Method For Determining The Biodegradability Of Surfactants

The awareness and development of 'biodegradable' surfactants pre-dates current pressures by the environmental movement by nearly three decades, wherein a responsible industry mutually agreed to replace 'hard', non-biodegradable com ponents of household detergents by 'soft', biodegradable alternatives, without course to legislation. The only requirement at that time was for surfactants used in detergents to exhibit a 'primary biodegradability' in excess of 80%; this referring to the disap pearance or removal from solution of the intact surface active material as de tected by specified analytical techniques. This proved useful, as observed environmental impacts of surfactants, e.g. visible foam on rivers, are associated with the intact molecule. Test methods for 'primary biodegradability' were eventually enshrined in EU legislation for nonionic surfactants (Directive 821242/EEC, amended 73/404IEEC) and for anionic surfactants (Directive 8212431EEC, amended 73/405IEEC). No approved test methods and resultant legislation have been developed for cationic and amphoteric surfactants to date. The environmental classification of chemical substances, which of course includes surfactants, and associated risk assessment utilises a second criterion 'ready biodegradability'. This may be assessed by a number of methods which monitor oxygen uptake (BOD), carbon dioxide production or removal of dis solved organic carbon (DOC). Some surfactants which comply with the above Detergents Directive are borderline when it comes to 'ready biodegradability'.

This book contains a collection of different biodegradation research activities where biological processes take place. The book has two main sections: A) Polymers and Surfactants Biodegradation and B) Biodegradation: Microbial Behaviour.

"Presents the most comprehensive coverage available of the detection, isolation, identification, and estimation of all anionic surfactants in a wide variety of samples in trace and macro quantities. Features new chapters on volumetric and trace analysis, molecular and mass spectroscopy, and chromatographic processes."

Holberg (materials and surface chemistry, Chalmers U. of Technology, Sweden) presents updated versions of the first edition's eleven chapters and includes six new chapters, mostly dealing with the concept of natural surfactants. Each chapter deals with a particular class of surfactant and is present.

The book summarizes and reviews the environmental and human safety of two classes of nonionic surfactants-alcohol ethoxylates (AE) and alkylphenol ethoxylates (APE). This unique resource contains critical data from published sources as well as from unpublished studies submitted by Soap and Detergent Association member companies. It reviews information on product chemistry and analysis, biodegradation, environmental levels (including fate and distribution), aquatic toxicity, and human safety. Recently developed analytical techniques for the extraction, separation, detection, and measurement of nonionic surfactants and their metabolites in environmental samples are described. Results of biodegradation studies performed with a variety of test systems are tabulated, as are results of field studies at wastewater treatment plants. Reported comparisons of environmental levels with results of acute and chronic aquatic toxicity tests are provided. The information on the toxicity and irritation potential of AE and APE surfactants includes data from in vitro, mammalian, and human studies.