Heavy Metal Study
Description
Research Hypothesis The study hypothesizes that heavy metal concentrations in soils from a granitic terrain in South India are influenced by both geogenic (natural geological factors) and anthropogenic (human-induced) sources. It suggests that metals like arsenic (As), cobalt (Co), chromium (Cr), copper (Cu), and zinc (Zn) exhibit spatial variation, with higher concentrations indicating potential contamination from activities such as pesticide and fertilizer use, alongside natural contributions from granitic geology. Data Overview This dataset includes heavy metal concentrations (As, Ba, Co, Cr, Cu, Mo, Ni, Pb, Rb, Sr, V, Y, Zn, Zr) measured in 44 soil samples collected from South India's granitic terrain. Concentrations, expressed in mg/kg, range from 3.4 to 543.4 mg/kg depending on the element. Measurements were obtained using X-ray fluorescence (XRF) spectroscopy, ensuring precision and reliability. Each sample is uniquely identified, and the dataset is structured with columns representing metal types and their concentrations. Notable Findings Spatial Distribution: Elevated concentrations of As, Pb, and Cr were identified in the study area's northwestern region, suggesting localized contamination due to human activities or natural enrichment from granitic rocks. Contamination Levels: Geo-accumulation Index (Igeo) indicates moderate contamination, particularly for As, Pb, and Cr, influenced by geogenic and anthropogenic factors. Anthropogenic Influence: Principal Component Analysis (PCA) shows fertilizers and pesticides contribute significantly to contamination, especially for Cu and Ni. Health Risk: Non-carcinogenic risks (hazard index, HI) for children and adults were below the safe limit (HI < 1) for most samples, indicating no immediate chronic exposure risk. However, carcinogenic risks for As and Cr ingestion exceeded acceptable thresholds in many samples, especially for children, highlighting potential long-term health concerns. Interpretation and Use of the Data This dataset provides critical insights into the spatial distribution and health risks of heavy metals in soils from granitic terrains. It supports land management planning, health risk assessments, and environmental policies aimed at mitigating contamination. Researchers can use it to explore contamination sources, assess ecosystem impacts, and develop sustainable soil management practices.
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Study Area and Sampling: The study was conducted in a granitic terrain in South India, known for its unique geological composition and susceptibility to both geogenic and anthropogenic influences. A total of 44 soil samples were collected from the top 0–15 cm layer using a random sampling method to ensure representative coverage of the study area. The sampling points were georeferenced using a GPS device, and locations were selected based on land use patterns, proximity to agricultural activities, and natural granitic exposures. Sample Preparation: The collected soil samples were air-dried to remove moisture, sieved through a 2 mm mesh to remove debris, and homogenized. Subsamples of 10 g each were ground to a fine powder for chemical analysis. Instrumentation: The concentrations of heavy metals were determined using an X-ray fluorescence (XRF) spectrometer, a non-destructive analytical technique ideal for quantifying elemental composition in soil. The XRF instrument was calibrated with certified reference materials to ensure accuracy. Detection limits for each metal were carefully considered to ensure reliable measurements. Methodology: Elemental Analysis: Each powdered sample was subjected to XRF analysis to measure concentrations of 14 heavy metals, including As, Ba, Co, Cr, Cu, Mo, Ni, Pb, Rb, Sr, V, Y, Zn, and Zr. Quality Control: Analytical precision and accuracy were assessed through repeated measurements, blank samples, and standards. The coefficient of variation was kept below 5% for all elements. Data Analysis Data were statistically analyzed to understand the spatial distribution, sources, and potential health risks of heavy metals. Geo-accumulation Index (Igeo) was calculated to evaluate contamination levels. Principal Component Analysis (PCA) identified anthropogenic and geogenic influences on heavy metal distribution. Health Risk Assessment followed standard U.S. EPA guidelines to calculate the hazard index (HI) and total carcinogenic risk (TCR) for children and adults through ingestion, dermal contact, and inhalation pathways. Reproducibility This workflow is reproducible by ensuring proper sample collection, preparation, and XRF analysis following the described methods. Software like ArcGIS was used for mapping spatial distributions, and statistical analysis was performed using Python. Standard operating protocols (SOPs) were followed throughout the study to maintain consistency and reliability.