Soil heavy metals contamination and health risk of an endemic plant in southeast of Damavand Mt., Iran.

Considering the toxicological effects of some heavy metals (HMs) in which directly related to mortality and carcinogenicity in the population by their entrance from plants through livestock grazing, and medical skin cream, the rehabilitation of contaminated sites through phytoremediation by native plants might be quite challenging. Diplotaenia damavandica Mozaff. ex-Hedge & Lamond, is used as medical skin creams due to the existence of specific ingredients, which can be effective in treating skin disease. In the present study, the plant and associated soil sampling were performed around the boundary of D. damavandica. The concentration was measured using the Inductively coupled plasma mass spectrometry (ICP-MS). The results revealed the effect of existing endemic plants on reducing the average concentration of lead and zinc in soil by 40 and 60%, respectively, due to phytoremediation. EDX confirmed the presence of Pb and Zn in root and shoot tissues. Based on the results of this study, D. damavandica is an endemic perennial herbaceous plant with 60% biomass and prosperous root systems, which can grow in low contaminated areas of Pb in the southeast of Damavand Mt. Hence, the HMs pattern indicated less often in the aerial parts except for lead, which should be examined more carefully for skin cream uses.

Heavy metal mapping, source identification, and ecological risk assessment in the International Hamoun wetland, Sistan region, Iran.

This study is aimed at assessing the ecological risk of heavy metals (HMs) in the International Hamoun wetland, southeastern Iran. Twenty sediment samples were collected from the wetland surface for geochemical analysis of 23 HMs. The inverse distance weighting (IDW) technique was used to map the HMs. The single and multi-element pollution indicators and PER index (PERI) were respectively used to determine the contamination intensity and PER level. The principal components analysis (PCA) was performed to identify the HM source. The mean concentration of cesium (Cs: 5.2 µg/g), selenium (Se: 0.9 µg/g), and tellurium (Te: 0.2 µg/g) was higher than their mean values in the Earth's crust. The enrichment factor (EF) showed the Hamoun was high to extremely enriched by Te, As, and Se. The geo-accumulation index (GeoI) revealed the highest level of contamination caused by As, barium (Ba), cobalt (Co), chromium (Cr), cuprum (Cu), ferrum (Fe), manganese (Mn), nickel (Ni), lead (Pb), rubidium(Rb), titanium (Ti), vanadium(V), yttrium (Y), and zinc (Zn) in most study sites. The sediment contamination factor in more than 55% of the sediment samples was between 8 and 16, indicating very high contamination intensity in the studied wetland. The PER values were between 80 and 160 in more than 60% of the sediment samples, suggesting a considerable risk in the wetland. The PCA showed both anthropogenic and crustal activities were effective in increasing the concentration of HMs in the wetland. The largest ecological risk was due to arsenic (As) and cadmium (Cd). It is recommended to pay more attention to these HMs, which could cause more environmental pollution in the International Hamoun wetland, southeastern Iran.

Dust mitigation by the application of treated sewage effluent (TSE) in Iran.

Considering the presence of 274 dusty days in 2021 in Zabol city, Iran, the present study aimed to evaluate the feasibility of using treated sewage effluent (TSE) for dust mitigation with natural methods of increasing land cover. Hence, first of all, the identification of sewage treatment facilities along with the volume and chemical status was carried out and compared to the various national and international legislation. Then, field investigation on land use and land cover, along with literature review on dust origins, sand detachment areas, and sand corridors in the study area will be assisted for optimal area suggestion. Note that, in the present study it was assumed that the application of TSE for wetting the surface to vegetation restoration resulted in wind erosion control in critical foci. The results showed that, so far, a total of 39,000 m3/day could be treated, in the whole study area. The TSE volume calculated based on two scenarios consisting, (1) data obtained from the related organization, and (2) based the capacity of the wastewater plant is 2.8 and 5.1 mcm/year, respectively. Additionally, the study of TSE quality and its comparison to various regulation such as FAO, USEPA, INS, and CWQI indicated the applicability of transforming TSE to 14 km away from the WWT planet daily for rehabilitation of Hammon Hirmand through irrigation of T.stricta to increase the vegetation cover to above 30%.

Monitoring the water surface of wetlands in Iran and their relationship with air pollution in nearby cities.

Understanding the impact of wetland water area (WWA) fluctuations on air pollution in nearby cities is of great environmental importance. This study is the first effort for investigating the WWA changes in Iran and their impacts on air pollution in the surrounding cities during different seasons. Three-hourly data related to wind speed, wind direction, and horizontal visibility recorded in meteorological stations around Iranian wetlands were used to identify cities located in the direction of dusty winds blown from shrinking wetlands in Iran. Meteorological data were also used to calculate the pollution of dust storm index (PDSI) as a representative of dust pollution in the surrounding areas. Global water surface (GWS) product for a long-term period (1988 to 2018) was used to monitor the WWA in Iran. The correlation between PDSI in dusty cities and WWA in nearby wetlands were analyzed using the Pearson correlation coefficient (r). The results showed that the cities located around Hamoun, Jazmourian, Parishan, and Hourolazim wetlands were affected by dusty winds blown from the wetlands in most seasons. However, the cities around Gavkhouni International Wetland have been affected by the winds only in the warm season. In winter and spring, the strongest negative correlations between PDSI-WWA was respectively observed in Shiraz-Parishan (r = - 0.33; p-value < 0.05) and Zabol-Hamoun (r = - 0.32, p-value < 0.05). However, in the summer and autumn, no strong correlation was observed between the studied variables. On the annual scale, 25% and 15% of changes in dust pollution across the cities around the Hamoun and Parishan international Wetlands were due to the decrease in their water area from 1988 to 2018. On a seasonal scale, about 11% of the changes in PDSI were due to changes in the water area in these wetlands. These results can be useful for implementing air pollution reduction programs in cities affected by dusty winds blowing from the destroyed wetlands.