Experimental and numerical study of cadmium fate and transport mechanisms during artificial recharge in agricultural regions

IF 4.9 Q2 ENGINEERING, ENVIRONMENTAL

Groundwater for Sustainable Development Pub Date : 2024-09-07 DOI:10.1016/j.gsd.2024.101327

Himanshu Rawat, Kartik Jadav, Ajit Kumar, Basant Yadav

{"title":"Experimental and numerical study of cadmium fate and transport mechanisms during artificial recharge in agricultural regions","authors":"Himanshu Rawat, Kartik Jadav, Ajit Kumar, Basant Yadav","doi":"10.1016/j.gsd.2024.101327","DOIUrl":null,"url":null,"abstract":"<div>Agricultural Managed Aquifer Recharge (AgMAR) uses agricultural lands and floodwater to enhance groundwater recharge, but its effectiveness can be hindered by heavy metals like cadmium (Cd), which pose risks to groundwater quality. Cd is particularly concerning due to its high mobility and persistence in the environment. This study investigates Cd's fate and transport in agricultural regions during MAR, focusing on sandy loam soils through batch and column experiments. Equilibrium and kinetic batch studies were conducted under varying Cd concentrations and exposure times to quantify the adsorption capacity and rate. HYDRUS-2D was used to simulate Cd's transport in soil under various ponding depths and Cd concentrations. Results showed a maximum Cd adsorption capacity of 439.58 mg/kg, with the Freundlich isotherm providing a better fit (R2 = 0.98) and indicating heterogeneous adsorption sites (n = 0.389). The kinetic experiment indicated chemisorption as the predominant mechanism, with an equilibrium adsorption capacity of 236.49 mg/kg. The pseudo-second-order kinetic model (rate constant 0.0016 h⁻1, R2 = 0.99) suggested that adsorption kinetics are influenced by Cd concentration and available adsorption sites. The column experimental findings supported by HYDRUS-2D modeling successfully explained the fate and transport of Cd within the soil columns. The model fitted parameter values for Freundlich adsorption isotherm coefficient (KF), linearity factor (Nu), and kinetic rate coefficient are (α) 47.37 L/kg, 0.00389 cm³/ppm and 0.0029 min⁻1, respectively. Modeling scenarios further elucidated the transport dynamics of Cd under simulated AgMAR conditions. Modeling scenarios indicated that with constant ponding of 5 cm over a year, Cd at 20 and 40 ppb concentrations in floodwater could potentially migrate below root zone systems. This study highlights the critical role of understanding Cd fate and transport in optimizing AgMAR systems and reducing Cd pollution risks, providing valuable insights for developing effective monitoring and management strategies.</div>","PeriodicalId":37879,"journal":{"name":"Groundwater for Sustainable Development","volume":"27 ","pages":"Article 101327"},"PeriodicalIF":4.9000,"publicationDate":"2024-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Groundwater for Sustainable Development","FirstCategoryId":"1085","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S2352801X24002509","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"ENGINEERING, ENVIRONMENTAL","Score":null,"Total":0}

引用次数: 0

Abstract

Agricultural Managed Aquifer Recharge (AgMAR) uses agricultural lands and floodwater to enhance groundwater recharge, but its effectiveness can be hindered by heavy metals like cadmium (Cd), which pose risks to groundwater quality. Cd is particularly concerning due to its high mobility and persistence in the environment. This study investigates Cd's fate and transport in agricultural regions during MAR, focusing on sandy loam soils through batch and column experiments. Equilibrium and kinetic batch studies were conducted under varying Cd concentrations and exposure times to quantify the adsorption capacity and rate. HYDRUS-2D was used to simulate Cd's transport in soil under various ponding depths and Cd concentrations. Results showed a maximum Cd adsorption capacity of 439.58 mg/kg, with the Freundlich isotherm providing a better fit (R² = 0.98) and indicating heterogeneous adsorption sites (n = 0.389). The kinetic experiment indicated chemisorption as the predominant mechanism, with an equilibrium adsorption capacity of 236.49 mg/kg. The pseudo-second-order kinetic model (rate constant 0.0016 h⁻¹, R² = 0.99) suggested that adsorption kinetics are influenced by Cd concentration and available adsorption sites. The column experimental findings supported by HYDRUS-2D modeling successfully explained the fate and transport of Cd within the soil columns. The model fitted parameter values for Freundlich adsorption isotherm coefficient (KF), linearity factor (Nu), and kinetic rate coefficient are (α) 47.37 L/kg, 0.00389 cm³/ppm and 0.0029 min⁻¹, respectively. Modeling scenarios further elucidated the transport dynamics of Cd under simulated AgMAR conditions. Modeling scenarios indicated that with constant ponding of 5 cm over a year, Cd at 20 and 40 ppb concentrations in floodwater could potentially migrate below root zone systems. This study highlights the critical role of understanding Cd fate and transport in optimizing AgMAR systems and reducing Cd pollution risks, providing valuable insights for developing effective monitoring and management strategies.

