Abstract
The proper assessment of trace element concentrations in the north Nile Delta of Egypt is needed in order to reduce the high levels of toxic elements in contaminated soils. The objectives of this study were to assess the risks of contamination for four trace elements (nickel (Ni), cobalt (Co), chromium (Cr), and boron (B)) in three different layers of the soil using the geoaccumulation index (I-geo) and pollution load index (PLI) supported by GIS, as well as to evaluate the performance of partial least-square regression (PLSR) and multiple linear regression (MLR) in estimating the PLI based on data for the four trace elements in the three different soil layers. The results show a widespread contamination of I-geo Ni, Co, Cr, and B in the three different layers of the soil. The I-geo values varied from 0 to 4.74 for Ni, 0 to 6.56 for Co, 0 to 4.11 for Cr, and 0 to 4.57 for B. According to I-geo classification, the status of Ni, Cr, and B ranged from uncontaminated/moderately contaminated to strongly/extremely contaminated. Co ranged from uncontaminated/moderately contaminated to extremely contaminated. There were no significant differences in the values of I-geo for Ni, Co, Cr, and B in the three different layers of the soil. According to the PLI classification, the majority of the samples were very highly polluted. For example, 4.76% and 95.24% of the samples were unpolluted and very highly polluted, respectively, in the surface layer of the soil profiles. Additionally, 14.29% and 85.71% of the samples were unpolluted and very highly polluted, respectively, in the subsurface layer of the soil profiles. Both calibration (Cal.) and validation (Val.) models of the PLSR and MLR showed the highest performance in predicting the PLI based on data for the four studied trace elements, as an alternative method. The validation (Val.) models performed the best in predicting the PLI, with R2 = 0.89–0.93 in the surface layer, 0.91–0.96 in the subsurface layer, 0.89–0.94 in the lowest layers, and 0.92–0.94 across the three different layers. In conclusion, the integration of the I-geo, PLI, GIS technique, and multivariate models is a valuable and applicable approach for the assessment of the risk of contamination for trace elements, and the PLSR and MLR models could be used through applying chemometric techniques to evaluate the PLI in different layers of the soil.
Highlights
Land degradation is one of the most serious environmental problems facing the world today
The objectives of this study were to (i) map soil pollution according to four trace elements (Ni, Co, Cr, and B) based on I-geo using the GIS technique for soil profiles in three soil layers; (ii) assess the risk of contamination for four trace elements using I-geo and pollution load index (PLI) in three different soil layers; and (iii) evaluate the performance of partial least-square regression (PLSR)
The northern part of the Nile Delta is in the arid region, while the southern part is in the hyper-arid region, according to a map of the global distribution of arid regions
Summary
Land degradation is one of the most serious environmental problems facing the world today. Due to various degradation processes, about 6 million hectares of agricultural land around the world have become less productive [1]. Due to the increasing number of factories and their emissions, urban growth, increasing traffic volumes, and the use of wastewater and waste deposits, the quality of the Nile Delta’s land is worsening [2]. The Nile Delta (an area of approximately 20,000 km2 ) represents only 2.3% of Egypt’s area but 46% of the total cultivated area (55,040 km2 ) [3,4]. On the Nile Delta, the proportion of agricultural land is 63%, due to the suitable soil characteristics and the existence of irrigation systems [5]. The Nile Delta is dependent on wastewater for irrigation operations
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
