Dataset of elemental compositions and pollution indices of soil and sediments: Nile River and delta -Egypt

This data is the first comprehensive baseline data on the geochemical composition of soil and sediments along the Nile River and Delta in Egypt that was subjected and analyzed by instrumental neutron activation analysis INAA. These data supported the research articles that were done to evaluate the elemental compositions and pollution sources in 176 sampling locations through 133 soil and 43 sediments samples along the Egyptian section of the Nile River and Delta – Egypt. “Geochemistry of sediments and surface soils from the Nile delta and lower Nile valley studied by epithermal neutron activation analysis” Arafa [1], “Major and trace element distribution in soil and sediments from the Egyptian central Nile valley” Badawy [2], and “Assessment of industrial contamination of agricultural soil adjacent to Sadat city, Egypt” Badawy [3]. The samples were analyzed by means of instrumental neutron activation analysis INAA and the concentrations in mg/kg of 28 major and trace elements are obtained. The quality control of the analytical measurements was carried out using different certified reference materials. Multivariate statistical analyses were applied. A total of eight individual and complex pollution indices were calculated in terms of the quantification of pollution extent and selection of the proper index based on the method and purpose of calculations. The spatial distribution of pollution load index PLI was mapped using GIS-technology. The normalized concentrations of the determined elements show no significant difference between soil and sediments concentrations and this, however, may be explained by the fact that origin of soil mainly is the sediments. To a clear extent, the concentrations of Ti (8017, 9672 mg/kg), V (124, 143 mg/kg), Cr (126, 160 mg/kg), and Zr (296, 318 mg/kg) are observed to be high in soil and sediments, respectively relative to other elements. Zr/Sc ratio shows a reduced sedimentary recycling and this may be explained by the tremendous influence of Aswan High Dam in preventing sediments supply from Ethiopian Highlights. Eventually, the pollution indices prove their suitability for assessing the individual and integrative contamination and show that there is no overall contamination. However, there are some contaminated localities mainly in Delta and mostly due to the dense population and anthropogenic activities. The data can be used as a raw data for constructing the first ecological atlas and evaluation of the ecological situation in terms of geochemistry and pollution.

carried out using different certified reference materials. Multivariate statistical analyses were applied. A total of eight individual and complex pollution indices were calculated in terms of the quantification of pollution extent and selection of the proper index based on the method and purpose of calculations. The spatial distribution of pollution load index PLI was mapped using GIStechnology. The normalized concentrations of the determined elements show no significant difference between soil and sediments concentrations and this, however, may be explained by the fact that origin of soil mainly is the sediments. To a clear extent, the concentrations of Ti (8017, 9672 mg/kg), V (124, 143 mg/kg), Cr (126, 160 mg/kg), and Zr (296, 318 mg/kg) are observed to be high in soil and sediments, respectively relative to other elements. Zr/Sc ratio shows a reduced sedimentary recycling and this may be explained by the tremendous influence of Aswan High Dam in preventing sediments supply from Ethiopian Highlights. Eventually, the pollution indices prove their suitability for assessing the individual and integrative contamination and show that there is no overall contamination. However, there are some contaminated localities mainly in Delta and mostly due to the dense population and anthropogenic activities. The data can be used as a raw data for constructing the first ecological atlas and evaluation of the ecological situation in terms of geochemistry and pollution.

Data description
Nile River is one of the longest rivers in the world and is the artery of fresh water for 11 Nile River basin countries [4,5]. Nowadays, many factors affect the sharp decrement of water quality and sedimentological processes, for instance industrial, domestic, and agricultural pollution. Since the construction of the High Dam in Aswan 1964, the flow of the Nile cycle and sediment discharge has been disrupted [6]. These data were extracted in the period from 2011 to 2017 by collecting 176 samples (133 soil and 43 sediments) along the two banks of the Egyptian Nile River and Delta as in Fig. 1. The elemental compositions in mg/kg of 28 major and trace elements (Na, Mg, Al, Ca, Sc, Ti, V, Cr, Mn, Fe, Ni, Co, Zn, As, Br, Rb, Sr, Zr, Sb, Ba, Cs, La, Ce, Sm, Tb, Hf, Th, and U).
The obtained data are provided in the supplementary materials Table SM1 and descriptive statistics are shown in Fig. 2. Furthermore, to elucidate the sources of pollution; eight pollution indices (6 complex and 2 individual) were calculated and their outcome was given in Table SM2. The description, features of the studied areas, discussion, and interpretations of findings are given in details in Arafa [1]; Badawy [2]; Badawy [3]. Multivariate statistical analysis was employed to extract more information about the provenance of soil and sediments as in Fig. 3. The discriminatory analysis shows broadly similar traits between soil and sediments. Both soil and sediments are in a good matching with the corresponding values reported for upper continental crust UCC by Rudnick and Gao [7], for world average sediments WSedA by Viers [8], for Post-Archean Australian shale average PAAS by Taylor and McLennan [9], for world average soil WSA by Kabata-Pendias [10]. The interaction plot as illustrated in Fig. 4 proves this finding, as the soil and sediments data are in line, except a slight difference in case of Na, Mg, Ti, V, As, and U.
Principal component analysis PCA and cluster analysis CA were used to group symmetrical geochemical elements and the highest contribution of soil and sediments to the 1st two PCAs (individuals and variables) is given in Fig. SM1. The pollution indices were calculated and PCA was used to get the proper pollution index as in Fig. 5. The spatial distribution of the pollution load index PLI is given in Fig. SM2.

