Date of Award

Spring 2019

Degree Name

Bachelor of Science

Major

Environmental Science

First Advisor

Amber L. Pitt

Second Advisor

Arianne Bazilio

Third Advisor

Alison J. Draper

Abstract

Ponds are ecologically important as centers for biodiversity, and those within urbanized watersheds typically have altered hydrology, morphology, and water chemistry. The accumulation of heavy metals, such as mercury (Hg), in subaqueous pond sediments has the potential to harm pond ecosystems, but the behavior of Hg in urban ponds is poorly understood. I investigated spatial variability of mercury accumulation within the sediments of two urban ponds: Beachland Park Pond in West Hartford, CT, USA, and Keney Park Pond, in Hartford, CT, USA. I collected 5 samples from 14 distinct sites around each pond’s perimeter. I analyzed the fine (<63 >μm) fractions of each sediment sample directly for total Hg. In Beachland Park Pond, mean Hg concentration exceeded the Threshold Effect Concentration (TEC) at four sample sites, and the Probable Effect Concentration (PEC) at a site on the northeastern shore of the pond. An analysis of variance (ANOVA) and post hoc Tukey test revealed that mean mercury concentration at this site differed significantly from all other sites (F = 4.635, df = 13, 56, p < 0.0001). In Keney Park Pond, mean Hg concentration exceeded TEC at one site in the southwestern corner of the pond. The statistical analysis revealed that this site differed significantly from most others (F = 42.4, df = 13, 56, p < 2 x 10-16). The relative lack of variability among most sample sites was to be expected due to ubiquitous atmospheric deposition of mercury, and additional mercury sources must be considered for the sites which exceed the TEC. More research is needed to investigate sources of Hg in areas of high concentration, as well as temporal variation in mercury concentration.

Comments

Senior thesis completed at Trinity College, Hartford CT for the degree of Bachelor of Science in Environmental Science.

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