Hydrochemical Insight and Groundwater Supply: A Case Study of Patagonia?s Chubut River

TORRES AMÉRICO I.; NIENCHESKI LUIS F.; CAMPODÓNICO VERENA A.; PASQUINI ANDREA I.; FALESCHINI MAURICIO; DEPETRIS, PEDRO J.

Anthropogenic Pollution of Aquatic Ecosystems

Springer Nature

Lugar: Suiza; Año: 2021; p. 205 - 228

The aim of this chapter is to assess the groundwater discharge componentin the hydrological budget of NE Patagonia?s Chubut River (CHR), using222Rn as a quantitative groundwater tracer. The main hydrological characteristics ofCHR are also presented. The annual mean discharges at Valle Inferior havedecreased at a mean rate of 10 m3 per decade. Anthropogenic impacts?such aswastewater discharge?are observed in surface waters. The 222Rn mass balanceindicated that the groundwater inflow to the CHR ranged between 2.0 and5.4 m3 s−1. Thus, such groundwater inputs may account for approximately 6?24%of the total water delivered by CHR to the SW Atlantic Ocean. However, a negativeflux (−1.3 m3 s−1) was recorded in another sampling site suggesting that the river islosing water to the aquifer. The nutrient fluxes toward the ocean were higher inwinter than in spring. The silicic acid flux (1.175 106 mol d−1) was the highest,followed by the total inorganic nitrogen (0.08 106 mol d−1) and then byphosphorus (0.024 106 mol d−1). Such nitrogen flux would support a productionrate of 7.42 106 g C d−1. The results presented in this study indicate that SGDrepresents a relevant process, which takes place in the CHR?s estuarine zone.