Analysis Distribution of Iron (Fe) and Hexavalent Chromium (Cr⁶⁺) Contaminants in Shallow Groundwater Due To Leachate Around Landfill Terjun, Medan City

¹ Departement of Environmental Engineering, Faculty Engineering, Universitas Sumatera Utara, Padang Bulan, Kota Medan, 20155, Indonesia
² Departement of Civil Engineering, Faculty Engineering, Universitas Negeri Padang, Padang Utara, Kota Padang, 25173, Indonesia

^* Corresponding author: ronaldsiregar@usu.ac.id

Abstract

Terjun Landfill Area is currently in a transition period from an open dumping system to a sanitary landfill. The resulting leachate can spread through infiltration into the soil. Leachate seepage into groundwater will affect groundwater quality. This research aims to analyze the distribution of iron (Fe) and hexavalent chromium (Cr⁶⁺) contaminants in shallow groundwater resulting from leachate around the Terjun Landfill Area. Model simulations were carried out using the Domenico Robbins (1990) model using the MathLab. The results show that the metal pollutants Fe and Cr⁶⁺ in residents’ wells have exceeded the quality standards in Minister of Health Regulation Number 2 of 2023. The results show that the pollutants Fe and Cr⁶⁺ have spread up to > 700 m from the landfill. Fe contamination in the estimated 40 years since the landfill operated was spread over a distance of 750 meters with a pollutant concentration of 0.066 mg/L, and in 50 years it increased to 0.092 mg/L. Meanwhile Cr⁶⁺ contamination over a period of 40 years at a distance of 750 meters spread with a concentration of 0.426 mg/L and increased in the 50th year by 0.600 mg/L.