Navegando por Palavras-chave "Anti-incrustante"

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    Áreas marinhas protegidas da América do Sul sob ameaça do tributilestanho (TBT)
    (Universidade Federal de São Paulo, 2017-12-15) Machado, Fabiano Bender [UNIFESP]; Castro, Ítalo Braga [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    The tributyltin (TBT) is a compound used in marine antifouling systems since the 1960’s. It is a hazardous chemical presenting high environmental toxicity and responsible for inducing imposex in more than 250 gastropod species molluscs. Banned worldwide in 2008, but is still used in small vessels and its effects have been detected over the last years in Marine Protected Areas (MPA). The present study evaluated, based on available literature data and in a case study if MPAs from South American coast are under threat of TBT contamination.To do so, a georeferenced database was constructed with data published in 55 scientific review papers (published between 2002 and 2017) that evaluated this type of contamination in the coastal zones of South America. These data were overlaid with data from the World Database Protected Areas (WDPA), showing TBT contamination and imposex incidence in 54 marine MPAs between the years 2002 and 2017. Among these areas, there are MPAs from different categories located in Argentina, Brazil, Chile, Ecuador and Venezuela. These observations indicate a worrying situation regarding the protection of the South American protected areas against the impacts caused by environmental inputs of hazardous chemical substances. In the second phase of the study, a case study aimed at assessing the impacts of TBT was performed through the collection and analysis of the presence of imposex in individuals of Stramonita brasiliensis. In this study, 16 out of 17 sampled sites evaluated inside Environmental Protected Areas from north and central coast of São Paulo state presented evidence of imposex incidence. Although the imposex levels detected in these areas have been low, they are indicative of local contamination by TBT, probably used in naval antifouling systems of small vessels. Considering that MPAs are designed to protect natural resources, the results of the present study indicate that the objectives of South American MPAs may be compromised. Therefore, changes in legislation regulating the use of TBT in ships, regulation of navigation in MPAs, and a policy that considers the chemical risks to which MPAs are exposed should contribute to preventing and / or reducing such threat.
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    Desenvolvimento de uma metodologia eletroanalítica para a determinação de pesticida anti-incrustante diuron em ambiente marinho
    (Universidade Federal de São Paulo, 2017-10-30) Morita, Isabela Miyahira [UNIFESP]; Simões, Fabio Ruiz [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    Considering the history of environmental impacts caused by antifouling contamination, it is necessary to monitor these biocides, among them the pesticide Diuron. In this bias the electroanalysis brings advantages such as fast readings and possibility of portability and in situ application of its systems. Furthermore, its association with carbon nanotubes (CNT) for sensor modification makes it possible to increase the sensitivity and selectivity of the methods. This work aimed to develop an electroanalytical methodology for the determination of Diuron in seawater with the aid of the techniques of cyclic voltammetry (CV), square wave voltammetry (SWV) and differential pulse voltammetry (DPV) with a glassy carbon electrode (GCE) modified with layers of a dispersion of functionalized MWCNTs, applied by casting. The qualitative studies, carried out by CV, aimed the identification and study of the oxidation process of Diuron. For the quantitative analyzes, performed by SWV and DPV, the parameters of each technique were optimized and the best number of MWCNT layers for GCE modification was studied. The calibration curves were delimited by standard addition and the LOD and LOQ of each technique were determined. The methodology developed by DPV GCE-MWCNT electrode - most sensitive - achieved LOD = 1.96 x 10-7 mol L-1 and LOQ = 6.53 x 10-7 mol L-1, results comparable to other methodologies described in literature. The applicability of the method was ascertained by two seawater recovery tests (76% and 124% recovery).
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    Efeitos da exposição simultânea ao biocida DCOIT e acidificação marinha sobre o anfípode escavador Tiburonella viscana
    (Universidade Federal de São Paulo, 2024-05-28) Mandelli, Wanessa Gentil [UNIFESP]; Moreira, Lucas Buruaem [UNIFESP]; Choueri, Rodrigo Brasil [UNIFESP]; http://lattes.cnpq.br/0408418557980214; http://lattes.cnpq.br/8251258719894689; http://lattes.cnpq.br/5209075236705771; Universidade Federal de São Paulo (UNIFESP)
    O aumento das concentrações de CO2 (dióxido de carbono) leva a dissociação de íons de hidrogênio, e portanto ao fenômeno de acidificação marinha. De acordo com os cenários projetados pelo Painel Intergovernamental sobre Mudanças Climáticas (IPCC) a acidificação pode ocasionar uma redução de 0,3 a 0,4 unidades nos valores de pH da superfície do oceano até o final do século. Outro fator que atua na redução da biodiversidade marinha é a introdução de resíduos químicos pelas atividades humanas. Na atividade de navegação, para a prevenção do problema de colonização de estruturas submersas, incluindo cascos de embarcações, por organismos incrustantes, as superfícies são revestidas por tintas especiais a fim de formar um filme para evitar o assentamento de organismos, chamadas tinta anti-incrustantes. Essas tintas agravam a problemática da poluição marinha, uma vez que têm substâncias biocidas na sua formulação. O biocida anti-incrustante DCOIT, é utilizado principalmente pela sua rápida degradação no ambiente marinho, entretanto os resíduos dessa substância já foram encontrados em matrizes ambientais de várias localidades do mundo. O DCOIT apresenta alta hidrofobicidade e lipofilicidade, tendo o sedimento como seu destino final. O objetivo do presente estudo foi determinar, de forma combinada, os efeitos tóxicos do DCOIT em cenários de acidificação marinha utilizando a resposta de biomarcadores do anfípodo escavador Tiburonella viscana como parâmetro de efeitos subletais em exposições de fase sólida. As concentrações crescentes de DCOIT causaram inibição da resposta da GST, AChE e dano em DNA nos pHs 7,7 e 7,4. Para LPO, houve aumento na resposta para o pH intermediário. Este estudo também mostrou evidências da ação oxidativa e genotóxica do DCOIT, e dos mecanismos de desintoxicação e defesa do T. viscana. Espera-se que os resultados gerados por este estudo gerem informações sobre os riscos ecológicos associados a essa substância num cenário de mudanças climáticas e que possam auxiliar no seu monitoramento, gestão e controle.
