In NE Estonia alkaline pollution dominates, issued mostly from power stations and cement plant. The alkalinity of dust in NE Estonia grounds on Ca and K compounds. Very high pH values of snow water have been measured, even 12 at one of the main sources – Kunda cement plant. The pH of bog-pools water of investigated bogs have increased to 7,5 (Varudi bog) 6,6 (N part of Sämi-Kuristiku bog), 6,9 (central part of Sämi-Kuristiku bog), 6,7 (S part of Sämi-Kuristiku bog), 5,3 (Uljaste bog) and 4,5 (Sirtsi bog), compared with 3,6 (Männikjärve – Endla Nature Reserve).The most sensitive plants of bogs to alkaline pollution are Sphagnum mosses (cover of Sphagnum mosses – fig. 1e). The most sensitive are hollow and pool species. The most acidiphilous species are ridge species, therefore they survive a bit of greater pollution (tab.1). Sphagnum mosses, liverworts of bogs and Polytrichum strictum (fig. 2i) die out simultaneously. After the extinction of Sphagnum mosses lets hollows moss-free (fig. 1b – älves). At least the area shall be covered with fen mosses (fig. 2k,l). We may see negative correlation between cover of mosses and vascular plants, specially in hollows and on pool banks (lauka kallas) fig. 1a – vascular plants, fig. 1b – mosses). We can see increased cover of some bog plants (fig 2c-e, j) on areas of decreased moss cover. On the bog areas, covered with fen mosses (Varudi bog), has begun extinction of many vascular plants of bogs (fig. 2a,b,d,e). The most important vascular plant, immigrated to polluted bogs is Trichophorum alpinum (fig. 2g). On moss-free banks of pools (Sämi-Kuristiku bog) we can see a wery dense community of draft vegetative Urticularia minor and Drosera spp.. The bog-pools of Varudi bog are covered with Potamogeton natans and other macrophytes.

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