Selected sediment characteristics are shown in
Table 2. The sediments were slightly alkaline with
pH ranging from 7.0-8.9. Sediment organic matter
ranged from 0.2-6.2 % with high values (>4%)
found in estuarine sediments, especially at
Bangpakong, Weru and Trat estuaries where the
sediments were also high in CEC (>20 cmol kg-1).
CaCO3 content in the sediments was between 0.13-
12.4 % with high values found in Laem Chabang
area from Bang Pra - Na Klua (zone C). Higher Fe
oxides contents were also observed in the sediments
than Mn oxides. The high Fe oxides were mainly
found at estuaries in Trat and Chanthaburi Provinces,
whereas the high Mn oxides were mainly
found at Bangpakong estuary.