Abstract Image

查看原文本刊更多论文

农业地区人工补给过程中镉归宿与迁移机制的实验和数值研究

农业管理含水层回灌（AgMAR）利用农业用地和洪水来加强地下水回灌，但其有效性可能会受到镉（Cd）等重金属的阻碍，而镉会对地下水质量构成威胁。镉在环境中的高流动性和持久性尤其令人担忧。本研究通过间歇实验和柱状实验，以沙壤土为重点，研究了镉在 MAR 期间在农业地区的归宿和迁移。在不同的镉浓度和暴露时间下进行了平衡和动力学批处理研究，以量化吸附能力和吸附速率。使用 HYDRUS-2D 模拟了不同积水深度和镉浓度下镉在土壤中的迁移。结果表明，镉的最大吸附容量为 439.58 毫克/千克，Freundlich 等温线具有更好的拟合效果（R2 = 0.98），并表明存在异质吸附位点（n = 0.389）。动力学实验表明化学吸附是主要机制，平衡吸附容量为 236.49 毫克/千克。伪二阶动力学模型（速率常数 0.0016 h-1，R2 = 0.99）表明，吸附动力学受镉浓度和可用吸附位点的影响。在 HYDRUS-2D 模型的支持下，土柱实验结果成功地解释了镉在土柱中的归宿和迁移。模型拟合的 Freundlich 吸附等温线系数 (KF)、线性系数 (Nu) 和动力学速率系数的参数值分别为 (α) 47.37 L/kg、0.00389 cm³/ppm 和 0.0029 min-1。模拟情景进一步阐明了镉在模拟 AgMAR 条件下的迁移动力学。模拟情景表明，在一年内持续积水 5 厘米的情况下，洪水中浓度为 20 和 40 ppb 的镉有可能迁移到根系以下。这项研究强调了了解镉的归宿和迁移对优化农业水处理系统和降低镉污染风险的关键作用，为制定有效的监测和管理策略提供了宝贵的见解。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

求助全文

约1分钟内获得全文求助全文

来源期刊

Groundwater for Sustainable Development Social Sciences-Geography, Planning and Development

CiteScore

11.50

自引率

10.20%

发文量

152

期刊介绍： Groundwater for Sustainable Development is directed to different stakeholders and professionals, including government and non-governmental organizations, international funding agencies, universities, public water institutions, public health and other public/private sector professionals, and other relevant institutions. It is aimed at professionals, academics and students in the fields of disciplines such as: groundwater and its connection to surface hydrology and environment, soil sciences, engineering, ecology, microbiology, atmospheric sciences, analytical chemistry, hydro-engineering, water technology, environmental ethics, economics, public health, policy, as well as social sciences, legal disciplines, or any other area connected with water issues. The objectives of this journal are to facilitate: • The improvement of effective and sustainable management of water resources across the globe. • The improvement of human access to groundwater resources in adequate quantity and good quality. • The meeting of the increasing demand for drinking and irrigation water needed for food security to contribute to a social and economically sound human development. • The creation of a global inter- and multidisciplinary platform and forum to improve our understanding of groundwater resources and to advocate their effective and sustainable management and protection against contamination. • Interdisciplinary information exchange and to stimulate scientific research in the fields of groundwater related sciences and social and health sciences required to achieve the United Nations Millennium Development Goals for sustainable development.