Water quality evaluation of cyprinid pond based production system effluent

Abstract

Aquaculture is the fastest growing food production sector, according to FAO report. Romanian aquaculture has an estimated production of 10000 tones per year, most of it being provided by cyprinids pond aquaculture production systems. However, pond aquaculture rises certain problems regarding the sustainability, as large concentrations of nitrogen and phosphorus may be recorded in effluents. Therefore, the aim of our study is to evaluate the sustainability of a single pond based cyprinids production system, situated in Galaţi - Romania, by analysing the water quality of the effluent. Water samples were collected from the pond effluent and the following analysis were determined: temperature (T°C), dissolved oxygen (DO), pH, nitrites (NO2), ammonia (NH3),orthophosphates (PO4),total zinc (Zn) chlorides (Cl-), bicarbonates (HCO3-), electro conductivity (EC) and total dissolved solids (TDS).The results were compared to the present national legislation (HG no. 202/2002) regarding the water quality in cyprinid farming and also to water quality criteria for aquaculture. Statistical analysis included normality test Kolmogorov Smirnov in order to determine the distribution of the registered data and Pearson correlation coefficient was applied for the analyzed parameters. The main conclusion of this research was that the technological water of the studied fish pond is suitable for fish rearing and sustainable for the environment, in terms of temperature, DO, pH, Cl-, HCO3-, Zn, EC and TDS. However, NO2, NH3 and PO4 concentrations were above the admissible limit imposed by the romanian legislation. Therefore, in order to improve sustainabily it is recommended that various modern multi-trophic technics should be applied, so that phosphorus and nitrogen compounds are valorized at maximum capacity.