Portland State University. Environmental Sciences and Resources Ph. D. Program
Date of Award
Doctor of Philosophy (Ph.D.) in Environmental Sciences and Resources: Chemistry
Environmental Science and Management
3, x, 139 leaves: ill. 28 cm.
Health and environmental sciences, DDT (Insecticide), Humus
The fate and transport of insoluble, hydrophobic organic pollutants in the aquatic environment constitutes a prominent area of concern. It is thought that pollutants of this nature may exist in association with organic carbon, which is predominantly aquatic humus. This type of association could significantly affect the kinetics of such transformation processes as volatilization or chemical and biological degradation of the pollutant. While dissolved organic matter (DOM) comprises the bulk of organic carbon (or aquatic humus) in natural waters, the interaction between naturally occurring DOM and insoluble organic pollutants has not been quantified. The work presented in this dissertation is an effort to quantify the effect of dissolved organic matter on the solubility in water and, hence, the transport of hydrophobic organic compounds (specifically, DDT) in the environment. Saturated aqueous solutions of DDT were generated by a method that is different from those used by other workers. Within a closed system, an excess of solid DDT was allowed to vaporize and enter an aqueous solution through the gas phase. The concentration of DDT in solution increased with time, leveling off when equilibrium and a saturated solution was established. The solubility of p,p'-DDT in distilled water was determined to be 1.87 (+OR-) .01 ppb. The solubility of the o,p'-DDT isomer in distilled water was determined to be 4.88 (+OR-) .03 ppb. The concentrations of p,p'-DDT and o,p'-DDT in distilled water solutions containing dissolved organic matter were definitely higher than the aqueous solubilities of these compounds. A minimum value for the DDT/DOM partition coefficient (K(,p)) in water was determined. This partition coefficient, when normalized to organic carbon, is referred to as K(,oc) (K(,oc) = K(,p)/fraction organic carbon). A minimum log K(,oc) for both p,p'-DDT and o,p'-DDT was determined to be 4.7 (+OR-) .2 log units. Under environmental conditions, this partition coefficient indicates that the majority of DDT present in aqueous systems will be associated with dissolved organic matter.
Blunk, Dan Philip, "Investigation of the contribution of aquatic humus to the transport of DDT in the environment" (1982). Dissertations and Theses. Paper 796.