Impact of desalination plant brine discharge on macrobenthic communities in the Persian Gulf

Abstract

This research investigates the ecological impacts of desalination plant discharges on sediment quality and macrobenthic communities in the coastal waters of Bushehr City, Iran, located within the Persian Gulf. Spanning from November 2019 to October 2020, the study involved meticulous sampling of 288 sediment samples from 24 strategically selected stations—half of which were influenced by brine discharges from a desalination facility releasing approximately 45,000 cubic meters of treated wastewater daily, while the other half served as controls. The study employed a comprehensive methodology that integrated fieldwork focused on macrobenthos as biological indicators. A total of 62 macrobenthic taxa were identified, with a notable diversity of mollusks, including 35 gastropod taxa, which represented 56% of the total abundance. The application of ecological indices, including the AZTI Marine Biotic Index (AMBI), Margalef's richness, Shannon-Wiener diversity, and Pielou's evenness, revealed significant declines in biodiversity metrics near discharge points, highlighting the detrimental effects of pollution. Statistical analyses confirmed a negative correlation between the AMBI index and both the Shannon and Margalef indices, while a positive association was observed between the AMBI index and total organic matter (TOM), highlighting its effectiveness in assessing organic enrichment. These findings emphasize the complex interplay between ecological health indicators and environmental stressors, such as salinity, and highlight the importance of utilizing biological indices within coastal management frameworks. Ultimately, this research provides critical insights for developing targeted strategies to enhance the sustainable management of coastal ecosystems, ensuring the preservation of biodiversity and ecological integrity in the face of anthropogenic pressures.