In 2018, Akvaplan-niva, on behalf of a landowner in the area, assessed the consequences of the construction work for the environmental condition in Namsen. The report concludes as follows: “The regulation of Namsvannet with a new landfill dam seems to have significant shortcomings when it comes to safeguarding the environment, biological diversity, habitat types and flood diversion” . Among other things, it was pointed out that approx. 500 meters of the natural river bed had been drained, a waterfall had been blown away and a puddle, of significance to the population of ducks in the area, had been removed. In addition, it was concluded that the construction work had resulted in discharges of heavy metal-containing sludge and that the sludge, which has elevated levels of nickel and chromium, had spread several kilometers down Namsen. Microscopy analyzes of the sludge ,which comes from greenstone, showed that the masses have sharp-edged and needle-shaped particles that can have a negative effect on aquatic organisms.
The Veterinary Institute, in collaboration with Akvaplan-niva, has now carried out new analyzes of sludge from Namsen. The report from this work was recently published in a news item from the Veterinary Institute. The report concludes that measurements of heavy metals in sludge downstream of the new landfill dam in Namsvatnet, show elevated levels of copper, chromium and nickel. and that the metals and sludge can have negative effects on the flora and fauna of the watercourse.