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Metal Binding Properties of Leaf Litter Extracts: II. A Bioassay Technique
Author(s) -
Blaser P.,
Landolt W.,
Flühler H.
Publication year - 1980
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1980.03615995004400040010x
Subject(s) - chemistry , algae , metal , stability constants of complexes , environmental chemistry , ionic strength , bioassay , metal ions in aqueous solution , litter , ionic bonding , ion , botany , aqueous solution , organic chemistry , ecology , biology
A biological method is proposed to determine the maximum Cu binding ability and the conditional stability constant of leaf litter extracts. Free cupric ions reduce the 14 CO 2 ‐uptake of algae. In the presence of complex forming organic substances the observed depression of the relative CO 2 uptake can be considered as a measure of the unbound ionic Cu concentration. Comparing the CO 2 ‐uptake response function of solutions, with and without organic constituents spiked with variable amounts of Cu, yields a functional relationship between bound and free Cu. These functions can be interpreted with a sequential form of the Langmuir equation from which the maximum binding ability and the conditional stability constant are obtained. The presence of algae, modifies the complexing parameters, indicating that the values measured with nonbiological methods require careful interpretation when their significance in natural soils is considered.