Veri¿cação da contaminação por dimetoato e aldicarb em fígado de tilápias do Nilo ( Oreochromis niloticus) coletados em dois frigorí¿cos do Estado do Paraná Veri¿cation of contamination by dimetoato and aldicarb in liver of Nile tilapias (Oreochromis niloticus) collected in two cold-storages in the State of Paraná

The importance of ?sh as a protein source in food is unquestionable, but its role as an indicator of environmental contamination is also very important. This study aimed to analysis the livers of Nile tilapia ( Oreochromis niloticus ), collected from commercial cold-storages in two municipal districts in the State of Parana, for investigation of contamination by organophosphorus compounds and carbamates. It was collected 30 samples of Nile tilapias ( O. niloticus ) liver in the cold-storage A and 45 samples in the cold-storage B, totaling 75 samples. At each location were three visits, and at random, collected the samples from July 2006 to May 2007. For extraction and analysis of samples it was used the qualitative