THE SORPTION AND TRANSPORT OF TRICLOSAN IN NATURAL SOILS

Triclosan (5-Chloro-2-[2,4-dichlorophenoxy]phenol) is complex organic compound that is used as an antibacterial agent in many common personal care products such as toothpaste and soap. It has a pKa of 8.14 and a log K_ow of 4.8, and it is soluble in water up to 10 mgL^-1. Its presence in the environment is entirely a result of human activity, but little is known about the behavior of this chemical in the environment. Triclosan is released to waterways through waste water treatment plant effluent, and has potential to be released to soils through the spreading of WWTP sludge. The main objective of this study is to determine sorption and transport of triclosan in natural soils using column experiments. Soil samples taken from the Francis Marion National Forest with high clay content and high Total Organic Carbon percentages will be used. Due to high sorption rates found in WWTP sludge, the triclosan will likely highly sorb to organic soils and sorb less effectively to clay rich soils. Separate experiments will also be conducted with triclosan in order to determine the ability of the chemical to undergo photodegradation. Current published data on the photodegradation of triclosan is inconsistent, as half-lives in water range from a half hour to 8 days. The rate of photodegradation of triclosan in water could indicate its persistence in WWTP effluent. The findings of this study will aid in determining the fate of triclosan as a pollutant in the environment and will expand upon knowledge of the behavior of organic pollutants in soil environments.