Identifier

etd-08272004-102750

Degree

Master of Science (MS)

Department

Environmental Sciences

Document Type

Thesis

Abstract

A quality assurance testing of the ECLOX-M™, a rapid water quality indicator used in potential terrorist attacks, was evaluated for its adequacy in nine regional Louisiana water systems. The ECLOX-M™ system uses enhanced chemiluminescence to measure toxicity in water by integration of a mixture of luminol (C8H7O3N3), and an oxidant in the presence of a catalyst enzyme - horseradish peroxidase (HRP). Water samples were tested for chemiluminescence, chlorine content, pH, and arsenic and/or nerve agent/pesticide contamination. In addition, three toxic industrial chemical standards were evaluated (mercury, a volatile liquid mixture, and a volatile gas mixture) and two nerve agent/pesticide standards (atrazine, and a regulated pesticide mixture). Additional tests included: three replicates of each contaminant at two concentration levels; three replicates of each regional water sample; and chemical standard spikes on each water sample. A metal mixture and a volatile organic compound (VOC) mixture were evaluated to determine the machine's sensitivity to chemical mixtures. Lastly, two ECLOX-M™'s were tested simultaneously to determine their precision and accuracy. Testing revealed a significant difference in the inhibition % for the nine regional water samples. A one-way ANOVA and a student T-test revealed a significant difference in inhibition % between concentrations for all chemical standards tested. A trend was seen with chemicals and water samples in which the standard deviation for inhibition % increases as the toxicity of the sample decreases. An additive effect on inhibition % was hypothesized for the chemical mixtures. Instead an inhibitory effect was seen for the metal mixture, and a synergistic effect was seen for the VOC mixture. This suggests that the ECLOX-M™ is not capable of detecting components or interactions between components within a mixture. The simultaneous testing revealed no significant difference between the performances of the two machines. Lastly, there was a significant difference between the regional water sample pH levels, (p ≤ 0.01). It is suggested that water systems with complex water matrices consider using multiple testing methods, as ECLOX-M™ alone is not an accurate indicator of contamination. Detection of added contaminants is difficult to ascertain if clean water produces high light inhibition.

Date

2004

Document Availability at the Time of Submission

Release the entire work immediately for access worldwide.

Committee Chair

John Pine

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