Starting in the 1970s and continuing throughout the 1980s, U.S.
Environmental Protection Agency [EPA] funded research which
showed that burying household garbage in the ground poisons the
groundwater. On several occasions, EPA spelled out in detail the
reasons why all landfills leak.
Then in late 1991, after several years of deliberation, EPA chief
William Reilly issued final landfill regulations that allow the
continued burial of raw garbage in landfills.
EPA's 1991 regulations require an expensive landfill design: two
liners in the ground and an impervious plastic cover over the
landfill after it has been filled with garbage.
This is "state of the art" technology, the very best that modern engineers can
build. However, EPA officials still expect such landfills to
fail and eventually poison groundwater. As early as 1978, EPA knew why all landfills eventually leak. The
main culprit is water. Once water gets into a landfill, it mixes
with the garbage, producing a toxic leachate ("garbage juice"),
which is then pulled downward by gravity until it reaches the
groundwater. Therefore, the goal of landfill designers (and
regulators) is to keep landfills dry for the length of time that
the garbage is dangerous, which is forever.
Now a 1992 report from a California engineering-consulting firm,
G. Fred Lee & Associates, has examined recent scientific studies
and has confirmed once again why modern "dry tomb" landfill
technology will always fail and should always be expected to
poison groundwater.
The new report, authored by Fred Lee and Anne Jones, reviews
recent evidence--much of it produced by government-funded
research--that landfill liners leak for a variety of reasons;
that leachate collection systems clog up and thus fail to prevent
landfill leakage; that landfill leachate will remain a danger to
groundwater for thousands of years; that even low-rainfall areas
are not safe for landfill placement; that gravel pits and canyons
are particularly dangerous locations for landfills; that
maintaining a single landfill's cap for the duration of the
hazard would cost hundreds of billions, or even trillions, of
dollars; that groundwater monitoring cannot be expected to detect
landfill leakage; that groundwater, once it is contaminated,
cannot be cleaned up and must be considered permanently
destroyed; and that groundwater is a limited and diminishing
resource which modern societies grow more dependent on as time
passes.
A 1990 examination of the best available landfill liners
concluded that brand-new state-of-the-art liners of high density
polyethylene (HDPE) can be expected to leak at the rate of about
20 gallons per acre per day (200 liters per hectare per day) even
if they are installed with the very best and most expensive
quality-control procedures. This rate of leakage is caused by
pinholes during manufacture, and by holes created when the seams
are welded together during landfill construction. (Landfill
liners are rolled out like huge carpets and then are welded
together, side by side, to create a continuous field of plastic.)
Now examination of actual landfill liners reveals that even the
best seams contain some holes.
In addition to leakage caused by pinholes and failed seams, new
scientific evidence indicates that HDPE (high density
polyethylene, the preferred liner for landfills) allows some
chemicals to pass through it quite readily. A 1991 report from
University of Wisconsin shows that dilute solutions of common
solvents, such as xylenes, toluene, trichloroethylene (TCE), and
methylene chloride, penetrate HDPE in one to thirteen days. Even
an HDPE sheet 100 mils thick (a tenth of an inch)--the thickness
used in the most expensive landfills) is penetrated by solvents
in less than two weeks.
Another problem that has recently become apparent with HDPE
liners is "stress cracking" or "brittle fracture." For reasons
that are not well understood, polyethylenes, including HDPE,
become brittle and develop cracks. A 1990 paper published by the
American Society for Testing Materials revealed that HDPE liners
have failed from stress cracks in only two years of use.
Polyethylene pipe, intended to give 50 years of service, has
failed in two years.
Lee and Jones sum up "While the
long-term stability of geomembranes (flexible membrane liners) in
landfills cannot be defined, there is no doubt that they will
eventually fail to function as an impermeable barrier to leachate
transport from a landfill to groundwater. Further, and most
importantly at this time, there are no test methods, having
demonstrated reliability, with which to evaluate long-term
performance of flexible membrane liners."
Recent scientific studies of clay indicate that landfill liners
of compacted clay leak readily too. For example, a 1990 study
concludes,
IF A NATURALLY OCCURRING CLAY SOIL IS COMPACTED TO HIGH
DENSITY, THEREBY PRODUCING A MATERIAL WITH VERY LOW HYDRAULIC
CONDUCTIVITY, AND IF IT IS MAINTAINED WITHIN THE SAME RANGES OF
TEMPERATURE, PRESSURE, AND CHEMICAL AND BIOLOGICAL ENVIRONMENT,
IT WOULD BE EXPECTED TO FUNCTION WELL AS A SEEPAGE BARRIER
INDEFINITELY. IN WASTE CONTAINMENT APPLICATIONS, HOWEVER,
CONDITIONS DO NOT REMAIN THE SAME. THE PERMEATION [PENETRATION]
OF A COMPACTED CLAY LINER BY CHEMICALS OF MANY TYPES IS
INEVITABLE, SINCE NO COMPACTED CLAY OR ANY OTHER TYPE OF LINER
MATERIAL IS EITHER TOTALLY IMPERVIOUS OR IMMUNE TO CHEMICAL
INTERACTIONS OF VARIOUS TYPES.
The 1992 study by Lee and Jones is an excellent resource for
anyone wanting to understand why landfills always fail. In their
footnotes, they cite 18 other studies of landfill problems that
they themselves have authored, so their expertise is
unquestionable, their information reliable, their arguments solid.
There has been sufficient scientific evidence available for a
decade to convince any reasonable person that landfills leak
poisons into our water supplies, and are therefore anti-social.
The question remains: what will it take to convince
government--specifically EPA--to base policy on its own
scientific studies and its own understanding?
