Date of Award

8-2001

Level of Access Assigned by Author

Open-Access Thesis

Degree Name

Master of Science (MS)

Department

Ecology and Environmental Sciences

Advisor

Howard H. Patterson

Second Committee Member

Jeffrey S. Kahl

Third Committee Member

Touradj Solouki

Abstract

The Maine Department of Environmental Protection (DEP) currently monitors river dioxin levels through the sampling and destructive analysis of fish. Recent state law mandates that by December 31, 2002, the dioxin concentrations in fish downstream of a bleached Kraft pulp and paper mill are not to exceed the concentrations in fish upstream of the mill (38 M.R.S.A. §420-A). The objective of this thesis project was to develop an alternate method for determining Kraft mill compliance to this Dioxin law. This new method that uses semipermeable membrane devices (SPMDs) circumvents many of the concerns generated by the upstream-downstream fish test. An important advantage is that the SPMDs sample current dioxin concentrations at fixed sites. Over the course of two field seasons, we assessed the feasibility of using SPMDs to monitor dioxin concentrations in Maine rivers. The 1999 field season focused on developing viable field and laboratory SPMD methods. Field methods included design of the vertical deployment apparatus for the SPMDs and determination of which environmental conditions to monitor. In the laboratory, the final SPMD extraction and cleanup methods included extraction by dialysis of the entire SPMD into hexane followed by two cleanup methods: acidified silica gel slurry to remove residual lipids and gel permeation chromatography to remove interference through size exclusion. The final laboratory analysis involved EPA Method 1613B and high resolution gas chromatography 1 high resolution mass spectrometry (HRGC/HRMS). For the 2000 field season we applied the developed methods to assess the effects of varying environmental conditions on SPMD sampling and to test two pairs of upstream-downstream sites: one on the Androscoggin River and one on the Kennebec River. A preliminary investigation of the effect of varying environmental conditions on SPMD dioxin concentrations was conducted. The positive temperature correlation and negative water velocity correlation with SPMD dioxin concentrations are significant and require further research. Investigations indicated that there was no statistical difference between upstream and downstream dioxin concentrations at both pairs of sites. The effects of environmental conditions on SPMD dioxin concentrations need to be further studied with experimental designs that allow for additional statistical tests; otherwise, a permeability reference compound for dioxin should be identified to correct SPMD concentrations for varying environmental conditions at the sites during a deployment. Repeating the 2000 field season experimental design provides for comparisons to be made between years and all current hypotheses may be re-evaluated. This thesis identifies a potentially significant alternative to compare with the rest of the dioxin monitoring data gathered during the 2000 field season, the various sample types and species of fish as well as caged freshwater mussels. The Department of Environmental Protection's evaluation of all available data will bring the state of Maine closer to determining the most appropriate upstream-downstream test.

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