The Comparison of Three Environmental Metrics for Cd, Cu, and Ni in the Agricultural Region of the Mid Continent of USA

Abstract

Enrichment factor (EF), potential ecological risk assessment (PERI), and geoaccumulation (I geo) were employed to measure degree the of contamination Cd, Cu, and Ni in soils in Iowa (IA), Kansas (KS, and Nebraska (NE). Cd and Cu were measured as minimal enrichment and low risk using EF and PERI indexes. This study aims to study the regional distribution of chemical elements to determine the source of the elements and which evaluation tools may be applied to determine the quality and the health of the soil. The presence of significant concentrations of different biologically active chemical substances, such as agricultural additives can affect the status and functioning of the soil microbial biogenesis, soil fertility, and human health. Nevertheless, Cd measured uncontaminated to moderately contaminated while Cu, and Ni indicated uncontaminated (I geo ≤ 0) in the soil. EF of Cd is the highest EF of three heavy metals, Cd > Cu > Ni. The highest value of EF of Cd is observed in KS (1.65) followed by NE (1.25) and IA (1.22). However, enrichment degree of Cu is approximately similar in IA (1.11) and KS (1.01) while enrichment degree of Ni is lowest and its average in NE (1.07), IA (0.76, KS (0.82), and NE (0.92). Igeo showed high value Cd estimated at 0.36 in KS followed by 0.29 in NE and 0.18 in IA, which indicate to the possibility of the soil contamination with the Cd originated from human inputs. In addition, high value of Cu in IA in the soil is sourced from human applications as well. PERI showed serious ecological risk pollution of Ni in the soils of IA, KS, and NE. According to the evaluating standard of PERI, Ni is classified as a very high risk in IA (2784.5), in KS (1883.1), in NE (1154.6) while Cd and Cu are estimated as low risk of soil contamination.

Keywords: soil chemistry, chemical elements, soil contamination, PERI, EF, I geo, geochemical mapping, Regional Geochemical Mapping (RGM).

DOI: 10.7176/JEES/10-6-09

Publication date:June 30^th 2020