Experimental design, materials, and methods
A total of 176 soil samples (133) and sediments (43), each weighing about 1 kg, were collected from the two banks along with the Egyptian sector of the river Nile and Delta as shown in Fig. 1. The samples were collected in conformity with the recommendations suggested by IAEA [11]. The soil samples were collected by the systematic grid sampling protocol (50 m Â 50 m) from the accessible areas along the Nile River and Delta as well at 17e45 cm depth. Soil samples were collected from rural and urban areas. The soil texture was clay, sandy, and silty clay mixed sources, While the sediment samples were taken from the banks of the Nile River and floodplain at 1e3 m depth where the nearest point to the water level. The sediments mainly were silty clay and silty clay loam. The collected samples were twice pretreated; (i) the samples were thoroughly cleaned of plant debris, any other extraneous materials, and air-dried at room temperature to a constant weight. Later, they were grinded and homogenized using an agate ball mill. Finally, 100 g of each sample were zip-packed and sent to be subjected to epithermal neutron activation analysis at REGATA station at IBR-2M pulsed reactor in Frank Laboratory

Value of the Data
Knowledge of the elemental composition gives a better understanding about the geochemistry of soil and sediments of Nile River and Delta. For the first time in Egypt a comprehensive baseline data is given about the major and trace elements in agricultural soil and surface sediments along the Nile River. It can be used to distinguish between the natural content of elements and the anthropological concentrations These data can be used as a supportive tool to the decision makers in all the regulatory bodies related to agricultural and industrial fields. Ministries of ecology, industry, and agriculture can use these data for more interpretation and explaining some issues. These data can be considered as a background or a baseline for construction an ecological atlas for Egypt in terms of major and trace elements. It can be used to examine any dynamics or changes in the future.
for   by Frontasyeva and Pavlov [12]. However, a concise description of the analytical scheme for soil and sediments will be presented. To determine the short-lived isotopes in soil and sediment samples, each sample was irradiated for 1 min in channel 2, after 3e5 min of decay, was measured for 15 min. The distance between irradiation and measurement positions 60 m and the transportation time for polyethylene capsule is 10e20 sec. However, in case of determining the long-lived isotopes; samples were irradiated for approximately 3 days in the Cd-screened channel 1 with a neutron flux of 1.8 Â 10 11 n/cm 2 .sec. Samples were repacked and measured twice. The 1st time is after 7 days of decay for 45 min. While the 2nd time after approximately 30 days of decay for 90 min. In this case the distance is 70 m and the transportation time for aluminum capsule is 3e8 sec. Gamma spectra of the Fig. 3. Ternary discriminating plot of Sc-La-Th, illustrates a good matching between the obtained data and those reported for upper continental crust UCC by Rudnick and Gao [7], for world average sediments WSedA by Viers [8], for Post-Archean Australian shale average PAAS by Taylor and McLennan [9], for world average soil WSA by Kabata-Pendias [10]. samples were measured by Ge (Li) detector or by HPGe detector with the resolution of 2.5e3 keV or of 1.9 keV, respectively, for the 1332 keV line of the 60 Co. The software Genie 2000 was used to store, display, and analyze the gamma spectra. The other software developed at FLNP was used to calculate concentrations of the elements in the samples. The analytical errors of the concentrations of the elements of interest range from 3 to 15%. More details about irradiation time for short and long-lived isotopes, neutron flux, channels, pneumatic transport system of the REGATA installation, and automation system for measurement using sample changer were published elsewhere [1e3,12e14]. The quality control of the analytical measurements using NAA was carried out using certified reference materials NIST standard reference materials (SRM) 1547-Peach Leaves, NIST SRM 1575а-Pine Needles, NIST SRM 1633b -Coal Fly Ash, NIST SRM1632с -Coal (Bituminous), NIST SRM 2709 e San Joaquin Soil, IRMM SRM 667 -Estuarine Sediment. SRM material varied between 1% and 10% with the exception of Rb, Ti, Ni, Mo, Au, Hf, W, and I for which the differences were 17% for Rb, 20% for Ti and Ni, 30% for Mo and Au, 33% for Hf and W, and 39% for I.
In order to calculate the pollution indices, the assessment of the geochemical background should be provided. Having a background value or a baseline value of the element in the examined soil or sediment samples is useful in terms of distinguishing between the natural content of elements and the anthropological concentrations. Therefore, two kinds of background were reported by Kowalska [15]. Reference and local or natural geochemistry background. The average content of heavy metals given in the literature, which can vary greatly due to localization differences and soil type, could be considered the reference geochemical background RGB. While the local or natural geochemical background LGB is the concentration of heavy metals conditioned by natural processes characteristic of a particular area [16,17]. In these data, the reference geochemical background of the upper continental crust UCC values reported by Rudnick and Gao [7] were considered. The pollution extent was quantified based on two approaches the individual and complex pollution indices. The individual levels of pollution from each analyzed metals can be calculated using individual pollution indices. While complex pollution indices   It estimates the quality of soil and sediments, PI avg was first employed by Qingjie [20] PI avg values higher than unity show a lower soil or sediment quality, which is conditioned by a high contamination level 7 Nemerow Pollution Index PINem describe contamination of soil in a more integrated approach, considering the content of more than one heavy metal or a sum of individual indices. The indices, used formula, parameters, description, and interpretation classes for the most widely used pollution indices based on different approaches are summarized in Table 1.