L1 /
5
CH3041
HUMIC MATTER
• (2) Humic Matter (» 50%): is operationally defined as the material that is trapped on a XAD-8 resin column. The material collected may be further subdivided into:
« Humic
acids content is: » 10%
ppt at pH=2 molecular weights 1000 - 5000
ppt at pH=2 molecular weights 1000 - 5000
« Fulvic acids content is: » 40%
no ppt pH>1 molecular weights 500 - 1500
no ppt pH>1 molecular weights 500 - 1500
• Oceans the
DOM is around 1mg / L.
• Freshwater DOM is around 4mg / L.
• Material which is
not trapped on the XAD-8 column and
is acidic in nature is referred
to as the hydrophilic fraction (» 30%) – in the seriously hard to characterise category.
to as the hydrophilic fraction (» 30%) – in the seriously hard to characterise category.
• The amount of DOM in the C cycle is larger than the amount of C in terrestrial biota.
