[en] This Working Report presents the main results of Posiva Oy's environmental monitoring programme on Olkiluoto Island in 2005. This is the second annual report. Monitoring has been carried out for varying time periods depending on the sector: some monitoring activities performed by TVO originate from the 1970s, others connected with the construction of the final disposal repository for nuclear waste and the underground research facility ONKALO have just started. The system supervised by Posiva Oy produces input for biosphere modelling for long-term safety purposes as well as for environmental impact analyses. In 2005 the deposition collectors and nearby needles caught some dust from the rock piling and crushing activities and traffic. Noise was another clear effect, originating mostly from OL3 construction, rock piling and crushing area and the concrete station. The studies further confirmed that the vegetation, forests, soils and animal life are typical of a coastal region within the same vegetation zone. The nearby marine environment is affected by the cooling water from the nuclear power plant, to varying extents depending on the organism and the distance. Monitoring of marine environments as well as radionuclide analyses at the moment produce reference data for the future and create a basis for the construction of a model, as no input from Posiva's activities will influence these areas for a long time. (orig.)