LETTERS: Marion County residents need to hear the truth about clay liners for landfills

Yes, it is time for factual information about landfills. Community residents have a right to be concerned about this issue.

In 1990, the state of Virginia decided to invite commercial landfills in to enhance revenues. Recently, two of their seven new “state-of-the-art” dumps were found to have sprung leaks, according to the Washington Post. Groundwater tests found elevated levels of lead, chromium and other substances.

The main purpose of this letter is to dispel, once and for all, the myth that “clay is our savior.” In other words, that a clay liner supposedly will protect groundwater from contamination.

American and Canadian scientists who have studied clay liners have found that organic chemicals are moving through them much more rapidly than was previously thought possible. Research results were published in a journal of the American Chemical Society. It turns out that engineers and landfill designers have not understood the physical principles by which chemicals pass through clay.

Chemicals can move through even the tightest clay liner in the world in two basic ways: advection and diffusion. Advection can be thought of as the “normal” movement of water through the soil, traveling through the spaces between clay particles as if those spaces were pipes. When clay is compacted, these spaces are very small but still present.

Diffusion is the second way fluids flow between clay particles. Engineers who design landfills have, until now, simply ignored it. All molecules are in constant motion, with hotter molecules moving more rapidly than cooler ones. Due to this motion, molecules tend to move from a more concentrated chemical solution to a less concentrated one.

Consequently, the concentrated chemicals inside a landfill tend to move through the bottom clay liner even if there is no pressure pushing them downward.

The Canadian-American research team has shown that diffusion is a real mechanism by which substantial quantities of dangerous chemicals are moving through clay liners. This is not just theory! Organic chemicals like benzene will move through a three-foot thick clay liner in about five years.

These scientists conclude that a landfill only two and a half acres in size will pollute groundwater with 42 pounds of benzene per year, which is enough to contaminate over one billion gallons of water. In their report, the researchers cite eight prior studies that reached similar conclusions about chemical movement through clay.

Another researcher, J. A. Cherry, points out that when leaks occur in minimum design Subtitle D landfills, the leachate moves out in plumes that are only a few meters wide at the point of compliance (i.e., where groundwater monitoring wells are located).

Obviously, the width of these plumes varies depending upon the aquifer material. A plume width of a few meters applies only to landfills sited above homogenous sand aquifer systems.

However, for fractured rock systems like in a quarry, the plumes of leachate will be even narrower because they travel through fractures in the rock.

So why is this important? Regulatory agencies rely on monitoring wells spaced hundreds of feet apart to detect pollution. Each well has a zone of capture of about one foot from the well in many aquifer systems. In order to detect pollution from a rock quarry, the wells would have to be no more than 10 feet apart.

The bottom line is, under present regulations, pollution from a rock quarry landfill could easily go undetected until adjacent property owners notice a problem with their wells.

These well-known deficiencies in minimum Subtitle D landfills have led at least eight states to conclude that they do not protect groundwater. Some countries in western Europe and even Ontario, Canada, will not allow minimum Subtitle D landfills to be constructed because of their inevitable failure.

It is only a matter of time until the Environmental Protection Agency will be forced to recognize deficiencies in their landfill regulations and implement stricter guidelines. Individuals and communities need to make informed decisions based upon reliable scientific information.

The facts are there if one wants to dig for them, and they do withstand dispute, public scrutiny and media hype.

More from article archives
ORIGINALLY WRITTEN Madison Mae Meyer Paul and Rikki Meyer of Hillsboro announce...
Read More