Ecological and geochemical features of mercury accumulation in coniferous wood in the Altai Region

Abstract

Determination of the level of mercury load on the territory of the Altai Region was carried out using the dendrogeochemistry method. The study area is located in the north-west of the Altai Region within the Kulunda Plain. The studied trees were represented by Scots pine (Pinus sylvestris L.) and siberian larch (Larix sibirica L.). The average concentrations of mercury in the cores of all studied trees vary in a wide range: 2-493 ng/g. The maximum average contents are observed at the extreme sampling points: south and north - on the periphery of the sampling area. The research covers the time interval: 1952-2018. There is a period with a significant increase in the average mercury content in tree rings from 1957 to 1990, after which there was a sharp decrease in the concentration of the element. Numerous extremes are observed in the interval: 1978-1988. Calculations of geoecological parameters of mercury load in the study area showed an excess of mercury content in tree rings above background values, as well as the noosphere clarke, average for terrestrial plants and living matter. Almost all studied trees are characterized by a similar pattern of mercury accumulation in trees. A connection was revealed in the accumulation of mercury in wood cores of coniferous trees with the substrate, as well as pine needles. Mercury accumulated by pine needles affects the concentration of the element in the pine litter, and thereby the level of pollutant in the substrate. A high proportion of bioavailable forms of mercury in dark chestnut soils and southern chernozems. When accumulating an element, it is important to take into account the amount and duration of precipitation both during the year and during the growing season.