Caspian Journal of Environmental Sciences
Volume:19 Issue: 2, Spring 2021

Aras River and its reservoir play an important role in fisheries and water supplies in the northwest of Iran. It is considered that the river water is polluted by various anthropogenic activities. This study was performed to determine the histopathologic effects of water pollution on a fish species, Leuciscus aspius inhabiting the river. In July 2015, the fish were caught in two different stations of Aras River in Poldasht, Iran. The histopathological abnormalities were detected microscopically and evaluated with quantitative analyses in three organs of the fish. Hypertrophy, filament dilatation, lamellar epithelial liftings, thickening of filament, especially curve, a decrease of the mean length, necrosis, fusion, and lifting in lamellae were observed in gills. Main histopathological abnormalities in the liver were non-homogenous parenchyma, the proliferation of hepatopancreas, congestion, and degeneration of central vein, increasing melanomacrophage aggregates, and sinusoidal dilations. The observed changes in kidney included the degenerations of renal tubules, increasing melanomacrophage aggregates, pyknotic nuclei and vacuolization in proximal and distal tubule epithelial cells, and lymphocyte infiltration in renal parenchyma. It was found that the frequencies of the histological lesions were higher  in the liver in comparison with other organs. It was concluded that the increased  histopathological alteration in the fish tissues may be related to the presence and elevated  toxic contaminants in the river.

The article is devoted to the study of seasonal dynamics and quantity of the zoobenthos distribution in the north-west part of the South Caspian Sea. During the research covering the period from 2009 until 2010, 59 macrobenthos organisms belonging to the ten systemic groups were identified. Maximum quantity of species was identified in spring and summer (31 - 59 species), while minimum in autumn (24 - 42 species). Maximum development of organisms was identified in summer (146.27 g m-2), while minimum in autumn (77.12 g m-2). The key role in the benthos biomass formation belonged to shellfish, comprising 67.7 to 69.1% of total benthos biomass.

Olfaction in fishes is biologically-essential chemoreceptors. It provokes important behaviors for the survival of fish such as feeding, reproduction, avoiding predator and intraspecific communication. Pesticides can affect the olfactory epithelium and genes related to olfactory transduction and impair olfactory function.  The present study aims to determine how toxicity of diazinon impacts olfaction of Caspian roach, Rutilus caspicus in histological and gene levels. We exposed fish (0.7 ± 0.05 g in weight) to 0, 1, 2 and 3 mg L-1 diazinon (60 fish in each 3- replicate 60-L glass tank) for 7 days in freshwater. Diazinon concentrations were chosen based on reports on its concentration in surface waters. Mortality rate, histological events of olfactory epithelium, and genes expression at the 7th day after diazinon exposure included a significant decrease in the number of olfactory receptor cells (ORCs), while increased goblet cells (GCs). In addition, G protein αi (Gpαi) was significantly upregulated, whereas calmodulin-dependent kinase II α (CaMKIIα) was significantly downregulated after 7 days as compared to the control group. These results indicate that diazinon can impair olfactory function through effect on the olfactory epithelium and olfactory signal transduction pathways in the Caspian roach fingerlings.

Water quality indices are among the current techniques for monitoring rivers. Among the general indices of water quality, applying the national sanitation foundation water quality index (NSFWQI) results in precise research outcomes in a short period. Moreover, it enables the classification of river water quality of different stations with a simple expression. The present study, through applying NSFWQI as a water quality index, aimed at determining the water quality of Pasikhan River, located in the north of Guilan Province, Iran. Six sampling stations were set up along the river mainstream, and water samples were collected from these stations during 4 seasons (from autumn 2015 to summer 2016). Nine parameters including water temperature, turbidity, fecal coliform, NO3-, TS, PO43-, pH, DO, and BOD were measured through standard methods. Based on the results, the quality of the river’s water was categorized in the medium and bad classes in all sampling stations for all seasons. Moreover, the results showed that during the sampling seasons, the minimum average of NSFWQI was 52.00 ± 3.94 in the 4th station, while the maximum was 59.50 ± 1.50 in the 3rd station. However, both of them were in the category of medium quality. In general, the water quality values of the stations varied from 46 to 70 in different seasons. According to the results, the Pasikhan River’s water quality is ranked in the category of medium quality.

Different types of scale deformities have been reported from fishes worldwide, however there is no available study on the abnormal scales in the genus Garra except for G. variabilis. In the present study, scale deformities of three species of Garra including G. rufa, G. persica and Garra sp. from 6 sites of the Iranian drainages were examined and described. Different deformations were observed in focus, anterior, posterior and lateral sides of scales in the studied species, showing both slight and severe abnormalities. The occurrence of twin scales was one of the most interesting cases among various types of scale deformities observed on G. persica and Garra sp. Genetic disorders, diseases (including infection and lesions), developmental anomalies, incomplete regeneration after wounding, physical, and chemical environmental variables including pollutions might be considered as potential factors for scale abnormalities remained to be investigated.

