Elemental composition of soils in Düzce, Türkiye: a land use-based evaluation of geogenic and anthropogenic...

Understanding early-stage anthropogenic influences on soil geochemistry is essential for sustainable land management and environmental risk prevention. This study aims to assess the elemental composition of soils in Düzce (Türkiye) and to identify geogenic and anthropogenic influences across different land use types. A total of 30 soil samples were collected from agricultural (n = 15) and non-agricultural (n = 15) areas using a composite sampling approach. Elemental concentrations were determined by ICP-OES, and contamination levels were evaluated using EF, Igeo, CF, PLI, and PERI indices. Multivariate statistical analyses (PCA and correlation) and spatial distribution mapping were applied to identify potential sources and distribution patterns. The soil geochemistry is primarily controlled by lithogenic factors, with major elements (Si, Al, Fe, Ca, K) dominating the composition. Although most element concentrations remain within global background ranges, distinct localized enrichments were identified, particularly for Mo, Cd, Sb, Sn, and Cu, reflecting the combined influence of natural geochemical variability and localized anthropogenic inputs. Multivariate analyses suggested that the observed elemental associations may reflect both geogenic controls and anthropogenic influences, including regional geology, agricultural practices, traffic emissions, fossil fuel combustion, and industrial activities. While the overall pollution indices suggest a low current contamination status, the detected enrichment patterns indicate localized geochemical variability superimposed on a predominantly lithogenic background, with some elements potentially influenced by anthropogenic activities. These findings highlight the importance of continued environmental monitoring to distinguish natural geochemical variability from emerging anthropogenic influences and to support informed land management strategies.