To assess the roadside soils contamination with Pb, Cd, and Zn, 34 soil samples were collected along Alexandria-Marsa Matruh highway, Egypt, and analyzed by using the atomic absorption. The contamination with these metals was evaluated by applying index of geoaccumulation(Igeo), contamination factor (CF), pollution load index (PLI), the single ecological risk index(Ei), and the potential ecological risk index (PERI). The average concentrations of Pb, Cd, and Zn were 38.2, 2.3, and 43.4 μg/g, respectively.Igeoindicates the pollution of soil with Pb and Cd as opposed to Zn.Eishows that the roadside soils had low risk from Pb and Zn and had considerable to high risk from Cd. Most of the samples (62%) present low PERI risk associated with metal exposure and the rest of the samples (38%) are of moderate PERI. The bioavailable fraction (EDTA-Extract) was 72.5 and 37.5% for Pb and Cd contents, respectively. These results indicate the remarkable effect of vehicular and agricultural activities on Pb and Cd contents in soil.

Gerga district contains different activities, urban, agriculture, and industry, which can impact adversely on the soil quality. Sixteen samples of the agricultural soil (0–30-cm depth) were collected to investigate the pollution of soil with trace elements (Co, Ni, Pb, and Mn). The statistical techniques were applied to discriminate the sources of these elements. The studied soil ranged from uncontaminated to moderately contaminated with the studied trace elements based on the contamination factor index. The statistical analyses indicated the anthropogenic source of Co, Ni, and Pb as well as the natural source of Mn. The statistical analyses assisted in the discrimination of natural and anthropogenic sources of trace elements in the investigated soil samples. Mn is mainly of natural origin, affected by pedogenic factor, whereas traffic emissions and phosphate fertilizer, as well as domestic activities, are relevant sources of Co, Ni, and Pb elements in the studied soil. Consequently, the recommendation is periodic environmental monitoring and minimizing the fertilization rate.

Siwa Oasis is of great historical, environmental, and scientific importance, as it contains unique archeological and geological features. Groundwater is the main source of freshwater in that oasis. The carbonate aquifer groundwater, used for irrigation, was sampled to evaluate factors controlling quality changes spatially and temporally by applying hydrochemical and statistical analyses. The salinity of the aquifer varied spatially from 1367 to 8645 mg/l based on one hydrogeological condition, with the highest TDS (> 5432.5 mg/l, 25% of samples) at the central part of the study area. Temporally, the salinity changed slightly from 3754.3 mg/l (in 2014) to 4222.4 mg/l (in 2020). The cession of illegal wells, pumping control, and excavation of formed salts have a noticeable impact on salinity (mediate the increase in salinity) and ions. However, about 61% of the studied samples can be considered unsuitable for irrigation owing to salinity and can harm plant yield. The heavy metals studied (Fe, Mn, Cu, Pb), except Cd, were within the permissible limit for irrigation water. Finally, it is proposed to construct desalination stations to enhance water quality for irrigation in the study area and set up many companies for salt extraction.