THE IMPACTS OF BRINE INFLUX FROM ZWARA DESALINATION PLANT ON THE MARINE ENVIRONMENT تأثير تدفّق المياه المالحة المركّزة من محطة تحلية زوارة على البيئة البحرية

This study investigates the environmental impacts of brine discharge from Zwara Desalination Plant (ZDP) on the surrounding marine ecosystem along the Libyan coastline. Field data were collected from nineteen sampling stations near the plant outfall to assess variations in physicochemical parameters of seawater, sediment characteristics, and benthic community composition. Key parameters analyzed included salinity, temperature, pH, dissolved oxygen, major ions, and nutrient concentrations, alongside sediment grain size and organic content. Results revealed significant spatial variations in physicochemical properties, with elevated salinity (up to 47 psu), temperature, and ion concentrations (e.g., Na⁺, Cl⁻, Mg²⁺, SO₄²⁻) detected near the discharge point. These changes were associated with reduced dissolved oxygen levels and altered seawater chemistry. Principal Component Analysis (PCA) indicated that total hardness, ion concentrations, and temperature were the dominant factors influencing environmental variability. Biological analysis identified notable shifts in benthic community composition, with sensitive seagrass species such as Posidonia oceanica showing strong spatial dependence and significant correlations with environmental parameters and sediment organic content. The findings demonstrate that brine discharge from thermal desalination processes can significantly alter marine environmental conditions, potentially affecting biodiversity, especially seagrass ecosystems. The study highlights the need for sustainable brine management strategies, such as improved dilution, alternative disposal techniques, and implementation of environmentally responsible practices like Zero Liquid Discharge (ZLD), to mitigate ecological impacts and ensure long-term sustainability of desalination activities.