Environmental Geochemistry of Metals: Investigation and Remediation
Soil and ground water 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
ground water. Chemical manipulation of aquifer material and ground
water 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
ground water 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, plutonium-239 and -240,
strontium-90, tritium, and others is also presented in the short
course. The course also 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 ground
water. 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.