Fish-farming water quality and environmental concerns in Argentina: a regional approach

Abstract

In spite of the steady increase in fish farming in Argentina, studies on water quality are scarce. Eight fish farms from two different regions in the northeast and east of Argentina were studied to explore source and effluent water quality. Ammonium (NH4 ? ), nitrate (NO3 - ), and nitrite (NO2 - ) levels were measured. High nitrate concentrations in water source were observed in the eastern region farms. An increase in NH4 ? ,N O 3 - , and NO2 - in effluent water was determined in most of the sampled farms. Heavy metals (i.e., cadmium, chromium, copper, iron, manganese, nickel, and zinc) and arsenic concentra- tions were analyzed. Heavy metal concentrations were below the detection limit in the northern region. However, As was detected in the water source of five farms and was over the recommended limit (100 lgl -1 ) for aquaculture in one. An increase in Mn and Zn concentrations in effluent water was observed in two farms. The lack of treatment of the effluent water in these farms leads to an increase of nutrients and heavy metal concen- trations in the surrounding areas. Environmental effects of fish-farming practices in Argentina are discussed.