Catchment approach to passive sampling of Irish waters

Abstract

The challenges of monitoring our waters for compliance with WFD and the expansion of the list of organic chemicals that are to be added for monitoring, provides impetus for investigation of alternative monitoring approaches such as passive sampling. The work being carried out represents an important collaboration between two research centres (DCU & MI) together with agency (EA UK and Inland Fisheries Ireland) and industry (TelLab) to assess the potential of passive sampling in monitoring priority pollutants in Ireland. The impact of this study may lie in the establishment of a capability to utilise passive sampling in the monitoring programme in Ireland for WFD. This project pilots the use of passive sampling technology (PDMS and POCIS) combined with biota monitoring to assess the presence of priority substances in Irish surface waters. The project focuses in particular on new pollutants earmarked as candidates for the Annex X priority substances list under the EU Water Framework Directive e.g. E2 and EE2, pharmaceuticals, pesticides, PFOS etc. This considers the implications for compliance with current and proposed EQS and investigates the potential for incorporating passive sampling and biota testing in future compliance, investigative and trend monitoring. . Results of water, biota and passive sampling will be presented together for samples collected in the Dublin catchment. A separate study on the occurrence of the pyrethroid pesticide cypermethrin was also conducted. Several sites along the River Liffey, Dublin, were sampled for pharmaceutical as well as other organic pollutants. A POCIS device was deployed at each location and water samples were collected at T-0 and T-4weeks. There are a number of potential point sources of pollution to this catchment with 3 wastewater treatment plants in the area. Pyrethroids have a low toxicity relative to other pesticides (specifically the organochlorines) so have recently been used in place of more toxic pesticides. Cypermethrin has been shown to accumulate in passive sampling devices. This study involved collection of water samples alongside PDMS and SPMD samplers. Cypermethrin was detected in high levels in the water and PDMS samplers. Passive sampling devices can be a useful supporting technique in a ‘toolbox’ for monitoring within the WFD and other environmental programs. From the investigation of work to date it is clear that passive sampling can play an important role in screening of waters for emerging contaminants, especially for hydrophobic subtances where they could be incorporated into a risk based approach to monitoring. Also, passive sampling has demonstrated that it has a role to play in trend monitoring to illustrate where waters are improving in quality over time, thereby offering the WFD monitoring programme a valuable tool. Keywords: passive sampling, surface waters, coastal waters, WFD