Interaction of formaldehyde with soil humic substances: Separation by GFC and characterization by H-1-NMR Spectroscopy

摘要

Humic substances (HS) are major components of soil organic matter. They are structurally complex, containing a wide variety of functional groups, depending on such factors as their age and the parent material from which they are derived (Wershaw 1999). Despite their extensive distribution (in soils, lakes, rivers and seas) much remains to be discovered about their specific chemical structure and their subsequent interactions with chemicals in the environment. The question of how HS affect the activity, sorption, bioavailability and survival rate of pesticides becomes a major issue as these compounds are applied to an ever-increasing area of agricultural land (the area treated in the UK has increased four-fold from 1974 to 1996 according to Thomasand Wardman (1999)). Formaldehyde is present in the environment both as a result of natural processes (decomposition of plant residues) and from man-made sources (industrial production and emissions), and is considered an environmental contaminant due todetection at levels higher than background concentrations. Formaldehyde has a variety of uses in many industries but direct contact with the soil occurs due to agricultural application of formaldehyde as a fumigant, fungicide or bactericide (Tomlin 2000