TRIHALOMETHANE AND HALOACETIC ACID FORMATION POTENTIAL OF TROPICAL PEAT WATER: EFFECT OF TIDAL AND SEASONAL VARIATIONS

Abstract

The existence of humic substances in peat water impacts the presence of the dissolved organic
matter (DOM) which is the precursor of trihalomethanes (THMs) and haloacetic acids (HAAs). However,
information on DOM characteristics, THMs and HAAs Formation Potential (THMFP and HAAFP) in tropical
peat water are still limited. This study aimed to determine the correlations between DOM, THMFP, and
HAAFP during dry and rainy seasons in tropical peat water in Indonesia. Samples of peat water are taken from
the water canal and tidally affected river on Sumatera’s peatland during the rainy season and dry season to
determine the effects of the seasons and tides. DOM measured by dissolved organic carbon (DOC), specific
ultraviolet absorbance and the ratio of E465/E665 while THMFP determined from a total of THMFP4
measurements and HAAFP determined from measurement of total HAAFP5. Compared to dry season, values
of all organic parameters on rainy season were higher but fewer in river. Canal water has a higher DOC while
river water has a higher chloride and bromide content. Increasing of DOC in the rainy season correlates with
increasing of THMFP4 and HAAFP5. THMFP4 is dominated by chloroform on canal while brominated THMs
predominate in river water which correlates with the presence of bromide. Chlorinated HAAs dominate
HAAFP5 in canal water while brominated HAAs increases in the river. Seasons and tides affect the appearance
of bromide contaminants in water that affects the form of THMFP and HAAFP.