Environmental impacts of aquaculture in urban wastewater

The role of aquaculture in world food production is increasing very fast, contributing with more than 40% for the total production of aquatic organisms. The general approach in modern aquaculture resembles much that of industrial agriculture and husbandry, with large energy subsidies and the usage of many chemicals in, predominantly, monoculture systems, with a large ecological footprint. In spite of the large body of regulation available worldwide, there are important ecologic, economic and social impacts in many countries as a result of aquaculture. In some cases, the anticipation of these impacts by local populations represents a negative feedback for aquaculture development. In the present work, a review of those impacts is presented, followed by a discussion of the carrying capacity concept, then by presenting some approaches and methods that may help planning aquaculture developments including the Drives Pressures States Impacts Responses framework, modeling and Decision Support Systems and, finally, by a synthesis of aquaculture related legislation worldwide. In the 21st century the fresh water scarcity increased very rapidly due to the urbanization and industrialization process. In these conditions the urban wastewater plays an important role in the water usage criteria. In this aspect, in all the major cities, wastewater treatment plants have been constructed to treat the urban wastewater in view of decreasing the water scarcity. The presence of nutrients in the wastewater is considered as beneficial to agricultural and aquaculture practices. The contaminants present in the wastewater pose health risks directly to agricultural and aquaculture system and indirectly to the consumers as the long term application of the wastewater may result in the accumulation of toxic elements in fishes. In this way the heavy metals will circulate among the food chain and food web to cause adverse effects on human health as well as on soil health. In the present study an attempt has been made to study the characteristics of urban wastewater at wastewater treatment plant of Mysuru city, also heavy metal concentration was studied in fishes and wastewater.