Urban soil pollution with heavy metals is one of the environmental problems in recent years, especially in industrial cities. The aim of this study is to evaluate the role of geogenic and anthropogenic sources in the urban soil pollution in Yazd, Iran. For this purpose, 30 top-soil (0–10 cm) samples from Yazd within an area of 136.37 Km² and population of nearly 656 thousand are collected, and the concentration of heavy elements is measured. To evaluate factors affecting the concentration of heavy elements in urban soils and determine their possible sources, Multivariate statistical analysis, including correlation coefficient, principal components analysis (PCA) and cluster analysis (CA) are performed. Enrichment Factor (EF), Geo-accumulation index (I_geo), and Modified potential ecological Risk Index (MRI) are used to assess the level and extension of contamination. Results of this study suggest that As, Cd, Pb and Zn are affected by anthropogenic source, while the concentrations of Fe, Mn, Ni, Cr, Co, Cu and Cs have come from mostly natural geologic sources. As, Cd and Pb are considerably enriched in the area, provided moderately enriched for the elements Mn, Zn and Cu. However, the other heavy elements show minimal enrichment. I_geo reveal that Co, Cr, Cs, Cu, Fe, Mn, Zn and Ni with negative values are unpolluted, Pb posed unpolluted to moderately polluted, and As and Cd represent high polluted. Based on the results of the ecological risk factor, the heavy metals of Mn, Ni, Cr, Zn and Cu have a low ecological risk level. More specifically, we find that Pb shows a moderated ecological risk in 39% of the urban soil in the studied area. As and Cd with respectively 100 and 72% contribution have considerable and very high ecological risk. According to the results of MRI, the area is in a very high ecological risk level, and appropriate management practice is essential to reduce the pollution of heavy elements in this area.

Soil pollution is a highlighted concern of modern society, particularly in developing countries. The Drosh-Shishi valley, which is a hilly region near Afghanistan with a land area of around 15,000 km², is situated in the south of Chitral District (Pakistan) and has a population of approximately 450,000. Nowadays, this region is being explored for soil pollution, specifically heavy metals which pose a potential risk to human health. Therefore, our main goal was to investigate possible sources of heavy metals’ spread and to assess the content levels in soil and the associated risks for human. We collected 34 representative samples from transported sediments and 31 from agricultural crops. We analyzed the soil samples for the contents of Cd, Co, Cr, Cu, Mn, Ni, Pb, and Zn using ICP-OES analyzers. These values were used to obtain the contamination factor (CF) and to estimate the potential health risk caused by heavy metals according to the USEPA dose–response model. Our results suggest that the heavy metal pollution has a geogenic source, but it is also aggregated by chemical fertilizers used in farming. Regarding levels, most of the metals except Pb showed contents above the permissible level, with CF values from moderate to high. Overall, Cu and Ni showed a significant total cancer risk (TCR > 1 × 10⁻⁴) in children. Therefore, we conclude that heavy metal pollution is causing a serious threat to humans in this area, and we recommend that authorities should make more efforts in monitoring the heavy metals content in soils to reduce potential health risks.

The influence of a combined system of jet injection through the pier and bed suction on the reduction of local scour around a circular pier was investigated in a laboratory flume. Experiments were conducted for two water depths (10·5 and 28 cm) under 1-jet and 3-jet injection and different angles between the jets, with bed suction rate Q_s/Q₀ = 2%, in turbulent flow and clear-water scouring conditions. The results show that the bed suction modifies the effect of jet scouring and reduces the local scour and sediment transport at the pier (36% for scour depth, 25 and 42% for the area and volume of scour hole). The maximum reduction of the scour depth was about 50% (about 20, 39 and 39% for the area, volume and the upstream slope of the scour hole respectively) in the best configurations for a combined countermeasure.