Effects of Gamma Irradiation on an Aquatic Fulvic Acid
1991 (English)In: Humic substances in the aquatic and terrestrial environment : proceedings of an international symposium, Linköping, Sweden, August 21-23, 1989 / [ed] B. Allard, H. Borén and A. Grimvall, Berlin Heidelberg New York: Springer, 1991, 233-241 p.Chapter in book (Refereed)
An aquatic fulvic acid was irradiated with gamma radiation from a 60Co-source (dose range 0-48 Mrad), as part of a larger study of the transformation and decomposition of humic substances in natura! aquatic systems. Experiments were performed at two concentrations (1000 mg/l and 100 mg/l) and at various pH-values (2-10). The fulvic acid transformation was studied by monitoring optical density (UV-spectroscopy ), molecular weight distribution (GPC-technique) and total dissolved organic carbon (TOC). A general decrease in TOC with increasing radiation dose was observed: the initial G-value of about 5 decreased with the increasing dose to a minimum value of 0.2-0.3. A simultaneous increase in molecular weight (Mn rose from approximately 2000 to a maximum of about 4000) was observed in the acidic samples (pH 2-4) at a dose below 10 Mrad. Natural background radiation can significantly contribute to the degradation of dissolved humic substances in deep groundwaters, considering the observed G-value for low doses (about 5) and the otherwise high chemical stability of the fulvic acid fraction even after long residence times (103-104 y) in the ground.
Place, publisher, year, edition, pages
Berlin Heidelberg New York: Springer, 1991. 233-241 p.
, Lecture Notes in Earth Science, ISSN 0930-0317 ; 33
Environmental Sciences related to Agriculture and Land-use Chemical Sciences
IdentifiersURN: urn:nbn:se:liu:diva-112201ISBN: 3-540-53702-3OAI: oai:DiVA.org:liu-112201DiVA: diva2:764106