To figure out whether this quantity of mercury is a lot or a little, you can look at it in two different ways. However, as Mr. Volland points out, no one really knows how mercury moves when it is released into the air. The standard air dispersion model may be entirely inappropriate for estimating how the mercury will mix with fresh air. In addition, the standard air dispersion model assumes that the pollutant is being emitted into a rural environment with level, open ground. Lastly, Mr. Volland argues that dispersion models are not very accurate, even under ideal conditions, and the wide variations in the characteristics of the garbage entering an incinerator make air dispersion modeling particularly subject to error.
Mercury attacks the human central nervous system, particularly the brain.
It is a potent poison, the effects of which have been well documented. It is therefore a matter of great importance if the EPA's air dispersion models are in error and local people are exposed to mercury in greater concentrations than good health will allow. The second way to ask whether a given release of mercury is large or small, is to look at the absolute amount released. Mercury readily enters the food chain and accumulates in fish and other wildlife. Many waters of the United States are already contaminated with mercury at levels that have caused health authorities to issue warnings and bans against eating fish from those waters.