E5 COD [mg l-1] YEAR: 1979 Determined by KMnO4 meth Station Surface --------------------- Harangga 2.30 Prapat 2.80 Mogang 2.24 Onan Run 2.15 Porsea 2.06 Hashingg 1.30 Tomok 1.53 Sabulan 1.72 Muara 1.36 Balige 1.24