Wastewater-based urban aquaculture systems in Ho Chi Minh City, Vietnam.

Abstract

Abstract Steady increases in population and economic activity, as well as a lack of environmental infrastructure, have resulted in severe surface water pollution within Ho Chi Minh City. The clear boundary between urban and rural areas has faded. In this context, farmers and their counterparts have tried to set up appropriate wastewater-based urban aquaculture systems, which is a challenge that faces constraints. Eight major types of wastewater-based urban aquaculture systems occur within the urban area, mostly conducted on a trial-and-error basis. These are: (i) water morning-glory (Ipomoea aquatica), (ii) lotus (Nupher lotus), (iii) lotus and duckweed (Lemnaceae), (iv) water mimosa (Neptunia oleracea) and duckweed, (v) water mimosa, (vi) duckweed and growout of fish (tilapia, Oreochromis spp.), (vii) fish nursing and rearing and (viii) ornamental fish culture. Farming practices of these systems and their establishment and evolution under urbanization pressure are described. Generally, farming practice depends on cultured species, topographical characteristics of the landscape and pollution level of the water being used. Over the years, urbanization has not caused these wastewater-based urban aquaculture systems to disappear, but has pushed them away to more distant sites. Aquaculture products from wastewater-based urban aquaculture systems have been accepted in local markets as both animal and human food. Neither claims nor public health incidents associated with these products have been reported so far. The necessity of research for improvement of production efficiency and food safety of wastewater grown products, and the possible role of these systems within the context of sustainable water management in Ho Chi Minh City, are discussed.