Date of Award

4-1986

Degree Name

Doctor of Philosophy

Department

Science Studies

First Advisor

Dr. Clarence J. Goodnight

Second Advisor

Dr. George G. Malllnson

Third Advisor

Dr. William B. Harrison

Abstract

The purpose of this study was to investigate the extent to which acid precipitation contributes acidity and heavy metals to lake environments. Asylum and Bonnie Castle Lakes, both located in the western portion of Kalamazoo County, served as the study sites. Precipitation samples were also taken at a site close to both lakes. Using the Hach Colorimeter, a preliminary study was undertaken to determine concentrations of the major cations (H('+), NH(,4)('+), K('+) and Ca('2+)), and major anions (NO(,3)('-), SO(,4)('2-), and PO(,4)('3-)). The main study dealt with the metal concentrations (Mn, Fe, Cu, Zn, and Pb) in rain/snow water, lakewaters, sediment, and aquatic vegetation of lakes. The data for the main study were provided by Atomic Absorption Spectrophotometry (AA), and Particle Induced X-Ray Emission (PIXE) methods. For the water quality analysis by PIXE, the "vapor filtration" procedure was used to prepare the lakewater and rain/snow water samples. The sediments and macrophyte (Chara) samples used in the PIXE process were dried in order to make target pellets. The pellets were then analyzed by PIXE.

As a result of the study, the following conclusions emerged: (1) The pH values for precipitation ranged from 3.9-5.82, with an event average of pH 4.67. (2) Although both receive similar amounts of acid deposition, Asylum Lake was alkaline, whereas, Bonnie Castle Lake remained neutral. (3) The acidity of precipitation was 800-1000 times greater than that of the water of Asylum, and 200-300 times greater than that of Bonnie Castle Lake. (4) Because of the groundwater flow characteristics around Asylum Lake, this lake did not receive a substantial portion of its total input as direct precipitation. However, the diluting effects of precipitation coupled with the absence of any contribution from hardwater sources such as groundwater, may be important in the water chemistry of Bonnie Castle Lake. (5) The acidic precipitation was associated with deposition of metals such as Zn, Fe, Cu, and Pb, resulting in elevation of their concentrations in the study lakes. Zn and Fe were the major elements present in precipitation. (6) Except for Cu, the concentrations of all heavy metals were higher in the solid phases, sediment and/or vegetation, than in the lakewaters.

Access Setting

Dissertation-Open Access

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