Leaf area index (LAI), a dimensionless biophysical variable is considered as one of the most important factors in characterizing canopy structure. It estimates the amount of foliage area per unit of ground area and helps indirectly to assess biomass and energy balance in an ecosystem. Remote sensing techniques established a strong correlation between the vegetation reflectance characteristics in red and near infra-red bands and LAI. Good number of image derived vegetation indices has been applied so far to estimate LAI successfully. In this paper correlation is established between field-collected LAI and three soil adjusted vegetation indices, i.e., SAVI, MSAVI and OSAVI derived from IRS-LISS-III data in deltaic ecosystem in Sagar Island of West Bengal, India. LAI was estimated from OSAVI for the whole island as OSAVI yielded best result (R2= 0.92). Coarse resolution MODIS LAI (MOD 15A3) product was counter-validated with respect to the LISS-III derived LAI image following the upscale validation approach. Out of the six best-fit models applied, the logistic regression showed strong positive correspondence between the two products (R2 = 0.71). Uncertainty of the model was also assessed and probable reasons were identified.

A huge amount of azo-dye wastewater is generated annually by the textile industry. At present, the improper disposal of azo dyes to water bodies causes considerable concern as it can disrupt the ecosystem and, because of their toxicity and carcinogenicity, constitutes a possible environmental and health problem. Because of its cheap, environmentally safe, and sustainable properties, chemical, physical, and biological methods have been used to treat azo-dye wastewater, and biological technology has been recognized as a promising technique. Azo dyes are one of the most pollutant synthetic dyes to the environment. Azo dyes can be transmitted through a food chain and may be associated with problems of toxicity, carcinogenicity, and mutagenesis. In this study, contaminated soil with two Azo dyes, Reactive Blue (RB) and Reactive Red (RR) was used in sorghum planting (Sorghum bicolor L. Moench) using different dye concentrations (0, 0.05, 0.1, 0.2 g Kg-1 soil). Increased concentration of the dye caused significant alterations in the morphological characteristics of sorghum, such as steam length, leaves number and leaf area. There was a slight decrease in the plant content of total chlorophyll and carotenoids, while a significant variation in CAT and SOD enzyme activities was observed by increased dye concentration in the soil for both dyes compared to the control group. In addition, a significant increase in proline content was found at higher dye concentrations.

The Argan tree or Argania spinosa</em> L. is a plant in the Sapotaceae family. It is an endemic tree from Morocco. This study aims to evaluate the phytochemical and antiradical potential of different parts of Argan for the further valorization of this organic material. Seeds, kernels, pulps, leaves, and branches were targeted for this purpose and were soxhlet extracted with methanol. Amongst the different parts, leaves displayed the greatest DPPH radical scavenging ability with an IC50</sub> value (4.37 µg mL-1</sup>) close to that of ascorbic acid (1.97 µg mL-1</sup>). This observation was true for the ABTS assay as well. Accordingly, leaf extract was also the highest in polyphenols content (TPC) content, while seeds recorded the lowest value. The results were not so different for the flavonoid content, where leaf extract recorded the highest content. The leaves and branch of Agran seem to be the richest in antioxidant agents, as shown by the gathered data and results. Hence, it could be used as an important source of natural antioxidants.

Environmental pollution is one of the most important and main problems that the world is facing today. Global production and use of chemical compounds, many of which are resistant to biodegradation, have increased significantly in recent decades. These compounds enter the environment after consumption, and therefore, it is necessary to provide solutions to reduce consumption and remove pollutants from the environment. Removing the textile dyes of crystal violet (CV) and methylene blue (MB) from aqueous solution by CNT/TiO2</sub> surface was studied. We considered several physio-chemical parameters for example, contact time, primary concentration dye (5-50 mg L-1</sup>), adsorbent amount (0.01-0.1 gm), as well as temperature (15, 35, and 50 °C) in technique batch-adsorption. The output appeared absorbing two favorable dyes MB, CV at the basic pH. Moreover, removal present elevated by the increased amount of adsorbent, while decreased by uprising the primary concentration of dye, and agitation time bath of the two dyes. The adsorption capacity (Qe) upraised by the increased contact time and initial concentration of dyes, and then declined by the adsorbent weight and the procedure of temperature. The equilibrium data were estimated utilizing Freundlich and Langmuir isotherms. The Freundlich isotherm describes the best uptake of MB and CV dyes. The adsorption of CV and MB in the present study on the CNT/TiO2</sub> was heterogeneous with multi-layers. The results have shown immense potential, and it was found that the correlation coefficient value deals with the dyes, while the Langmuir equation did not exhibit good correlation of dyes.

