Kualitas Perairan Sungai Brangkal Mojokerto Berdasarkan Indeks Keanekaragaman Makrozoobentos

Quality of Waters of The Brangkal Mojokerto River based on the Macrozoobenthic Diversity Index

Sungai Brangkal ialah sungai yang termasuk kedalam Kabupaten Mojokerto bermula dari desa Miji sampai desa Kauman hingga ke sungai Brantas. Di bantaran sungai ditemukan sampah yang terbungkus plastik dan menumpuk, selain itu pabrik-pabrik di sekitar membuang limbah ke sungai sehingga menurunkan kualitas perairan. Penelitian ini bertujuan untuk menganalis kualitas perairan Sungai Brangkal Mojokerto. Metode yang digunakan yaitu observasi dengan 3 stasiun, pengambilan sampel makrozoobentos menggunakan metode purposive random sampling, penelitian ini dilaksanakan pada bulan September-November 2020. Parameter fisik kimia yang diamati meliputi suhu, pH, kedalaman, kecepatan arus, kecerahan, DO, COD, BOD, kandungan Pb dalam sampel air, dan kandungan Pb dalam tubuh makrozoobentos. Sampel makrozoobentos diambil menggunakan van veen grab, kemudian sampel diidentifikasi hingga tingkat spesies. Terdapat 4 jenis makrozoobentos yang ditemukan yaitu Pomacea canaliculata, Gecarcinucoidea, Melanoides tuberculata, dan Filopaludina javanica. Indeks keanekaragaman makrozoobentos dihitung menggunakan rumus Shannon-Wiener. Hasil penelitian menunjukkan bahwa kualitas perairan Sungai Brangkal Mojokerto termasuk kategori pencemaran sedang dengan nilai DO 0,153333 ppm, dan nilai BOD 0,156667 ppm, serta indeks keanekaragaman makrozoobentos di Sungai Brangkal Mojokerto yaitu 1,137981 yang artinya keanekaragaman tergolong jenis sedang.

Brangkal River is a river that belongs to Mojokerto Regency starting from Miji Village, to Kauman Village until the Brantas River. On the riverbank, there was found trash wrapped in plastic bags and piled up, meanwhile the factories around the river dumped their waste into the river, it could reducing the quality of the waters. The purpose of this research is to analyze the quality of the waters of the Brangkal River. The method of this research is observation with 3 stations, macrozoobenthic sampling using purposive random sampling method. The physical and chemical parameters observed included temperature, pH, water deepness, speed of the water flow, brightness of the water, DO, COD, BOD, Pb metal content in water samples, and Pb metal content in the macrozoobenthic body. Macrozoobenthic samples were taken using van veen grab, then the samples were identified into species level. There are 4 species of macrozoobenthos found, they are Pomacea canaliculata, Gecarcinucoidea, Melanoides tuberculata, and Filopaludina javanica. The macrozoobenthic diversity index was calculated using the Shannon-Wiener formula. The results showed that the quality of the waters of the iBrangkal River was included in the moderate pollution category with DO value is 0,153333 ppm, and BOD value is 0,156667 ppm, and the macrozoobenthic diversity index in the Brangkal River is 1.1-1.2 means classified in moderate diversity.