Contamination Assessment of Heavy Metals in Agricultural Soil, in the Liwa Area (UAE)

Abstract

The Liwa area is a primary food production area in the United Arab Emirates (UAE) and has intensively been used for agriculture. This study investigates the pollution levels with heavy metals in agricultural soils from the Liwa area. Thirty-two soil samples were analyzed for Mn, Zn, Cr, Ni, Cu, Pb, Cd, Co, and As. Results revealed that heavy metal levels varied in the ranges 220.02–311.21, 42.39–66.92, 43.43–71.55, 32.86–52.12, 10.29–21.70, 2.83–8.84, 0.46–0.69, 0.03–0.37 mg/kg for Mn, Zn, Cr, Ni, Cu, Pb, Cd, Co, and As, respectively. All samples presented low As concentrations with an average of 0.01 mg/kg. The variations in bulk metal contents in the soil samples were related to multiple sources, including agrochemicals, atmospheric dust containing heavy metals, and traffic-related metals. Enrichment factor analysis indicates that Cd, Ni, Zn, and Cr were highly enriched in soils, and they could originate from non-crustal sources. Based on the geo-accumulation index (Igeo), the soil samples appeared uncontaminated with Mn, Cr, Zn, Pb, Co, As, Cu, uncontaminated to moderately contaminated with Ni and moderately contaminated with Cd. The contamination factors suggest low contamination, except for Ni, which showed moderate contamination. The average pollution load index (PLI) revealed unpolluted to low pollution of all soil samples. The ecological risk assessment (PERI) showed that all heavy metals posed a low risk, except for Cd which exhibited a high ecological risk.

Assessment of Metals Concentrations in Soils of Abu Dhabi Emirate Using Pollution Indices and Multivariate Statistics

“…This indicates the common origin of these pollutants, spread from the neighboring industrial sites or resulted from the traffic, as presented in Section 3.1 . This result is in concordance with the finding from [ 38 , 52 , 53 ].…”

“…Literature survey reveals different multivariate GIS approaches for determining the heavy metal contamination in agricultural soil [8,[43][44][45][46][47][48][49][50] in many parts of the world, but only a few articles are focusing on the analysis of the metals concentrations in soils [38], sediments [51][52][53] and water [54][55][56][57], in the United Arab Emirates. Apart from the mentioned articles [38,[51][52][53][54][55][56][57], only one study [58] presents the soil characteristics in the Eastern Arabian Desert Region using as investigation tools the ICP-OES with GIS Mapping.…”

“…Scientists studied pollution levels in the soil by a variety of methods, like testing statistical hypotheses [ 7 ], regression models [ 9 ], regional models [ 2 ], geostatistical analysis [ 17 ]. Multivariate statistical methods [ 11 , 12 , 38 ] provide a valuable tool for simplifying complex data sets by unifying the study of many variables into a single analysis. Unlike univariate or bivariate methods, this technique correlates large data sets to determine the relationships between variables.…”

Study of Atmospheric Pollution and Health Risk Assessment: A Case Study for the Sharjah and Ajman Emirates (UAE)

“…Atmosphere 2021, 12, 1442 2 of 17 A significant ecological and public health concern is associated with the environmental contamination and heavy metals' ultimate toxic effect [8][9][10][11][12][13][14][15]. Although many heavy metals are essential micronutrients necessary for various biochemical and physiological processes and functions [8], excessive exposure to these agents results in a wide range of adverse health effects and diseases [16].…”

“…Recent studies have demonstrated that road dust is a significant source of air pollution with heavy metals [21][22][23] and is a leading factor affecting human health [21,24,25]. Indeed, in the UAE, results of ecological risk assessments showed that Cd and Hg in road dust constitute a high public health risk [12,18]. The primary sources of heavy metal in road dust are soil materials, vehicle exhaust emissions, atmospheric deposition, and industrial and commercial activities [26][27][28].…”