First Steps to understanding Intrinsic Vulnerability to Contamination of Karst Aquifers in Various South American and Caribbean Countries

Abstract

Protecting 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.

Varovanje podzemne vode na kraških vodonosnikih je izjemno pomembno. V veliko pomoč pri pravilnem odločanju na pod-lagi dejanskih okoljskih značilnosti, ki vplivajo na to, kako zlahka lahko onesnaževalo, uporabljeno na površini tal, zaradi antropo-genih dejavnosti in lastnosti onesnaževal doseže podzemno vodo, so lahko karte ranljivosti. Z metodami za opredelitev ranljivosti, ki temeljijo na pristopu COST Action 620, se lahko pri uporabi na proučevanem območju pridobijo nasprotujoči si rezultati. Glavni cilj te študije je zagotoviti pregled akademskih raziskav o metodologijah za ugotavljanje notranje ranljivosti kraških vodonosnikov, ki se uporabljajo v južnoameriških in karibskih državah. Poleg tega je podan opis študij, povezanih s kraškimi vodonosniki, pri čemer v nekaterih primerih ni specifičnih in-formacij o notranji ranljivosti. Cilj je spodbuditi in pomagati pri razvoju specifičnih metod za opredelitev kraške ranljivosti v teh regijah. Za dosego teh ciljev je bil opravljen sistematičen pregled literature, ki je vključeval študije, izvedene v institucijah, kot so univerze, nacionalni inštituti za vode in geološke službe. V regi-jah je bilo uporabljenih več metod, kot so COP, DRASTIC, RISK, EPIK, PI, PaPRIka in slovenski pristop. Poleg teh je bilo nekaj poskusov za pripravo specifične metodologije, ki bi najbolje us-trezala posebnostim kraških vodonosnikov v regijah. V Južni Ameriki in na Karibih je skoraj 5 % vseh karbonatnih kamnin na svetu. V nekaterih državah so veliki predeli prekriti s kraškimi kamninami, na primer v Peruju 15,4 %, na Kubi 67 % in v Mehiki 25,29 %. Po ocenah več kot 10 milijonov ljudi v Mehiki uporablja vodo iz kraških sistemov. Na Kubi 33 % vse razpoložljive količine vode izvira iz podzemne vode, 91,51 % pa s kraških vodonos-nikov. V Mehiki je bilo opravljenih 13 študij o pomenu kraških vodonosnikov, s katerimi so obravnavali večinoma polotok Ju-katan ter Brazilijo (9 študij), Kubo (5), Kolumbijo (1) in Peru (1). V večini drugih držav v regijah je informacij o tej temi malo. V nekaterih študijah so glede na regionalne značilnosti tropskega krasa rezultati neusklajeni.