Vermiculite-Lizardite Industrial Wastes Promote Plant Growth in a Peat Soil Affected by a Cu/Ni Smelter: a Case Study at the Kola Peninsula, Russia

Abstract

Some industrial barren areas are extreme habitats created by the deposition of airborne pollutants from non-ferrous smelters. One of such barrens exists in the vicinities of the Cu/Ni smelter, located at the Kola Peninsula, Murmansk region, Russia. This study aimed at evaluating in laboratory conditions the efficiency of various vermiculite-lizardite wastes (industrial wastes of local origin) as soil amendments for plant growth promotion. Peat topsoil (0–20 cm) was collected in the vicinity of the Cu/Ni smelter. Total soil concentrations were 1612, 1481, and 63 mg kg−1 for Ni, Cu, and Co, respectively, and soil pH was 4.3. Soils were amended with lime waste and different types of vermiculite-lizardite wastes (coarse, fine, and thermo-activated at 700 °C), leaving one soil untreated. Weekly wetting-drying cycles, performed during 1 month, allowed amendments to react in the soil. All soils were cultivated with Lolium perenne L. for 21 days under controlled conditions. The plant growth was not influenced by high soil Cu concentration, while Ni and Co caused phytotoxicity. A mix of 10% (w/w) of different vermiculite-lizardite wastes with 10% (w/w) of lime improved the plant growth. Thermo-activated waste showed the best results for promoting plant growth and reducing foliar Ni concentrations from 1022 to 88–117 mg kg−1. However, the plants presented Ni phytotoxicity even in the amended soils and this requires further studies to find a way to reduce it.