Amendment to Louisiana Statewide Order 29-B Suggested Modifications for Barium Criteria

Abstract

ABSTRACT This study was conducted to address the problem of inconsistent barium (Ba) analyses and the need to de-fine an acceptable criteria level. The study provides both mechanistic and comparative data in support of suggested changes in the Amendment to Statewide Order 29-B. Initial non-hazardous oilfield waste (NOW) studies, which served as the basis for Ba criteria, used 1979 ERA protocol for estimating total metal contents. Three published revisions have since been made by EPA concerning Test Methods for Evaluating Solid Wastes (SW-846, 1982; SW-846, 1984; and SW-846, 1986), Sample size was the principal difference reflected in the revised protocols; sample size decreasedover time. Experiments were designed and conducted to provide a method for determining "true" total Ba for comparison to SW-846 protocol. Regression analyses comparing SW-846 Ba as the dependent variable and corresponding total Ba as the independent variable showed the data best fit a polynomial (Y = -3.29 x 10 b(X)Z + 0.43 (X) + 376) with a r2 = 86%. Multiple linear regression analyses showed SW-846 Ba levels a function of the matrix pH, salinity, oil & grease, and "true" total Ba content. A metals fractionation by sequential chemical extrac-tion technique demonstrated that Ba remains in a solid phase (barite form), evenafter being circulated down hole and subjected to extreme heat and strongly alka-line reactions. Chemical distributions varied signi-ficantly in response to mixing NOW solids with native soil and subjecting mixtures to reducing (diminished oxygen tension) conditions. Total Ba and oxygen ten-sion (redox potential) were found to have the greatest affect on Ba activity.