Impacts of Decommissioning and Upgrading Urban Wastewater Treatment Plants on the Water Quality in a Shellfish Farming Coastal Lagoon (Ria Formosa, South Portugal)

Cravo, A Ria Formosa is a productive coastal lagoon, located on the south coast of Portugal, and represents the largest national producer of shellfish bivalves (ca. 90% production). This ecosystem is subjected to various anthropogenic pressures, including the discharge of urban wastewater treatment plants (UWWTP), which impacts the lagoon water quality. This study aimed to assess the impact of alterations in the functioning of two UWWTP on the water quality of Ria Formosa, based on chemical variables, phytoplankton composition (including potential harmful species) and faecal contamination