| Origin of high fluoride contents in groundwater of the Santa Maria Formation, Guarany Aquifer System, southern Brazil |
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| 作者姓名： | Ari Roisenberg Maria Paula C. Marimon Antonio P. Viero |
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| 作者单位： | [1]Institute of Geosciences, Federal University of Rio Grande do Sul, Porto Alegre, Brazil [2]Geography Department, State University of Santa Catarina, Florianopolis, Brazil |
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| 摘 要： | Fluoride anomalies （up to 11 mg/L） have been detected in the porous confined Santa Maria Aquifer （Guarany Aquifer System） in the central region of Rio Grande do Sul State, southern Brazil, leading to endemic fluorosis. Two hypotheses are investigated concerning the fluoride origin： contamination by long-term phosphate-fertilizer application due to extensive tobacco plantation or lithogeochemical affiliation from regional rocks. The results are discussed based on statistical and geochemical modeling and stable isotope data of water, nitrate and sulfate. Field monitoring of phreatic and confined aquifer during two years and laboratory leaching and retention experiments were performed. Regional statistical analysis （factorial and cluster analysis） on the basis of 350 wells discriminates four different hydrochemical groups in the confined aquifer, considering magnesium, calcium bicarbonate, sodium chlorinate and sodium bicarbonate as specific parameters. The last two groups reach higher fluoride contents and represent deeper aquifer levels where geochemical modeling shows carbonates （calcite and dolomite） are of super-saturation. The laboratory experiments confirmed that local soils with high CTC and aluminum contents （Udults） represent an efficient geochemical barrier, preserving the aquifer from fluoride contamination and supporting remediation strategies for fluoride removal. δ^18O and δD groundwater data and the local meteoric water line （LMWL） indicate that local precipitation is the main groundwater recharge source in the area.
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| 关 键 词： | 氟化物 氟中毒 肥料 同位素 环境污染 巴西 地球化学模型 |
Origin of high fluoride contents in groundwater of the Santa Maria Formation, Guarany Aquifer System, southern Brazil |
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| Ari Roisenberg Maria Paula C. Marimon Antonio P. Viero.Origin of high fluoride contents in groundwater of the Santa Maria Formation, Guarany Aquifer System, southern Brazil[J].Chinese Journal of Geochemistry,2006,25(B08):121-121. |
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| Abstract: | |
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| Keywords: | fluoride fluorosis fertilizer stable isotope contamination |
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