Assessing the quality and heavy metal contamination of soil in tea gardens around Magurchara gas blowout in Bangladesh using multivariate and soil quality index methods

Abstract

Explosive gas blowouts cause severe damage to gas-bearing rocks, structures, local tectonic settings, and the environment. Bangladesh has seen three high-profile gas explosions. One of these is the Magurchara gas well blowout in Kamalganj union, Moulvibazar district, on June 14, 1997. Soil erosion was the most important problem in the surrounding area, particularly the tea gardens. This study's goal was to analyze the soil quality around the Magurchara gas well blowout in the Kamalganj union. In this case, soil samples were collected (some near the well, others further away) and analyzed in the laboratory. Soil bulk density (BD), soil porosity (SP), soil moisture content (SOM), pH, total nitrogen (TN), soil organic carbon (SOC), and soil organic matter (SOM) have been measured, and the results show that in most places, the values do not fulfill the requirements for good tea plant growth. Heavy metal concentrations were evaluated using digestion and an atomic absorption spectrophotometer (AAS). Interpolation was performed to depict the heavy metal distribution in the research area. Soil contamination was assessed utilizing the geo-accumulation index, contamination factor, ecological risk, and enrichment factor. Multivariate statistical methods like principal component analysis (PCA) and cluster analysis (CA) were utilized to assess soil quality. The results show that tea garden soils are contaminated, and the high quantity of Cd in the research region implies severe contamination. The mean ecological risk index (Eri) for five heavy metals was Cd > Pb > Cu > Ni > Zn, indicating a future moderate risk to the environment. This study also demonstrated Cd to be a serious concern to the environment and tea plantation soils. The existing quality of the soil surrounding the blowout is unfavorable for tea plant growth. Despite its flaws, this study will certainly help to understand the current state of tea garden soils near the gas well blowout and lay the groundwork for future studies in this area.