An Overall Perspective for the Study of Emerging Contaminants in Karst Aquifers

Abstract

Karst aquifers are essential drinking water sources, representing about 25% of the total available sources globally. Groundwater ecosystems consist of fissured carbonate rocks commonly covered with canopy collapse sinkholes. The open nature of karst aquifers makes them susceptible to rapidly transporting contaminants from the surface in dissolved and particulate forms. The principal aim of this review is to contribute to filling the gap in knowledge regarding major concerns affecting karst aquifers and understanding their vulnerabilities and dynamics. The principal groundwater pollutants of relevance are detailed in the present work, including well-known issues, such as the input of agriculture and its role in water quality. Emerging pollutants such as microplastics, still poorly studied in the groundwater systems, were also considered. Case studies for each typology of pollutant were highlighted, as their relative concerns for karst environments. Final considerations underlined an approach for studying karst environments more focused on understanding dynamics and links among different pollutants inputs and their drivers than on individual sources and impacts.

Microplastics in Groundwater: Pathways, Occurrence, and Monitoring Challenges

“…The average concentration of MPs in the sediment was 3,350,000 particles per cubic meter, i.e., 600,000 times higher than the average concentration of 5.57 particles per cubic meter detected in water. This difference is expected to be even greater in lakes due to the lower water flow velocities, which facilitate sedimentation processes [6].…”

“…While only a small proportion of the plastics produced is recycled or incinerated, the majority is accumulated in natural environments or landfills [4]. MPs have attracted considerable attention as an emerging pollutant and have been recognised as a key contributor to environmental pollution [5][6][7].…”

“…MPs are present in atmospheric, terrestrial, and aquatic environments [21][22][23][24][25][26][27][28] and thus also in the water cycle [29]. Due to their presence in the environment and the threat they pose to the ecosystem [30], MPs have received considerable attention as newly emerging pollutants [5,6,31,32].…”

Hydrochemical Characteristics and Evolution under the Influence of Multiple Anthropogenic Activities in Karst Aquifers, Northern China

“…Karst regions, covering only 7-12% of Earth's terrestrial areas, provide vital karst groundwater resources and support 20-25% of the global population's drinking water demands [1,2]. Karst aquifers are typically formed from rock dissolution due to erosion and extensive water-rock interactions, creating networks of fissures, cracks, holes, and conduits.…”

A First Step towards Developing a Decision Support System Based on the Integration of Environmental Monitoring Activities for Regional Water Resource Protection

“…The territory of the Puglia region and the environmental matrices are constantly under pressure due to numerous factors. The results of regional monitoring of underground rivers and aquifers indicate the presence of several threats [3,4].…”