The influence of mining wastes from the Russia's Arctic zone on the plants development

This paper contains an integrated phytotesting-based assessment of the impact on the biota of the mining waste generated in Arctic zone of the Russian Federation (Murmansk Region, Russia). In order to collect as unbiased as possible data on plant growth and development, a number of test cultures of various classes were used, including monocotyledonous and dicotyledonous plants (Avéna satíva L., Lepidium sativum, Tríticum aestivum L., Trifolium praténse L.). Concentration tailings of apatite-nepheline, complex and loparite ores were studied using eluate and contact methods. Eluate phytotesting showed different levels of response in the test cultures when exposed to the native extracts of the concentration tailings. In the most sensitive cultures, the root length inhibition effect (of loparite ore concentration tailings) was less than 15%, which does not exceed the threshold inhibition value required for the phytotoxic effect to be established. When testing diluted extracts, manifestations of the hormetic (stimulating) effect were observed in some of the test cultures. Hazard class V was experimentally confirmed in the examined plant species. It was found that oats and wheat are more sensitive compared to watercress and clover — both when exposed to aqueous extracts and when germinating seeds in a substrate. The greatest plant inhibition effect was observed in loparite ore concentration tailings, which supports the conclusion that the likelihood of spontaneous revegetation of mining waste dumps is minimal and that comprehensive land remediation methods need to be developed. The results of contact phytotesting indicate the good prospects of tailings dump reclamation by mixing the top layer of the tailings with fertile soil in different ratios.