Source apportionment of human wastewater contamination impacts on karst springs in Ireland

Luka Vucinic*, David O’Connell, Donata Dubber, Patrice Behan, Quentin Crowley, Catherine Coxon, Laurence Gill

*Corresponding author for this work

Research output: Contribution to conferenceAbstractpeer-review

Abstract

Karst aquifers are extremely complex and challenging to understand, as well as exceptionally vulnerable to pollution. In Ireland, low-lying karst catchments exhibit a lot of surface water – groundwater interactions which makes them very susceptible to direct contamination. Groundwater pollution can be associated with a variety of sources making it a complicated problem to solve. In rural and suburban areas, human wastewater effluent (from on-site domestic wastewater treatment systems) and agricultural sources are generally considered among the most significant threats to groundwater quality. However, significant knowledge gaps exist with respect to linking pollutants with specific origins which is needed in order to quantify the various pollution impacts on karst groundwater resources. Thus, investigations of the occurrence, fate and transport (and transformations, where applicable) of source-specific contaminants are crucial for the protection and management of karst aquifers. It is difficult to distinguish between human wastewater effluent and agricultural pollution impacts on karst aquifers using only traditional water quality parameters or any single environmental tracing method. Hence, the impact of microbial and chemical contaminants of human wastewater origin on groundwater quality must be assessed using a multiple-tracer approach, ideally targeting source-specific tracers. An overview of the results obtained during the research conducted throughout the last several years at nine karst catchments in Ireland using a range of methodologies in order to determine and quantify domestic wastewater pollution impacts on karst springs will be presented. Microbial pollution was assessed using flow cytometric fingerprinting and faecal indicator bacteria, while chemical pollution impact assessment included the analysis of fluorescent whitening compounds (FWCs; well-known indicators of human contamination since their origin is mainly from laundry detergents), specific anion ratio signatures (Cl/Br), quantification and identification of microplastic particles using Fourier-transform infrared spectroscopy (FTIR), and faecal sterol and stanol profiles and ratios. The results show that detection and quantification of source specific chemicals, microplastic particles, specific anion ratio signatures, and microbial fingerprinting methodologies in parallel can provide sufficient information for decision making processes and adaptive management strategies. Notably, whilst some of the techniques used are not capable of being able to link pollutants directly with any particular pollution source, they can still quantify specific pollutants, in some cases to a very high accuracy, thereby determining the overall impacts of contaminants on groundwater quality at karst springs.
Original languageEnglish
Number of pages2
Publication statusPublished - 2021
Externally publishedYes
EventVirtual Multidisciplinary Conference “Karst: From top to bottom” - Belgrade, Serbia
Duration: 6 Jun 20217 Jun 2021
https://www.karst.edu.rs/en/index.html (Link to Conference de=tails from organisations website.. )

Conference

ConferenceVirtual Multidisciplinary Conference “Karst: From top to bottom”
Country/TerritorySerbia
CityBelgrade
Period6/06/217/06/21
Internet address

Keywords

  • karst springs
  • groundwater contamination
  • chemical and microbial fingerprinting
  • microplastics
  • on-site domestic wastewater treatment systems

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