Barium Sulfate: A Protocol for Determining Higher Site-Specific Barium Cleanup Levels

Abstract Although different barium compounds are known to exhibit vastly different toxicities, cleanup standards for barium in soil or sediment at environmental corrective action sites are typically based on total barium concentration without regard for the specific barium compounds present. However, the Texas Commission on Environmental Quality (TCEQ) has recently agreed that the insoluble barium compound barium sulfate (i.e., barite) is not a compound of concern with regard to human health, thereby eliminating the need for cleanup standards or site remediation for this compound. The TCEQ still requires that their barium cleanup standards be applied to any soluble barium compounds that may be present at a site. To allow the application of barium cleanup standards to soluble barium compounds while excluding barium sulfate, we have developed a protocol to measure the concentration of soluble barium in soil or sediment samples that may contain both barium sulfate and soluble barium compounds. In this paper, we present (1) a review of the toxicity and regulation of soluble barium compounds and insoluble barium sulfate, and (2) a description of our protocol to measure the concentration of soluble barium compounds in soil and sediment samples and the validation of this protocol.