Elemental composition of surface soils in Nature Park Shumen Plateau and Shumen City, Bulgaria

Abstract

Anthropogenic activities cause environmental pollution and alter biogeochemical cycles. Soils in cities and their vicinity are exposed to different pollutants. Nature Park Shumen Plateau is a protected area situated in the proximity of Shumen (Bulgaria). The aim of this research was to compare elemental composition of surface soil samples from Nature Park with two areas in Shumen city. Soil samples from seven sites on the territory of Nature Park and from two urban sites were collected. The elemental composition of the samples was determined using Energy Dispersive X-Ray Fluorescence technique. Principal component analysis and cluster analysis were performed to interpret the complex data. The content of 24 elements was determined: Br, Y, Zr, Mo, Ag, Cd, Sn, Sb, I, Cs, Ba, La, Ce Si, K, Ca, Ti, Mn, Fe, Cu, Zn, Rb, Sr, and Pb. Results presented here and previously showed that concentrations of heavy metals Cu, Zn, Cd and Pb are below the upper limit according to Bulgarian legislation. Concentrations of Mn and Fe in samples from Nature Park were comparable to the literature data reported for unpolluted areas. Principal component analysis and cluster analysis show similarity of the content of 24 elements between samples from Nature Park and from Shumen city. These findings are in accordance with our previous positive results from Allium-test: cytogenetic endpoints showed a presence of harmful compounds in Nature Park soils. The content of heavy metals in the surface soils studied show a lack of environmental risk for Nature Park. However, a similar distribution pattern of the investigated elements in the park and two anthropologically influenced areas in Shumen city indicated a potential hazard in Nature Park.

Visitors’ opinions on the environmental protection in Shumen Plateau Nature Park from the negative anthropogenic impact of a nearby city, Bulgaria

“…Only the youngest informants (up to the age of 29) don't answer "No, there is no negative impact". Our previous results show the presence of watersoluble contaminants in the soil and waters of the Nature Park Shumen Plateau, which are probably result of heating with solid fuels in Shumen (Koleva et al, 2018a;Koleva et al, 2018b;Koynova et al, 2018). However, a lot of research are focused on effect of air pollution on human health (Mace et al, 2004;Mabahwi et al, 2014;Burns et al, 2020).…”

“…We have also found that environmental protection of the park is not enough. There is a degree of air pollution in the park as a result of adverse anthropogenic impact from activities in the nearby city (Koleva et al, 2018a;Koleva et al, 2018b;Koynova et al, 2018). Therefore, ecosystem services provided by peri-urban nature parks may be compromised and limited.…”