Author (Your Name)

Ivan Mihajlov, Colby College

Date of Award


Document Type

Honors Thesis (Open Access)


Colby College. Chemistry Dept.


D. Whitney King

Second Advisor

J D. Shosa


In order to evaluate the causes and conditions that lead to cyanobacteria blooms in northern temperate lakes, studies of nutrients such as total phosphorus, total nitrogen, phosphate, and nitrate are necessary. Sensitive, environmentally friendly and cost-effective techniques were developed to detect ppb-level nitrates and phosphates in the lake water. Phosphate was analyzed by luminol chemiluminescence, while the quantification of nitrate was performed by capillary electrophoresis (CE) using indirect UV detection, with a background electrolyte consisting of pyromellitic acid, hexamethonium hydroxide and triethanolamine. Sample injection methods for the CE were optimized for the analysis in Belgrade Lakes, Maine. Vertical profiles of four different lakes in this watershed were taken in winter period, including the data for nitrate, phosphate, dissolved oxygen (DO) and temperature. While temperature profiles were characteristic of ice-cover season, and phosphate was uniformly distributed between different depths, nitrate and DO showed a high degree of vertical stratification. Elevated levels of nitrate, in comparison to other lakes, were noted in East Pond and, to a lesser extent, in North Pond. A link may exist between this discovery and the fact that East Pond suffers from the most severe summer algal blooms.


Nutrient pollution of water -- Maine -- Belgrade Lakes, Water -- Pollution -- Measurement -- Maine -- Belgrade Lakes, Water -- Phosphorus content -- Maine -- Belgrade Lakes, Water -- Nitrogen content -- Maine -- Belgrade Lakes

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