peer reviewed | Reducing the bioavailability of both cadmium (Cd) and arsenic (As) in paddy fields is a worldwide challenge. The authors investigated whether ridge cultivation combined with biochar or calcium-magnesium-phosphorus (CMP) fertilizer effectively reduces the accumulation of Cd and As in rice grains. Field trial showed that applying biochar or CMP on the ridges was similar to the continuous flooding, which maintained grain Cd at a low level, but grain As was reduced by 55.6%, 46.8% (IIyou28) and 61.9%, 59.3% (Ruiyou 399). Compared with ridging alone, the application of biochar or CMP decreased grain Cd by 38.7%, 37.8% (IIyou28) and 67.58%, 60.98% (Ruiyou399), and reduced grain As by 38.9%, 26.9% (IIyou28) and 39.7%, 35.5% (Ruiyou 399). Microcosm experiment showed that applying biochar and CMP on the ridges decreased As in soil solution by 75.6% and 82.5%, respectively, and kept Cd at a comparably low level at 0.13–0.15 μg L−1. Aggregated boosted tree (ABT) analysis revealed that ridge cultivation combined with soil amendments altered soil pH, redox state (Eh) and enhanced the interaction of Ca, Fe, Mn with As and Cd, which promoted the concerted reduction of As and Cd bioavailability. Application of biochar on the ridges enhanced the effects of Ca and Mn to maintain a low level of Cd, and enhanced the effects of pH to reduce As in soil solution. Similar to ridging alone, applying CMP on the ridges enhanced the effects of Mn to reduce As in soil solution, and enhanced the effects of pH and Mn to maintain Cd at a low level. Ridging also promoted the association of As with poorly/well-crystalline Fe/Al and the association of Cd on Mn-oxides. This study provides an effective and environmentally friendly method to decrease Cd and As bioavailability in paddy fields and mitigate Cd and As accumulation in rice grain.

peer reviewed | Pollution particularly affects coastal ecosystems due to their proximity to anthropic sources. Among those en- vironments, harbours are subjected to marine traffic but also to accidental and chronic pollution. These areas are thus exposed to complex mixtures of contaminants such as trace elements and organic contaminants which can impact marine species, habitats, and ecosystem services. The monitoring of these compounds is thus a crucial issue for assessment of environmental health. In this context, the aim of the present work was to evaluate the chemical contamination of harbours in Corsica (NW Mediterranean) by measuring the bioaccumulation of trace elements, polycyclic aromatic hydrocarbons, and polychlorinated biphenyls in mussels, limpets, and sea cu- cumbers. The human health risks associated with seafood consumption were also assessed. Results reveal a relatively low contamination in the Corsican harbours studied compared to larger Mediterranean ports and suggest that the potential health risk for consumers eating seafood is low. | Quality of the marine environment in the Mediterranean port areas (QUAMPO)

peer reviewed | The levels of eighteen trace elements (TEs) were evaluated in association with stable isotopes (δ15N, δ34S, and δ13C) in feathers and eggs of five migratory species breeding on the Antarctic Peninsula to test the factors that influence their exposure to contaminants. The feathers of seabirds migrating to the Northern Hemisphere (South polar skua) have concentrations (mean ± SD, μg. g-1) of Li (1.71 ± 2.08) and Mg (1169.5 ± 366.8) one order of magnitude higher than southern migrants, such as Snowy sheathbill Li (0.01 ± 0.005) and Mg (499.6 ± 111.9). Feathers had significantly higher concentrations for 11 of a total of 18 metals measured compared to eggs. South polar skua have higher concentrations of all TEs in eggs compared to antarctic tern. Therefore, the present study showed that migration and trophic ecology (δ15N, δ13C, and δ34S) influence Fe, Mn, Cu, and Se concentrations in feathers of Antarctic seabirds. The concentrations of Cu, Mn, Rb, Zn, Pb, Cd, Cr are higher than previously reported, which may be due to increased local and global human activities.

