Analisis Daya Tampung Beban Pencemaran Fosfor Dan Dampak Keramba Jaring Apung Di Danau Laut Tawar, Aceh Tengah

Abstract

Danau Laut Tawar di Kabupaten Aceh Tengah, Indonesia, memiliki luas permukaan 5.862 ha, garis pantai 49,75 km, kedalaman maksimum 84,23 m, kedalaman rata-rata 25,19 m, dan daerah tangkapan air seluas 18.877 ha. Danau ini merupakan danau tektonik dan bersifat multiguna seperti berperan sebagai sumber plasma nutfah, air baku air minum dan pertanian, perikanan, dan sumber pembangkit listrik tenaga air. Aktivitas antropogenik akibat pemanfaatan sumber daya di daerah tangkapan air dan perairan meningkatkan pemuatan fosfor ke perairan tersebut. Penelitian ini bertujuan untuk menghitung kapasitas beban fosfor dan dampak kegiatan keramba jaring apung terhadap pencemaran fosfor di Danau Laut Tawar. Data primer dan sekunder dikumpulkan dan dianalisis menggunakan berbagai pendekatan seperti studi literatur, pemodelan, pengukuran in-situ serta ex-situ, dan wawancara. Hasil penelitian menunjukkan konsentrasi fosfor di perairan Danau Laut Tawar sebesar 34,00 mg m-3. Beban fosfor dari daerah tangkapan air sebesar 5,19 mg m-3, dengan alokasi beban fosfor sebesar 0,74 mg m-3. Baku mutu fosfor ditetapkan sebesar 40,00 mg m-3, sehingga daya tampung beban pencemaran fosfor mencapai 1,04 ton tahun-1. Keramba jaring apung pada danau memiliki luas 4,46 ha dan menghasilkan limbah fosfor sebanyak 5,25 ton tahun-1 yang terlarut ke perairan danau. Nilai tersebut lebih tinggi dari daya tampung beban pencemaran fosfor pada danau dan memengaruhi kondisi alaminya serta aktivitas yang dilakukan di sekitar danau. Lake Laut Tawar in Central Aceh, Indonesia, covers an area of 5,862 ha with a coastline length of 49.75 km, a maximum depth of 84.23 m, an average depth of 25.19 m, and a catchment area of 18,877 ha. The lake is a tectonic-formed water body and serves various biological and economic functions such as biodiversity resources, water sources for drinking water and agriculture, fisheries, and hydroelectricity. Anthropogenic pressures from economic activities around and within the lake have increased phosphor loading in the water body. This study aimed to determine the phosphor loading capacity and the contribution of floating net cage operation on phosphor pollution in Lake Laut Tawar. Primary and secondary data were collected and analyzed using various approaches such as documents, modeling, in-situ and ex-situ measurements, and interviews. The results showed that the phosphor concentration in the Lake Laut Tawar waters reached 34.00 mg m-3. The phosphor load from the catchment area was 5.19 mg m-3, with the phosphor load allocation of 0.74 mg m-3. The maximum threshold for phosphor concentration in a lake is set at 40.00 mg m-3, bringing the phosphor pollution load capacity of the lake to 1.04 tons year-1. However, the floating net cages in the lake covered an area of 4.46 ha and produced 5.25 tons year-1 of phosphorus waste which dissolved into the lake waters. This value exceeds the phosphorus load capacity of the lake and subsequently affects the lake's natural state and the ecosystem services it provides.