Analisis Kualitas Air dan Status Mutu Danau Toba di Desa Paropo Kecamatan Silahisabungan Kabupaten Dairi

Abstract

Lake Toba water in Paropo Village is frequently used by the local people for numerous activities such as floating net cages, washing clothes, net fishing, watering plants, tourism area, port and others. Waste from public activities is feared to affect the water quality of Lake Toba. This situation could cause the water unfit to be used for its intended purposes and may have negative effects on public health. The objectives of this study were to analyse water and the quality status of Lake Toba in Paropo Village, Silahisabungan Subdistrict, Dairi District. This study is a descriptive study. Samples were taken from 5 locations based on pollution sources, with nine measurement parameters. The result showed that DO ranged from 4,03 mg/L to 7,74 mg/L, with point 1, 2, and 3 not meeting the quality standards. BOD ranged from 0,11 mg/L to 3,4 mg/L, with point 1, 2, and 3 exceeding the quality standard. COD ranged from 6,9 mg/L to 17,8 mg/L, with point 2 and 4 exceeding the quality standard. Total coliform ranged from 1.500 to 16.000 MPN/100 mL. Other parameters that still in the saved quality standard were temperature (27-28,8°C), TDS (32-33 mg/L), pH (8,07- 8,53), chloride (5,998-7,498 mg/L) and lead (0,000005-0,000082 mg/L. The average of Pollution Index from the five locations was 2,6 so it can be concluded that the water quality of Lake Toba in Paropo Village is slightly polluted (1,0 < PI ≤ 5,0). Therefore, the role of local government and community is needed to improve the water quality of Lake Toba in Paropo Village.