Shallow Groundwater Pollution Index Around the Location of Griyo Mulyo Landfill (Jabon Landfill) in Jabon District, Sidoarjo Regency, East Java, Indonesia

The leachate coming from the landfill is a serious problem. This is because the leachate water can contaminate the wells of the residents around the landfill. This research was conducted at Jabon Landfill located in Jabon District of Sidoarjo Regency, East Java Province, Indonesia. Jabon Landfill has been operating since 2003 with a controlled landfill system that has triggered environmental risks due to the leachate output. The purpose of this study was to determine the classification of the shallow groundwater quality status based on the pollution index (PI) around Jabon Landfill at a distance of around 250 meters, 500 meters and 1,000 meters from the landfill. The pollution index was determined by analyzing the pollutant concentration consisting of these following parameters: pH, BOD, COD and Fe. The results of the analysis show that the pH parameter had a higher value than the pH at Jabon Landfill of 7.2–7.5. The pH at Jabon Landfill was 6.35. The Fe parameter shows that the value of 1.694 in the groundwater well closest to Jabon Landfill and the wells further away indicates that the Fe concentration was lower for the latter, namely 0.081 at a distance of up to 200 meters. On the basis of the Pollution Index, the highest value was 5.45 at Well 7 is located 196 m from Jabon Landfill. Meanwhile, the well furthest from Jabon Landfill at a distance of 1,000 m showed a lightly polluted status with a Pollution Index of 1.91. The further the location of the well away from Jabon Landfill, the Pollution Index value tended to decrease. This means that the pollution status generally improves. Overall, the pollution status of the 18 wells shows that 2 wells are moderately polluted, 15 wells are lightly polluted and 1 well is in good condition.