{
  "abstract": "Elevated arsenic concentrations in groundwater pose health risks. Geogenic arsenic contamination is driven by biogeochemical mobilization and groundwater dynamics. Intensive pumping can initially exacerbate contamination by drawing arsenic or mobilizing organic matter into aquifers, but over longer time scales may also promote dilution and flushing in some settings. To better understand the mechanisms controlling arsenic concentrations, we examined changes over two decades in Hanoi (Vietnam), a hotspot of geogenic arsenic contamination and groundwater pumping. Arsenic concentrations from 470 wells sampled in the year 2000 were compared with 434 wells sampled in the same area in 2013 and 2023. Median concentrations declined from 14 to 8 μg/L between 2000 and 2023, while mean concentrations and the proportion of high-arsenic wells (>100 μg/L) remained similar. Using hydrochemical and groundwater-level data, CatBoost models combined with SHAP analysis assessed changes in predictor importance. In 2000, arsenic was more strongly associated with redox predictors, whereas groundwater-level predictors became more important in 2023. Within wells used to evaluate groundwater-level change (n = 251), larger decadal declines were associated with lower arsenic concentrations (median = 31 μg/L) than wells without declines (median = 120 μg/L). We hypothesize a decadal mechanism shift, from redox to hydrological controls, particularly driving arsenic declines.",
  "abstract_shown": true,
  "affiliations": [
    "Department of Water Resources and Drinking Water, Eawag: Swiss Federal Institute of Aquatic Science and Technology, Dubendorf 8600, Switzerland",
    "Department of Environmental Systems Science (D-USYS), Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich, Zurich 8092, Switzerland",
    "Department of Geoscience, University of Wisconsin–Madison, Madison, Wisconsin 53706, United States",
    "Key Laboratory of Analytical Technology for Environmental Quality and Food Safety Control (KLATEFOS), VNU University of Science, Hanoi 11417, Vietnam",
    "National Center for Water Resources Planning and Investigation (NAWAPI), Water Research Institute, Hanoi 10000, Vietnam",
    "Vietnam Water and Environment Association, Hanoi 11307, Vietnam"
  ],
  "article_type": "research article",
  "arxiv": null,
  "author_total": 12,
  "authors": [
    {
      "affs": [
        0,
        1
      ],
      "name": "David Haaf"
    },
    {
      "affs": [
        0,
        1
      ],
      "name": "Michael McGlade",
      "orcid": "0009-0008-8730-765X"
    },
    {
      "affs": [
        0,
        1,
        2
      ],
      "name": "Athena A. Nghiem"
    },
    {
      "affs": [
        3
      ],
      "name": "Duyen Thi Vu"
    },
    {
      "affs": [
        0,
        1
      ],
      "name": "Tobias Steinert"
    },
    {
      "affs": [
        3
      ],
      "name": "Viet Hung Pham"
    },
    {
      "affs": [
        4
      ],
      "name": "Linh Khanh Bui"
    },
    {
      "affs": [
        5
      ],
      "name": "Thanh Ngoc Tong"
    },
    {
      "affs": [
        4
      ],
      "name": "Duong Du Bui"
    },
    {
      "affs": [
        0,
        1
      ],
      "name": "Andrea Stenke"
    },
    {
      "affs": [
        0
      ],
      "name": "Michael Berg",
      "orcid": "0000-0002-7342-4061"
    },
    {
      "affs": [
        0,
        1
      ],
      "name": "Lenny H. E. Winkel",
      "orcid": "0000-0001-7586-7256"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/5esz59tewgncw.bib",
  "cited_by": 0,
  "doi": "10.1021/acs.est.6c07700",
  "fulltext_url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC13738782/",
  "id": "5esz59tewgncw",
  "issns": [
    "0013-936X",
    "1520-5851"
  ],
  "landing_url": "https://doi.org/10.1021/acs.est.6c07700",
  "language": "en",
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "heading",
      "Article"
    ],
    [
      "heading",
      "Occurrence, Fate, and Transport of Aquatic and Terrestrial Contaminants"
    ],
    [
      "openalex",
      "2304|Arsenic contamination and mitigation"
    ]
  ],
  "openalex": "W7222893538",
  "pdf_url": null,
  "pmcid": "PMC13738782",
  "pmid": "42975464",
  "published": "2026-10-18",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/5esz59tewgncw.ris",
  "sources": [
    {
      "first_seen": "2026-11-09T12:23:42Z",
      "native_id": "PMC13738782",
      "source": "pmc",
      "url": "https://doi.org/10.1021/acs.est.6c07700"
    }
  ],
  "subjects": [
    {
      "field": "chemistry",
      "origin": "openalex:2304|Arsenic contamination and mitigation",
      "subfield": "environmental"
    }
  ],
  "title": "Modeled Groundwater Decline is Associated with Lower Arsenic Concentrations in Hanoi",
  "title_text": "Modeled Groundwater Decline is Associated with Lower Arsenic Concentrations in Hanoi",
  "type": "peer-reviewed",
  "updated_at": "2026-11-09T12:23:42Z",
  "url": "https://research.draconitic.com/paper/5esz59tewgncw",
  "venue": "Environmental Science & Technology",
  "versions": []
}