National Ground Water Association

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.