Analisis Pengelolaan Sungai di Area Penambangan Emas Berdasarkan Daya Tampung Beban Pencemaran (Studi Kasus: Hulu Sungai Taluduyunu, Provinsi Gorontalo

Abstract

Aktivitas penambangan emas tanpa izin (PETI) telah menjadi ancaman serius terhadap ekosistem perairan tawar di Indonesia, khususnya di hulu Sungai Taluduyunu, Kabupaten Pohuwato, Provinsi Gorontalo. Sungai sepanjang 8,3 kilometer ini berfungsi sebagai sumber air baku PDAM Tirta Moolango yang melayani kebutuhan harian sekitar 19.686 penduduk. Sejak awal tahun 2010-an, proliferasi penambangan emas berbasis ekskavator telah mengubah karakteristik fisik dan kimia sungai secara drastis. Permasalahan utama yang dihadapi adalah degradasi kualitas air akibat peningkatan beban sedimen tersuspensi, namun hingga saat ini belum tersedia data daya tampung beban pencemaran (DTBP) sebagai basis data dalam menganalisis status mutu air, menghitung daya tampung beban pencemaran, dan merumuskan analisis pengelolaan sungai yang melibatkan multipihak. Pengambilan data dilakukan di segmen hulu Sungai Taluduyunu, Desa Hulawa, Kecamatan Buntulia, pada September 2023 pada saat musim kemarau untuk memperoleh kondisi hidrologi stabil yang representatif. Pengambilan sampel menggunakan metode purposive sampling di empat lokasi yang merepresentasikan gradien pencemaran dari kondisi stakeholder hingga zona terdampak intensif. Lokasi SR1 (Air Terang) berfungsi sebagai titik referensi di hulu aktivitas tambang dengan vegetasi riparian utuh, sementara SR2, SR3, dan SR4 merepresentasikan zona terdampak dengan intensitas penambangan yang bervariasi. Sebanyak 24 parameter fisika-kimia air dianalisis mengacu pada Peraturan Pemerintah Nomor 22 Tahun 2021 tentang baku mutu air Kelas II. Status mutu air dievaluasi menggunakan metode indeks pencemaran sesuai Keputusan Menteri Lingkungan Hidup Nomor 115 Tahun 2003, dengan klasifikasi berdasarkan nilai indeks: baik (0 – 1,0), cemar ringan (1,0 – 5,0), cemar sedang (5,0 – 10,0), dan cemar berat (lebih dari 10,0). Daya tampung beban pencemaran dihitung menggunakan metode neraca massa berdasarkan Keputusan Menteri Lingkungan Hidup Nomor 110 Tahun 2003, dengan membandingkan beban pencemaran aktual terhadap kapasitas asimilasi maksimum sungai. Prioritas analisis pengelolaan ditentukan melalui Analytical Hierarchy Process (AHP) yang melibatkan empat responden kunci: pemerintah (Dinas Lingkungan Hidup), penambang PETI (perwakilan asosiasi penambang), perusahaan tambang resmi (petugas lingkungan), dan masyarakat lokal (kepala desa). Hasil analisis laboratorium menunjukkan bahwa Total Suspended Solids (TSS) merupakan polutan dominan yang menyebabkan degradasi kualitas air. Konsentrasi TSS di lokasi referensi SR1 tercatat 13 mg/L, kemudian melonjak drastis di zona penambangan: SR2 mencapai 2.590 mg/L (51,8 kali lipat di atas baku mutu 50 mg/L), SR3 mencapai 21.000 mg/L (420 kali