I have 30 years of experience, and specialize in the field of environmental science with specific knowledge in the areas of geochemistry, water contamination and water purification. I have published on such topics as origin of ore deposits, corrosion scales in drinking water systems and constructed wetlands for remediation of acid mine drainage. I have testified on groundwater contamination, radioactive waste storage and groundwater-surface water interaction. I have worked on the chemistry of toxic metals from the source water to the tap in 12 countries.