Análise de metais pesados da herpetofauna aquática (crocodilya e testudines) em um ambiente lêntico de mata atlântica, Nordeste do Brasil

Abstract

Chemical pollution has been a recurring problem due to the great damage that generates environmental health. Testudines and Crocodilians are singled out as good biomonitors, bringing relevant information about levels of contamination in aquatic environments. The main objective of this study was to detect the levels of heavy metals (Al, Cd, Cu, Cr, Pb, Mn, Zn, Fe and Ni) in blood of Testudines and Crocodilians captured between 2014-2018 in a reservoir in the state of Pernambuco and concomitantly to obtain a current diagnosis on the procedures adopted in the analyzes of heavy metals that use these animals in an interval of ten years. The animals were captured and information on size and sex were collected as well as biological material. The blood was digested in HNO3, after which the samples were read on the ICP-OES and FAAS equipment. 40 samples of Testudines (Kinosternon scorpioides, Phrynops geoffroanus, Mesoclemmys tuberculata) and 40 Crocodilians (Caiman latirostris) were analyzed. Alligators presented the highest levels in all elements in relation to the Testudines. The relationship between size and concentration was significant only for Testudines in the Fe, Cu and Pb elements (p <0,05); in Crocodilians this relation was identified when comparing two of the three age groups for Al (p = 0,0569), being the other elements not significant. Sex did not influence the concentrations in both taxa (p> 0,05). Significant differences between concentration and the three species of Testudines studied were observed only for Cu (p = 0,0240) and Fe (p = 0,0196), in which M. tuberculata had higher concentrations (5,01 mg / L and 105,50 mg / L respectively). Pearson's correlation test showed high correlations between Cr and Ni (R = 0,98), Cd and Cr (R = 0,95), Pb and Ni (R = 0,94), Cd and Pb (R = 0,93), Pb and Cr (R = 0,93), Cd and Ni (R = 0,92). Regarding the second chapter, 37 articles were analyzed regarding the heavy metals theme in aquatic herpetofauna. The most used specimens in these studies were the Alligator mississipiensis (Crocodililya) and Podocnemideos (Amazon Testudines). Hg (12,5%) was the most studied element in biological samples such as blood (29%) and muscle (22,5%). Samples are mostly sampled in FAAS (52%) by Vapor-Frio (CVASF) (54,5%). It is concluded that although the animals do not exhibit clinical symptoms of intoxication, they present worrying levels of heavy metals that can reflect in the communities that make use of the spring. In addition, blood proved to be a good predictor of acute contamination and should be used as a noninvasive model in monitoring studies.