Microbiological Quality of Coastal Recreational Waters in Port Harcourt, Rivers State

Microbiological contamination of coastal recreational waters poses risks of gastrointestinal illness, skin infections, and respiratory disease for beach users and is an important dimension of coastal environmental health management. This study conducts a systematic assessment of the microbiological quality of coastal and creek recreational waters used by Port Harcourt communities in Rivers State, South South Nigeria, applying quantitative microbial risk assessment to estimate pathogen exposure and health burden. Water samples are collected biweekly over twelve months at seven recreational water sites encompassing creek swimming areas and the Trans-Amadi shoreline, analysed for indicator organisms (Escherichia coli, intestinal enterococci, total coliforms) and selected pathogens (Vibrio cholerae, Salmonella typhi, norovirus GI and GII) using standard membrane filtration, chromogenic culture media, and quantitative polymerase chain reaction methods. Environmental variables (rainfall, tidal level, proximity to sewage outfall) are measured concurrently. Quantitative microbial risk assessment models estimate daily infection risk for three recreational exposure scenarios: full body contact swimming, wading, and children's play. Risk is expressed as annual gastrointestinal illness incidence per 1,000 recreational water users and compared against WHO Guidelines for Safe Recreational Water Environments thresholds. Findings are expected to reveal that all sites exceed WHO enterococci action thresholds following significant rainfall events, with Vibrio cholerae detected at four of seven sites year-round. Recommendations address investment in sewage treatment infrastructure and implementation of recreational water quality advisories. Keywords: microbiological water quality, recreational waters, Port Harcourt, quantitative microbial risk assessment, enteric pathogens