Determination of cadmium and lead in cetacean Dolphinidae tissue from the coast of Bahia state in Brazil by GFAAS

Abstract

In the present study, cadmium and lead in the muscle, lung, liver and kidney of dolphins (Sotalia guianensis and Stenella clymene) of the Bahia coast in the northwest of Brazil were determined by graphite furnace atomic absorption spectrometry. Samples were digested using a diluted oxidant mixture (HNO3+H2O2) with a microwave heating programperformed in five steps. The optimized temperatures and chemicalmodifier for the pyrolysis and atomizationwere 700 °C, 1400 °C and Pd plus Mg for Cd, and 900 °C, 1800 °C and NH4H2PO4 for Pb, respectively. Characteristic masses and limits of detections (n=20, 3σ) for Cd and Pb were 1.6 and 9.0 pg and 0.82 ng g−1 and 0.50 ng g−1, respectively. Repeatability ranged from0.87 to 8.22% for Cd and 4.31 to 8.09% for Pb.The found concentrations presented no statistical differences at the 95% confidence level when compared with the ICP OES methods. Addition and recovery tests were also performed and the results ranged between 87 and 112% for both elements. Samples of cetacean Dolphinidae (S. guianensis and S. clymene) were analyzed, and the higher concentrations ranged from 0.09 to 46.2 μg g−1 for Cd and 0.04 to 0.47 μg g−1 for Pb in liver, and from 0.133 to 277 μg g−1 for Cd in the kidney.