Monitoring of Ground Forest Fire Impact on Heavy Metals Content in Edafic Horizons

Abstract

Fires in natural ecosystems cause catastrophic consequences on a global scale. These fires are caused by landscape-transforming factors, which include dust and gas pollution of the atmosphere, destruction of forests and living organisms, pollution of ecosystems with dangerous toxic compounds and heavy metals. The aim of the presented research is to investigate the influence of ground forest fires on the concentration of mobile forms of heavy metals in different soil horizons. Sampling of soils of pyrogenic origin was carried out from 4 plots according to operating standards on the territory of Rava-Rusky forestry near the village of Lavrykiv, Zhovkva district, Lviv region (Ukraine). Soil sampling for investigation of migration of heavy metals was carried out taking into account the number of years spent after burning of meadow vegetation and forest litter. The most contaminated with heavy metals is site #2 (completely burned out 2 years before the experiment). There is a significant accumulation of cadmium in edaphic horizons (0.31 – 0.66 mg/kg), the value is close to the maximum allowable concentrations for soils (0.7 mg/kg). Also in this area the highest content of mobile forms of nickel (1.52 – 2.80 mg/kg) was detected, while the maximum allowable concentrations for soils is 4 mg/kg. The lowest content of heavy metals is in the site #1, which was exposed to fire long before the start of monitoring – 3.5 years. Here the values of mobile forms of heavy metals are close to the background. Vegetation in burnt areas at the first year of post-pyrogenic development is characterized by spontaneous single species. In 2–3 years it is characterized by a group arrangement. Complete natural overgrowth of the burnt area (natural vegetative reclamation) occurs 4–5 years after combustion. Monitoring the impact of ground forest fires on the concentration of heavy metals in edaphic horizons is important in terms of environmental renaturalization and the development of preventive measures for forest fires and fires in natural ecosystems.