Loads of Pollution to Lake Toba and Their Impacts

Lakes provide various ecosystem services that support biotic habitats and human life. In contrast, many lakes in the world are degraded due to pollutant supply from surrounding areas activities lake. Lake Toba, which is largest lake Indonesia, has indicated a polluted condition. However, source load of each not yet known. A study been conducted determine nutrient organic levels entering represented by Total Phosphorus (TP) Chemical Oxygen Demand (COD), respectively. Observations were carried out November 2017 at 22 locations, i.e., 12 inlet rivers debouching 10 sites The impact was assessed water class criteria based on COD, waters trophic status TP, vertical oxygen profile representing cage aquaculture (CA) non-cage (NCA) areas. Based COD government regulation number 82/2001, quality inlets III IV. area, NCA III, while CA tends be Estimated TP loading catchment area 138 tonnes/yr, activity 570.33 tonnes/yr. Pollutants have caused worsening class, increasing column anoxia hypolimnion layer eutrophication Toba.