local or systemic effects (see also 5.6.1.2). Further studies showed that aluminium oxide fibres of inhalable size did not produce fibrosis or malignancies after 2 year inhalation (see also 5.6.1.2). Finally, aluminium oxide (CAS: 1344 -28 -1) has been characterized as a non-hazardous nuisance dust; the higher the concentration of dust the greater the risk of irritation to the respiratory system and mechanical irritation to the eyes . As a result aluminium oxide should be addressed as a benign dust (poorly soluble dust with low toxicity).

No studies on acute toxicity of aluminium nitride inhalation are available in literature. This substance however disintegrates into aluminium hydroxide and ammonia upon contact with water and bodily fluids as will happen within the respiratory tract.Aluminium hydroxide (alumina hydrate) (CAS:21645 -51 -2)is an inert dust which is extensively used in pharmaceuticals, personal care products and foodstuffs, thus its safety has been verified. Aluminium hydroxide is purchased as an antacid drug or against hyperphosphataemia under a variety of brand names in Europe and US (Alamag®, Maalox®, Mylanta® Alternagel®, Alu-Cap®, Dialume®, Amphojel®, Alu-Tab®, Aloh-Gel® etc). Aluminium hydroxide is also used as an adjuvant to the diphtheria and pertussis toxoid for infant immunization. In, aluminium hydroxide is an approved colour additive (CI 77002) that may be used in all types of cosmetics and personal care products (Annex IV of Cosmetics Directive 76/768/EEC). FDA also permits aluminium hydroxide to be used as anindirect food additive. The wide use of aluminium hydroxide even in injecting preparations verifies its high safety profile. Furthermore, aluminium hydroxide has been characterized as a non-hazardous nuisance dust; the higher the concentration of dust the greater the risk of irritation to the respiratory system and mechanical irritation to the eyes . As a result aluminium hydroxide should be addressed as a benign dust (poorly soluble dust with low toxicity).

 

Ammonia is an upper respiratory irritant which has been extensively studied due to its frequent production during a variety of industrial and biological activities. 
An acute toxicity study on ammonia inhalation is available which may be used for derivation of LC50 inhalation for aluminium dross.

If all AlN (15% w/w of Al dross) is stoichiometrically transformed to ammonia an amount of 1677 mg AlN (11.18 g Al dross/L) would be needed for exertion of the aforementioned toxicological effect. It can therefore be claimed that the produced ammonia does not contribute to the toxicological effects of acute inhalation of Al dross.

Concerning the constituents of Aluminum dross the median lethal concentrations causing 50% lethality are: 

LC50 (Aluminium dross): study technically non-feasible

LC50 (Aluminium metal): LC50>1 mg/L,non-hazardous nuisance dust

LC50 (Aluminium oxide) : -, non-hazardous nuisance dust

LC50 (Aluminium hydroxide) :-, non-hazardous nuisance dust

LC50 (ammonia)> 11.18 g /L (extrapolated to Al dros

The overall results of the OECD Guideline 403 (Acute Inhalation Toxicity test substance preparation indicate that the physical properties of the test substance prevented the achievement of the required consistency for proper aerosolization. Therefore, the EPA guidelines for acute inhalation testing could not be satisfied and a waiver from this testing should be granted.

Justification for classification or non-classification

No LD50 could be determined at the Acute Oral Toxicity test. No mortalities or other adverse effects were observed at the highest dose of 2000mg/kg of body weight. Therefore, LDoral50>2000mg/kg bw.

The inhalation study was not technically feasible, since it was not possible to generate an appropriate inhalation atmosphere in the laboratory.

Dermal exposure is not considered relevant due to absence of absorption through the skin for all constituents of the substance.

The impurities of aluminium dross are either of insignificant toxicological profile or of concentrations insufficient to trigger relevant classification for the whole mixture