Efficiency of usage evergreen plants as test objects of hygiene monitoring in an industrial city

The use of effective plant test-objects in hygienic monitoring allows obtaining an integrated assessment of the anthropogenic and technogenic impact on the initial chain of the trophic level, which contributes to the adoption of measures to reduce risks to human health.

The aim of the study is the scientific substantiation of the effectiveness of using evergreen plants as test systems for assessing the safety of the environment from priority pollutants-heavy metals.

Material and methods. The research was conducted in Vladikavkaz city, where “Elektrotsink” (Pb - Zn - Cd production), “Pobedit” (W - Mo - Re - Co-production), “Gazoapparat” (electroplating), “Kristall” (production of copper-nickel alloys) and others plants are located. The objects of research were the three most represented types of evergreen plants: Picea abies, Picea pungens, and Thuja occidentalis, widely used in urban gardening. Young and old needles were taken from the trees. The collection districts corresponded to relatively clean areas and areas with increased anthropogenic pollution. The concentration of heavy metals was determined by using a flame atomic absorption spectrometer “Kvant-2A”. We calculated the average value and the standard error of the average, the Pearson correlation coefficient.

Results. Heavy metals were detected in all plant species (regardless of districts for sample collection) in concentrations: Cd: 0.035-2.0; Pb: 0.34-19.7; Cu: 0.006-4.48; Zn: 0.014-449.1 mg/kg. It was proved that the species have a similar tropism to the same elements (correlation coefficients from 0.78 to 0.91); the accumulation of metals in old needles relative to young ones is characterized by a direct relationship for Zn>Pb>Cd (k_Zn - 1.71, k_Pb - 1.58 k_Cd - 1.27) and the reverse for copper (k_Cu - 0.96).

Conclusion. Patterns of bioaccumulation of heavy metals in the tissues of evergreen plants identify the degree of anthropogenic impact on the environment and determine the prospects for using Picea abies, Picea pungens, and Thuja occidentalis as a sensitive indicator for assessing the safety of plant species.