Evaluating the Environmental Impacts of Desalination Plant Brine Discharge using Marine Organisms as Bioindicators

Desalination plants are an increasingly common solution to address water scarcity, particularly in arid and semi-arid coastal regions. However, the brine discharge from these plants can have significant impacts on the surrounding marine environment. This study investigated the use of biotic taxa as bioindicators to assess the environmental impact of desalination plant brine discharge. The study was conducted near a large-scale desalination plant in Dahab City on the Gulf of Aqaba, South Sinai, Egypt. The study area was divided into three distinct zones: Zone 1 (standard zone), Zone 2 (discharge zone), and Zone 3 (mixing zone). Water salinity and distribution of marine taxa as bioindicators were investigated during summer and winter seasons. Salinity recorded its highest value at zone (2), while, the lowest value was at zone (1). Seagrasses were recorded only in zone (1) and disappeared in other zones. Unexpectedly, the sea cucumber species have been recorded in abundance in zone (2) closer to the discharge pipe, where salinity is high. Echinoderms are potential sentinel taxon to gauge the impact produced by brine discharge. On the contrary, coral colonies particularly stony corals only appeared at zones (1) and (3), where the salinity was low. Corals are reputed to have a low tolerance to salinity fluctuations. The current study concluded that water discharged from desalination plants adversely affects coral reefs and seagrasses more significantly than other marine creatures.