An Analysis of Environmental Effects of Kirkuk Landfill's Leachate on Groundwater Pollution

The study examined how sanitary landfill waste and its leachate affected groundwater quality in the Kirkuk Governorate, Iraq. Seven sites were selected to monitor groundwater contamination from the landfill cell to the nearest residential area to calculate their samples' leachate pollution and water quality indices. Physical, chemical, and biological parameters were measured for such environmental indicators. Groundwater maps have been predicted using GIS techniques. The nine-month test period ran from February to November 2024. The results demonstrated that leachate concentrations affect groundwater properties. The amounts of Chemical Oxygen Demand (COD), Biochemical oxygen demand (BOD), $\mathrm{SO}_4^{-2}, \mathrm{PO}_4^{-3}, \mathrm{NH}_3^{+}$, and phenol) were greater than permitted by WHO recommendations. Only the vicinity of the landfill cell showed the effects of heavy metals like Cr and Ni, while the residential areas remained unaffected. The LPI results for leachate samples ranged from 25.43 to 40.52. Also, the WQI of the test sites (GW1, GW2, GW3, and GW4) revealed that they were unsuitable for human use without treatment, whereas the groundwater at the other sites (GW5, GW6, and GW7) was adequate for limited irrigation. The findings of the correlation study indicated that the majority of the parameters had a substantial association with one another. The strong negative correlation between distance and parameters indicates that pollutant concentrations decrease when the distance from the landfill increases. The research recommends adopting scientific and technological means to mitigate pollution by using special pipe networks to prevent leachate leakage from the landfill cells and using modern techniques to treat leachate before it reaches the groundwater.