lipat), dan SR4 sebesar 2.500 mg/L (50 kali lipat). Indeks Pencemaran tertinggi tercatat di SR3 dengan nilai 10,01 (sangat tercemar), diikuti oleh SR2 dan SR4 dengan nilai 6,78 dan 6,73 (tercemar sedang), sementara SR1 tetap dalam kondisi baik dengan nilai 0,73. Perhitungan beban pencemaran menunjukkan kondisi kritis dimana beban TSS aktual telah melampaui kapasitas asimilasi sungai secara ekstrem. Beban TSS melonjak dari 2.246,40 kg/hari di SR1 menjadi 492.307,20 kg/hari di SR2 dan mencapai puncak 3.447.360 kg/hari di SR3, sebelum turun menjadi 1.296.000 kg/hari di SR4. Total beban TSS aktual mencapai 5.237.913,6 kg/hari, sementara daya tampung maksimum sungai hanya 52.272 kg/hari, menghasilkan tingkat pelampauan sebesar 100,20 kali lipat. Kondisi ini mengindikasikan bahwa 99,01 % dari total beban pencemaran harus direduksi untuk mengembalikan sungai pada kondisi yang memenuhi baku mutu Kelas II. Lokasi SR3 sebagai hotspot penambangan dengan debit 1,9 m3/s memiliki kapasitas DTBP hanya 8.208 kg/hari, namun menerima beban aktual 3.447.360 kg/hari, menunjukkan pelampauan 420 kali lipat yang mengkonfirmasi hilangnya kemampuan asimilasi sungai secara total. Analisis AHP dengan Consistency Ratio 0,076 (di bawah 0,10) mengidentifikasi hierarki prioritas pengelolaan yang terstruktur. Kriteria kebijakan mendominasi dengan bobot 61,61 %, diikuti sumber daya manusia (19,95 %), anggaran (12,10 %), dan infrastruktur (6,34 %). Analisis penetapan daya tampung beban pencemaran meraih prioritas tertinggi dengan bobot 34,11 %, diikuti penetapan kelas sungai (26,38 %), sosialisasi dan kampanye (18,40 %), pengawasan dan monitoring (13,27 %), serta penegakan hukum (7,84 %). Prioritas yang tinggi terhadap instrumen kebijakan dibandingkan analisis operasional mencerminkan konsensus stakeholder bahwa kerangka regulasi yang kuat menjadi prasyarat keberhasilan intervensi pengelolaan. Penelitian ini menemukan bahwa ancaman utama bagi integritas ekologis Sungai Taluduyunu adalah sedimentasi ekstrem, bukan pencemaran organik atau kimia. Pelampauan DTBP hingga 100 kali lipat menjadikan sungai ini sebagai salah satu kasus terburuk yang terdokumentasi dalam literatur global terkait penambangan emas rakyat. Pendekatan integratif yang menggabungkan penilaian kapasitas asimilasi dan penetapan prioritas partisipatif melalui AHP menawarkan kerangka yang dapat direplikasi untuk pengelolaan sungai di wilayah dengan tekanan aktivitas ekstraktif informal. Implikasi praktisnya adalah pentingnya penetapan batas beban pencemaran formal sebagai dasar alokasi discharge yang terukur dan mekanisme akuntabilitas dalam pengelolaan sungai berkelanjutan bagi kawasan sumber air yang melayani 19.931 penduduk. Analisis pengelolaan perlu mengintegrasikan solusi teknis, mekanisme institusional, dan pendekatan partisipatif guna mendukung keberhasilan jangka panjang serta pencapaian SDG 6 dan SDG 15.

