WATER RESOURCES RESEARCH GRANT PROPOSAL
Project ID: 2003NJ42B
Title: Microbial respiration of arsenic and selenium
Project Type: Research
Focus Categories: Toxic Substances, Water Quality
Keywords: arsenic selenium oxidation-reduction redox anerobic soils sediments microbial transformation
Start Date: 03/01/2003
End Date: 03/01/2004
Federal Funds: $3925.00
Matching Funds: $21383.00
Congressional District: 6
Principal Investigators: Narasingarao, Priya; Haggblom, Max
Abstract: The primary goal
of this study is to elucidate the role of microorganisms involved in redox
transformations of arsenic and selenium in anaerobic soils and sediments.
In the absence of oxygen, microorganisms use a wide range of electron acceptors
from nitrate through iron, sulphate and carbonate for their respiration.Recent
evidence indicates that there are microorganisms that exist in nature which
are capable of utilizing arsenate or selenate for respiration by the process
of dissimilatory arsenate or selenate reduction. There have been some studies
on arsenate reduction coupled to respiration. An organism from the genus Desulfitobacterium
has been shown to reduce both As (V) and Se (VI). Desulfitobacterium strains
are also known to reductively dechlorinate chlorinated ethenes (Niggemyer
et al. 2001). These types of strains may be used to remediate contaminated
environments. They would precipitate As (V) and Se (VI) as arsenic sulphides
and elemental selenium while reductively dehaloginating chlorinated hydrocarbons.
This study focuses on the microbial transformations that occur in the anaerobic
zone because these are central in determining the mobility of arsenic and
selenium in the environment.
The main objectives and some questions that will be addressed are:
Ø How diverse are the microorganisms that have the capability to carry out dissimilatory arsenate or selenate reduction and how widely are they present in the environment in particular New Jersey where arsenic rich soils are found.
Ø Is the reduction of arsenate and selenate coupled to respiration in these organisms?
Ø How do other electron acceptors such as nitrate compete for carbon source in the same environment?
Ø What is the metabolic diversity of arsenate and selenate reducing bacteria in terms of carbon requirements?