irly obvious, innocuous, and relatively inexpensive amelioration has ever been practiced at a sanitary (garbage/ refuse) landfill, although "solidification/ stabilization" with Portland cement to form, essentially, concrete blocks of such materials is a standard practice at hazardous waste landfills (12:714).
Webster and Loehr (12) leached cadmium, chromium, and lead from crushed, broken-up particles of concrete with both successively lower and lower pH leachants (i. e., more and more acidic ones) and with seawater, a relatively high-pH (8.3) liquid. The acidic leachants used in EPA-mandated tests of leaching potential tended to cause rather severe solubilization of the metals and of the calcium (alkalinity) structure of the crushed particles; whereas the seawater was a much less effective leachant of either metals or alkalinity (12:718-19). In the end, "Acidic leaching tests provide for much more severe conditions than the [crushed rather than intact] concrete products are likely to encounter in real-world applications" (12:720). So, placing solid materials in the ground does not destine them, necessarily, for eventual leaching.
In studies of the movements of leachate in sanitary landfills at sites as disparate as Australia (13) and South Africa (2), workers have found that leachate production in semiarid (low-rainfall) areas of the world is still driven by a portion of local rainfall's seeping through the landfill, even if as little as 1-7% of that rainfall is involved (13:266). In South Africa, it was noted that long periods of unsaturated flow in a landfill can produce a gradient for the leachate that is actually upward, driven by evaporation at the surface, rather than downward during or immediately following rainfall and the pooling of surface runoff (2:267).
From much more theoretical studies of mathematical models (n the United States), Ostroff (7) has warned that some hydrologic modeling of landfill leachate pro...