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Effects of environmental variables on binding of a PCB congener by dissolved humic substances
Author(s) -
Jota Mary Anne T.,
Hassett John P.
Publication year - 1991
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1002/etc.5620100408
Subject(s) - humic acid , chemistry , dissolved organic carbon , environmental chemistry , ionic strength , van der waals force , aqueous solution , organic matter , inorganic chemistry , organic chemistry , molecule , fertilizer
The magnitude of the binding interaction of dissolved organic matter with 2,2′,5,5′‐tetrachlorobiphenyl is affected by several environmental parameters: pH, ionic strength of the aqueous media, molecular weight and the source of the binding agent. Temperature has little effect. The binding constant for Aldrich humic acid is on the order of 1 × 10 5 . Humic acids extracted from soil and water samples have lower binding capabilities than Aldrich humic acid ( K DOC range: 0.24 × 10 5 ‐0.64 × 10 5 ), whereas the fulvic acid and dissolved organic matter samples have K DOC s near the method detection limit (0.086 × 10 5 and 0.0076 × 10 5 , respectively). Thermodynamic studies show the binding interaction to be entropy driven with ΔH° similar to that of van der Waals's interaction.