Date of Award

2025

Document Type

Honors Thesis (Open Access)

Department

Colby College. Economics Dept.

Advisor(s)

Michael Donihue

Second Advisor

Jen Meredith

Abstract

This study investigates the impact of per- and polyfluoroalkyl substances (PFAS) on cancer prevalence throughout Maine. The main contribution of this project is the database constructed to examine cancer rates at a novel aggregation area: watersheds. By using a watershed as the aggregation area, this study gains insight into the threat that spreading sludge as fertilizer on agricultural fields poses to human health through groundwater pathways. Using geospatial analysis and an ordinary least squares regression model, this study estimates the effect of the presence of PFAS in a watershed from 2017 to 2021, in addition to estimating the impact of the historical spread of agricultural fertilizer sludge in a watershed. The regression results are positive and statistically significant for both the presence of PFAS in a watershed (p-value < 0.01) and the historical spread of sludge (p-value < 0.01), meaning that the presence of PFAS and sludge are correlated with higher cancer diagnosis rates. The interaction term between the two is negative and significant (p-value < 0.01). Through this study, effect of the presence of PFAS on cancer diagnosis rates is isolated, likely because sludge is a source and not the compound heavily linked to cancer prevalence. The main implication of this study is that more research is necessary to investigate pollutants and contributors to cancer prevalence rates at the watershed level. Additionally, the state of Maine has implemented steps toward decreasing PFAS contamination but should now take steps to minimize the impact of the already polluted fields on human health outcomes.

Keywords

Sludge, Cancer Prevalence, PFAS, Forever Chemicals, Health

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