Molecular determination of arsenate respiring bacteria in estuarine sediments and groundwater

UNCW Author/Contributor (non-UNCW co-authors, if there are any, appear on document)
Holly G. Oates (Creator)
Institution
The University of North Carolina Wilmington (UNCW )
Web Site: http://library.uncw.edu/
Advisor
Bongkeun Song

Abstract: Arsenic is a well-known metalloid and carcinogen with both natural and anthropogenic origins. Arsenic occurs naturally in the environment as two primary inorganic forms: arsenate [As(V)] and arsenite [As(III)]. Microbes mediate the presence and quantity of these two arsenic species through oxidation and reduction processes. Dissimilatory As(V) respiring bacteria (DARB) contain As(V) respiratory reductase (arrA) genes and reduce As(V) to As(III), therefore enhancing the solubility of arsenic. Thus, the detection of the genes encoding As(V) respiratory reductases could interpret the presence and involvement of DARB in arsenic mobilization. With water samples collected from two NC wells, and sediment collected from Shem Creek, South Carolina the presence of DARB using arrA genes as genetic markers were determined and the As(V) reduction activities were monitored via enrichment culture techniques. Based on molecular analysis, the DARB in the NC wells are closely related to Geobacter uraniumreducens while those in Shem Creek sediments are related to Desulfosporosinus Y5. Anaerobic enrichment cultures were established with NC well water and Shem Creek sediment to determine the rate of As(V) reduction. The rates for all of the sites involved showed that the DARB could have a significant impact on the arsenic levels in the environment. Thus, this study demonstrates the presence and diversity of DARB in these environments and their contributions to the arsenic contamination in NC residential drinking water wells, and in the Shem Creek estuary.

Additional Information

Publication
Thesis
A Thesis Submitted to the University of North Carolina at Wilmington in Partial Fulfillment of the Requirement for the Degree of Masters of Science
Language: English
Date: 2009
Keywords
Arsenic compounds--Environmental aspects, Groundwater--Microbiology
Subjects
Arsenic compounds -- Environmental aspects
Groundwater -- Microbiology