Science and Regulation of Arsenic in Groundwater

Kate Magee, 616 FM 1960 Road West #575, Houston, TX 77090: kate.magee@c-ka.com

Arsenic is commonly associated with oil and gas, mining, manufacturing, and agricultural sites. It may be either naturally-occurring or an introduced contaminant. In cases where arsenic has been released into the environment, site-specific geochemical conditions dictate its fate and transport. State agencies have differing guidelines and standards for risk assessment and remediation of sites affected by arsenic. 

This presentation will include a summary of potential arsenic contaminant sources (e.g., the use of corrosion inhibitors, disposal of arsenic-containing brines, condensate/crude oil, and mine tailings, use of arsenic-based herbicides, etc.). Geochemical parameters that influence arsenic speciation (arsenate vs. arsenite), mobility, and toxicity will also be presented. These include oxidation reduction potential, dissolved oxygen, and the presence of hydrous ferric oxides, among others. A comparison of state guidelines will also be presented and will include Louisiana, Texas, New Mexico, Oklahoma, as well as Montana, North Dakota, and Pennsylvania. The history and occurrence of arsenic in Louisiana will also be discussed.