Occurrence of fecal indicator bacteria and microbial source tracking markers along the Texas Gulf Coast adjoining two...

This study investigates the occurrence and sources of fecal contamination along the Texas Gulf Coast, focusing on two barrier islands: Sargent Beach and Matagorda Peninsula. Surface water samples from six sites were collected over 19 months and analyzed for fecal indicator bacteria (FIB) and microbial source tracking (MST) markers, including human (HF183), canine (BacCan), avian (GFD), and enterococci (Entero1) markers. Culturable enterococci were detected in all samples, often exceeding safety thresholds, indicating widespread fecal contamination. Statistical analyses revealed significant differences in marker concentrations among sites (ANOVA, p < 0.05) and correlations between marker levels and environmental parameters. Entero1 was the most prevalent marker, showing significant differences among sites (Kruskal-Wallis Test, p < 0.05). HF183 was less frequently detected, suggesting limited human fecal pollution. BacCan was more common in Sargent Beach, correlating with higher population density and developed land. GFD was consistently present, reflecting the significant impact of avian sources. Spearman's rank correlation analysis showed moderate positive correlations between Entero1 and both GFD and BacCan (p < 0.05). The study highlights the need for targeted management practices to mitigate fecal pollution, emphasizing the importance of addressing canine and avian sources. Recommendations include public education on pet waste management, improved septic system management practices, and potential management of gull populations. This research provides critical insights for beach management authorities to enhance water quality and protect public health along the Texas Gulf Coast.