Details

Autor(en) / Beteiligte

• Lynam, D.R.
• Pfeifer, G.D.
• Fort, B.F.
• Ter Haar, G.L.
• Hollrah, D.P.

Titel

Atmospheric exposure to manganese from use of methylcyclopentadienyl manganese tricarbonyl (MMT) performance additive

Ist Teil von

• The Science of the total environment, 1994-01, Vol.146, p.103-109

Ort / Verlag

Elsevier B.V

Erscheinungsjahr

1994

Quelle

Elsevier Journal Backfiles on ScienceDirect (DFG Nationallizenzen)

Beschreibungen/Notizen

• A number of methods were utilized to estimate the impact on atmospheric levels of airborne manganese resulting from adding methylcyclopentadienyl manganese tricarbonyl (MMT) to unleaded gasoline in the USA at a rate 0.03125 g/gal (1 USgal = 3.78541 dm 3). In addition, personal exposures to airborne manganese resulting from MMT use were both estimated and measured. Environmental models predicted manganese-in-air levels in most USA urban areas would increase less than 0.02 μg/m 3 if MMT were used in all unleaded gasoline. Because of the extremely high traffic density and unique atmospheric and geographic features around Los Angeles, slightly higher levels are predicted for this area. These estimates are based on the assumption that ∼ 30% of the manganese combusted is emitted from the tailpipe. In studies involving light-duty vehicles equipped with filters to trap particles, slightly less than 30% of the manganese was emitted. Studies using emission tunnels indicated only ∼ 10–15% of the manganese in the combusted gasoline was emitted from the tailpipe. MMT has been used in unleaded gasoline in Canada for ∼ 13 years. In Toronto, manganese-in-air levels average ∼ 0.04–0.05 μg/m 3, in good agreement with environmental models. Exposures of the general population to airborne manganese were also measured in Toronto. The 24-h average exposures for a group of typical office workers ranged from 0.002 to 0.048 μg/m 3, (mean, 0.013; S.D., 0.009; n = 33). Cab drivers, who because of the time spent in traffic, could be considered as the most highly exposed individuals, had 24-h average exposures ranging from 0.015 to 0.049 μg/m 3 (mean, 0.035; S.D., 0.010; n = 10). Several organizations have set exposure standards for manganese in the general population. The World Health Organization states exposures to airborne levels of manganese of 1.0 μg/m 3 or below over a lifetime should protect even highly sensitive individuals. In the USA, the Agency for Toxic Substances and Disease Registry suggests lifetime exposures below 2.0 μg/m 3 should be protective of the most sensitive individuals. The USA EPA has set a reference concentration ( R f C) for manganese of 0.4 μg/m 3. The R f C is protective of highly sensitive segments of the population over a lifetime of exposure. All of the methods demonstrate that exposures would be well below even the very conservative R f C.