Jesus told his followers that a city set on a hill cannot be hidden. Although neither his intended nor historical context, this statement is certainly true of the communities that have sprouted prominently atop the infamous trash heaps of places like Calcutta and Mexico City. These, of course, are not the only cities that have sprung up on top of garbage.
Other cultures are more subtle about the fact that mountains of discard and ruin lie beneath their cities. Mankind has often chosen to build cities in layers, covering the ruins of a past with a sheathing of new structures and usages. In Europe, it is not uncommon for a tired tourist to sit down and rest on a stone wall jutting above the earth’s surface by a foot or two, an indication of ancient Roman days. In the New World, there are old street surfaces being uncovered and restored to the original stones that were left by ships unloading ballast as they took on rice and cotton to re-cross the Atlantic. Coastal colonial towns used their refuse as part of landfill projects to push back the tides and build wharves and fortresses.
Regardless of the complexity or relative simplicity of cultures, they all leave behind debris from their work and play, giving archaeologists and anthropologists clues for piecing together a picture from the past. Sometimes, however, the decoding efforts come up against an impasse. There are many mounds around the globe that still stymie historians’ interpretation efforts.
Which leads to the question of how our own culture’s mounds, known as landfills, will fare by the pen of future historians. Preserved scraps of printed material and broken bits of house wares should be fairly easily understood but what will the interpretation be of the enormous deposits of fetid plastic-skinned paper products that are sure to be found there? What conclusions will they draw about the foundation upon which they built their cities – the bizarre foundation of adult diapers?
It is hard to believe, but almost 10% of household garbage today is made up of diapers. In that figure, according to some sources, adult diapers outnumber baby diapers by more than 2 to 1. While this may come as a bit of a surprise, it starts to make sense when considering the demographic shift that is changing our nation as most baby boomers head into the senior years. Diapers of all sorts contribute to the third largest source of landfill content and it is not hard to see that as life expectancy rises and the population ages, the increase of adult diapers will require much more of this disposal space.
An aluminum can takes about 200 years to completely break down under typical landfill conditions. Shockingly, an adult diaper takes the same amount of time, more in some calculations, to disintegrate under the same circumstances. Oxygen is a key element for decomposition to take place and well maintained landfills ironically starve the garbage of this necessary ingredient. To manage the putrid nastiness of a landfill and to keep the public’s health as shielded from their trash as much as possible, many landfill sites try to apply a six inch layer of soil over the top of daily dumpings. This oxygen depriving burial and compacting works in tandem with public health efforts to keep oxidizing water out and leachate in, and leads to what is known as “dry tomb effect”. Refuse is inadvertently mummified, making for fascinating future archaeology, especially when considering the inevitable density of adult diapers that will be encountered.
Aptly, when considering its major diaper content, a defunct and undeveloped landfill is called a brownfield. Over time cities expand and encroach on the acreage where previous generations once jettisoned everything from bed springs to soiled absorbent underwear and this real estate value rises. What once appeared to be a bummer of an investment proposition starts to look pretty savvy. Brownfields turn green with lawns and parks and new cities are set on hills of hidden history.