WATER QUALITY: Analytical Methods - Sulfate-Reducing Bacteria (Multiple-Tube Technique)


                                              March 18, 1974

QUALITY OF WATER BRANCH TECHNICAL MEMORANDUM NO. 74.12

Subject: WATER QUALITY: Analytical Methods - Sulfate-Reducing
         Bacteria (Multiple-Tube Technique)

The attached provisional method can be used for the detection and
quantification of all forms of sulfate-reducing bacteria and is
applicable for all waters including brines of high salt content.

Sulfate-reducing bacteria, which occur only in reducing environ-
ments, are obligate anaerobes (able to function only in the
absence of oxygen). They are responsible for the reduction of
sulfate (504-2) to sulfide (S-2) in the anaerobic decomposition of
organic matter

The sulfate-reducing bacteria may be encountered in ground water,
deep lakes, waterlogged soils, harbors and estuaries, and muds
from lake and stream bottoms. The organisms are important in the
sulfur cycle of lakes, where they generally occur in the boundary
layer between oxidizing and reducing zones in sediment and in
water.

Sulfate-reducing bacteria liberate hydrogen sulfide (H2S) gas. 
The gas is responsible for the excessive corrosion of various  
surfaces, as well as being odorous and highly toxic. Hydrogen
sulfide odors emanating from sanitary landfills often can be
attributed to sulfate-reducing bacteria.

The bacteria have been implicated in numerous instances of
corrosion of buried pipelines. Rusty water and offensive odors
at isolated points in water-supply distribution systems are
often attributed to sulfate-reducing bacteria. The organisms
are reported to be the most common organisms found in the slimes
that plug tubes of cooling systems or line the tube walls thereby
acting as insulators and decreasing efficicncy.

Questions or comments pertaining to the procedure should be 
directed to the Chief, Quality of Water Branch Mail Stop 412, 
Reston, Virginia).



                               R. J. Pickering

Attachment

WRD Distribution: A, FO-LS, PO- SL