Aluminum

Synonyms

Aluminum metal; Aluminum powder; Elemental aluminum; [NIOSH]

Category

Elements, Metallic

Description

Silvery-white, malleable, ductile, odorless metal; [NIOSH]

Sources/Uses

Used in metal/alloys (electrical wires, construction, automobiles, aircraft, appliances, cooking utensils, and foil), compounds (cosmetics, deodorants, catalysts, flocculating agents for water treatment, and drugs), finely divided dusts and flakes (thermite welding and pyrotechnics), and aluminum alkyls (mainly catalysts); [ACGIH] Foods containing relatively large amounts of aluminum include spices, baking powder, processed cheese, pancake mixes, pickled vegetables, and tea; Highest occupational exposures are in aluminum powder production and welding (often >100 ug/L in urine), followed by electrolytic production and corundum production (sometimes >100 ug/L in urine), and then other industries in which workers' urine concentrations of Al are seldom >100 ug/L (electrolytic production with new technology, aluminum sulfate production, grinding, melting and foundry, and optoelectronic manufacturing; [Nordberg, p. 551-2]

Comments

One of the difficulties in studying the adverse effects of aluminum is the frequent contamination of biological specimens with aluminum from the environment, e.g., improperly cleaned glassware. More than 95% of aluminum is excreted in the urine. The occupational lung disease "Shaver's disease" was thought to be caused by chronic inhalation of dusts containing aluminum minerals such as bauxite and corundum, often contaminated with silica. Studies of workers in Europe confirmed that stamped aluminum powder, even in the absence of silica, caused lung fibrosis (aluminosis) in past decades. Stamped aluminum powder is mainly used to make pyrotechnics; it commonly contains lubricating agents such as stearin or mineral oils. A study of a group of 64 aluminum welders for 1-24 years found no evidence of pulmonary fibrosis. Evidence of neurotoxicity was found in welders with urine aluminum levels >100 ug/L compared with welders with lower levels. Whether or not the neurobehavioral effects are reversible is not known. High levels of aluminum e.g., in dialysis patients or after chronic use of antacids, can interfere with bone remodeling and contribute to osteomalacia. Total parenteral nutrition solutions containing more that 4-5 ug/day can cause increased aluminum levels associated with CNS and bone toxicity. [Nordberg, p. 549-62] The TLV applies to insoluble aluminum compounds (metal, aluminum oxide, stamped aluminum, aluminum in bauxite ore dust, emery). Workers exposed to high levels of aluminum dust (40 years of exposure at 2.5 mg/m3) have x-ray and mild pulmonary function changes. In studies of animals chronically inhaling aluminum oxide, 2.45 mg Al/m3 is the NOAEL. The cases of aluminosis in Germany were related to the mineral oil used as a lubricant. Levels measured in patients with dialysis encephalopathy (59 ug/L in serum and 330 ug/L in urine) are estimated to be equivalent to workers being exposed for 40 years to 1.6 mg/m3. Klatzo et al. in 1965 suggested that aluminum played a role in the pathogenesis of Alzheimer's disease. That hypothesis is no longer supported. [ACGIH] The cause of "potroom asthma" in aluminum smelter workers is unknown. Hazards present in this environment include fluorides, sulfur dioxide, and coal tar pitch volatiles. There is no convincing evidence of an allergic mechanism. Potroom asthma develops from 1 week to 10 years after first exposure. [Asthma in the Workplace, p. 298-9] Interstitial fibrosis among aluminum powder workers was reported in the 1940s. [Harber, p. 488] Occupational asthma in a welder (manual metal arc welding on aluminium) and a foundry worker (aluminum chloride) confirmed by bronchoprovocation testing; [Malo] Aluminum metal can cause contact urticaria; [Kanerva, p. 219] Aluminum welders in the train and truck manufacturing industry with an average 15 years of experience had no increased symptoms compared to the control group. Measured air levels of total dust were 5-8 mg/m3. [Reference #1] Trialkylaluminum compounds are potentially corrosive to the skin and respiratory tract, but they are very reactive with air and water and "practically never gain systemic access to exert internal toxicity." [Sullivan, p. 981] Soluble aluminum compounds include nitrates, acetates, sulfates, chlorides, bromides, iodides, and salts of Na, K, and ammonium; Insoluble aluminum compounds include all hydroxides, carbonates, and phosphates that are not ammonium compounds; [Nordberg, p. 15] See "Aluminum production."

Reference Link #1

Biomedical References

Insufficient data

Yes

1 mg/m3, respirable fraction

15 mg/m3(total dust), 5 mg/m3(respirable fraction)

1.5 mg/m3 (respirable fraction), 4 mg/m3 (inhalable fraction)

Explanatory Notes

NFPA flammability for "Aluminum powder, uncoated"; Melting Point = 1220 degrees F; TLV for Aluminum metal [7429-90-5] and insoluble compounds; [ACGIH]

Depends on duration of exposure; if over 10 years, then urinary: 6 months; if under 1 year, then urinary: 9 days;; [TDR, p. 75]

Reference Link #2

may ignite at ambient temp

Yes

Yes

Other CNS neurotoxin

Not Classifiable

Diseases

Occupational diseases associated with exposure to this agent:

• Asthma, occupational
• Contact urticaria
• Pneumoconioses, other

Processes

Industrial Processes with risk of exposure:

• Aluminum Producing
• Metal Thermal Spraying
• Semiconductor Manufacturing
• Welding