This study takes the pozzolanic activity, risk assessment and heavy metal migration and release of water-based drilling chips (WDCs) to promote its building materials utilization. Firstly, systematically analyses the pozzolanic activity of WDCs. Secondly, clarifies the ecological environment risk value and human health index of WDCs, and finally reveals the migration and release mechanism of heavy metals of WDCs. The study shows that the combined content of SiO2, Al2O3, CaO and Fe2O3 exceeds 70%, and the 28-day activity index reachs over 65%, indicating excellent pozzolanic activity. WDCs can participate in secondary hydration reactions with cementitious materials, with 4# WDCs exhibiting the best performance. Through the risk environmental risk assessment, it was shown that the four groups of different WDCs do not have potential risk to the ecological environment. However, human health risk assessments reveal that Cr may pose potential carcinogenic risks through oral ingestion, dermal contact, and inhalation, Meanwhile, the calculated risk control values for the three routes of Cr were 1.56 mg/kg, 1.22 mg/kg, 3.40 mg/kg. The calculated emission risk values for Ba and Cl from the four WDCs were 6.78 mg/m3, 6.66 mg/m3, 6.95 mg/m3, and 26.72 mg/m3 and 2450.3 mg/m3, 2125.6 mg/m3, 929.9 mg/m3, and 620.0 mg/m3, respectively. Heavy metal leaching tests fitted the parabolic equation. The migration mechanism was further validated by calculating the slope of the logarithmic cumulative release curve (rc), revealing distinct diffusion behaviors of heavy metals in different stages. And the cumulative release of Cr, As, and Ba after 15 years in 1 # and 2 # is approximately 26.2 mg/kg, 1.2 mg/kg, 22 mg/kg, 62.4 mg/kg, 1.8 mg/kg, 22.2 mg/kg. The hydration reaction of WDCs promotes ion substitution and crystalline transformation, where Ca2+ is replaced by heavy metal ions, resulting in different leaching rates. Finally, CiteSpace visualization analysis identified a research trend shift from environmental risk assessment to resource utilization, highlighting the growing focus on the sustainable application of WDCs.This study provides new theoretical insights and technical guidance for the safe utilization, heavy metal risk control, and resource-based recycling of WDCs, thereby promoting their sustainable application in the construction materials industry.

Risk assessment and migration rule of heavy metals in WDCs of shale gas and its building materials utilization and visual analysis

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发表日期：

2025年6月17日

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Chao-qiang Wang,
Yan Ying,
Zhong Chen,
Wen Ren

摘要

This study takes the pozzolanic activity, risk assessment and heavy metal migration and release of water-based drilling chips (WDCs) to promote its building materials utilization. Firstly, systematically analyses the pozzolanic activity of WDCs. Secondly, clarifies the ecological environment risk value and human health index of WDCs, and finally reveals the migration and release mechanism of heavy metals of WDCs. The study shows that the combined content of SiO₂, Al₂O₃, CaO and Fe₂O₃ exceeds 70%, and the 28-day activity index reachs over 65%, indicating excellent pozzolanic activity. WDCs can participate in secondary hydration reactions with cementitious materials, with 4# WDCs exhibiting the best performance. Through the risk environmental risk assessment, it was shown that the four groups of different WDCs do not have potential risk to the ecological environment. However, human health risk assessments reveal that Cr may pose potential carcinogenic risks through oral ingestion, dermal contact, and inhalation, Meanwhile, the calculated risk control values for the three routes of Cr were 1.56 mg/kg, 1.22 mg/kg, 3.40 mg/kg. The calculated emission risk values for Ba and Cl from the four WDCs were 6.78 mg/m³, 6.66 mg/m³, 6.95 mg/m³, and 26.72 mg/m³ and 2450.3 mg/m³, 2125.6 mg/m³, 929.9 mg/m³, and 620.0 mg/m³, respectively. Heavy metal leaching tests fitted the parabolic equation. The migration mechanism was further validated by calculating the slope of the logarithmic cumulative release curve (rc), revealing distinct diffusion behaviors of heavy metals in different stages. And the cumulative release of Cr, As, and Ba after 15 years in 1 # and 2 # is approximately 26.2 mg/kg, 1.2 mg/kg, 22 mg/kg, 62.4 mg/kg, 1.8 mg/kg, 22.2 mg/kg. The hydration reaction of WDCs promotes ion substitution and crystalline transformation, where Ca²⁺ is replaced by heavy metal ions, resulting in different leaching rates. Finally, CiteSpace visualization analysis identified a research trend shift from environmental risk assessment to resource utilization, highlighting the growing focus on the sustainable application of WDCs.This study provides new theoretical insights and technical guidance for the safe utilization, heavy metal risk control, and resource-based recycling of WDCs, thereby promoting their sustainable application in the construction materials industry.