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    Influência dos teores de carbono orgânico na toxicidade do irgarol sobre comunidades meiofaunais
    (Universidade Federal de São Paulo, 2017-04-27) Silva, Cecilia Simon da [UNIFESP]; Castro, Ítalo Braga [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    After the international ban of Tributyltin-based antifouling paints, Irgarol 1051 has become one of the most used biocide in naval paints. Because its high affinity for particulate matter, this compound tends to accumulate in the sediments and may produce deleterious effects on benthic organisms. Considering the partition coefficient with total organic carbon (TOC), the bioavailability of Irgarol can be influenced by the TOC amounts in sediment samples. Thus, the present study aimed to experimentally evaluate the influence of TOC levels on Irgarol toxicity over the structure of meiofaunal communities. Sediment samples, Rich (SR) and Poor in TOC (SP) were collected in the sub-tidal zones from Itaguaré Beach (Bertioga-SP) and used to set up a microcosm experiment including control groups (control and acetone control) and different spike levels (high, medium and low) of Irgarol. Considering the univariate results, total meiofauna and nematode densities were lower in SP compared to SR but it did not differ between contaminated and control treatments . Tardigrade densities decreased in contaminated treatments only in SP, while Ostracoda densities were lower in the contaminated treatments of both sediment types. The multivariate structure of the fauna presented a genus-specific response of the nematode assemblages to contamination and this response diferred between SP and SR. After 7 days of exposure, there was a decrease in the densities of Sabatieria sp. and Viscosia sp. After 35 days no differences were observed between treatments and each microcosm developed in a singular way. SR showed a delayed response, since only after 35 days it was possible to detect differences in the structure ofby the increase in densities of a few nematode genera at low and medium concentrations of Irgarol. In the same treatments, lower densities of the genus Daptonema sp. and Sphaerotheristus sp were observed. The multivariate structure of the meiofauna clearly demonstrated the differential effect of Irgarol on populations of sediments rich and poor in TOC. These results corroborate the hypothesis that the toxicity of Irgarol to meiofauna is influenced by the carbon content of the sediment, probably due to the preferential partitioning of this biocide in TOC rich sediments.
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    Toxicidade de sedimentos contaminados com clorotalonil em laboratório, sobre organismos marinhos
    (Universidade Federal de São Paulo, 2016-10-08) Morais, Lucas Gonçalves [UNIFESP]; Choueri, Rodrigo Brasil [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    Considering that the Chlorothalonil (2,4,5,6-tetracloroisoftalonitrila) has been used in anti-fouling paints, their presence in aquatic environments and the lack of information about their toxicity to marine organisms - especially when associated with sediment - the present study aims to evaluate the toxicity of Chlorothalonil on different marine organisms. Sediment obtained from a reference area were contaminated in laboratory (spiking) in order to comprise environmental concentration ranges which vary between 0.01 μg g -1 and 0.1 μg g-1 in addition a concentration below (0.001 μg g -1) and two concentrations above (1 μg g-1 and 10 μg g-1). Bioassays were performed with: (i) Anomalocardia flexuosa in which biomarkers were analyzed in gills and digestive glands; (ii) Nitocra sp. (fertility); (iii) Tiburonella viscana (mortality); (iv) and Artemia salina (mortality). Data were analyzed using one-way ANOVA and the post hoc Bonferroni, integration of data was performed by a principal component analysis (FA / PCA). The GPX activity increased in the gills, only in the concentration 0.001 μg g-1. In the digestive gland was increased GPX activity at 0.01 μg g-1; 1 μg g-1 and 10 μg g-1. The amount of GSH in digestive gland decreased compared to the control at 0.01 μg g-1 and 0.1 μg g-1. The GST activity was inhibited in gills only in concentration 1 μg g-1. The LPO increased significantly in gills only in concentration 10 μg g-1. In digestive gland increased LPO concentrations occurred in 0.1 μg g-1 and 10 μg g-1. The DNA damage was significant in gills at concentrations of 1 ug g-1 and 10 μg g-1. The study that evaluated reproductive Nitocra sp. It showed that the higher concentration of Chlorothalonil (10 μg g-1) was able to decrease significantly the number of progeny. Studies with aquatic invertebrates showed that Chlorothalonil is able to affect significantly the embryonic development of marine invertebrates, which may suggest a teratogenic effect of biocide. In the trial in viscana T., the concentration of 10 μg g-1 showed a dramatic acute effect, in which could not find any living organism in the first days of exposure. In the test with A. salina, concentration 1 μg g-1 and 10 μg g-1 caused significant acute effect compared to the control, indicating that the contaminated sediment was able to provide the contaminant to the water column. In general, although the effect concentrations are higher than ambient concentrations reported, attention must be paid in respect of that compound in the marine environment because the data Chlorothalonil concentrations in sediments are scarce.