The protection of waters in Europe is regulated by the Water Framework Directive (WFD), which is mandatory for all European Union members. Detecting and monitoring the level of contaminants in seawater and inland waterways is a key element of the WFD.
In many cases it is very difficult or even impossible, by traditional techniques so, there is an urgent need to find accurate, reliable, easy and cost-efficient alternatives.
Passive sampling devices (PSDs) have several advantages compared to conventional monitoring methods, and the labile concentrations determined by PSDs are recognised to provide a better scientific basis for risk assessment.
However, the 2013 EQS (Environmental Qualtiy Standards) Directive (2013/39/EU) states that EQSs are defined as dissolved concentrations (metals), total concentrations in whole water (organic contaminants), or concentrations in biota (hydrophobic organics).
This legally binding definition remains an obstacle to the use of PSDs in compliance monitoring within the EU.
Some metals are part of the WFD priority substances list and the applicability of a type of PSD called Diffusive Gradient in Thin films (DGTs) to evaluate metal contamination is more than proven by a number of scientific works that have addressed this task.