Abstract

Roopali Ghode, Rajashree Muley and Rajkamal Sarin*

A study has been conducted to determine the influence of pH on speciation and distribution of barium and chromium in drilling mud. Samples on equilibration under controlled conditions were subjected to sequential extration procedure to fractionate the heavy metals into the designated forms of exchangeable, absorbed, organicaly bound, carbonate and residual phases, thus providing insight into the potential availability of the heavy metals for possible release into groundwaters and/or surface waters. The major portion of both the metals studied was found in the carbonate and residual forms with relative distribution among these forms depending on the pH. Generally, decreasing pH caused a shift from the residual form towards the carbonate or organic forms of metals. The occurrence of metals in more stable organic, carbonate and residual forms in drilling mud, coupled with no significant release to the aqueous phase upon varying pH indicates the resistance of these metals to remobilization from drilling mud.

Speciation; Heavy metals; Barium; Chromium; Drilling mud; Sequential extraction

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