Environmental Dilemma of Humic Substances: Being Adsorbents and Being Carcinogens
International Journal of Environmental Science and Development
Humic materials can be classified as soluble in high pH, soluble in all pH's, and insoluble in all pH's (IHA). In this study, humic substances in the environment were discussed, and their different environmental contributions, either positive or negative, were investigated. Some humic substances help the water treatment while some others cause carcinogenic matter accumulation in water. This dilemma was discussed with different examples. In the first part of this study, IHA was used as adsorbent
... in removal of some metals, chemical oxygen demand (COD) and color from water. The results were presented together with literature results. IHA could adsorb various heavy metals in 10 to 300 mg/g capacity interval, while COD removal performance was 2270 mg/g. In the second part of the study, soluble humic matter in natural waters and disinfection by-products (DBP) formation upon chlorination of such waters were discussed. Humic fractions were important precusors of DBP's such as trihalomethanes (THMs) and haloacetic acids (HAAs). Depending on the water resource, the humic substances, THM and HAA formation potentials and types and quantities of the compounds may differ, but all are bioaccumulative and potentially carcinogenic. The study investigated the two different faces of humic substances in the environment.