I am sure you are familiar with the book on the Standard Methods for Analyzing Water and Wastewater.  I don't have one anymore.  But go to those tests for organics, etc. and look up the background references that they used to set up preservation and storage guides.  It may not tell you exactly who or why they decided on preservation techniques, but someone in a lab probably did due diligence in trying techniques, and determining breakdown rates under different scenarios.  The details are seldom published, but reviewing the references and authors might give you potential contacts to find out some of the lab based and chemical theory behind the procedures.