In this study an assessment is made of the negative impacts of wastewater irrigation on soils and crops sampled along the Khoshk River channel in suburban area of Shiraz City, SW Iran. For this purpose, samples of soil profiles (0-60 cm in depth) and crops were collected from two wastewater irrigated sites and a tube well-irrigated (control) site. Total concentrations of the five heavy metals (Ni, Pb, Cd, Zn and Cr) and their phytoavailable contents were determined. The Pollution Load Indexes (PLIs) and Contamination Factors (CFs) for soils and Hazard quotients (Sigma HQ) for some vegetables were also calculated. The results showed the use of untreated wastewater has caused the following changes as compared to control site: (1) a 20-30% increase in organic matter content of soil; (2) increase in pH by 2-3 units; (3) significant concentration increase in Ex-Ca especially in top layers of soil resulting in high CEC; (4) build up of heavy metals (notably Pb and Ni) in topsoil above Maximum Permissible Limits (MPLs) indicating a moderate contamination (PLI > 1, CF > 2.5); (5) contamination of some vegetables (spinach and lettuce) with Cd due to its high phytoavailability in topsoil causing a HQ > 1; (6) excessive accumulation of Ni and Pb in wheat due to continual addition of heavy metals through long-term wastewater application. The study concludes that strict protection measures, stringent guidelines and an integrated system for the treatment and recycling of wastewater are needed to minimize the negative impacts of wastewater irrigation in the study area.

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In this study, the total concentration and speciation of trace elements (As, Cr, Cu, Cd, Pb, Zn, and Ni), in sediments of the Maharlu saline Lake, SW Iran are investigated. Comparison with sediment quality guidelines, calculation of the enrichment factors, and trace metal profiles in the Khoshk River inflow point indicate that Maharlu Lake is in the threat of contamination, especially with respect to Ni and Cd. Sequential extraction analysis reveals that elemental speciation in this lake is strongly affected by oxidizing condition of the lake water. The studied elements (except Cr) are mainly associated with oxide phases, as a result of prevailing oxidizing conditions of the lake and also probably due to the source of elements. The ratio of metals in mobile fractions to sum of fractions in lake sediments is very low. However, metal ratios (except for Cr) in mobile fractions are much higher in surface sediments, indicating the impact of anthropogenic loading of trace metals in the recent years.

Rivers are one of the most environmentally vulnerable sources for contamination. Since the rivers pass through the cities, industrial and agricultural centers, these have been considered as place to dispose the sewages. This issue is more important when the river is one of the main sources of water supplying for drinking, agricultural and industrial utilizations. The goal of the present study was assessing the physicochemical characteristics of the Tireh River water. The Tireh River is the main river in the Karkheh catchment in the Iran. To this end, 14 sampling stations for measuring the physicochemical properties of Tireh River along the two main cities (Borujerd and Dorud) were measured. The results showed that (except SO 4) Mg, Ca and other anions and cations have concentrations under WHO standard limitation. Almost all samples have suitable conditions for drinking with regard to the WHO standard and in comparison with agricultural standard (FAO Standard), and the potential of water is suitable for irrigation purposes. According to Wilcox diagram, 78 % of samples were at the C3-S1 and 21.5 % were at C2-S1 classes. The piper diagram shows that most of samples are bicarbonate and calcic facies.