Investigation of human sewage pollution and pathogen analysis at Florida Gulf coast beaches

Abstract

Aims: Water quality at two Florida beaches was compared using faecal indicator bacteria measurements, microbial source tracking (MST) methods for detecting human source pollution and the assessment of pathogen presence. These values were also compared before and after remediation of wastewater infrastructure at one beach.

Methods and results: Faecal coliforms, Escherichia coli and enterococci were enumerated in estuarine water and sediment samples. PCR assays for the human-associated esp gene of Enterococcus faecium and human polyomaviruses (HPyVs) were used to detect human sewage. Culturable Salmonella and enteric viruses were also analysed. MST identified human sewage contamination at one beach, leading to repair of a sewer main and relocation of portable restrooms. Exceedances of Florida recreational water regulatory standards were significantly reduced after remediation (by 52% for faecal coliforms and 39% for enterococci), and the frequency of detection of MST markers decreased. Coxsackie virus B4 and HPyVs were codetected following a major sewage spill, but Salmonella was not detected during the study.

Conclusions: These data indicate that infrastructure remediation significantly reduced pollution from human sewage at the impacted beach.

Significance and impact of the study: A comprehensive microbial water quality study that can identify contamination sources through the use of MST markers and close collaboration with local/and state agencies can result in tangible actions to improve recreational water quality and safety.