Latin America is characterized by renewable water resources representing an opportunity for sustainable environmental and socio-economic development. Promoting the knowledge regarding groundwater resources and capability is thus pivotal, also considering that water availability and sustainable use is often prevented by social inequality and lack of education and planning. The Agua Futura Project, supported by Italian Agency for Development Cooperation (AICS) and performed through a joint venture of research institutions (CNR, UNIFI, UNIROMA-Sapienza, INGV, USAC-Guatemala, UES-El Salvador) and ONGs (ISCOS, ACRA), concerned this topic by addressing water resources scarcity and quality of pilot sites in Guatemala and El Salvador. The present work is specifically aimed at depicting the hydrogeochemical features of Asunción Mita pilot site, an urban/agricultural context located in an area of volcanic origin in the Rio Ostúa basin (Jutiapa, SE Guatemala) also characterized by the presence of mines and hydrothermal emissions. The effective groundwater potential and the possible causes of contamination, by identifying the main solutes and pollutant sources and the principal geochemical processes acting in both groundwater and surface waters, were verified and assessed. 3 surveys (March 2019, October 2019, February 2020) were carried out to highlight possible hydrogeochemical variability associated with the different seasonal conditions, during which physicochemical measurements and water samplings were performed. The analytical determinations concerned: i) main anions (HCO3, Cl, SO4, F, Br, NO3) and N-species (NO2 and NH4); ii) main cations (Na, K, Mg, Ca); iii) trace elements; iv) water isotopes (δ18O, δD and 87Sr/86Sr). The δD-H2O and δ18O-H2O values indicate that most waters have a meteoric origin and a Ca-HCO3 composition, typically characterizing worldwide superficial waters and shallow aquifers. The (Mg, Ca)-HCO3 composition of some samples could instead indicate interaction processes with mafic rocks (e.g., basalts). This distinction is also highlighted by Sr isotopes, as 87Sr/86Sr greater than 0.7050 may indicate an interaction with carbonate rocks, whilst volcanic rocks in the region are generally near 0.7040. On the contrary, two samples are characterized by a δ18O-shift, which is typical of water-rock interaction processes under geothermal conditions, in accordance with their Na-(Cl, HCO3) composition, relatively high TDS values and As, B and Li contents, and Cl/SO4 ratio >1. N-species indicate that inputs from anthropogenic sources are also present, e.g., sewage discharges, or farming activities to which the inhabitants are largely devoted. Within this heterogeneous framework, some springs north of Asunción Mita, being fed by relatively high altitudes (like those of Suchitan volcano, 1700-1750 m a.s.l.), seem to represent a homogeneous groundwater body characterized by a good water quality, which is thus one of the main local water resources.
Hydrogeochemical characterization of Asunción Mita (Jutiapa, Guatemala) pilot site: assessment of groundwater resources potentiality and pollution in the framework of the Agua Futura Project / Cabassi J., Vaselli O., Venturi S., Nisi B., Doveri M., Chemeri L., Di Spigno M., Franceschi L., Cornacchia I., Agostini S., Caprai A., Pomoni E., Luna Aroche J.R.. - ELETTRONICO. - (2023), pp. 0-0. (Intervento presentato al convegno Congresso congiunto SIMP, SGI, SOGEI, AIV "The Geoscience paradigm: Resources, Risks and future perspectives").
Hydrogeochemical characterization of Asunción Mita (Jutiapa, Guatemala) pilot site: assessment of groundwater resources potentiality and pollution in the framework of the Agua Futura Project
Vaselli O.;Venturi S.;
2023
Abstract
Latin America is characterized by renewable water resources representing an opportunity for sustainable environmental and socio-economic development. Promoting the knowledge regarding groundwater resources and capability is thus pivotal, also considering that water availability and sustainable use is often prevented by social inequality and lack of education and planning. The Agua Futura Project, supported by Italian Agency for Development Cooperation (AICS) and performed through a joint venture of research institutions (CNR, UNIFI, UNIROMA-Sapienza, INGV, USAC-Guatemala, UES-El Salvador) and ONGs (ISCOS, ACRA), concerned this topic by addressing water resources scarcity and quality of pilot sites in Guatemala and El Salvador. The present work is specifically aimed at depicting the hydrogeochemical features of Asunción Mita pilot site, an urban/agricultural context located in an area of volcanic origin in the Rio Ostúa basin (Jutiapa, SE Guatemala) also characterized by the presence of mines and hydrothermal emissions. The effective groundwater potential and the possible causes of contamination, by identifying the main solutes and pollutant sources and the principal geochemical processes acting in both groundwater and surface waters, were verified and assessed. 3 surveys (March 2019, October 2019, February 2020) were carried out to highlight possible hydrogeochemical variability associated with the different seasonal conditions, during which physicochemical measurements and water samplings were performed. The analytical determinations concerned: i) main anions (HCO3, Cl, SO4, F, Br, NO3) and N-species (NO2 and NH4); ii) main cations (Na, K, Mg, Ca); iii) trace elements; iv) water isotopes (δ18O, δD and 87Sr/86Sr). The δD-H2O and δ18O-H2O values indicate that most waters have a meteoric origin and a Ca-HCO3 composition, typically characterizing worldwide superficial waters and shallow aquifers. The (Mg, Ca)-HCO3 composition of some samples could instead indicate interaction processes with mafic rocks (e.g., basalts). This distinction is also highlighted by Sr isotopes, as 87Sr/86Sr greater than 0.7050 may indicate an interaction with carbonate rocks, whilst volcanic rocks in the region are generally near 0.7040. On the contrary, two samples are characterized by a δ18O-shift, which is typical of water-rock interaction processes under geothermal conditions, in accordance with their Na-(Cl, HCO3) composition, relatively high TDS values and As, B and Li contents, and Cl/SO4 ratio >1. N-species indicate that inputs from anthropogenic sources are also present, e.g., sewage discharges, or farming activities to which the inhabitants are largely devoted. Within this heterogeneous framework, some springs north of Asunción Mita, being fed by relatively high altitudes (like those of Suchitan volcano, 1700-1750 m a.s.l.), seem to represent a homogeneous groundwater body characterized by a good water quality, which is thus one of the main local water resources.
I documenti in FLORE sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
