Radioactivity in produced water from Norwegian oil and gas installations – concentrations, bioavailability, and doses to marine biota

¹ Institute for Energy Technology (IFE), Norway
² Present affiliation: Primus.inter.pares as
³ The Foundation for Scientific and Industrial Research at the Norwegian Institute of Technology (SINTEF), Norway
⁴ Norwegian Institute for Water Research (NIVA), Norway
⁵ Present affiliation: University of Oslo
⁶ National Institute of Nutrition and Seafood Research (NIFES), Norway

Corresponding author: d.o.eriksen@kjemi.uio.no

Abstract

Large amount of produced water, containing elevated levels of radionuclides (mainly ²²⁶Ra and ²²⁸Ra), is discharged to the sea~in connection with oil and gas production on the Norwegian continental shelf. The main objective of this project has been to establish radiological safe discharge limits for radium associated with other components in produced water. We present a summary of the methodology developed and the overall results obtained. Our results show that presence of added chemicals like scale inhibitors in the produced water have a marked influence on the speciation of radium, i.e. formation of radium and barium sulphates when produced water is mixed with seawater. Radium's behaviour in the sea has been modelled using the DREAM model. Also, we have showed that the bioavailability of radium may be increased due to presence of scale inhibitors. Juvenile cod has been exposed to radium through food and from water. The uptake in different organs, i.e. skin, gills, liver, blood, and kidneys, show large variability, but is modest in all organs.