DETECTION OF MICROBIAL SULFATE-REDUCTION ASSOCIATED WITH BURIED STAINLESS STEEL COUPONS

摘要

The objective of this study was to demonstrate applicability of an innovative radioactive isotope method for imaging microbial activity in geological materials to a comprehensive study of metal corrosion. The method was tested on a sample of stainless steel coupons that had been buried as part of a corrosion study initiated in 1970 by the National Bureau of Standards (now National Institute of Standards and Testing or NIST). The images showed evidence of microbial activity that could be mapped on a millimeter scale to coupon surfaces. A second more conventional isotope tracer method was also used to provide a quantitative measure of the same type of microbial activity in soil proximal to the buried coupons. Together the techniques offer a method for detecting low metabolic levels of microbial activity that have the potential for significant cumulative corrosion effects to metals. The methods are particularly applicable to monitoring steel components that are expected to remain buried and in tact for very long periods as in nuclear waste storage applications.