Bacterial and Viral Source Tracking in the Sparkill Creek Watersheds
Authors: Acevedo Kimberly L. 
Published: June 2021

Microbial contamination of critical water sources is an important issue in urbanized areas faced throughout the world. Particularly concerning in Rockland County, NY is the contamination of the Sparkill Creek. The creek was placed on the “impaired waters list” by the NYS DEC in 2010, and the source and type of contamination has yet to be determined. The Sparkill Creek is unique in that it exceeds the acceptable levels for the indicator organism Enterococcus, specifically 24 times higher than what is allowed. It was our expectation that a thorough examination of multiple indicators and species level determination of the aquatic microbiome would inform the investigation into source of the contamination. The diversity of somatic coliphage and Gram negative bacteria were examined in dry and wet weather conditions, and correlated to nitrate and phosphate levels of the water, along with coliform and E. coli levels. Phage typing using family‐specific primers resulted in the identification of Myoviridae (25%), Siphoviridae (31.25%), and Microviridae (.06%). Plaque size distributions were determined and enough evidence suggests there is a significant difference between collections 1 and 3. Significant differences (p,0.05) were found in levels of E. coli and coliform levels when collections were taken in June and July, while there was not a correlation to nitrate and phosphate levels. A site‐by‐site analysis showed increased significance when looking at E. coli and coliform counts, as the sites approached New Jersey, particularly in Mill pond, Skating pond and the Marsh. Sequencing of cultured bacteria grown on EMB aerobically showed patterns of species found throughout most sites like Enterobacter amnigenus. While some were only specific to site like Brevundimonas diminuta. Stenotrophomonans retroflexus was identified in this way, correlating to only dry weather in 37.2% of the collection. Further investigation into the cause of this correlation is underway.

By means of water quality analysis, it is evident that south of the Sparkill Creek, water filtration slows down as it enters Jersey. Upon re‐entering New York, E. coli and coliform counts increase therefore suggesting the contamination exponentially increases in New Jersey. P‐values of less than 0.05 were obtained when comparing Spruce street, (the first site of the Sparkill Creek) and Skating pond (the first site re‐entering New York,) indicates enough evidence to suggest significance amongst the numbers counted. Most significantly, Stenotrophomonas retroflexus, a species novel to the region seems to favor dry conditions as opposed to wet conditions, and was found in 37% of the samples sent for DNA sequencing. Additionally, the emergence of increased amounts of fecal indicators as the creek enters New Jersey provide the public with a better understanding of the source of its contamination.

Support or Funding Information

ASM‐URF Fellowship

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.