peer reviewed | The impact of climate change on water resource availability and soil quality is more and more emphasized under the Mediterranean basin, mostly characterized by drought and extreme weather conditions. The present study aims to investigate how electromagnetic induction technique and soil mapping combined with crop yield data can be used to optimize phosphorus (P) use efficiency by chickpea crop under drip fertigation system. The study was carried out on a 2.5-ha agricultural plot and the agronomic experiments in two growing cycles of chickpea crop. Soil spatial variability was first assessed by the measurement of soil apparent electrical conductivity (ECa) using the CMD Mini-Explorer sensor, and then, soil physicochemical properties were evaluated based on an oriented soil sampling scheme to explore other soil spatial variabilities influencing chickpea yield and quality. Data from the first agronomic experiment were used in geostatistical, multiple linear regression (MLR), and fuzzy c-means unsupervised classification algorithms to properly identify P drip fertigation management zones (MZs). Results from the Person's correlation analysis revealed that chickpea grain yield was more influenced by soil ECa (r = - 0.56), pH (r = - 0.84), ECe (r = - 0.6), P content (r = 0.72), and calcium (Ca) content (r = - 0.83). The proposed MLR-based model to predict chickpea grain yield showed good performances with a normalized root mean square error (NRMSE) of 0.11% and a coefficient of determination (R2) equal to 0.69. The identified MZs were verified by the one-way variance analysis for the studied soil and plant attributes, revealing that the first MZ1 presents a high grain yield, high soil P content, and low ECa. The low fertility MZ2 located in the south part of the studied site presented a low chickpea grain yield due to the low P content and the high ECa. Moreover, the application of P-variable rate fertigation regimes in the second field experiment significantly improved P use efficiency, chickpea grain yield, seed quality, and farmer income by 18%, 12%, 9%, and 136 $/ha, respectively, as compared to the conventional drip fertigation practices. The approach proposed in this study can greatly contribute to optimizing agro-input use efficiency under drip fertigation system, thereby improving farmers' incomes, preserving the ecosystem, and ensuring sustainable cropping systems in the Mediterranean climate.

peer reviewed | Contamination of land and aquatic ecosystems with heavy metals (HMs) is a global issue having the persistent potential to damage the quality of food and water. In the present study, Tagetes erecta L. plants were used to assess their potential to uptake HMs from wastewater. Plants were grown in soil for 20 days and then transplanted in hydroponic system containing Hoagland nutrient solution. After more than 15 days of growth, plants were then subjected to wastewater from tannery and surgical industries in different concentrations ranging from 25 to 100% in combination of citric acid (5 and 10 mM). After 6 weeks of treatment, plants were collected and segmented into roots, stem, and leaves for characterizing the morphological properties including plant height, roots length, fresh and dry mass of roots, stem, and leaves. For evaluation of the effect of wastewater on the plants, photosynthetic pigments; soluble proteins; reactive oxygen species (ROS); antioxidant enzymes SOD, POD, CAT, and APX; and metal accumulation were analyzed. Application of industrial wastewater revealed a significant effect on plant morphology under wastewater treatments. Overall growth and physiological attributes of plant decreased, and metal accumulation enhanced with increasing concentration of wastewater. Similarly, the production of ROS and antioxidant enzymes were also increased. Chlorophyll, protein content, and enzyme production enhanced with CA (5 and 10 mM) mediation; however, ROS production and EL were reduced. Metals analysis showed that the maximum accumulation of Pb was in roots, while Cr and Ni in the stem which further increased under CA mediation. Overall, the metal accumulation ability was in the order of Pb > Ni > Cr under CA.

peer reviewed | This study analyzed the potential use of Payment for Ecosystem Services (PES) as a strategy for improving water supply management. This study focused on the Siminehroud Sub-basin due to its high importance to the Basin of Urmia Lake (UL). Siminehroud is the second provider of water (by volume) to Urmia Lake. To evaluate the technical and economic feasibility of a PES scheme, the current land use map was extracted using satellite imagery. In addition, the two algorithms of Support Vector Machines (SVMs) and Maximum Likelihood (ML) are used for Landsat images classification, rather than analyzing the relationship between land use and ecosystem services. Then, the most relevant ecosystem services provided in the region were evaluated using the Benefit Transfer Method. In the last step, by designing and implementing a survey, on the one hand, the local farmers' Willingness to Accept (WTA) cash payments for reducing the area they cultivate, and on the other hand, the farmers' Willingness to Pay (WTP) for managing the water consumption were determined. The results illustrated that the WTA program is more acceptable among the beneficiaries. It is also notable that this program needs very high governmental funding. Furthermore, the results of the program indicate that the land area out of the cultivation cycle will gradually increase while the price of agricultural water will also increase.

