Anthropogenically disturbed potentially toxic elements in roadside topsoils of a suburban region of Bishkek, Central Asia

Abstract

The ecological environment in Central Asia is vulnerable to pressure from human activity due to the physical geography and climatic fragility of this region. A set of indicators suitable for the future assessment of this pressure needs to be proposed.Thirty-six topsoil samples (0-5 cm) were collected from roadsides in a suburban region of Bishkek, the capital of the Kyrgyz Republic in Central Asia, and a risk assessment of anthropogenically disturbed potentially toxic elements (PTEs) was systematically conducted with classic statistical methods. The results of detrended correspondence analysis and principal component analysis clearly showed that topsoil samples with high contents of PTEs (Pb, Zn and Cu) were strongly affected by traffic within a distance threshold of 200 m and that anthropogenic effects decreased significantly with increasing distance from the highway. The enrichment factor and anthropogenic contribution for Pb were the highest among the three PTEs, with average values of 2.0% and 47.4%, respectively, suggesting enrichment. However, the results of the human health risk assessment also indicated that noncarcinogenic risks did not occur for any of the anthropogenic PTEs. The reported method provides a new systematic pathway to reveal anthropogenic influences on the geochemical composition of soil. The conclusions of this work will be highly valuable as important guidelines for agriculture, and the results of the PTE contents will provide a scientific basis for soil collection in future studies. K E Y W O R D Santhropogenic factors, Central Asia, human health risk, potentially toxic elements, roadside soils 284 |

Sustainable soil use and management: An interdisciplinary and systematic approach

“…Anthropogenic soil pollution in under-developed regions where industrial activities are less intensive can also occur due to traffic and mining related emissions, etc. For instance, a recent study in a suburban area of Central Asia showed that Pb, Zn, and Cu can accumulate to high levels in soils because of road traffic up to 200 m away (Ma et al, 2019).…”

Spatial Distribution and Health Risk Assessment of Potentially Toxic Elements in Surface Soils of Bosten Lake Basin, Central Asia

“…Based on the risk assessment calculation for heavy metal pollution, the hazard quotient (HQ) via the ingestion (HQ ing ) of surface soils are higher than those via inhalation (HQ inh ) and dermal absorption (HQ dermal ) (Table 3). Different from the degree of pollution in other economically developed regions around the world [65], the health risk index value for potentially toxic elements is less than one (Table 3), which is similar to that for the Issyk-Kul basin [66] and a suburban region of Bishkek [28] in the same arid region of Central Asia. Although this result reflects that the concentration of potentially toxic elements in arid areas has not reached a hazardous level, some potentially toxic elements (As, Cd, Sb, and Hg) have been significantly affected by the surface environment and they need to be paid enough attention.…”

“…Research often focuses on the influence of human activities on land use and land cover changes [22,23], and soil degradation in Central Asia [24,25,26,27]. However, studies on potentially toxic elements in soils in this region have been scarce [28]. By studying the current risk state of potentially toxic elements in soils in this typical region, we can obtain a better understanding of the distribution of potentially toxic elements with different influential factors in Central Asia.…”

Spatial and Vertical Variations and Heavy Metal Enrichments in Irrigated Soils of the Syr Darya River Watershed, Aral Sea Basin, Kazakhstan

“…From a global perspective, heavy metal pollution in soil caused by human activities has become increasingly serious [68,69]. According to existing studies in central Asia (e.g., the Lake Issyk-kul Basin [70] and the suburban region of Bishkek [71]), although the human health risk is low, it is affected by human activity. As shown in this paper, although the content of potentially toxic elements was not harmful to human health (Table 1, the thresholds of Zn, Cu, Cd, Ni, Co for HI = 1 were 107 × 10 3 , 14.4 × 10 3 , 254, 7.2 × 10 3 , and 6.2 × 10 3 mg kg −1 , respectively), it is also necessary to study the enrichment of potentially toxic elements caused by human activities.…”