CONCLUSION
The concentrations of lead and copper in
the river water in some areas of the Tha Chin River
were found to be higher than the standard values.
During the wet season, high concentrations of
zinc, in excess of standard values, were observed
also. The native aquatic plant species Ipomoea
aquatica and Neptunia oleracea were found to
accumulate high concentrations of the same heavy
metals. Statistical analysis revealed that copper in
I. aquatica had a positive correlation with copper
in the surrounding water. The overall results
demonstrated that I. aquatica and N. oleracea
can be used to remediate heavy metal pollution
in water.