Submarine groundwater discharge (SGD) is the hidden portion of water that discharges into the ocean across the ocean-land interface, and it is considered one of the hydrological cycle's major components. Two decades ago, SGD in South America was undocumented, and significant advances on this field has occurred since then. This paper presents the results of SGD investigations, a compilation of the SGD estimations, and the areas lacking of data in South America. The compilation of observed SGD in South America shows that groundwater seepage from the land to the ocean occurs in many environments along the coast. Considering only the few regions for which the total SGD flux was estimated, the SGD flux (ca. 1.2 × 108 m3 day-1) is equivalent in volume to almost 70% of Amazon River discharge. Although the study of SGD in South America has greatly advanced, many uninvestigated sites and key questions remain.

A descarga de água subterrânea ("Submarine Groundwater Discharge"; SGD) é um importante elo entre continente-oceano. No Brasil, embora haja um crescente interesse em estudos sobre este tema, eles ainda são raros e se restringem às zonas costeiras. A presente investigação explora as evidências SGD na Plataforma Continental do Sul do Brasil, as quais incluem isótopos de rádio, nutrientes dissolvidos e distribuição das massas d'água. Os resultados indicam que a SGD pode ocorrer na Plataforma Continental na região do Albardão, próximo a um paleocanal localizado a 50 km da costa. Esse paleocanal pode, assim, ser o caminho preferencial de entrada de nutrientes e de águas subterrâneas ricas em metais na plataforma continental.

Submarine Groundwater Discharge (SGD) has been recognized as an important component of the ocean-continent interface. The few previous studies in Brazil have focused on nearshore areas. This paper explores SGD on the Southern Brazilian Continental Shelf using multiple lines of evidence that include radium isotopes, dissolved nutrients, and water mass observations. The results indicated that SGD may be occurring on the Continental Shelf in the Albardão region, near a paleochannel located 50 km offshore. This paleochannel may thus be a preferential pathway for the delivery of nutrient- and metal-enriched groundwater and porewater into continental shelf waters.

This study optimized and validated a method to perform chemical speciation of inorganic arsenic in water samples collected under the Monitoring Program of the Port of Rio Grande-RS in July and October 2010 from the Laguna dos Patos Estuary (RS, Brazil). The flow injection hydride generation atomic absorption spectrometry technique was employed, allowing quantification of As3+ and As5+ present in estuarine water samples. Data interpretation for results generated using the improved method for analyzing water samples collected from Laguna dos Patos Estuary was done by main components analysis.