Posiva publishes Working Reports and Posiva Reports. From the year 2006 nearly all the reports have been published on our webpage and they can be found in the databank. In the databank you can also find our Annual Reviews and some other publications as well. You can also find print-quality pictures and useful links in the databank.

Recent publications

Workreport 2017-12



Studies on the Aquatic Environment at Olkiluoto and Reference Area: 5. Reference Lakes in 2013–2014


Kirkkala, T., Mikkilä, E., Koivunen, S.



Page count:



This working report presents the results of Posiva’s sampling campaigns in Lakes Poosjärvi and Kivijärvi, Finland, in 2013–2014. These so-called reference lakes are considered to resemble the aquatic systems expected to form at the Olkiluoto repository site due to the post-glacial land uplift in a time scale relevant to deep disposal of nuclear waste. The aim of the studies was to continue the sampling campaign started in 2010 in order to improve the knowledge of the lake ecosystems and to produce new input data to the modelling underpinning the repository safety cases. The studies from other reference lakes Koskeljärvi and Lutanjärvi are published in the Posiva Working Report 2016-50.

In the field campaign, a main objective was to estimate the areal biomass distribution and measure the dimensions of both the characteristic aquatic plants and animals. Another main objective was to estimate the transfer of different indigenous elements, (especially C-14, Cl, I, Sr, Mo, Ag, Se, Nb, Cs, Ni, Pd, Pb and Sn) considered analogues for their long-lived radioisotopes in the safety case modelling, from the water to aquatic organisms, as well as to estimate their sorption into the surface sediment. Surface water, plankton, sediment, macrophyte, macrobenthos, mussel and fish samples were collected for biomass and dimension measurements and for analysis of their element composition. In addition, water-to-biota concentration ratios and element distribution coefficients (Kd) in the sediment were calculated. The sampling procedures, pre-treatment methods and analytical methods were basically similar to methods used in pervious studies.


Water quality; surface sediment; aquatic macrophytes; fish; macrobenthos; biomass; body dimensions; element concentration; water-to-biota concentration ratio; solid/liquid distribution coefficient (Kd); biosphere assessment; safety case


WR 2017-12_web (pdf) (7.7 MB)
APPENDIX B - Water samples (xlsx) (70.9 KB)
APPENDIX C - Sediment samples (xlsx) (123.2 KB)
APPENDIX D - Macrophytes (xlsx) (685.4 KB)
APPENDIX E - Plankton (xlsx) (69.6 KB)
APPENDIX F - Macrobenthos (xlsx) (179.7 KB)
APPENDIX G - Fish samples (xlsx) (46.8 KB)


Share article:
This website stores cookies on your computer. These cookies are used to improve our website and provide more personalised services to you.


To make this site work properly, we sometimes place small data files called cookies on your device. Most big websites do this too.

1. What are cookies?

A cookie is a small text file that a website saves on your computer or mobile device when you visit the site. It enables the website to remember your actions and preferences (such as login, language, font size and other display preferences) over a period of time, so you don’t have to keep re-entering them whenever you come back to the site or browse from one page to another.

2. How do we use cookies?

A number of our pages use cookies to remember your actions and preferences (such as login, language, font size and other display preferences.)

Also, some videos embedded in our pages use a cookie to anonymously gather statistics on how you got there and what videos you visited.

Enabling these cookies is not strictly necessary for the website to work but it will provide you with a better browsing experience. You can delete or block these cookies, but if you do that some features of this site may not work as intended.

The cookie-related information is not used to identify you personally and the pattern data is fully under our control. These cookies are not used for any purpose other than those described here.

3. How to control cookies

You can control and/or delete cookies as you wish – for details, see You can delete all cookies that are already on your computer and you can set most browsers to prevent them from being placed. If you do this, however, you may have to manually adjust some preferences every time you visit a site and some services and functionalities may not work.