The Role of Particulate and Colloidal Material in the Fate and Transport of Endocrine Disrupting Compounds from Engineered Systems

Partition coefficients for several size fractions of colloidal organic particles derived from different wastewater treatment processes were calculated by fluorescence quenching. The polycyclic aromatic hydrocarbons (PAHs) probes utilized in these experiments were pyrene,17β-estradiol and ethinylestradiol. The calculated colloidal-water partition coefficient (Kcoc) showed high variability in relation to the commonly applied octanolwater partition coefficient (Kow). However, there was good agreement between Kcoc for each probe and the molar extinction coefficient (ε280) for the various size fractions. Both Kcoc and ε280 increased with decreasing size fraction, and this relationship was more pronounced in membrane derived colloidal organic particles when compared to organic colloids from a conventional system. Similarly, there was a substantial increase in both parameters after 30-days aerobic digestion. These results suggest that the aromatic content of organic colloidal materials from wastewater treatment facilities increases with decreasing size fractions, and that aromatic content plays a significant role in fate and transport of PAHs. The significance of this research is a better understanding of the relationship between treatment process configuration, operational parameters and discharge of endocrine disrupting compounds.