Exposição De Cetáceos a Compostos Butilestânicos: Uma Revisão

Abstract

RESUMODurante as últimas décadas, observou-se um aumento da preocupação em relação aos ecossistemas marinhos devido à grande entrada de poluentes, resultando em efeitos deletérios em organismos aquáticos e seres humanos. Dentre as atividades humanas que podem introduzir compostos tóxicos persistentes e bioacumulativos (PBTs) no ambiente marinho está o uso de tintas anti-incrustrantes, aplicadas nos cascos de navios para evitar que algas, mexilhões e outros organismos se fixem às embarcações. Não raramente, compostos organoestânicos (OTs) como o Tributilestanho (TBT) ou o Trifenilestanho (TPT) constituíam o princípio ativo de tal preparado. Devido à alta toxicidade desses compostos, a IMO (Organização Marítima Internacional), baniu totalmente o uso dos mesmos. Como os OTs são prontamente bioacumulados, elevadas concentrações vêm sendo encontradas em cetáceos. A presente revisão aborda a elevada exposição de mamíferos marinhos aos OTs e a possível influência de parâmetros biológicos, discutindo dados relativos às concentrações hepáticas de diversas espécies de cetáceos em diferentes regiões do globo. Elevados níveis de TBT foram encontrados em cetáceos mesmo após seu banimento, sendo tais altas concentrações observadas principalmente em espécies ocorrentes em países desenvolvidos. Palavras-chave: Agente anti-incrustante; estanho; TBT; toxicidade ABSTRACT CETACEAN EXPOSURE TO BUTYLTIN COMPOUNDS: A REVIEW. During the last decades, the large pollutant input has led to an increased concern over marine ecosystems. This environmental contamination results in deleterious effects on aquatic organisms and humans. Among the anthropogenic activities that may introduce persistent bioaccumulative toxicants (PBTs) into the marine environment is the use of antifouling paint. It is applied on ship hulls and other floating structures to prevent algae, mussels and other organisms to fix on these surfaces. Often, organotin compounds (OTs), such as Tributyltin (TBT) or Triphenyltin (TPT), constitute the active ingredient in these mixtures. Due to the high toxicity of these compounds, the IMO (International Maritime Organization) completely banned their use. As OTs are readily bioaccumulated, high concentrations have been found in cetaceans. This review covers the high marine mammal exposure to OTs and the possible influence of biological parameters. Additionally, data on hepatic OT levels in a number of cetacean species from all over the world are discussed. High TBT levels were found in cetaceans even after the ban. These high concentrations were observed mainly in species from developed countries.

Total tin (TSn) biomagnification: Evaluating organotin trophic flow and dispersion using hepatic TSn concentrations and stable isotope (C, N) data of nektonic organisms from Brazil

“…hair in mammals and feathers in birds) constitutes an elimination route for organometallic compounds (Guruge et al, 1996;Kim et al, 1996a), which increases the importance of analysing dolphin samples for measuring exposure to OTs, as cetaceans do not have hair. The absence of one elimination pathway for OTs in dolphins, associated to their apparent inferior capacity for metabolizing butyl and phenyltins (Tanabe, 1999), generates higher OT concentrations in their tissues in comparison to other mammals (Schilithz et al, 2013).…”

“…The rationale that supported that approach was generated by landmark papers (Hai Le et al, 1999;Takahashi et al, 2000) that demonstrated organotin compounds to be the major contributors to the hepatic tin burden in marine mammals. The approach was also based on the fact that the percentage uptake of inorganic tin species through gastrointestinal mucosa is extremely low in mammals, as well as on the opposite scenario for OTs, i. e., organotin compounds are efficiently absorbed through the same via (Schilithz et al, 2013). In addition, the evaluation of animal exposure to OTs through total tin determination has recently been adopted for fish as well (Zhang et al, 2016).…”