Contamination and ecological risk assessment of trace elements in sediments of the Anzali Wetland, Northern Iran.

In this paper, concentrations of some heavy metals in surficial sediments of the International Anzali Wetland were measured, this wetland is located in the northern part of Iran. Sediment pollution levels were examined and analyzed using reliable pollution indices including Pollution Load Index (PLI), Geoaccumulation Index (Igeo) and Enrichment Factor (CF), and finally it was revealed that heavy metal pollution ranged from low to moderate loads in the wetland. According to Sediment Quality Guidelines (SQGs) and Ecological Risk Index (ERI), it was concluded that As and Ni may have significant toxic impacts on aquatic organisms and also according to Effect Range Median (ERM), the toxicity probability of sediments in the Anzali wetland was estimated at 21%.

Modeling and prediction of future ecotourism conditions applying system dynamics.

The ecotourism industry is one of the largest industries and has an important role in the economic social and cultural development of societies, especially in developing countries. Policymaking and planning procedures in this industry require the application of the methods that can appropriately model mutual and complex interactions and contacts. System dynamics is an accurate modeling method to simulate complex systems in a structured way and to design more effective policies by using these complex systems. In this study, the interactions and dynamics of the main components of ecotourism (effective variables) in the Taleghan area are modeled using system dynamics. To formulate and model simulations in the period between 2005 and 2015 was considered, and then extending the period of investigation, the model simulation was performed till the year 2025. Among the most important results of this study is the effect of the environment on the demand for ecotourism. Environmental degradation and the degradation of the quality of the environment lead to a reduced demand for ecotourism. This study predicts the future of ecotourism by this dynamic and designs a group of policies for the sustainable and comprehensive development of ecotourism on the basis of the behavior of the model variables in order to prevent the degradation of environment and simultaneously ensure that ecotourism demand is not negatively affected. Finally, the best policy "depending construction to the state of the area environment" was selected among them.