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eISSN: 2083-5906
ISSN: 1230-1485
ISSN: 1230-1485
ORIGINAL RESEARCH
Coupled Hydrochemical Controls on Fluoride
Enrichment in Ca-Rich Mine Water: Insights
from Saturation Indices and PMF
1
School of Resources and Civil Engineering, Suzhou University, Suzhou, 234000 Anhui, China
2
Coal Industry Engineering Research Center for Exploration and Early Warning of Mine Water Disaster,
Anhui University of Science and Technology, 232000, Huainan, Anhui, China
3
School of Environment and Surveying and Mapping Engineering, Suzhou University, Suzhou, 234000, Anhui, China
Submission date: 2026-01-16
Final revision date: 2026-02-20
Acceptance date: 2026-03-31
Online publication date: 2026-08-03
Corresponding author
Hongbao Dai
School of Environment and Surveying and Mapping Engineering, Suzhou University, Suzhou, 234000, Anhui, China
School of Environment and Surveying and Mapping Engineering, Suzhou University, Suzhou, 234000, Anhui, China
KEYWORDS
high-fluoride mine waterhydrochemical processesfluoride enrichmentpositive matrix factorization (PMF)
TOPICS
ABSTRACT
Fluoride enrichment in mine water is an emerging environmental concern in carbonate-hosted
mining regions, yet its controlling mechanisms remain insufficiently constrained. This study
investigates fluoride enrichment in 106 mine water samples from the Huaibei Coalfield, eastern China,
using integrated hydrochemical analysis, mineral saturation indices, and positive matrix factorization
(PMF). High-fluoride mine water is characterized by the coexistence of elevated Ca2+ and F‒, deviating
from the conventional Ca-F antagonistic model typical of low-Ca groundwater. Saturation index results
show that most samples remain undersaturated with respect to fluorite, and fluorite saturation is reached
only after substantial fluoride accumulation, indicating that fluorite precipitation does not effectively
limit fluoride levels. Weakly alkaline, bicarbonate-buffered conditions combined with prolonged waterrock
interaction and evaporative concentration create favorable environments for fluoride persistence.
PMF results reveal that fluorine-bearing mineral dissolution is the dominant contributor to fluoride
enrichment (31.80%), followed by reverse cation exchange (28.75%), evaporative concentration (20.24%),
and competitive adsorption (19.22%). These findings demonstrate that fluoride accumulation in Ca-rich
mine water is driven by multiple coupled hydrochemical processes rather than a single mechanism,
and they provide a quantitative framework for assessing fluoride contamination in similar mining
environments.
CONFLICT OF INTEREST
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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| eISSN: | 2083-5906 |
| ISSN: | 1230-1485 |
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