However, this index depends on the choice of
an appropriate natural background value. Since
there are no metal background values for this study
area, the crustal average values (Taylor 1964) were
used to calculate this index. Results of Igeo values
of the sediment heavy metals are given in Table 2
and Figure 3. According to the Igeo classification,
the study area may be considered moderately polluted
with Pb (Igeo > 1) in some locations with the
highest contamination observed at Map Ta Phut
Industrial Estate. This may be due to the input of
various industries around and automobile aerosol
lead. In addition, a lower degree of pollution was
found in the sediments by Cu (at Prasae estuary
and Kung Kraben Bay), Zn (at Chon Buri Bay),
and Mn (at Bangpakong estuary). There was no
pollution from Hg, Cd and Ni in the sediments and
Fe could be neglected due to very low Igeo value
obtained (Igeo =