Enumerating Escherichia coli (E. coli) Concentrations and Evaluating Optical Brighteners as a Potential Indicator of Human Wastewater Contamination in La Nana Bayou, Banita Creek, and their tributaries, Nacogdoches, Texas

<p>La Nana Bayou was added to the Texas 303(d) list in 2000 after it failed to meet water quality standards set by the Texas Commission on Environmental Quality (TCEQ) for primary contact recreation due to elevated <em>Escherichia coli </em>(<em>E. coli</em>) levels. <em>E. coli</em> is a bacterial species commonly found in the intestines of humans and warm-blooded animals. It serves as an indicator of fecal contamination in freshwater, though its presence alone cannot identify the contamination source. Optical brighteners (OBs), chemicals found in laundry detergents, cleaning agents, toilet papers, and clothing, are unique to human wastewater. This study aimed to quantify <em>E. coli</em> concentrations and water quality in La Nana Creek, Banita Creek, and their tributaries, monitor OBs to evaluate this indicator for potential human wastewater contamination, assess watershed characteristics by classifying the 2024 Land Use Land Cover (LULC) of the La Nana Bayou watershed, and estimate its sediment load. Multiway Analysis of Variance (ANOVA) showed higher <em>E. coli</em> levels in Banita Creek compared to La Nana Bayou. In La Nana Bayou, sites LNB 9, UNT 1, LNB 8, and LNB A3 had significantly higher <em>E. coli</em> than other sites, while BONT 1, BON 5, and BONT 2 had notably higher levels within Banita Creek. The hotspots for <em>E. coli</em> in the watershed were BONT 1, BONT 2, and UNT 1. The geometric mean of <em>E. coli</em> exceeded the primary contact recreation threshold of 126 MPN/100 mL at all sites. Elevated <em>E. coli</em> levels were recorded in April and May across all the sites in both creeks. A weak correlation was found between <em>E. coli</em> and OBs in the overall watershed, and a strong correlation at sites TB 1, LNB 3, BON 2, BON 3, and LNT 4. Forest (32.37 %) was the dominant land cover, followed by Grassland/Pasture and developed land. An estimated 16.8 million kilograms of sediment are generated annually in the La Nana Bayou watershed, with approximately 98% (16,440,015 kg) originating from streambank erosion. This research identified sites at higher risk for <em>E. coli</em> contamination that could affect recreational safety and screened for likely human wastewater sources, providing a foundation for more targeted management and remediation efforts.</p>

Name thesis:degree_name

Master of Science - Forestry

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Forestry

Year dc:date.available

2025

Authors dc:creator

• Acharya, Swastika
• McBroom, Matthew
• Weng, Yuhui
• Zhang, Yanli

Contributors dc:contributor

• Dr. Matthew McBroom
• Dr. Yuhui Weng
• Dr. Yanli Zhang

• Escherichia coli
• Optical Brighteners
• Water Quality
• La Nana Bayou Watershed
• Environmental Public Health
• Forest Sciences
• Other Forestry and Forest Sciences

Repository record dc:identifier

https://scholarworks.sfasu.edu/etds/652

OAI identifier oai:identifier

oai:scholarworks.sfasu.edu:etds-1679