AREA A/B ENGINEERING REPORT - Waste Management

A3. POTENTIAL HEALTH IMPACTS OF MSW LANDFILL LEACHATE
A3.1 Technical Synopsis
Geosyntec Consultants
• Modern landfills are engineered to be closed systems that incorporate liner and
leachate collection systems to prevent release of contaminants to groundwater;
• Conclusions about health risks associated with modern MSW landfills cannot be
extrapolated from studies of older or different types of landfills; and
• Epidemiological studies clearly indicate the absence of a link between modern MSW
landfills and health impacts.
Seminal Supporting References: Redfearn & Roberts, 2002; DEFRA, et al., 2004, PhRMA
(2006).
A3.2 Summary of Supporting Body of Knowledge
In response to some public misconceptions that all liners will fail and that toxic compounds will be
released to groundwater and other landfill receptors, details regarding the large number of liner
performance design and operational practices available to prevent a release are discussed in
great detail in Appendix B. In brief, MSW landfills are engineered to be closed systems that
incorporate liner and liquids collection systems to prevent release of contaminants to the
environment. This concept is supported by the Interstate Technology and Regulatory Council’s
September 2006 Technical and Regulatory Guidance entitled “Evaluating, Optimizing, or Ending
Post-Closure Care at Municipal Solid Waste Landfills Based on Site-Specific Data Evaluations”
states (ITRC, 2006b): “…a solid waste landfill is a performance-based system that is constructed
and/or managed to minimize potential impacts from site-specific leachate, landfill gas, and/or
groundwater. [Wastes] contained within a landfill structure may represent a potential risk; however,
exposure to the wastes can be managed and evaluated on site-by-site basis to determine whether
such a condition represents a threat to [HHE].”
The potential for leachate to impact HHE is a function of the constituents it contains, the
availability of a pathway to a viable receptor, and the dose a receptor may be exposed to,
considering natural attenuation processes (i.e., fate) endured by the leachate during its transport
(e.g., biodegradation, dilution, and/or diffusion). Because of the extremely high effectiveness of
the containment systems at well-constructed modern Subtitle-D landfills and the institutional
controls that prevent direct contact of receptors with waste, the potential for leachate constituents
to impact a receptor via a surface water or groundwater pathway is unlikely to be significant. In
any evaluation of the “toxicity” of MSW leachate, it is also critical to note that effects are dosedependent.
Even essential minerals and vitamins – generally not considered to be toxic – can
MD10186.doc 113 29 March 2009