Pesquisa de metais pesados em peixes-bois marinhos (Trichechus manatus manatus Linnaeus, 1758)

Abstract

This study analyzed for the serum concentration of heavy metal cadmium (Cd), lead (Pb), copper (Cu) and chromium (Cr) in blood samples from 66 manatees (Trichechus manatus manatus) sound, both sexes (25 males and 41 females) kept under captive conditions in Brazil. The animals were classified according to age: neonate (≤ 30 days); puppy (31-730 days); youth (731-2190 days) and adult (> 2191 days). Blood was collected and then centrifuged to obtain serum, and subsequently digested in nitric acid and then subjected to a thermostated bath at 90°C for a period of one hour. For the quantification of the metals employed to Spectrometry Optical Emission Inductively Coupled Plasma (ICP OES). Among the 66 serum samples tested, 100% had levels of at least one of the metals, and only 7.57% submitted to simultaneous concentration (Cu), (Cd) and (Cr). There was no correlation between the serum concentration of metals and the variables: sex, age and environment. For the analysis of lead (Pb), the samples had concentrations outside the detection limit, thus were not evaluated statistically. The concentrations of heavy metals found in this study were higher than those reported in other studies. Among the possible sources of contamination various human activities are among the priorities. These results raise concerns regarding the health of animals and the means which are inserted. However the study of target specimen, according to their characteristics, proved efficient as a sentinel species. Additional researches regarding metal bioaccumulation in sirenians and in the environmentare required.