Evaluation of diffusive gradients in thin-films (DGTs) as a monitoring tool for the assessment of the chemical status of transitional waters within the Water Framework Directive

► DGTs provided reliable average labile metal concentrations in estuaries. ► DGT results were useful to determine potential environmental impact of estuaries. ► DGT measurements were consistent with the historical contamination of each estuary. ► The sampling strategy was cost-effective for trace metals evaluation in estuaries. ► DGTs seem to be a suitable tool for water chemical evaluation within the WFD.