Marine pollution in small island ecosystems and the impact of domestic wastewater

BACKGROUND AND OBJECTIVES: Small islands with high population density are facing various environmental problems such as domestic wastewater pollution. Generally, in small islands lacking adequate wastewater management, pollution from domestic sources can severely affect the health of marine ecosystem. Therefore, this study was conducted on one of the most densely populated islands, namely Bungin Island, in Sumbawa Regency, West Nusa Tenggara Province, Indonesia. This study sought to analyze the state of surface seawater as influenced by the pollution stemming from domestic wastewater contamination.METHODS: Water samples were collected from April to August 2024 during rainy and dry seasons. Three locations along marine area were tested ex-situ using six parameters for seawater, including physical, chemical, and microbiological. The assessment of marine water quality status was conducted through the application of the pollution index formula, which facilitated calculation and analysis. Alongside the analysis of surface seawater samples, this study incorporated domestic wastewater samples, employing seven parameters to evaluate and predict the pollution load affecting the aquatic ecosystem.RESULTS: The results showed that, in general, indications of light pollution were found at three test points in seawater of Bungin Island. Major pollution was influenced by the contribution of domestic activities. The key parameters identified during the dry season were the levels of dissolved oxygen and the values of total suspended solids. Meanwhile, the critical parameters in rainy season were salinity and orthophosphate values. Testing of domestic wastewater indicated that several quality indicators, such as chemical oxygen demand, total suspended solids, oil and grease, and total coliform, were below the acceptable quality thresholds. Consequently, this may lead to an escalation in the daily pollution load as time progresses. This pollution load was certainly a problem for marine ecosystem on Bungin Island.CONCLUSION: The increase in population over time on densely populated islands will cause problems in the future related to domestic wastewater problems that threaten marine ecosystem. To prevent the escalation of environmental problems in the future, it is imperative to undertake appropriate mitigation strategies. This study provides a real picture concerning the threat of environmental damage that threatens one of the most densely populated islands in the world. Additionally, the results present further information that is beneficial for the worldwide sustainability of aquatic ecosystems.