LICENCIAMENTO AMBIENTAL E DIVERSOS
URI permanente para esta coleçãohttps://bdc.icmbio.gov.br/handle/cecav/6
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Resultados da Pesquisa
Item First Steps to understanding Intrinsic Vulnerability to Contamination of Karst Aquifers in Various South American and Caribbean Countries(2023) Souza, Rogério Tadeu de; Travassos, Luiz Eduardo Panisset; Heredia, Olga Susana; Paparas, Mariana Alicia; Sicilia, Silvia Alejandra; Patat, Franco Urbani; Ortega, Rosa María Valcarce; Rodríguez, Moraima Fernández; Corrales, Liane Gamboa; Enríquez, Nathalia Vanessa Uasapud; Duarte, Yameli G. Aguilar; Bautista, FranciscoProtecting groundwater in karst aquifers is extremely important. Vulnerability maps can greatly help proper decision making based on physical environmental attributes that influence how easily a contaminant applied to the land surface can reach groundwater due to anthropogenic activities, and the properties of the contaminants. Methods for determining vulnerability based on the COST Action 620 Approach, when applied in the study area, may lead to contradictory results. The main purpose of this study is to provide an overview of academic research on intrinsic karst aquifer vulnerability methodologies applied in South American and Caribbean countries. Secondly, it describes studies related to karst aquifers that, in some cases, lack specific information on intrinsic vulnerability. The objective is to encourage and to help develop specific methods for determining karst vulnerability in these regions. To achieve these purposes, a systematic literature review was conducted including studies conducted at institutions such as universities, national water institutes, and by geological services. Several methods have been used in the region such as COP, DRASTIC, RISK, EPIK, PI, PaPRIka, and the Slovene Approach. And some attempts have been made to develop a specific methodology that best suits the specificities of the region’s karst aquifers. South America and the Caribbean have almost 5 % of the world´s carbonate rocks. Some countries have large extensions of their territory covered by karst rocks, such as Peru, 15.4 %; Cuba, 67 %; and Mexico 25.29 %. Estimates indicate that more than 10 million people use water from karst systems in Mexico. In Cuba, 33 % of all available water volume originates from groundwater, and 91.51 % from karst aquifers. In Mexico, 13 studies have been conducted on the importance of karst aquifers, which mostly address the Yucatan Peninsula, followed by Brazil (9 studies), Cuba (5), Colombia (1) and Peru (1). Information about the theme is scarce in most of the other countries in the region. Some studies have incongruent results given the regional characteristics of tropical karst.- An approach to map karst groundwater potentiality in an urban area, Sete Lagoas, Brazil(2020-09-28) Magnabosco, Rafael; Galvão, Paulo; de Carvalho, Ana MacielDue to complex hydrogeological contexts, mapping groundwater potential zones in karst regions is a difficult task. This study was conducted on a karst terrain in Sete Lagoas, Brazil, where rapid urban growth without adequate water resources management resulted in the drilling of unproductive wells and possible aquifer over-exploitation due to the concentration of wells. The objective was to develop a method for mapping groundwater potentiality for karst aquifers, serving as water resources management tool, based on 3D geological modelling, field work and pumping test data, remote sensing, geophysics analysis and production of thematic maps, resulting in the hydrogeological conceptual model. The groundwater potentiality map showed that most potential zones are on the central area, limited by grabens, where limestones are in contact with unconsolidated sediments, on areas with higher density of morphostructural and geophysical lineaments, mainly in east–west and north–east directions, near karst surface features, on thicker karstified zones, with higher recharge rates.
- Natural background levels and validation of the assessment of intrinsic vulnerability to the contamination in the Carste Lagoa Santa Protection Unit, Minas Gerais, Brazil(2019-12-21) Aragão, Frederico; Nunes Menegasse Velásquez, Leila; Galvão, Paulo; de Castro Tayer, Thiaggo; Nogueira Lucon, Thiago; Ruchkys de Azevedo, ÚrsulaThe contamination of karst aquifers by anthropogenic activities causes a major issue regarding environmental policies, since they present high sensitivity, influenced by unique features such as dolines, swallow holes, and conduits. This paper is focused on the Carste Lagoa Santa Protection Unit, MG, Brazil, and presents three main objectives: to determine the natural background levels of chloride, nitrate, sulfate, and phosphate; to indicate the locations where the concentrations of those parameters exceed the natural background levels in the existing vulnerability map and, finally, to determine the proportion of the areas (in percentage) where this surpassing occurs, according to the vulnerability classes (high, moderate and low). Results have shown values (90th percentile) of 2.4 mg/L, 1.0 mg/L, 5.3 mg/L, and 0.1 mg/L, for Cl−, NO3−, SO4−2, and PO4−3, respectively, indicating that for all four parameters, there were areas (mainly distributed within moderate vulnerability portions) where the values were surpassed, which suggests anthropogenic activity due to the presence of urban settlements and agricultural activities. Therefore, the proposal of natural background levels was essential to understand the hydrochemistry of the studied region.