Illegal gold mining (PETI) activities have emerged as a critical threat to freshwater ecosystems in Indonesia, particularly in the upper Taluduyunu River, Pohuwato Regency, Gorontalo Province. This 8.3 km river serves as the raw water source for PDAM Tirta Moolango, supplying the daily needs of approximately 19,686 residents. Since the early 2010s, the proliferation of excavator-based artisanal gold mining has drastically altered the river's physical and chemical characteristics. The primary challenge is water quality degradation due to increased suspended sediment loads; however, pollution load capacity data as a basis for measurable pollution control policy have been unavailable. This study aimed to assess the water quality status, calculate the pollution load capacity, and formulate a river management analysis for multi-stakeholders. The research was conducted in the upper segment of the Taluduyunu River, Hulawa Village, Buntulia District, during September 2023 in the dry season to obtain stable and representative hydrological conditions. Sampling employed a purposive sampling method at four analytical locations representing the pollution gradient from baseline conditions to intensively impacted zones. Location SR1 (Air Terang) functioned as a reference point upstream of mining activities with intact riparian vegetation, while SR2, SR3, and SR4 represented impacted zones with varying mining intensities. A total of 24 physical-chemical water parameters were analyzed in accordance with Government Regulation Number 22 of 2021 on Class II water quality standards. Water quality status was evaluated using the Pollution Index method according to Ministry of Environment Decree Number 115 of 2003, with classification based on index values: good (0.0 – 1.0), slightly polluted (1.0-5.0), moderately polluted (5.0 – 10.0), and heavily polluted (above 10.0). Pollution load capacity was calculated using the mass balance method based on the Ministry of Environment Decree Number 110 of 2003, by comparing the actual pollution load with the river's maximum assimilative capacity. Management analysis priorities were determined through the Analytical Hierarchy Process (AHP) involving four key stakeholders: government (Environmental Agency), PETI miners (association representative), formal mining company (environmental officer), and local community (village head). Laboratory analysis results demonstrated that Total Suspended Solids (TSS) constituted the dominant pollutant causing water quality degradation. TSS concentration at reference location SR1 was recorded at 13 milligrams per liter, then increased drastically in mining zones: SR2 reached 2,590 milligrams per liter (51.8-fold above the 50 milligrams per liter standard), SR3 reached 21,000 milligrams per liter (420-fold), and SR4 reached 2,500 milligrams per liter (50-fold). The highest Pollution Index was recorded at SR3 with a value of 10.01 (heavily polluted), followed by SR2 and SR4 with values of 6.78 and 6.73 (moderately polluted), while SR1 remained in good condition with a value of 0.73. Pollution load calculations revealed critical conditions in which actual TSS loads exceeded the river's assimilative capacity. TSS load increased from 2,246.40 kilograms per day at SR1 to 492,307.20 kilograms per day at SR2 and peaked at 3,447,360 kilograms per day at SR3, before decreasing to 1,296,000 kilograms per day at SR4. Total actual TSS load reached 5,237,913.6 kilograms per day, while the river's maximum carrying capacity was only 52,272 kilograms per day, resulting in an exceedance of 100.20-fold. This condition indicated that 99.01 % of the total pollution load must be reduced to restore the river to conditions meeting Class II quality standards. Location SR3, as the mining hotspot with a discharge of 1.9 cubic meters per second, had a capacity of only 8,208 kilograms per day but received an actual load of 3,447,360 kilograms per day, showing 420-fold exceedance that confirmed the complete loss of the river's assimilative capacity. AHP analysis with a Consistency Ratio of 0.076 (below 0.10) identified a structured hierarchy of management Analysis priorities. Policy criteria dominated with a weight of 61.61%, followed by human resources (19.95 %), budget (12.10 %), and infrastructure (6.34%). The Analysis of establishing pollution load capacity achieved the highest priority with a weight of 34.11%, followed by river classification (26.38%), socialization and campaigns (18.40%), supervision and monitoring (13.27%), and law enforcement (7.84%). The high priority assigned to policy instruments compared to operational analyses reflected baseline consensus that a strong regulatory framework is a prerequisite for successful management interventions. This study reveals that extreme sedimentation rather than organic or chemical pollution is the primary threat to the ecological integrity of the Taluduyunu River, with pollution load exceedance reaching up to 100 times the allowable limit, representing one of the most severe cases documented in the global literature on artisanal gold mining. An integrative approach combining an assessment of assimilative capacity with participatory priority setting through AHP provides a replicable framework for river management in areas affected by informal extractive activities. The practical implication is the establishment of formal pollution load limits as a critical foundation for measurable discharge allocation and accountability mechanisms in sustainable river management for critical water source areas serving nearly 19,931 people. Management analyses should integrate technical solutions, institutional mechanisms, and participatory approaches to support long-term success and the achievement of SDG 6 (Clean Water and Sanitation) and SDG 15 (Life on Land).