Chemical Contaminants and Water Quality in Shrimp Farms of Edavanakkadu Area, Cochin, India

Abstract

Aquaculture is gaining importance these days as catch from wild cannot keep up with the demand of the growing human population. But the culture system often encounters problems which are potentially harmful to consumers. This study was carried out in October to December 2012 in three randomly selected tiger shrimp (Penaeus monodon) farms of Edavanakkadu area, Cochin to evaluate the level of chemical contaminants and water quality. Shrimp samples were analysed for the presence of antibiotics such as chloramphenicol and nitrofuran metabolites. The content of heavy metals such as Cd, Co, Cu, Cr, Mn, Ni, Pb and Zn was evaluated in the samples of shrimp, water and sediment. The water quality parameters (temperature, pH, salinity, dissolved oxygen, biological oxygen demand, chemical oxygen demand, total alkalinity and total hardness) were also evaluated. Shrimp samples were found free of chloramphenicol, but 1-aminohydantoin (AHD), metabolite of the prohibited antibiotic nitrofurantoin was detected in shrimp samples from all three farms in the range of 6.39±0.56, 0.595±0.00 and 10.3±0.00 ppb respectively. This points to the serious situation of usage of the prohibited carcinogenic antibiotics in aquaculture. The levels of heavy metals in the shrimp samples were found to be negligible making them safe for human consumption. Comparatively higher levels of heavy metals were present in the sediment and lower levels in water samples. Most of the water quality parameters were within a normal range prescribed for shrimp culture.