Dengue Hemorrhagic Fever (DHF) depends on controlling Aedes aegypti mosquitoes and larvae. Currently, larvicide control still uses temefos larvicide, though several studies have reported resistance. Insecticides from plants can be used as an alternative. One of the plants reported to have larvicide potency was Melaleuca leucadendra leaves. This study aimed to look at ethanol extract of M.leucadendra leaves activity in killing A. aegypti larvae and LC50</sub> values ​​after a 24-h examination. This type of research was experimental design with post-test only control group design. M. leucadendra leaves was extracted through maceration process using 96% ethanol. The treatments consisted of 8 concentrations (mg L-1</sup>)  of 400 (0.04%); 1000 (0.1%); 1600 (0.16%); 2000 (0.2%); 10,000 (1%);  20,000 (2%); 30,000 (3%); 40,000 (4%) and the control group (0%). Each concentration was replicated four times and applied on twenty specimens of A. aegyptiat the third larval stage. The results showed that M.leucadendra has a lethal ability against A.aegypti. There was a correlation between the extract concentration and the larval mortality (p = 0.000; 95%). The extract concentrations of 0.04-0.2% caused <3% mortality, while the highest mortality (47.5%) achieved at the conc. of 4%. The LOGIT test showed that the number of LC50 </sub>was 3.7% (37,600 mg L-1</sup>) with 95% significance. A high concentration (></span>1%) of extract M. leucadendra caused turbid, greenish-gray color, and unpleasant smell on the water. Regarding the WHO bioassay guideline, etahnol extract of M. eucadendra leaves was less effective on killing A. aegypti larvae, though it causes lethal effect on it.

Forests, sensitive to fires, cover large parts of our planet. Rational protection of forests against fires, forest fire management, is a very important topic area. Our planet is facing the serious problem of global warming. The probabilities of long dry periods and strong winds are increasing functions of a warmer climate. Heat, dry conditions and strong winds increase the probabilities that fires start. Furthermore, if a fire starts, the stronger winds make the fires spread more rapidly and the destruction increases. Under the influence of global warming, we may expect more severe problems in forestry caused by wild fires. For all of these reasons, it is essential to investigate and optimize the general principles of the combined forestry and wild fire management problem. In this process, we should integrate the infrastructure and the fire fighting resources in the system as decision variables in the optimization problem. First, analytical methods are used to determine general results concerning how the optimal decisions are affected by increasing wind speed. The total system is analyzed with one dimensional optimization. Then, different combinations of decisions are optimized. The importance of optimal coordination is demonstrated. Finally, a particular numerical version of the optimization problem is constructed and studied. The main results, under the influence of global warming, are the following: In order to improve the expected total results, we should reduce the stock level in the forests, increase the level of fuel treatment, increase the capacity of fire fighting resources and increase the density of the road network. The total expected present value of all activities in a forest region are reduced even if optimal adjustments are made. These results are derived via analytical optimization and comparative statics analysis. They have also been confirmed via a numerical nonlineaer programming model where all decisions simultaneously are optimized.

A comprehensive understanding of plant associations, especially in transition areas can be achieved by identification of vegetation and study of relationships between plant species and environment. Borders of ecotones and forest communities (Tiremrud basin in the southern part of Tonekabon, Iran) were found based on environmental factors such as elevation, slope and changes in floristic patterns. Totally, 44 plots (20 × 20 m) were collected by the transect method with at least one sample plot per contour line and 50 m interval. A total number of tree species was recorded separately in each sample plot. Herbaceous species were sampled based on the Brown-Blanket cover percentage and frequency of vegetative elements by 5 × 2 m2</sup> micro plots in four corners and centre of each main plot. Four ecological groups were identified on altitudes 2070, 1236, 924, and 375 m above sea level with mean slopes of 43, 50, 40, and 59%, respectively. The first and fourth ecological groups were at the highest and the lowest elevations, respectively, while the second and third ones in the middle of the two groups. A comparison of ecological groups in terms of plant biodiversity indicated significant differences altogether. In terms of species diversity indices, Shannon-Wiener and Simpson-Pilo ​​revealed that the first, fourth, and second ecological groups had maximum, minimum, and average values, respectively. According to findings of this study, ecological groups had significant differences in terms of altitude factor.

