Passive sampling techniques for monitoring metals in transitional and coastal waters in the Atlantic region

Abstract

In highly dynamic systems, such as transitional and coastal waters, establishing their chemical status is challenging. MONITOOL is an exciting European project consisting of 16 Partners covering the Atlantic region from the Canary Islands to the Scottish Highlands and Islands, which aims to address this complex analytical challenge, responding to European Directive demands for the assessment of the chemical status of transitional and coastal waters. Diffusive Gradient in Thin Films (DGT), and passive samplers (PS), in general, are already widely used in investigative monitoring and there is an increasing interest in their use for the environmental assessment of water bodies, within European policies requirements. The main barrier hindering the regulatory acceptance of PS for compliance checking is the lack of appropriate Environmental Quality Standards (EQS). EQSs for metals are defined in the dissolved fraction, preventing the use of DGT-labile concentrations for the establishment of the chemical status of water bodies. The first sampling campaigns were performed during winter 2017/2018 in 4 selected sites (transitional and coastal sites) in each consortium region (8 regions). All partners followed the same protocol for sampling and analysis to minimize the operational variability. Priority metals (Cd, Ni, Pb) and other specific metals (Al, Ag, Cu, Cr, Co, Fe, Mn, Zn) were analysed in waters and in the DGT resins. Statistical analysis is being applied to study relationships between metal concentrations in DGT and in grab water samples. Suitable EQS for DGTs will be calculated on basis the statistical relations obtained previously. This will permit a better implementation of the Water Framework Directive in variable systems like transitional and coastal waters. The work presented here shows initial DGT results from the Irish sampling sites for selected target metals.