peer reviewed | Most scholars support the increase in carbon dioxide (CO2) emissions as one of the major causes of the increase in global climate change. Therefore, reducing CO2 emissions from the main emitter countries, including Iran as the sixth emitter, is important to deal with the harmful effects of global climate change. Accordingly, the main aim of this paper was to analyze the social, economic, and technical factors affecting CO2 emissions in Iran. Previous studies on diverse variables affecting emissions are not very accurate and reliable as they do not consider indirect effects. This study applied a structural equation model (SEM) to estimate the direct and indirect impacts of factors on the emissions by panel data for 28 provinces of Iran from 2003 to 2019. According to geographical location, three distinct regions, the north, center, and south of Iran were considered. The findings suggest that a 1% increase in social factor directly increased CO2 emissions by 2.23% (in the north) and 1.58% (in the center), but indirectly reduced emissions by 0.41% (in the north) and 0.92% (in the center). Hence, the total effects of the social factor on CO2 emissions were estimated at 1.82%, and 0.66% in the northern, and central regions, respectively. In addition, the total effects of the economic factor on CO2 emissions were estimated at 1.52%, and 0.73% in those regions. The results of this study showed that the direct effects of a technical factor on CO2 emissions were negative in the north and center. However, they were positive in the south of Iran. Based on the empirical results of this study, three policy implications are discussed in order to control CO2 emissions in regional distinctions of Iran as follows: First, policymakers should pay attention to the social factor, i.e., the growth of human capital in the southern region with the aim of increasing sustainable development. Second, Iranian policymakers must prevent unilaterally increasing gross domestic product (GDP) and financial development in the north and center. Third, policymakers should pay attention to the technical factor, i.e., improving energy efficiency, as well as upgrading information and communications technology (ICT) in the northern and central regions, and limiting the technical factor in the southern region.

peer reviewed | A dust storm is a major environmental problem affecting many arid regions worldwide. The novel contribution of this study is combining indicators extracted from RS- and statistic-based predictive models to spatial mapping of land susceptibility to dust emissions in a very important dust source area in the borders of Iran and Iraq (Khuzestan province in Iran and Al-Basrah and Maysan provinces in Iraq). In this research, remote sensing (RS) techniques and machine learning techniques, including multivariate adaptive regression spline (MARS), random forest (RF), and logistic regression (LR), were used for dust source identification and susceptibility map preparation. To this end, 152 DSA for the period of 2005-2020 were identified in the study area. Of these DSA data, 70% was assigned to the Dust Source Susceptibility Mapping (DSSM) (training dataset) and 30% to model validation. Consequently, six factors (i.e., soil, lithology, slope, normalized vegetation differential index (NDVI), geomorphology, and land use units) were prepared as DSA's independent and effective variables. The results of all three models indicated that land use had the most impact on DSA. The validation results of these models using the test data showed sub-curves of 0.92, 0.86, and 0.76 for the RF, MARS, and LR models, respectively. Also, results showed that the RF model outperformed MARS (AUC = 0.89) and LR (AUC = 0.78) methods. In all three models, high and very high susceptibility classes generally covered a large percentage of the case study. The highest percentage of dust source points was also in this susceptibility category. Overall, the results of this study can be useful for planners and managers to control and reduce the risk of negative dust consequences.

peer reviewed | Managers can determine the function of ecosystem services in decision-making processes through valuation. Ecological functions and processes that benefit people lead to ecosystem services. Valuing ecosystem services mean finding values for the benefits of ecosystem services. For the concepts related to ecosystem services and their valuation, categories in different articles have been presented. One of the most important issues is providing a suitable grouping for different methods and concepts of valuing ecosystem services. In this study, the most recent topics related to ecosystem service valuation methods were compiled and categorized by using the system theory. The aim of this study was to introduce some of the most important classical and modern methods and concepts of valuing ecosystem services. For this aim, a review of articles related to ecosystem service valuation methods, content analysis, and categorization of their contents was used to provide definitions, concepts, and categorization of different methods. To summarize, valuation methods are classified into two types: classical and modern methods. Classical approaches include the avoided cost method, the replacement cost method, the factor income method, the travel cost method, hedonic pricing, and contingent value. Modern methods include the basic value transfer method, deliberative ecosystem service valuation, valuation of climate change risks, and other cases that evolve every day in the world of science. Findings of the paper have the potential to be beneficial in comprehending the definitions and ideas of ecosystem services in ecosystem management, particularly in protected areas, participatory management, and pollutant research. This research can add to the worldwide literature on the valuing of ecosystem services while also determining the most pressing issues and difficulties of today, such as climate change, pollution, ecosystem management, and participatory management.