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Los Alamos National Laboratory (LANL) has disposed at least 17,500,000 ft³ of hazardous and radioactive wastes on-site at twenty-four different officially-designated material disposal areas (MDAs) since 1944.  Information about these sites is summarized in Table A-1, and, in more detail, in Tables B-1 through B-24.  The locations of these sites are shown in Figure A-1, and more detailed site maps are provided in Figures B-1 through B-24, which have been integrated into Tables B-1 through B-24.

These twenty-four dumps pose varying risks to the environment.  Sixteen are thought to pose "moderate" to "high" risk of long-term groundwater contamination by the New Mexico Environment Department (NMED).  Some of these dumps are on hills, or very close to canyons, and some are in zones of relatively high precipitation and hence infiltration of rain and snow.  At some sites, such as MDA P in Technical Area (TA) - 16, ground-water contamination has already occurred.

At almost all of the sites, there has been little to no action taken by LANL to prevent the movement of contaminants--such as capping the closed disposal sites so that rain and snowmelt cannot enter and mobilize the hazardous or radioactive constituents.  There are, at the present time, no definite plans or commitments to stabilize or remediate any of these sites, save MDA P, which is being entirely removed this year.  This lack of action persists despite the expenditure by the LANL Environmental Remediation program of more than $500 million in the past ten years.

The quantity of waste at each site ranges from 15,885 ft³ to 10,800,000 ft³.  In many cases the waste volume is unknown and must be estimated from old plans and maps.  In some cases the types of waste disposed are known fairly well; in other cases the contaminants present can only be inferred.  Least well known is the amount of each specific contaminant, such as plutonium or other radionuclide, that the disposal records (often crude) may show to be present.

LANL continues to generate and dispose of radioactive waste on-site at a facility called "Area G," which is the largest MDA (63 acres) and contains the most waste (10,800,000 ft3; enough to fill 1.4 million 55-gallon drums).  LANL would like to expand MDA-G by 66 acres, more than doubling its size.  Several small Indian ruins lie in the expansion path.

Historically, Area G has received a wide variety of wastes, including spent nuclear fuel and highly-radioactive fission products, to large quantities of plutonium and tritium, to building rubble and contaminated soil.  LANL maintains that only low level waste (LLW) is disposed there today.  The term "low-level," however, is somewhat misleading, as many types of LLW are highly radioactive.  Area G, for example, received spent nuclear reactor fuel.

MDA-G is also used for storage of transuranic waste (TRUW), about 60,000 drums' worth so far, which is to be eventually shipped to the Waste Isolation Pilot Plant (WIPP) in southern New Mexico.  According to Department of Energy (DOE) sources, an unknown but large fraction, perhaps 50%, of this so-called "TRUW" is actually LLW, and is likely to be buried on site.

Figure A-2 shows current waste generation rates for LANL for LLW, hazardous chemical wastes, low-level "mixed" (radioactive and chemically-hazardous) waste (LLMW), and both TRUW and TRU "mixed" waste (TRUMW), by principal generating facility.  Most of this waste originates in nuclear weapons programs.  Efforts to reduce waste generation have been made; further waste-minimization is in many cases possible.

The radioisotopes disposed in these dumps will eventually decay.  "Eventually" can be a very long time in some cases, leaving a legacy of environmental problems for generations to come.  Common radioactive isotopes disposed at LANL and their half-lives are shown below:

One of the most interesting mysteries regarding waste at LANL is the whereabouts of hundreds of kilograms of plutonium-239.  Some 610 kg are unaccounted for by program use.  This plutonium has been assumed by DOE to have been disposed, or stored, in MDAs at LANL.  Where is it?

In addition to the MDAs officially used for waste disposal, there are close to two thousand  contaminated sites at LANL, so-called "potential release sites" (PRSs).  Some of these contain large sources of contamination, others are almost entirely benign.  Many have not been thoroughly investigated, let alone stabilized or removed.  Some lie in canyon bottoms, in or near watercourses and floodways, while others receive runoff from parking lots and rooftops.  As in the case of the MDAs, there are no definite plans to remediate most of these sites.

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