Roach samples obtained near the Talvivaara mine show elevated levels of cadmium
In the second test fishing round, samples were obtained from the Kolmisoppi, Jormasjärvi and Kalliojärvi lakes in the Oulu water system, and from the Kivijärvi and Laakajärvi lakes in the Vuoksi water system. Test fishing was conducted by the Finnish Game and Fisheries Research Institute in the first quarter of 2013.
A preliminary assessment of the environmental impacts of the gypsum pond leakage at the Talvivaara mine, conducted by the Finnish Environment Institute (SYKE) in November 2012, indicates that lake Kolmisoppi forms part of the affected area and lakes Laakajärvi and Jormasjärvi belong to the slightly affected area.
Testing focused on common fish species
Fish species common to the area were selected for testing. In the waters located downstream from the Talvivaara mine, waste water has been found to accumulate at the bottom of the lake. For this reason, burbot was included in the tests as a typical demersal fish.
A total of 117 flesh samples were taken of the fish. The Finnish Food and Safety Authority Evira tested these samples for arsenic, mercury, cadmium, chrome, lead, nickel and uranium. The same samples were also tested for aluminium, copper, manganese and selenium. Spine samples from some of these fish were tested for the same chemical elements, excluding mercury.
Changes in concentrations of some elements
Based on the flesh samples taken in the second round, concentrations of chrome, manganese, aluminium and iron were lower for all fish than in samples obtained in the first round, while copper and zinc levels had risen slightly.
Concentrations of copper and zinc were slightly higher in the flesh samples of fish obtained in the second test fishing round. Levels of nickel, selenium, arsenic and uranium were approximately the same as in the samples obtained in the first test fishing round in November 2012.
With a few exceptions, mercury concentrations in fish were by and large below the permitted level for foods. These concentrations were within the normal variation range.
However, concentrations of mercury in freshwater predator fish such as large perch, pike, pike-perch and burbot can be high in normal conditions. According to Evira's recommendations, it is safe to eat freshwater pike once or twice a month, but people whose diet includes a lot of fish are advised to reduce their consumption of these predator fish. Pregnant and breastfeeding women are advised not to eat pike because of its mercury content.
Higher cadmium concentration, particularly in roach
In the second round, all fish caught in Lake Jormasjärvi had higher cadmium concentrations than in the first round. Although this difference is statistically significant, the concentrations in question remain below the maximum permitted level. However, the average cadmium concentration in roach did exceed the permitted threshold value, and in seven samples out of thirteen concentrations exceeded the maximum permitted level.
The cadmium concentration in burbot and roach caught in lake Kolmisoppi was above the permitted maximum level. Lake Kolmisoppi was not included in the first testing round.
For all fish caught in Lake Laakajärvi, the cadmium concentration remained unchanged from the first to the second round, and below the threshold value.
No uranium in fish spine
The amount of chrome and aluminium found in fish spine was smaller in the second than in the first round samples. The changes in concentrations were insignificant.
No uranium was found in fish spine in the first or second round samples.
Sample analysis continues
A third test fishing round has been conducted in these lakes, in accordance with a research plan prepared by Evira, the Finnish Game and Fisheries Research Institute and the Kainuu Centre for Economic Development, Transport and the Environment. Evira will test the samples for any tissue damage and for chemicals. For reference, fish samples have also been collected for reference from other water bodies that have not been affected by the discharges from the mine.
People living in the area affected by Talvivaara's operations are concerned about potential heavy metal accumulation in animal-based foods such as milk and meat. Evira will conduct a sampling of game and milk in this area in 2013.
Eija-Riitta Venäläinen, PhD, Senior Researcher,
Chemistry and Toxicology Research Unit, tel. +358 50 434 8378