Ability of Humic Acid in the Absorption of Heavy Metal Content of Lead and Iron in Fish Culture Media

The young coal mining pits (young pits) found in West Aceh cause many problems. These pits that form ponds have the potential to be utilized for aquaculture activities. However, the main problem faced in the young pits is the high content of heavy metals. This makes the ponds dangerous for fish farming. Hazardous heavy metals in coal mines are Pb and Fe. Humic acid is one of the materials that can be used to minimize heavy metals and increase water pH. The use of humic acid is more efficient because this technology is easy and cheap and the raw materials are abundant. Humic acid acts as a substance of cation exchange ability found in compost. This research has a long-term goal of making humic acid contained in compost as an alternative material that can minimize heavy metals Pb and Fe, so that it can be used for fish farming activities. The specific objective is to determine the best capacity (dose of humic acid) in minimizing heavy metals and increasing the pH of young pond water in former mines and its effect on fish farming. This research method used a completely randomized design consisting of one factor, namely the dose of humic acid (0 g/L, 2.5 g/L, 5 g/L, 7.5 g/L) and three replications. The results showed that humic acid was able to minimize the content of heavy metals Pb and Fe in coal mine water with the best dose of 5 g/L. The percentage reduction produced was more than 90%. The results of fish rearing using ex-mining pond water treated with humic acid showed that the survival rate and growth rate of fish were higher.