Radionuclides baseline assessment of water resources, sediments, source rocks, and NORM flux simulation prior to shale gas development in Brazil

IF 7.3 2区环境科学与生态学 Q1 ENVIRONMENTAL SCIENCES

Environmental Pollution Pub Date : 2025-10-02 DOI:10.1016/j.envpol.2025.127200

Gustavo Filemon Costa Lima , Hugo Guimarães Martins , Eduardo Duarte Marques , Rubens Martins Moreira , Emmanoel Vieira Silva-Filho , Carlos Alberto de Carvalho Filho

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引用次数: 0

Abstract

Hydraulic fracturing (fracking) is a controversial yet profitable technique used to stimulate ultra-low permeability reservoirs in unconventional hydrocarbon production. A significant environmental concern associated with fracking is its potential to mobilize radionuclides, leading to contamination aquifers, sediments, and surface waters. Despite this risk, the potential for radionuclide contamination in watersheds due to unconventional oil and gas operations is frequently underestimated, resulting in hazardous consequences globally, including health risk and ecosystem damage. One effective approach to mitigating such risks is establishment of environmental baselines prior to shale gas development. This study aims to establish a radionuclide baseline for surface water, groundwater, sediments, and source rocks in the São Francisco Basin (Brazil), prior to the introduction of unconventional gas production. The study also simulates radionuclide flux in produced water, a byproduct of hydraulic fracturing, and assesses annual dose of radioactivity exposure using Monte Carlo simulations. Radionuclides U-238, Th-232, K-40, Pb-210, Ra-226, and Ra-228 were analyzed using Neutron Activation Analysis (NAA) and gamma spectrometry. Environmental thresholds and geochemical background were calculated using 2mMAD (Median Absolute Deviation) whereas a multivariate statistical analysis was performed through Principal Components Analysis using Compositional Data transformations. A Monte Carlo simulation, based on 10,000 iterations, was used to compare potential NORM flux from fracking with natural background levels and those in other shale plays worldwide. Current radionuclide concentrations in water resources are low, however the NORM flux and Annual Exposure simulations indicate a potential radiological risk to water security in the event of unconventional gas production. This research provide novel insights into the NORM-related risks of fracking in the São Francisco Basin, offering a foundation for further assessments before shale gas development, which can be also used in unconventional reservoirs around the world.

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巴西页岩气开发前水资源、沉积物、烃源岩的放射性核素基线评估和NORM通量模拟

水力压裂是一种有争议但有利可图的非常规油气开采技术。与水力压裂法有关的一个重大环境问题是它可能调动放射性核素，导致含水层、沉积物和地表水受到污染。尽管存在这种风险，但由于非常规油气作业而导致的流域放射性核素污染的可能性往往被低估，从而在全球范围内造成危险后果，包括健康风险和生态系统破坏。降低此类风险的一种有效方法是在页岩气开发之前建立环境基线。本研究的目的是在引入非常规天然气生产之前，为 o Francisco盆地（巴西）的地表水、地下水、沉积物和烃源岩建立放射性核素基线。该研究还模拟了采出水中的放射性核素通量（水力压裂的副产品），并使用蒙特卡罗模拟评估了放射性暴露的年剂量。放射性核素U-238、Th-232、K-40、Pb-210、Ra-226和Ra-228采用中子活化分析（NAA）和伽马能谱分析。环境阈值和地球化学背景使用2mMAD（中位数绝对偏差）计算，并使用成分数据转换通过主成分分析进行多元统计分析。基于10,000次迭代的蒙特卡罗模拟，用于比较自然背景水平和全球其他页岩区的潜在NORM通量。目前水资源中的放射性核素浓度很低，但NORM通量和年暴露模拟表明，在非常规天然气生产的情况下，对水安全存在潜在的放射性风险。该研究为 o Francisco盆地压裂的norm相关风险提供了新的见解，为页岩气开发前的进一步评估提供了基础，也可用于世界各地的非常规储层。

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来源期刊

Environmental Pollution 环境科学-环境科学

CiteScore

16.00

自引率

6.70%

发文量

2082

审稿时长

2.9 months

期刊介绍： Environmental Pollution is an international peer-reviewed journal that publishes high-quality research papers and review articles covering all aspects of environmental pollution and its impacts on ecosystems and human health. Subject areas include, but are not limited to: • Sources and occurrences of pollutants that are clearly defined and measured in environmental compartments, food and food-related items, and human bodies; • Interlinks between contaminant exposure and biological, ecological, and human health effects, including those of climate change; • Contaminants of emerging concerns (including but not limited to antibiotic resistant microorganisms or genes, microplastics/nanoplastics, electronic wastes, light, and noise) and/or their biological, ecological, or human health effects; • Laboratory and field studies on the remediation/mitigation of environmental pollution via new techniques and with clear links to biological, ecological, or human health effects; • Modeling of pollution processes, patterns, or trends that is of clear environmental and/or human health interest; • New techniques that measure and examine environmental occurrences, transport, behavior, and effects of pollutants within the environment or the laboratory, provided that they can be clearly used to address problems within regional or global environmental compartments.