Environmental Health News

What's Working

  • Garden Mosaics projects promote science education while connecting young and old people as they work together in local gardens.
  • Hope Meadows is a planned inter-generational community containing foster and adoptive parents, children, and senior citizens
  • In August 2002, the Los Angeles Unified School District (LAUSD) Board voted to ban soft drinks from all of the district’s schools

#37 - EPA Says All Landfills Leak, Even Those Using Best Available Liners, 09-Aug-1987

People who are enthusiastic about garbage incinerators often fail to
mention that every incinerator has a landfill associated with it. The
ash left over from incineration needs to be landfilled, and the ash is
toxic. Some engineers (especially those employed to promote garbage
incinerators) try to argue that the toxic constituents of the ash will
remain safely in the landfill "forever." But this is a flawed view: the
weight of evidence and opinion in the technical world does not agree
with this argument. On the contrary, even the U.S. Environmental
Protection Agency says that all landfills will leak. The agency has
published this opinion on many occasions in the FEDERAL REGISTER. But
before we look at the EPA's reasons for believing all landfills will
leak, let's look at the way landfills are constructed:

A landfill is a carefully-engineered depression in the ground (or built
on top of the ground, resembling a football stadium) into which wastes
are put. The intention is to avoid any hydraulic [water-related]
connection between the wastes and the natural environment. To achieve
this goal, there are four important parts of all landfills: a bottom
liner, a leachate collection system, a cover, and the natural
hydrogeologic setting (the earth).

The hydrogeologic setting can be selected to slow the entry of wastes
into the natural environment. The other three components must be
engineered. The bottom liner can be one or more layers of clay or a
synthetic flexible membrane liner [FML], for example, a sheet of
plastic; the liner effectively creates a bathtub in the ground. The
leachate collection system consists of sloping the sides of the
landfill and putting pipes in the lowest places, to pump out
contaminated water and other fluids (leachate) as they accumulate; the
pumped leachate is treated at a wastewater treatment plant (and the
solids removed from the leachate during this step are returned to the
landfill, or are sent to some other landfill). The cover or cap will
consist of several sloped layers of clay or FML (to prevent rain from
intruding), overlain by a very permeable layer of sandy or gravely
soil, overlain by topsoil in which vegetation can root (to stabilize
the underlying layers of the cap).

Each of these components is critical to success. If the bottom liner
fails, wastes will migrate directly into the environment. If leachate
collection pipes clog up and leachate remains in the landfill, fluids
can build up in the bathtub; the resulting liquid pressure becomes the
main force driving waste out the bottom of the landfill when the bottom
liner fails. If the cover (cap) is not maintained, rain will enter the
landfill, resulting in buildup of leachate to the point where the
bathtub overflows its sides and wastes enter the environment.

In the FEDERAL REGISTER Feb. 5, 1981, the EPA first stated its opinion
that all landfills will eventually leak:

"There is good theoretical and empirical evidence that the hazardous
constituents that are placed in land disposal facilities very likely
will migrate from the facility into the broader environment. This may
occur several years, even many decades, after placement of the waste in
the facility, but data and scientific prediction indicate that, in most
cases, even with the applica tion of best available land disposal
technology, it will occur eventually." [pg. 11128]

"Manmade permeable materials that might be used for liners or covers
(e.g., membrane liners or other materials) are subject to eventual
deterioration, and although this might not occur for 10, 20 or more
years, it eventually occurs and, when it does, leachate will migrate
out of the facility." [pg. 11128]

"Unfortunately, at the present time, it is not technologically and
institutionally possible to contain wastes and constituents forever or
for the long time periods that may be necessary to allow adequate
degradation to be achieved." [pg. 11129]

"Consequently, the regulation of hazardous waste land disposal
facilities must proceed from the assumption that migration of hazardous
wastes and their constituents and by-products from a land disposal
facility will inevitably occur." [pg. 11129]

More than a year later, on July 26, 1982, the EPA again put its
opinions into the FEDERAL REGISTER, emphasizing that all landfills will
inevitably leak:

"A liner is a barrier technology that prevents or greatly restricts
migration of liquids into the ground. No liner, however, can keep all
liquids out of the ground for all time. Eventually liners will either
degrade, tear, or crack and will allow liquids to migrate out of the
unit." [pg. 32284]

"Some have argued that liners are devices that provide a perpetual seal
against any migration from a waste management unit. EPA has concluded
that the more reasonable assumption, based on what is known about the
pressures placed on liners over time, is that any liner will begin to
leak eventually." [pgs. 32284-32285].

In the FEDERAL REGISTER May 26, 1981, pgs. 28314 through 28328), the
EPA argued forcefully that all landfills will eventually leak. Another
EPA quote:

"Many organic constituents are stable (degrade very slowly); other
hazardous constituents (e.g., toxic metals) never degrade. Yet the
existing technology for disposing of hazardous wastes on or in the land
cannot confidently isolate these wastes from the environment forever.

"Since disposing of hazardous wastes in or on the land inevitable
[inevitably?] results in the release of hazardous constituents to the
environment at some time, any land disposal facility creates some
risk." [pg. 28315]

EPA went on to estimate that the duration of the hazard from a landfill
would be "many thousands of years." [pg. 28315] And the Agency said,
"The longer one wishes to contain waste, the more difficult the task
becomes. Synthetic liners and caps will degrade; soil liners and caps
may erode and crack. ...EPA is not aware of any field data showing
successful long-term containment of waste at facilities which have not
been maintained over time." [pg. 28324]

"Ultimately, waste reduction and resource recovery probably provide the
best alternative to land disposal," said the EPA [pg. 28325], though it
has never begun any programs to make this happen.

--Peter Montague


Descriptor terms: ash; epa; landfilling; soil; leachate; hazardous
waste; land; land disposal; heavy metals; water