Assessing Soil Pollution: An Investigation into Heavy Metal Contaminations in Roadside Soil in Aizawl, Northeast India

The study investigates the heavy metal contamination in the roadside soils of Aizawl, located in Northeast India, where the roadside soil is vulnerable to heavy metal pollution due to vehicular traffic and human activities. A systematic analysis was conducted at twelve sampling sites throughout the city from August 2020 to July 2021, with three replicates taken at each location. Metal concentrations were measured using atomic absorption spectrophotometry after acid digestion, following the USEPA 3050B method. The heavy metals analysed include copper (Cu), nickel (Ni), lead (Pb), and zinc (Zn). The mean metal concentrations at the selected sites range from 0.46 – 0.99 for Cu, 0.25 - 0.54 for Ni, 0.29 - 0.50 for Pb, and 1.35 - 1.84 for Zn. All measured metal concentrations exceeded the local average background values (ABVs), but they generally fall within the safe limits established by the Canadian and Chinese soil quality standards for residential areas. While all contamination levels fall within the moderately contaminated category based on the geo-accumulation index (Igeo), the pollution load index (PLI) indicated moderate to high levels of contamination by Cu at site S9 (Chanmari) and by Zn at sites S1 (Kulikawn), S5 (Bazar Bungkawn), S9 (Chanmari), and S12 (Khatla). The Pearson correlation analysis revealed a moderate positive correlation between copper and zinc, indicating a common source of pollution. Effect of monsoon Pb and Zn is also observed. The findings revealed varying metal concentrations at the different sites, with variations in the different sampling periods due to the influence of urbanization, human activities, vehicular traffic, and weather.