Applying rice straw as mulch blanket on recently-established embankment is one way to reduce the environmental impact of sediment yields from forest roads embankments. Effectiveness of straw, however, is often unknown and it is unclear how the rate of application should vary with factors such as slope. In this study, the effects of the percentage of straw cover and slope gradient in the embankment of forest roads on the runoff volume and soil erosion were studied using rainfall simulator in plots of 1 m × 1 m dimension. Straw effects were quantified in four treatments of rice straw cover (0%, 30%, 60% and 90%), three treatments of slopes (0-15%, 16-30%, and 30-45%), with three replications in each giving a total of 36 experimental plots. Runoff and sediment from each plot were recorded every two minutes during the simulated rainfall of 65 mm/h intensity for 16 minutes. The 16-min simulations divided into eight simulation periods. The results showed that an increase in straw cover (based on length and amount) resulted in an impressive decrease in the runoff volume and soil erosion. Moreover, investigating the effect of slopes indicated that the runoff volume was significantly different between 0-15% and 15-30% slope classes. In terms of sediment concentration (g mL-1</sup>) and sediment (g), there were significant differences between the study slopes (various slopes and covers). The results showed that rice straw can decrease soil erosion up to 90% in road embankments and the rice straw with the length of 5 cm was the most economical choice to protect soil from erosions.

Drought stress has been well documented as an effective parameter in reducing crop production. Hence, developing and releasing new genotypes adapted to water deficit conditions can be a constructive way to overcome to unsuitable environmental conditions. Canonical discriminant analysis (CDA) was used in combination with cluster analysis to evaluate the response of 14 rice genotypes using the drought stress tolerance indices under two conditions of irrigation and discontinued irrigation at a specific time. The CDA results revealed that the first canonical variable was under the influence of high coefficients for the stress tolerance index (STI), harmonic mean (HM), mean production (MP), geometric mean production (GMP), yield in normal conditions (Yp), and yield in stress condition (Ys).The canonical coefficients of the stress sensitivity index (SSI) and tolerance index (TOL) were significant in the second canonical variable. Accordingly, the first canonical variable distinguished the genotypes based on yield potential and stress tolerance, while the second one segregated the susceptible and tolerant genotypes. The scatter plot chart of two significant canonical variables distinguished three groups, and all pairs of Mahalanobis distances between groups were significant. The second group was recognized as the best group, since its genotypes had the maximum value for the first canonical variable, while most of these genotypes had low values for the second one. Therefore, the genotypes of this group (831, Fajr, Sepidrood and Sahel) can be selected as suitable genotypes for stress and non-stress conditions.

The adoption of the 2018 Convention on the Legal Status of the Caspian Sea is of great importance for the protection of the Caspian environment, as it establishes a clear legal status of the Caspian Sea. At the same time, the provisions of the Convention of 2018 and the Framework Convention for the Protection of the Marine Environment of the Caspian Sea of 2003 (Tehran Convention) require further addition, primarily in the form of additional protocols to the Tehran Convention. In addition, the development of international legal norms should facilitate the harmonization of applicable national legislation in the Caspian States. To study the relationship between international legal norms on environmental protection of the Caspian Sea and Russian national legislation and the possibility of supplementing the international legal regime with domestic norms.

methods of analysis and synthesis, empirical methods of comparison, description, interpretation; legal-dogmatic and method of interpretation of legal norms.

The author shows that while the provisions of the Tehran Convention, its protocols and the applicable legal acts of the Russian Federation generally comply, the national legislation establishes more detailed approaches to environmental protection of the Caspian region in certain aspects. In conclusion, the legislation of the Russian Federation may help to fill a number of gaps in regional international legal regulation of the Caspian environmental protection. In particular, it is relevant in terms of legal protection from oil spill damage, as well as in the area of river runoff regulation (within the context of the basin approach to the management of the Caspian Sea resources).

This study aims to investigate the ecological and environmental impacts of the tourism cluster as a driver of regional tourism market development. The tourism industry can lead to adverse effects on the environment and ecosystem. It can place immense pressure on an area and result in catastrophic impacts, including increased pollution, soil erosion, natural habitat loss, massive pressure on endangered species, and intensified vulnerability to forest fires. However, the tourism sector assumes a significant function in solving the regions' socio-economic problems by creating additional jobs, ensuring the growth of employment of the economically active population, and improving the welfare of the nation. Nowadays, tourism is one of the drivers of economic recovery, which has a stimulating effect on the development of such related fields of the economy as accommodation services, transportation services, communications, trade, souvenir production, catering, agricultural production, construction, pharmacy, etc. Tourism is important for the socio-economic development of many regions of the Russian Federation. For example, the Altai Territory has a high level of tourism-recreation potential, in the region. There are unique natural and tourism-recreation resources, objects of cultural and historical heritage, vital political, economic, sports and cultural events. Despite this, the lucrative industry's environmental damage should be taken into consideration and minimized as far as possible. To achieve the aim of this study, several methods were employed including a persuasive strategy for discernment, interconnection and association, general logical strategies such as methods of scientific abstraction, modeling, analysis and synthesis, as well as grouping and comparison, analysis of the regulatory framework, literary sources, statistical data and a comparative method. Finally, some recommendations were brought about to benefit from this increasingly popular industry, while keeping the damage to the environment to a minimum.