Department or Program



The Androscoggin River was one of the most polluted waterways in the United States in the 20th century. The river’s condition inspired Senator Edmund Muskie ‘36, who grew up in Rumford, to write the Clean Water Act (CWA) of 1972. Untreated mill waste and raw sewage were regularly discharged into the river from the late 1800s to the 1970s, increasing biological oxygen demand and depleting dissolved oxygen (DO). Growing concern for the state of the river led to increasing government regulations, first on sulfite waste discharge and later on all point source pollutants. Executives from the paper companies were tasked with studying and remediating the river from the 1940s to 1970s, however financial interests superseded environmental concerns and progress was slow. The major accomplishment of this committee was eliminating the sulfite pulping method in mills along the river by 1965 and adopting the Kraft pulping process, which produced less effluent. Later, the CWA prompted the construction of wastewater treatment facilities along the river, further reducing organic waste. No study since 1978 has sought to quantitatively analyze changes in DO beginning with the first water quality survey in 1930. Average August DO data from 1930-2019 was considered spatially and temporally to evaluate various remedial actions initiated by the paper companies and government. August data was used in this study because it is the most consistently sampled month and DO concentrations are generally at their lowest due to high temperatures and low water flows. Additionally, the average difference in DO during June, July, and September, in comparison to August, was evaluated. The shift from sulfite to Kraft pulping between 1959-1965 led to the first notable increase in DO since annual monitoring began in 1948. However, it was the CWA which led to the most significant improvements in water quality, elevating the average DO above 5 ppm at nearly every site following 1977 and making almost every stretch of the river habitable by fish yearround for the first time in at least 35 years. Results also indicate reduced variation in average DO between June to September post-CWA, compared to pre-CWA data. Surveys focused on the Gulf Island Pond, a 14-mile-long impoundment north of Lewiston, document slight improvement in surface water DO levels after 1992. The reduction of organic-rich municipal and industrial waste discharges has greatly improved DO in the Androscoggin River, however it continues to have the poorest water quality of Maine’s major rivers despite decades of remedial efforts

Level of Access

Restricted: Embargoed [Bates Community After Expiration]

First Advisor

Beverly Johnson

Date of Graduation


Degree Name

Bachelor of Science

Number of Pages



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