A main purpose of marine contaminant monitoring in Europe is to evaluate the chemical status and environmental quality under the Marine Strategy Framework Directive (MSFD), to monitor and achieve Good Environmental Status (GES). Characteristics of a good matrix for monitoring purposes are the potential to detect temporal trends or differences between sites or concentration levels in relation to a target value indicating GES. In Sweden we use muscle of herring and eggs of guillemot and White-tailed sea eagle (WTSE) to study changes in contaminant exposure and their effects. Herring is important in fisheries and has target levels set for contaminants in relation to GES. Adult guillemots and eagles in the Baltic Sea are mainly stationary. Guillemots feed largely on herring, WTSEs on fish and other fish-eaters. A higher trophic level may imply biomagnification, and, for example, DDE shows concentration ratios in lipids of 110 (guillemot/herring), 460 (WTSE/herring) and 4.2 (WTSE/guillemot). Banked, frozen guillemot eggs have been extensively used for retrospective temporal trend analyses for several chemicals. Ideally, the matrix should also be useful for biological effect monitoring. Eggshell and reproductive parameters are monitored in the WTSEs and guillemots. Reproductive problems and egg desiccation still occur among eagles, indicating an impact of contaminants and highlighting the importance of apex predators as environmental sentinels.