Soil contamination around porphyry copper mines: an example from a semi-arid climate.

Extraction and processing of disseminated metalliferous ores, porphyry copper in particular, results in significant tonnages of waste and can cause severe disturbances and contamination in natural ecosystems. This is particularly important in semi-arid climates where natural soils are often deprived of organic matter and nutrients. This study was conducted on seven sites around Sungun Copper Mine, northwest Iran. Soil texture, EC, pH, and concentrations of nutrients, organic matter, along with 16 metal and metalloids were measured in 94 soil samples. Results showed a gradient of contamination from low contamination in natural hillsides to high contamination in mine waste depositories, Waste Dump and Oxide Dump, alongside Pakhir and Sungun Rivers. Nutrient deficiency occurred in disturbed sites. The main contaminant point sources were Waste Dump, mine pit drainage, and Oxide Dump. The results of Non-metric multidimensional scaling ordination showed elevated Cd, Zn, Fe, Cu, Pb, As, Mo, Mn, Co, S concentrations, high EC, and higher sand percentage in the sites affected by mine waste and acid mine drainage. Geo-Accumulation and Potential Ecological Risk Indices indicated that Pakhir riverside, Sungun riverside, and Oxide Dump have severe to moderate levels of environmental risks. Positive correlations between certain metal elements suggest common sources and similar reaction pathways, which may contribute to their similar geochemical behaviour in transport, deposition, and interdependence. Overall, the deficiency of organic matter and nutrients along with the soil sandy texture in contaminated sites of Sungun Copper Mine are the main limiting factors in managing metal mobility and soil remediation.

Metal and metalloid accumulation in native plants around a copper mine site: implications for phytostabilization.

Mining activities can result in a pollution legacy of metal and metalloid containing soils and wastes. In this study concentrations of the metals and metalloids Al, As, Ca, Co, Cr, Cu, Fe, Mg, Mn, Mo, Ni, Pb, Zn, and the non-metals (P, S) were measured in the shoots of 35 different plant species spontaneously growing at four contaminated sites around the Sungun Copper Mine in East Azerbaijan (Iran) in order to evaluate their potential in phytoremediation of this area. The results show that metal and metalloid accumulation differed between the different species. None of the plant species exceeded the relevant trace element hyperaccumulation thresholds. Plant accumulation of Al was found to be relatively high in Achillea vermicularis (Asteraceae, with up to 5,280 µg g-1) and in Trifolium fragiferum (Fabaceae, with up to 4,895 µg g-1). Papaver dubium (Papaveraceae) had relatively high foliar Cu concentrations (with up to 294 µg g-1) while growing in the waste Rrock dump. Teucrium polium (Lamiaceae) had the highest concentrations of Pb (with up to 62 µg g-1). Most of the native species can be classed as metal-tolerant "excluder"-type species, and may, therefore, be suitable for phytostabilization of the mining wastes around the Sungun Copper Mine.

Plants growing on metalliferous soils are threatened by mining and mineral extraction. Identifying the flora in metal-contaminated soils and mineral wastes is of great importance for biodiversity conservation and for their use in future reclamation programs. This study adds valuable information on the potential of native plants for use in the phytoremediation of copper mines in Iran, as well as in other parts of the world with a similar geology and climate.

Evaluating economic and ecological management to determine the economic size of pastoral units for different climatic zones in the northeast of Iran.

Stocking rate and rangeland area are key variables to provide the livelihood of herders in different climatic zones. To evaluate the economic and ecological management of pastoral units, this study aims to determine the optimal economic size of pastoral units for livestock grazing use considering the ecological capacity of semi-arid rangelands in different climatic scenarios. Therefore, 12 pastoral units (an area of 47,355 ha) were selected in two climatic zones (summer and winter rangelands) in the Kalat region of Razavi Khorasan Province, Iran. By measuring forage production, carrying capacity was calculated. Based on the results, the costs of traditional livestock management in winter rangelands are higher than those of summer rangelands. Moreover, the current size of the assigned rangeland, especially the summer rangeland, is lower than that of the economic justification. The results emphasize that rangeland-based livestock husbandry cannot create a good livelihood for herders in the region, and it is necessary to pay special attention to other services and aspects, despite the existing ecological and socio-economic complexities. In this regard, providing multi-purpose rangeland use and useable technologies to better manage these areas is necessary to increase per capita household income and reduce the stocking rate in the region's rangelands. Ultimately, both increasing the level of available rangelands and reducing costs by applying new technology are required, as is the economic consideration of pastoral units by using rangelands for multiple purposes.

Economic sustainability assessment in semi-steppe rangelands.

This study was conducted to determine indices and components of economic sustainability assessment in the pastoral units of Sahand summer rangelands. The method was based on descriptive-analytical survey (experts and researchers) with questionnaires. Analysis of variance showed that the mean values of economic components are significantly different from each other and the efficiency component has the highest mean value (0.57). The analysis of rangeland pastoral units with the technique for order-preference by similarity to ideal solution (TOPSIS) indicated that from an economic sustainability standpoint, Garehgol (Ci = 0.519) and Badir Khan (Ci = 0.129), pastoral units ranked first and last, respectively. This study provides a clear understanding of existing resources and opportunities for policy makers that is crucial to approach economic sustainable development. Accordingly, this study can help better define sustainable development goals and monitor the progress of achieving them.