International legislation demand the monitoring of both priority and new substances of concern released into the aquatic environment. Monitoring of these compounds in the open ocean by classical grab sampling is costly and difficult to realise, which often results in low resolution data sets. Additionally, pollutant concentrations in seawater are often too low to be detected in grab samples without time-consuming and labour-intensive enrichment techniques. As an alternative mussels, which continuously concentrate waterborne pollutants in their tissues, can be used as natural active samplers. Furthermore, mussels provide information on bio-molecular effects. However, mussels can vary in size, growth and resistance against environmental influences like salinity and temperature, which may lead to variability of the pollutant enrichment processes. In contrast, artificial passive sampling devices made of e.g. silicone or low-density polyethylene mimic the active sampling through diffusion processes without the difficulties of natural variability. Both sampling strategies are cost effective and provide data of time-weighted average concentrations over the deployment period. In a joint research project of the Federal Maritime and Hydrographic Agency of Germany (BSH), the Helmholtz-Zentrum Geesthacht Zentrum für Material und Küstenforschung, Institute of Coastal Research (HZG) and the Center for Scientific Diving of the Alfred Wegener Institute for Polar and Marine Research (AWI) a variety of passive sampler devices as well as blue mussels (Mytilus edulis) are time-synchronously deployed at the COSYNA/MarGate underwater experimental field near Helgoland.