| Title | Arsenic - fluoride rich groundwaters in a volcanic-sedimentary aquifer in central Italy: background and anomalies |
| Abstract | This study explores the co-existence of arsenic and fluoride in a volcanic-sedimentary aquifer in central Italy, aiming
at identifying the risk areas for human health and the most likely processes deductible at regional/groundwater
body scale leading to the observed co-contamination in groundwater.
The study area is located in Latium (Central Italy) where undersaturated alkali-potassic formations largely outcrop,
belonging to three different volcanic apparatus of Plio-Pleistocene age.
Geochemical data from groundwater at 398 wells or springs are analyzed through statistical methods including
clustering/PCA and geostatistical analysis. 29% of the sampled groundwaters exceeds the drinking water standard
for F (1.5 mg/L), while 55% exceeds that for As (10.0 g/L). Multivariate statistics suggest a widespread process
of water-rock interaction with the K-alkaline volcanic formations releasing As, F, K, Si, V, Rb and PO4 to the
groundwater. As and F show a good correlation (Pearson's r = 0.61) and define a separate component, suggesting
that their background in groundwater might be governed by a common process.
While in the peripheral areas of the volcanic districts, dominated by sedimentary deposits, the As-F correlation
index does not present important fluctuations, Indicator Kriging shows specific As or F anomalies within the volcanic
groundwater bodies and along the Tyrrhenian coastline. These anomalies seem to correspond to the zones
with the highest thermal flux and/or are located near important structural lineaments. Fluoride anomalies close to
mining sites (fluorite) have also been observed. We hypothesize that, unlike the regional co-contamination, these
local anomalies are related to the upwelling of geothermal fluids along fracture/fault systems that mix with cold
groundwater, or to the interaction with mineral deposits particularly enriched of these elements. |
| Source | EGU General Assembly 2019, Vienna, 07-12/04/2019Geophysical research abstracts (Online) 21 |
| Keywords | Groundwaterco-contaminationclusteringgeochemical anomaliesIndicator Kriging |
| Journal | Geophysical research abstracts (Online) |
| Editor | Copernicus GmbH, Katlenburg-Lindau, Germania |
| Year | 2019 |
| Type | Abstract in atti di convegno |
| Authors | Daniele Parrone, Stefano Ghergo, Eleonora Frollini, David Rossi, Elisabetta Preziosi |
| Text | 439902 2019 Groundwater co contamination clustering geochemical anomalies Indicator Kriging Arsenic fluoride rich groundwaters in a volcanic sedimentary aquifer in central Italy background and anomalies Daniele Parrone, Stefano Ghergo, Eleonora Frollini, David Rossi, Elisabetta Preziosi IRSA, Water Research Institute National Research Council, Montelibretti RM , Italy Published version https //meetingorganizer.copernicus.org/EGU2019/EGU2019 7768.pdf 21 EGU General Assembly 2019 Vienna 07 12/04/2019 Internazionale Contributo This study explores the co existence of arsenic and fluoride in a volcanic sedimentary aquifer in central Italy, aiming at identifying the risk areas for human health and the most likely processes deductible at regional/groundwater body scale leading to the observed co contamination in groundwater. The study area is located in Latium Central Italy where undersaturated alkali potassic formations largely outcrop, belonging to three different volcanic apparatus of Plio Pleistocene age. Geochemical data from groundwater at 398 wells or springs are analyzed through statistical methods including clustering/PCA and geostatistical analysis. 29% of the sampled groundwaters exceeds the drinking water standard for F 1.5 mg/L , while 55% exceeds that for As 10.0 g/L . Multivariate statistics suggest a widespread process of water rock interaction with the K alkaline volcanic formations releasing As, F, K, Si, V, Rb and PO4 to the groundwater. As and F show a good correlation Pearson s r = 0.61 and define a separate component, suggesting that their background in groundwater might be governed by a common process. While in the peripheral areas of the volcanic districts, dominated by sedimentary deposits, the As F correlation index does not present important fluctuations, Indicator Kriging shows specific As or F anomalies within the volcanic groundwater bodies and along the Tyrrhenian coastline. These anomalies seem to correspond to the zones with the highest thermal flux and/or are located near important structural lineaments. Fluoride anomalies close to mining sites fluorite have also been observed. We hypothesize that, unlike the regional co contamination, these local anomalies are related to the upwelling of geothermal fluids along fracture/fault systems that mix with cold groundwater, or to the interaction with mineral deposits particularly enriched of these elements. Abstract in atti di convegno Copernicus GmbH 1607 7962 Geophysical research abstracts Online Geophysical research abstracts Online Geophys. res. abstr. Online Geophysical research abstracts. Online danieleparrone PARRONE DANIELE eleonorafrollini FROLLINI ELEONORA stefano.ghergo GHERGO STEFANO elisabetta.preziosi PREZIOSI ELISABETTA david rossi ROSSI DAVID |
