Fig. 8. Size fractions of dissolved and colloidal organic C (DOC) as percentages (average and SE) of total DOC in oxidation pond effluent (OPE) and in soil solutions displaced from sand-packed lysimeters. The lysimeters were irrigated for 6 to 7 mo with either (i) OPE or (ii) tap water or (iii) OPE (for 3 mo) and than with tap water. Irrigation was under the deficit-irrigation regime. The size fractions were separated sequentially with membranes having the depicted nominal cutoffs (in µm or kDa).