Soil contamination by heavy metals has become a significant environmental concern due to industrial activities, including oil and natural gas drilling operations.

A recent study, conducted in Andhra Pradesh, India, and published in the journal Nature, aimed to assess the spatial distribution, sources, and health risks associated with heavy metals in the topsoil near drilling sites.

The findings of this study shed light on the extent of contamination and provide valuable insights for environmental conservation and remediation efforts.

The study focused on analyzing the concentration of six heavy metals (Arsenic, Chromium, Copper, Nickel, Lead, and Zinc) in 139 topsoil samples collected around oil and natural gas drilling sites.

The results indicated varying concentrations of these heavy metals, with some samples exceeding the recommended limits.

The researchers also assessed soil contamination using various indices and conducted health risk assessments based on exposure factors and established guidelines.

The findings revealed significant non-carcinogenic and carcinogenic risks associated with certain heavy metals, highlighting the need for remedial measures to mitigate the contamination’s adverse effects.

The study was conducted in East and West Godavari districts, Andhra Pradesh, and involved the collection of 139 soil samples at a density of 1 sample per 12 km².

The samples were taken from the top 20 cm of the soil, considering that anthropogenic pollutants predominantly affect this layer.

The samples were analyzed for the concentration of heavy metals using high-resolution inductively coupled plasma mass spectrometry (HR-ICP-MS).

Quality assurance and quality control measures were implemented to ensure the accuracy and precision of the analytical results.

Additionally, geographical information system (GIS) techniques were employed to map the spatial distribution of heavy metals in the study area.

The analysis of the soil samples revealed a wide range of heavy metal concentrations.

Arsenic ranged from 0.1 to 16 mg/kg, Chromium from 3 to 707 mg/kg, Copper from 7 to 2324 mg/kg, Nickel from 14 to 234 mg/kg, Lead from 9 to 1664 mg/kg, and Zinc from 60 to 962 mg/kg.

Spatial distribution maps indicated higher pollution levels of Copper, Chromium, Zinc, and Nickel around the drilling sites compared to other regions.

The contamination of the soil was further assessed using indices such as the Index of Geoaccumulation (Igeo), Enrichment Factor (Ef), and Contamination Factor (Cf), which provided insights into the level of contamination.

The study highlighted multiple sources of heavy metal contamination, including industrial waste, petrochemical spills, atmospheric deposition, mine tailings, and the water and solid waste generated during oil and gas production and fracking operations.

The contamination of agricultural fields near drilling sites poses a significant threat to food supply and ecological well-being.

The research emphasized the importance of evaluating soil quality using various techniques and conducting ecological risk assessments to assess the potential risks to human health.


The study’s findings underscore the presence of heavy metal contamination in topsoil around oil and natural gas drilling sites in Andhra Pradesh, India.

The concentrations of certain heavy metals exceeded recommended limits, posing both non-carcinogenic and carcinogenic risks to human health.

The results provide crucial baseline information for the development of effective management strategies and remedial techniques to mitigate contamination and protect the environment.

The study emphasizes the need for sustainable practices in the extraction industry to minimize the point and non-point sources of contamination and safeguard the well-being of local populations and ecosystems.