AWWA WQTC62453

The ability to determine the source of pollution is a necessary first step to developing control plans.Bacterial source tracking (BST) is an important tool in identifying biological loadings to water bodies,and is thus critical in developing appropriate policies for source water protection. Bacterial BST is usedto identify sources of fecal contamination using methods such as rep-PCR DNA, ribotyping, antibioticresistance and carbon source utilization (Bryan et al., 2004; Carson et al, 2001; Guan et al, 2002;Hagedorn et al., 2003). The correct classification of a fecal source by BST ranged from just about 30%up to 100%. For BST to work most effectively, an extensive library of sample from the watershed mustbe developed.One of the drawbacks of BST is that discrepancies frequently occur between the species found in thewatershed and the species taken from the water column. Standard methods for water sampling are tocollect grab samples from the water column. No sampling of sediment is done. E. coli is capable ofadhering to particles and settling out of the water column, and if this sorptivity is strain specific, thenthis could explain the discrepancies that occur when using BST. Very little research has been performedon strain specific fate and transport of E. coli.This research investigated strain dependent differences in the ability of E. coli to sorb toparticles. Standard conditions with 2 g kaolinite, 10 mL sterilized river water adjusted to pH of 6.5,about 3 x 10⁶ cfu/mL starting concentration, and incubation for 20 minutes were used to perform theseexperiments. The data demonstrated drastic differences in the ability of E. coli strains to sorb tokaolinite, a common clay in the environment. E. coli isolated from avian speciessorbed very well, while E. coli isolated from a beef cow sorbed poorly. There was a 50-fold differencein the sorptivity between these strains. This could mean that the avian-based E. coli readily drop out ofthe water column, and because E. coli from beef cows do not, beef cow are the source measured by BSTin the water column even though the composition of the original mixed sample was much different. Includes 7 references, figure.

Product Details

Edition:

Vol. - No.

Published:

11/01/2005

Number of Pages:

3

File Size:

1 file , 160 KB