In the mid-1970’s, the concept of having a collection of standard humic and fulvic acids that would be available to scientists who study humic substances was promoted by several scientists, most notably Patrick MacCarthy of the Colorado School of Mines. He was joined by other noted scientists such as Ron Malcolm, Michael Hayes, Roger Swift, and Morris Schnitzer. Through the efforts of these and other scientists who studied humic substances in soils, sediments, and natural waters, the International Humic Substances Society (IHSS) was organized in 1981. With substantial support from the United States Geological Survey, the IHSS selected three solid-phase source materials (a soil, a peat, and a leonardite) and one water sample (a blackwater river) and then isolated a suite of standard humic and fulvic acids from those source materials. Additional hard work of many volunteers over the ensuing years has allowed additional reference humic and fulvic acids to be collected, and standard samples have been replenished whenever necessary.
The existence of this collection of standard and reference humic substances makes it possible, for the first time, for researchers throughout the world to compare critically their experimental results on humic substances. Samples of the original solid earth materials and the standard and reference humic substances are available from the IHSS on a cost-reimbursable basis. Unique features of the collection are: (1) it is accessible to researchers worldwide; (2) all materials originated from carefully chosen and specified locations; (3) all samples have been isolated by carefully controlled and supervised procedures that are fully documented; (4) all materials (both the isolated humic substances and the bulk solids) have been thoroughly homogenized; and (5) availability of the three bulk solids allows the comparison of different extractive methods.
Interested readers are referred to the following articles to learn more about the historical background of the IHSS and its collection of standard and reference humic substances:
- P. MacCarthy, “A Proposal to Establish a Reference Collection of Humic Materials for Interlaboratory Comparisons”. Geoderma, 16, 179-181 (1976).
- P. MacCarthy and R.L. Malcolm, “The Need to Establish a Reference Collection of Humic Substances”. In: Trace Organic Analysis: A New Frontier in Analytical Chemistry, S.N. Chesier and H.S. Hertz (Eds.), U.S. National Bureau of Standards Special Publication No. 519, Maryland, 793-796 (1979).
- R.L. Malcolm and P. MacCarthy, “A Proposal for Implementing a Reference Collection of Humic and Fulvic Acids”. In: Trace Organic Analysis: A New Frontier in Analytical Chemistry, S.N. Chesier and H.S. Hertz (Eds.), U.S. National Bureau of Standards Special Publication No. 519, Maryland, 789-792 (1979).
- P. MacCarthy and R.L. Malcolm, “Proposed Organizational Scheme and Experimental Methods for Establishing a Reference Collection of Humic Substances”. 11th Congress of the International Society of Soil Science, Edmonton, Canada, June 1978, Abstracts, 1, 57 -58.
- E.M. Thurman and R.L. Malcolm, “Preparative Isolation of Aquatic Humic Substances”. Environ. Sci. Technol., 15, 463-466 (1981).