Perth Laboratory – Public Seminar Series 2008

Fate of Two Endocrine Disrupting Chemicals in Selected Tropical Soils from Hawaii

Professor Chittaranjan Ray
Faculty of Engineering
University of Georgia, USA

Thursday 4 September 2008 at 3.30pm, CSIRO Auditorium

Abstract

Environmental significance of endocrine disrupting chemicals (EDCs), such as estrogenic hormones, has prompted scientists to study their fate and transport in soils and aquifer materials. EDCs are present at low concentrations in municipal wastewaters and in on-site waste disposal systems (such as septic tank effluents and cesspools). Land application of wastewater for aquifer recharge and crop irrigation and leakage of effluents from cesspools and septic tanks to ground water are some of the factors that motivated us to study the sorption and transport of these chemicals in tropical soils.

Two model EDCs, 17-beta estradiol (E2) and estrone (E1) were used on three tropical soils (two collected from two depths with varying organic carbon content and a volcanic cinder) from the island of soil to study EDC sorption. The transport experiments were conducted in packed columns of these soils. The soils were either irradiated using a Cobalt-60 source or were treated with 100mM sodium azide to inhibit microbial growth. Despite these attempts, the EDCs degraded in the batch slurry during sorption process. The degree of degradation was dependent on the type of soil. The surface soil samples adsorbed more EDCs compared to the bottom (low organic carbon) soil samples. The cinder had the lowest sorption capacity. During the sorption experiment, E1 was produced from E2; and the amount of E1 varied with soil type. Column studies also revealed that fast breakthroughs can occur in volcanic cinders. In other soils, transport of EDCs was enhanced when the leaching solution was prepared from filtered wastewater compared to deionized water. Also, a limited number of samples showed that the amount of dissolved manganese increased in soil slurry at the end of the sorption experiments. The fate of EDCs and their transport appeared to be controlled by more complex factors in tropical soils compared to that reported for temperate soils.

About the speaker

Chittaranjan Ray is a Professor of Water Resources and Environmental Engineering at the Faculty of Engineering, University of Georgia. Prior to that, he was a faculty member at the University of Hawaii. His research focuses on the study of the fate and transport of chemicals and pathogenic contaminants in soils and production of potable water using riverbank filtration. He received his Ph.D. in Civil Engineering from the University of Illinois at Urbana-Champaign. He also worked as a staff engineer with the firm of Arcadis Geraghty & Miller in New Jersey, USA assessing ground water contamination at hazardous waste sites.

For seminar information email Perth Seminars or phone (08) 9333 6221
Return to the main Seminars page