Date of Award

Fall 2000

Document Type

Thesis

Degree Name

Master of Science in Environmental Engineering - (M.S.)

Department

Civil and Environmental Engineering

First Advisor

Lisa Axe

Second Advisor

Trevor Tyson

Third Advisor

Daniel Watts

Fourth Advisor

Michael H. Ebinger

Fifth Advisor

Dittmar Hahn

Abstract

In an effort to improve tools in ecological risk assessment (ERA), an ERA software tool was developed and applied. Based on a preliminary evaluation of existing ecorisk models, the relative deficiencies were identified and included the need for a user-friendly interface, an interactive database management system (DBMS), and a comprehensive evaluation of exposure pathways. In this research, Visual Basic (VB) 6.0 and Microsoft SQL server were selected for developing the Windows-based interface and local DBMS, respectively. For the exposure estimate, Yuma and Aberdeen Proving Grounds were identified as baseline ecosystems. Terrestrial and aquatic plant and animal receptor selection was based on the U.S. EPA Guidelines for ERA. All potential exposure pathways were included. Overall, results of the case study of replacing electroplated chromium coatings with sputtered tantalum showed that the most significant exposure resulted from molybdenum and hexavalent chromium, which posed moderately high and slight potential adverse risks to aquatic and terrestrial species at both sites. On the other hand, tantalum (with vanadium as the surrogate) resulted in the least risk to the receptors within the studied areas. However, a slight potential adverse risk was also observed for a large faction of terrestrial mammals at both sites as a result of using sodium vanadate as surrogate for Ta. An uncertainty analysis was included to address the data quality and demonstrated that distribution coefficients have the most influence on the results.

Share

COinS