Evaluation of pollution levels in sediments from Lake Edku, Egypt using laser ablation inductively coupled plasma mass spectrometry.

The concentrations of 11 heavy metals in sediments from Lake Edku, Egypt were determined using LA-ICP-MS. The average concentrations of elements occurred in the order of Fe > V > Cr > Zn > Ni > Cu > Co > Pb > As > Sn > Mo with respective values of 4.67 %, 104.8, 77.9, 76.6, 59.2, 52, 27.8, 19.8, 4.14, 2.24, and 1.45 µg/g. Several pollution indices were used to evaluate individual and cumulative contamination levels. All HMs were found to be in the deficiency to minimal enrichment range based on the enrichment factor. The contamination factor indicated low contamination levels of Cr and As, low to moderate contamination levels of Fe, Ni, Zn, Mo, Sn, and Pb, and moderate contamination levels of Co and Cu. The pollution load index and contamination degree indicated the sediments to be polluted and moderately polluted, respectively.

Phytogeographical regions of Egypt: first open-source geospatial data and its applications.

OBJECTIVES: To our knowledge, this is the first attempt for digitizing the Egyptian phytogeographical regions through incorporation of Geographical Information Systems (GIS) techniques including geo-referencing ground data of old-history paper maps. The main objective for the current study was digitizing and creating the first open-source geospatial data for the Egyptian phytogeographical regions and to make them readily available for usage by researchers - making this study novel. DATA DESCRIPTION: Geospatial data were created for the Egyptian phytogeographical regions based on ground data paper map showing the boundaries of each region in the country, Egypt. Digitization of the boundaries of each region was executed using ArcMap 10.4 followed by quality checks executions for ensuring the quality and accuracy of the created geospatial data. The data created in this study are available as file geodatabase (.gdb) and shapefile. Having the Egyptian phytogeographical regions available for GIS analysts and cartographers as geospatial data is a powerful tool for further research applications including phytoremediation, biodiversity, conservation, GIS, and remote sensing studies.

Soils with more clay and dense vegetation were rich in soil carbon along Wadi Al-Sharaea, Makkah, Saudi Arabia.

In arid ecosystems, lack of vegetation and nutrients can negatively impact soil carbon (C) content. In the current study, our goals were to assess soil C stocks to a depth of 50 cm in an arid ecosystem (Wadi Al-Sharaea, Saudi Arabia) and determine their relation to different vegetation cover. To address our research objective, a total of 102 quadrate (randomly selected) were established along the desert wadi. Soil samples were collected to a depth of 50 cm with 5 cm interval, then Soil Bulk Density (SBD, g/cm3), Soil Organic C Content (SOC, g C/kg), and stocks (kg C/m2) were estimated. Both soil mechanical and chemical analyses were conducted for a composite soil sample. Study sites were categorized based on their visual vegetation cover (VC) percentage (%) into three major groups: 1) scarce vegetation cover (VC less than 25%); 2) medium vegetation cover (VC is higher than 25% and less than 75%); and lastly 3) dense vegetation cover (VC is higher than 75%). Soils were characterized by higher sand content (48.2%, both fine and coarse compiled) than silt (36.7 ± 1.64%) or clay (10.1 ± 1.28%). There were significant differences among soil Calcium (Ca) and Potassium (K) content (p < 0.05), while those plant communities with medium vegetation cover showed the highest soil content of Ca and K (1.7 ± 0.24 and 0.2 ± 0.03 meq/l, respectively). Plant communities with dense vegetation cover had the lowest SBD (1.96 ± 0.03 g/cm3) and the highest SOC stocks (14.9 ± 2.1 kg C/m2). Moreover, our data analyses indicated that SBD and SOC content had strong and negative correlation, where soils with dense vegetation cover had the most significant correlation (R2 = 0.95). Our results recommend that soil carbon stocks to a depth of 50 cm based on different vegetation cover of arid ecosystems should be implemented on global soil carbon budget to better elucidate factors controlling SOC content at the regional and global scales.

Sediment clays are trapping heavy metals in urban lakes: An indicator for severe industrial and agricultural influence on coastal wetlands at the Mediterranean coast of Egypt.

Coastal wetlands of the northern coast of Egypt have been impacted with higher loads of runoff, especially the large urbanized lakes of the Nile deltaic coast. Five urban lakes spanning the northern coast of Egypt (from east to west: Bardawil, Manzala, Burullus, Edku, and Mariut) were sampled for quantifying concentrations of heavy metals in their sediment and plant tissues. Sediment and plant tissues in lake Bardawil were the least contaminated, and the other lakes were moderately to highly polluted with Ni, Co, Cr, Pb, Zn, and Cu. Edku had the highest concentrations of Co, Cr, and Cu (19.83, 45.42 and 68.60 mg kg-1, respectively). The proportion of clay in sediment was significantly and positively correlated with Co and Ni in sediment (r = 0.7 and P ≤ 0.001), suggesting an important role of clay cation exchange capacity in the sorption of metals and removing them from the water column.