Soil and groundwater at many mining, industrial, and power utility
sites in the United States and elsewhere are contaminated by metals,
radionuclides, and other inorganic chemicals. Remediation by natural
attenuation, also known as intrinsic remediation, is a viable approach
for reducing the risk associated with metal/inorganic solute plumes in
groundwater. Chemical manipulation of aquifer material and groundwater
is also being implemented at some sites to immobilize redox-sensitive
contaminants, including chromium, technetium, and uranium.
Regulatory agencies support risk-based approaches to remediation
including intrinsic remediation for metal/inorganic contaminants. Collecting and interpreting site characterization data and information
must support intrinsic remediation options, which are technically
defensible. This includes assessment of the geochemistry of contaminants
of concern and quantification of geochemical properties of aquifer
material. Important geochemical interactions that influence fate and
transport of contaminants include aqueous speciation of native
groundwater and dissolved contaminants; distribution and abundance of
reactive minerals including hydrous ferric oxide, clay minerals, and
carbonate minerals; adsorption reactions; mineral equilibrium; and
radioactive decay. Designing an effective sampling program that supports
intrinsic remediation and chemical manipulation is based on a thorough
understanding of site hydrogeochemistry and hydrology.
This course provides practical information needed to effectively
evaluate intrinsic remediation and chemical manipulation of sites
contaminated with metals, nonmetals, and radionuclides. Chemicals of
concern discussed in this short course include aluminum, antimony,
arsenic, barium, beryllium, boron, cadmium, chromium, cobalt, copper,
iron, lead, manganese, mercury, molybdenum, nickel, nitrogen,
perchlorate, selenium, silver, thallium, uranium, vanadium, and zinc. Intrinsic remediation of radionuclides, including americium-241,
cesium-137, neptunium-237, plutonium-238, -239, and -240, strontium-90,
and tritium, as well as others, are also discussed. In addition, the
course consists of in-depth discussions on metals/inorganic geochemistry
and investigation methods, geochemical aspects of intrinsic remediation
of inorganic chemicals and radionuclides, and chemical manipulation of
aquifer material and groundwater.
The course emphasizes hydrogeochemical processes and field
implementation procedures for quantifying and assessing intrinsic
remediation and chemical manipulation of metal/inorganic contaminants. Data collection and analyses, assessment of hydrogeochemical processes,
quantification of contaminant mobility, and understanding regulatory
considerations involved in implementing intrinsic remediation and
chemical manipulation as viable restoration/remediation options are also
presented. Case histories are presented throughout the course. Class
exercises focusing on geochemical processes, intrinsic remediation, and
chemical manipulation are included each day of the course.