Minor tissue alterations but no accumulation of metals in the first Talvivaara fish samples
The purpose of the tissue studies was to examine the condition of the gills, liver and kidneys of roach, perch and burbot, and secondarily other species of fish as well, found in the watercourses studied. No signs of acute tissue destruction indicative of damage caused by acidic water or heavy metals, among other things, were established. Roach from River Kivijoki exhibited hyperplasia of the gill epithelium, which is probably due to parasitic infection. However, irritation caused by the Talvivaara leak cannot, with certainty, be ruled out as a partial cause of the hyperplasia.
A total of 83 samples were taken from the flesh of the fish and analysed for the heavy metals arsenic, mercury, cadmium, chromium, lead, nickel and uranium. The same samples were also analysed for aluminium and the trace elements copper, manganese and selenium. No concentrations in excess of the background values were observed in the analyses. The preliminary skeletal analyses showed no accumulation of uranium in the backbone.
Fish species commonly found in the area chosen as the object of study
The species of fish commonly found in the area were chosen as the object of study. Roach is known to be more sensitive to changes in water acidity than perch and burbot. In the watercourses downstream of the Talvivaara mine, wastewaters are found to accumulate in the deeps, for which reason burbot was included in the study as a typical demersal fish.
Wild fishes may evade conditions that are unfavourable for them, so the fish samples obtained by fishing may not exhibit pollution-induced alterations. On the other hand, fishes may swim into the area being studied from uncontaminated areas. However, the fishes now analysed yield background data against which any long-term changes in tissue alterations and heavy metal concentrations observed in subsequent samplings can be compared.
Given the slow accumulation of metals in fishes, the results were as expected. The monitoring of potential accumulations and tissue lesions will be continued.
At this stage of the research project Evira advises that the recommendations given in November 2012 by the Kainuu ELY Center for household and recreational use of the waters near Talvivaara and the recommended intake of fish should still be complied with.
Test fishing to continue
The Finnish Game and Fisheries Research Institute (FGFRI) carried out test fishing in the areas affected by wastewaters from Talvivaara between 15 and 27 November 2012 in accordance with the sampling and analysis plan drafted in collaboration with the Finnish Food Safety Authority Evira and the Centre for Economic Development, Transport and the Environment for Kainuu.
On the side of the Oulujoki river basin, the test fishing areas comprised River Kalliojoki, Lake Kalliojärvi, Lake Kolmisoppi and Lake Jormasjärvi, and on the side of the Vuoksi river basin, River Kivijoki, Lake Kivijärvi and Lake Laakajärvi. Fishing was also conducted in the Oulujoki river basin outside of potential leakage area in Lake Kivesjärvi, Paltamo.
In accordance with the sampling plan, FGFRI initiated a new round of test fishing in January 2013 for the purpose of chemical analyses. The test fishing by net will target the same lake areas as in November 2012. Additional fish samples will be collected from control areas that are not located within the area affected by the wastewaters. A third sampling round is foreseen to be implemented during the ice-free season, and the samples obtained will be assessed both histologically and chemically.
Finnish Game and Fisheries Research Institute: Talvivaara fish samples (in Finnish)
Kainuu ELY Center’s recommendations for household and recreational use of the waters near Talvivaara and the recommended intake of fish (in Finnish)
Tissue alterations in fishes: Senior Researcher, DVM Perttu Koski, tel. +358 (0)40 569 4541
Heavy metal determinations: Senior Researcher, PhD Eija-Riitta Venäläinen, tel. +358 (0)50 434 8378