Tingkat Pencemaran Logam Berat pada Sedimen dan Bioakumulasi pada Organisme Bentik di Teluk Benoa dan Nusa Lembongan, Bali

Abstract

Limbah antropogenik berasal dari aliran sungai di daratan dan aktivitas pelabuhan pendaratan ikan dan pariwisata bahari diperairan pesisir berpotensi menyumbang konsentrasi logam berat pada perairan dan selanjutnya berdampak pada biota di dalamnya. Penelitian ini bertujuan mengkaji tingkat pencemaran logam berat dan akumulasinya pada organisme bentik (makroalga, lamun dan bulu babi), dan kondisi pencemaran di perairan Teluk Benoa dan Nusa Lembongan. Sample sedimen makroalga, lamun dan bulu babi diambil pada beberapa stasiun keterwakilan di kedua area. Preparasi analisis logam berat menggunakan metode American Public Health Association dan diukur dengan menggunakan Atomic Absorption Spectrophotometry (AAS). Analisis potensi pencemaran menggunakan pendekatan faktor kontaminasi (CF), indeks beban pencemar (PLI), geoakumulasi (Igeo), faktor pengayaan (EF), indeks potensi kerusakan ekologi (RI) dan analisis bioakumulasi (BCF) pada organisme bentik. Konsentrasi Fe di sedimen dan biota sangat tinggi dibandingkan dengan konsentrasi Pb, Cd, Cu dan Cr, sebaliknya Konsentrasi rendah terjadi pada logam Cd dan Cr. Konsentrasi Fe, Cd dan Cu di sedimen lebih tinggi di Teluk Benoa, dan Pb dan Cr lebih tinggi di Nusa Lembongan. Tingkat kontaminasi Pb, Cu dan Cr masih berada di bawah standar guideline Australian and New Zealand Environment and Conservation Council (ANZECC/ARMCANZ), namun Cd sudah melebihi. Namun demikian, logam-logam sudah mengindikasikan adanya pengayaan atau kenaikan konsentrasi dengan tingkat variasi dari rendah sampai tinggi dan umumnya masuk pada kategori tidak tercemar sampai tercemar sedang (Cd). Semua logam telah terakumulasi dalam biota khususnya pada makroalga dan lamun. Hal ini menunjukkan bahwa keberadaan logam telah berdampak pada organisme termasuk sumberdaya laut yang berpotensi dikonsumsi. Dengan demikian, upaya pengelolaan pencemaran logam berat yang berasal dari aktivitas manusia perlu dilakukan agar meminimkan tingkat kerusakan ekosistim perairan pesisir di Teluk Benoa dan Nusa Lembongan.

Anthropogenic waste deriving from river flows, fishing port activities, and marine tourism can potentially contribute the concentration of heavy metals in the coastal waters and lead to affect the benthic flora and fauna. This study aims to determine the level of heavy metal pollution and its accumulation in benthic organisms (macroalgae, seagrass, and sea urchins) and to provide information on pollution conditions in Benoa Bay and Nusa Lembongan waters. Samples of sedimnets, macroalgae, seagrass and sea urchins were taken at several stations representing the two regions. Preparation for heavy metal analysis referred to the American Public Health Association method and were measured using Atomic Absorption Spectrophotometry (AAS). Analysis of potential pollution used the contamination factor (CF) approach, pollutant load index (PLI), geo-accumulation (Igeo), enrichment factor (EF), ecological damage potential index (RI), and bioaccumulation analysis (BCF) on benthic organisms. The concentrations of Fe in sediment and biota were very high compared to those of Pb, Cd, Cu and Cr, whereas low concentrations occur in the metals Cd and Cr. The concentrations of Fe, Cd, and Cu in sediments were high in Benoa Bay, and Pb and Cr were high in Nusa Lembongan. The contamination levels of Pb, Cu and Cr were still below those observed in guideline standards of the Australian and New Zealand Environment and Conservation Council (ANZECC/ARMCANZ), but Cd has exceeded these standards. However, the metal has shown enrichment or increase in concentration to various levels from low to high and generally catagorized into the unpolluted to moderately polluted (i.e. Cd). All metals have been accumulated highly in biota, especially in macroalgae and seagrass. This shows that the presence of metals has an impact on organisms including marine resources that have the potential to be consumed. Therefore, efforts to manage heavy metal pollution originating from human activities need to be carried out to minimize the harmful level to coastal water ecosystems in Benoa Bay and Nusa Lembongan.