Spatial distribution of heavy metals in soils around cement factory and health risk assessment: a case study of Canakkale-Ezine (NW Turkey)

Abstract

Sustainable use of agricultural land plays a crucial role in ensuring food security. For sustainable use of soils, it is very important to focus on the pollution status. This study was conducted on the soils in the northern part of the Ezine district in northwestern Turkey. The study aimed to determine the physicochemical properties of the soils in the vicinity of the cement plant, the concentrations of heavy metals, the spatial distribution of heavy metals, and their impact on the health of the local human population. Soil samples were collected from the cement plant in different directions (S,W, N, E, NE, SW) and at different distances (1, 3, 5, and 7 km) from 0–10 cm depth with three replicates. The soil samples were analyzed for texture, pH, electrical conductivity, lime, and heavy metals such as Cd, Co, Cu, Fe, Mn, Ni, Pb, and Zn. The soils had different textures (loam, sandy clay loam, loam, sandy loam), slightly alkaline pH, low lime content, and moderate organic matter content. Except for Cd and Pb, the average values of the other heavy metals (Co = 1.18 < 19 mg kg−1,Cr = 50.92 < 90 mg kg−1, Cu = 31.21 < 45 mg kg−1, Fe = 16,007 < 47,200 mg kg−1, Mn = 499.68 < 850 mg kg−1, Ni = 41.17 < 68 mg kg−1, Zn = 50.91 < 95 mg kg−1) in the soils were below the normal background level. The heavy metal contents of the soils in the study area are influenced by various sources (geological structure, agrochemicals used in agricultural activities, and vehicle traffic). The prevailing wind direction did not influence the local distribution of heavy metals in soils in the study area. The health risk assessment model studies showed that the hazard quotient values of less than 1 for adults and children indicate that the noncarcinogenic risks were insignificant. People exposed to heavy metals in the soils of the study area contaminated from various sources for a long time could be at carcinogenic risk. Since Cr and Pb exceed the acceptable risk range in children and Cr exceeds the acceptable risk range in adults, geochemical monitoring of soils should be conducted periodically by authorized institutions in the study area.