STUDI INTERKONEKSI SUNGAI CODE DAN AIRTANAH SEKITARNYA DENGAN MENGGUNAKAN APLIKASI ISOTOP ALAM UNTUK MENGETAHUI PENCEMARAN BAKTERI ESCHERICHIA COLI

ANTASHA RAHMATIKA MULYADI, Dr. Ir. Agus Budhie Wijatna, M.Si. ; Bungkus Pratikno, S.T., M.T.

2017 | Skripsi | S1 TEKNIK NUKLIR

Sungai Code terletak membelah pusat Kota Yogyakarta. Hasil pengujian yang dilakukan oleh Badan Lingkungan Hidup (BLH) provinsi DIY menyebutkan bahwa Sungai Code memiliki kandungan bakteri E.coli melebihi baku mutu yang ditetapkan. Air sungai dapat mengalir menuju airtanah penduduk sekitar sungai apabila tipe interaksi antara sungai dan airtanah adalah losing stream. Losing stream mengakibatkan airtanah penduduk dapat tercemar bakteri E.coli dari sungai. Penelitian ini bertujuan untuk menentukan tipe interaksi dan interkoneksi antara Sungai Code dengan airtanah (sumur) di sekitar bantaran Sungai Code, menentukan pencemaran E.coli pada airtanah yang disebabkan oleh sungai, dan menentukan genesis airtanah. Isotop alam deuterium (2H) dan oksigen-18 (18O) digunakan dalam penentuan interkoneksi sungai dengan airtanah dan genesis airtanah. Uji kandungan 2H dan 18O pada penelitian dilakukan dengan LGR DLT-100. Hasil analisis menunjukkan bahwa air sungai memiliki tipe interaksi losing stream pada lokasi pengambilan sampel airtanah A1 (07°46ʹ55,80ʺLS; 110°22ʹ15,96ʺBT), A2 (07°46ʹ54,84ʺLS; 110°22ʹ16,38ʺBT), A3 (07°46ʹ54,59ʺLS; 110°22ʹ16,31ʺBT), A4 (07°46ʹ53,88ʺLS; 110°22ʹ16,14ʺBT), dan A6 (07°46ʹ53,82ʺLS; 07°46ʹ53,82ʺBT). Sampel airtanah A7 (07°46ʹ54,12ʺLS; 110°22ʹ15,54ʺBT), A8 (07°46ʹ56,46ʺLS; 110°22ʹ14,1ʺBT), dan A9 (07°46ʹ56,11ʺLS; 110°22ʹ15,45ʺBT) memiliki genesis yang sama yaitu berasal dari airhujan. Pada sampel airtanah A1, A3, A4, dan A6 terjadi intrusi air sungai, yang mengakibatkan nilai Delta2H dan Delta18O mengalami pengkayaan. Sampel air sungai S1T (07°46ʹ55,79ʺLS; 110°22ʹ16,43ʺ BT) tidak memiliki interkoneksi dengan sampel airtanah sedangkan sampel air sungai S2T (07°46ʹ53,58ʺLS; 110°22ʹ16,98ʺBT) memiliki interkoneksi dengan sampel airtanah A2. Kandungan bakteri E.coli air sungai dan airtanah melebihi baku mutu yang ditetapkan. Sampel air sungai S1T dan S2T memiliki nilai kandungan bakteri E.coli yang sama dengan sampel airtanah A1, A2, A3, A4, A6, dan A7 yaitu lebih besar dan sama dengan 2400 MPN/100 mL. Kandungan bakteri E.coli pada A1, A2, A3, A4, dan A6 diduga berasal dari intrusi air sungai. Sampel airtanah A8 dan A9 memiliki kandungan bakteri E.coli sebesar 1100 MPN/100 mL.

Code River is located splitting the center of Yogyakarta City. The results of tests conducted by the Environment Agency DIY province mentioned that the Code River had E.coli bacteria content exceeding the established quality standard. River water can flow toward the groundwater of the people surrounding the river if the type of interaction between the river and groundwater is the losing stream. Losing stream lead the population groundwater to be contaminated by E.coli bacteria from the river. The objectives of this research were to determine the type of interaction and the interconnection between Code River and groundwater (wells) around Code River, to determine E.coli contamination on groundwater caused by river, and to determine groundwater genes. The deuterium (2H) and oxygen-18 (18O) isotopes were used in the determination of river interconnection between river and groundwater and groundwater genes. The 2H and 18O contents were performed by LGR DLT-100. The results of the analysis showed that river water had the type of losing stream interaction at the location of groundwater sampling of A1 (07°46ʹ55,80ʺS; 110°22ʹ15,96ʺE), A2 (07°46ʹ54,84ʺS; 110°22ʹ16,38ʺE), A3 (07°46ʹ54,59ʺS; 110°22ʹ16,31ʺE), A4 (07°46ʹ53,88ʺS; 110°22ʹ16,14ʺE), and A6 (07°46ʹ53,82ʺS; 07°46ʹ53,82ʺE). Groundwater samples of A7 (07°46ʹ54,12ʺS; 110°22ʹ15,54ʺE), A8 (07°46ʹ56,46ʺS; 110°22ʹ14,1ʺE), and A9 (07°46ʹ56,11ʺS; 110°22ʹ15,45ʺE) had the same genesis that came from rain water. The intrusion of river water occured in groundwater samples of A1, A3, A4, and A6, which caused enrichments of Delta2H and Delta18O. The sample of river water of S1T (07°46ʹ55,79ʺS; 110°22ʹ16,43ʺE) had no interconnection with groundwater samples while the samples of river water of S2T (07°46ʹ53,58ʺS; 110°22ʹ16,98ʺE) had interconnection with groundwater sample of A2. Escherichia coli bacteria contents in river water and groundwater exceeded the established quality standard. Samples of river water of S1T and S2T had the same value of E.coli bacteria as A1, A2, A3, A4, A6 and A7 groundwater samples of over 2400 MPN/100 mL. Escherichia coli bacteria contents in A1, A2, A3, A4, and A6 were predicted derived from river water intrusion. Groundwater samples of A8 and A9 contained E.coli bacteria of 1100 MPN/100 mL.

Kata Kunci : Sungai Code, 2H, 18O, Escherichia coli, interkoneksi, losing stream