Evaluasi kualitas air laut akibat aktivitas penginapan di atas laut di Pulau Derawan, Kabupaten Berau

Abstract

The rapid development of over-water lodgings in Derawan Island poses a threat to coastal water quality due to the lack of proper domestic wastewater treatment. This study aims to evaluate seawater quality against the Marine Water Quality Standards (Government Regulation No. 22 of 2021, Annex VIII) and identify organic pollution indicators and potential eutrophication risks. The research was conducted from October to December 2024 across 9 sampling stations categorized into three representative zones (PN1: high impact, PN2: moderate impact, PN3: control/reference). Physical and chemical parameters were measured both in situ and ex situ in the laboratory. Results showed that temperature (28.4-30.6^oC), TSS (0.0015-0.0145 mg/L), oil and grease (0.094-0.776 mg/L), and ammonia (0.032-0.223 mg/L) complied with environmental standards. However, three critical parameters violated the quality standards: water clarity (2.0-3.0 m; standard >5 m), dissolved oxygen (4.1-7.0 mg/L; standard >5 mg/L), and ortho-phosphate (0.027-0.039 mg/L; standard 0.015 mg/L). Direct discharge of untreated domestic wastewater (graywater and blackwater) along with tourist boat traffic are the primary drivers of DO depletion and elevated ortho-phosphate levels. These findings highlight an emerging risk of eutrophication that threatens the sustainability of coral reef ecosystems in Derawan Island.