The environmental risk of storing vehicles over the soil

Abstract

Automotive vehicles are a potential source of heavy metal contamination of the soil due to their lead-acid batteries and the use of metals in their structure and paint pigments. Understanding the characteristics of heavy metal soil contamination and identifying their environmental exposure provides important information for making decisions regarding remediation of contaminated soils. The objective of the present work was to evaluate metal contamination (Cd, Pb, Ni, Zn, Cu e Cr) in 35 soil samples (fraction<2 mm). The samples were collected from two unpaved/unsealed storage areas used by the Highway Patrol (Polícia Rodoviária Federal - PRF) for storing apprehended vehicles, one located in Araucária (AR) and one Colombo (CL), in the metropolitan region of Curitiba/PR, Brazil. Assays were performed to determine organic carbon (OC) and pH. For analysis of metals, the samples were prepared by acid digestion (method EPA 3050-B) and measured by ICP-OES. The results were evaluated according to Resolution CONAMA 420, geoaccumulation index (Igeo), contamination factor (CF) and Pearson correlation analysis. The textural composition of the soil at AR and CL reflect a high degree of heterogeneity and distinct chemical and physical characteristics. The AR site had a higher level of sand and a more acidic pH than CL, and concentrations of the analyzed elements between prevention and investigation values according to Resolution CONAMA 420/2009. The CL site had a higher concentration of clay and OC, and a less acidic pH than AR. Only one collected point at CL had a concentration of Cu above the prevention value. In both AR and CL, the element Cd was below detectability with methodology employed. The spatial distribution of the cars associated with the soil texture and the analyzed elements exhibited a random surface distribution of elements. The OC content, soil pH and texture associated with Igeo, CF and Pearson correlation suggests that both environments suffer an input of metals at different points. The input of heavy metals from stored vehicles and the possible anthropogenic impact on the soil is evident.