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| Author(s): |
Lucas Aparecido Rosa Leite
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | Botucatu. 2021-11-19. |
| Institution: | Universidade Estadual Paulista (Unesp). Instituto de Biociências. Botucatu |
| Defense date: | 2021-09-08 |
| Advisor: | Vanessa Doro Abdallah Kozlowiski |
| Abstract | |
Preventing environmental impacts that would jeopardize the structuring of the ecosystem. Among the organisms with potential for bioindication, there is a very peculiar and commonly overlooked group in biodiversity studies: parasites. Studies involving parasites and their potential as bioindicators of the environmental health have increased in recent decades, however, in the South American region it is still a little explored field of research. In the present study, the potential of parasites as bioindicators was assessed in two ways: the effect bioindication, and the bioindication of trace metals accumulation in two rivers in the state of São Paulo: the Jacaré-Pepira River and the Jacaré-Guaçú River. In the study with effect bioindication, the variation in the rates of prevalence, abundance, and intensity of five species of the Monogenea class (Gussevia astronoti, Gussevia asota, Anacanthorus serrasalmi, Rhinoxenus piranhus e Amphithecium speirocamarotum) was tested compared to the seasonality (dry and wet season), to the organic and inorganic chemical variables of the rivers waters, and in relation to the condition factors of its fish hosts Serrasalmus maculatus and Astronotus crassipinis. The results showed significant variations in the prevalence, abundance, and intensity rates of some of the monogenetic species tested, with G. asota showing interactions both with the chemical parameters of the water and with de condition factors of the hosts, proving to be the most sensitive species of the five analyzed. In the study with accumulation bioindication, the potential for trace metal accumulation of parasites belonging to three different taxa was evaluated: Cestoda (Proteocephalus macrophalus), Nematoda (Hysterothylacium sp.) and Digenea (Phyllodistomum sp.) parasites of Cichla kelberi and Hoplias malabaricus. The three species showed a high capacity for accumulation, specially cestodes and nematodes. In addition, it has been found that infected fish tend to concentrate less amounts of metals in their tissues than non-infected hosts. In general, our studies show that fish parasites in the Jacaré-Pepira and Jacaré-Guaçú rivers have potential for bioindication and can be used in diagnostic and environmental monitoring studies. In addition, the knowledge related to parasitism and bioindication in the neotropical region further expands. Finally, a study was carried out to assess the risk of contamination by human consumption and bioaccumulation of trace metals in the musculature of H. malabaricus, also from the Jacaré-Pepira and Jacaré-Guaçú rivers, where fish from the Jacaré-Guaçú River have trace metals concentrations significantly higher than those from the Jacaré-Pepira. In addition, in fish from the Jacaré-Guaçú River, the element Al had a hazard quotient (HQ) above 1, which indicates a possible risk of contamination if consumed by humans. Other elements that are worth mentioning are Cr and Cd. Cr was in concentrations much higher than the allowed by the Brazilian legislation, and Cd had a high bioconcentration factor, which may indicate a biomagnification process. (AU) | |
| FAPESP's process: | 17/00566-5 - Fish parasites as bioindicators of heavy metal accumulation in the Jacaré-Pepira and Jacaré-Guaçú rivers, Tietê-Jacaré River Basin, State of São Paulo, Brazil |
| Grantee: | Lucas Aparecido Rosa Leite |
| Support Opportunities: | Scholarships in Brazil - Doctorate |