Microbial source tracking in a coastal residential canal system

Area of Science:

• Environmental Science
• Microbiology
• Coastal Ecology

Background:

• Coastal residential canals are vital ecosystems vulnerable to pollution.
• Anthropogenic impacts on these systems require thorough investigation.
• Understanding water quality is crucial for ecosystem health and human safety.

Purpose of the Study:

• To comprehensively monitor water quality in a coastal residential canal.
• To assess nutrient levels, enterococci concentrations, and microbial sources.
• To evaluate the effectiveness of traditional indicators versus microbial source tracking (MST).

Main Methods:

• Collected water samples for analysis of nutrient levels, enterococci, and microbial markers (HF183 for human, DogBact for canine, LeeSeaGull for gull).
• Utilized quantitative PCR for microbial source tracking.
• Correlated microbial data with weather patterns and rainfall events.

Main Results:

• Enterococci detected in 50.6% of samples, generally below EPA marine water quality criteria.
• Human fecal marker (HF183) found in 10.9% of samples.
• Gull marker (LeeSeaGull) was highly prevalent (75.54%), increasing with days before rainfall.
• Canine marker (DogBact) was elevated in winter.
• One sample exceeded risk thresholds when combining human and gull markers.

Conclusions:

• Enterococci levels alone may not fully represent water quality risks in mixed-pollution environments.
• Microbial source tracking is essential for identifying specific pollution sources.
• Holistic monitoring combining traditional indicators and MST is recommended for coastal canals.