Estudo ecotoxicológico do biocida antiincrustante DCOIT (SEA-NINE™) em invertebrados marinhos neotropicais
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Data
2022-03-11
Autores
Campos, Bruno Galvão de
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Universidade Estadual Paulista (Unesp)
Resumo
Após a proibição das tintas anti-incrustantes à base de tributilestanho, o DCOIT (4,5-Dicloro-2- octilisotiazol-3(2H)-ona) tornou-se um dos biocidas anti-incrustantes mais utilizados. Além de ser considerado um contaminante pseudopersistente em áreas com alto tráfego de embarcações e tóxico para espécies não-alvo, a bioacumulação e a transferência trófica de DCOIT em organismos marinhos permanece desconhecido. O presente estudo está dividido em três capítulos que: I) apresentam, como revisão crítica, uma compilação de dados toxicológicos e ambientais dos biocidas mais comuns, e usa essas informações para uma avaliação de risco ecológico (ERA) dos 11 biocidas anti-incrustantes aprovados pela UE (PT21), que indicaram que DCOIT, diuron, diclofluanida, clorotalonil, CuSCN, Cu2O, medetomidina e zineb representam risco para ecossistemas costeiros. II) avaliou a degradação de DCOIT, Irgarol, Diuron e Diclofluanida durante uma fase de equilíbrio de sedimentos de 24 horas em três tempos e concentrações através de modelos de degradação cinética, resultando nas seguintes meias-vidas: DCOIT e Diuron: < 5 h; diclofluanida < 2 h; e Irgarol < 6h. Os resultados também indicaram que exceto diclofluanida, os biocidas anti-incrustantes mostraram que em 6 horas de equilíbrio a taxa de degradação é reduzida drasticamente. III) Investigou os efeitos subletais (bioquímicos, celular e histopatológico) de concentrações ambientalmente relevantes de DCOIT na ostra neotropical Crassostrea brasiliana exposta a concentrações crescentes de DCOIT. este estudo mostrou que o DCOIT causa efeitos negativos sobre C. brasiliana em todos os níveis de organização biológica. IV) Avaliou a toxicidade da água e do sedimento total do DCOIT no seguintes espécies: Perna perna (bivalve), Echinometra lucunter (ouriço-do-mar) Artemia sp (crustáceo), Nitrocra sp (copépode) e Tiburonella viscanna (anfípode). Os dados de toxicidade foram usados para calcular os pontos finais de perigo e risco ambiental que foram comparados com valores obtidos para as espécies temperadas, revelando que os organismos pelágicos tropicais estavam em média 1,7 vezes mais sensível ao DCOIT em comparação com espécies não tropicais. Para sedimentos DCOIT possivelmente apresenta risco na Coréia, Japão, Espanha, Malásia, Indonésia, Vietnã e Brasil. V) Investigou a bioacumulação, biomagnificação e transferência trófica de DCOIT e SiNC-DCOIT (um alternativa de nanoengenharia e menos toxica comaprado com o DCOIT) da microalga Tetraselmis chuii ao mexilhão Mytilus galloprovincialis durante a uptake de 24h e depuração de 72h, o que mostrou que os mexilhões internalizaram e metabolizaram rapidamente tanto DCOIT e SiNC-DCOIT, sendo considerados não bioacumuláveis. No entanto, a exposição via alimentar indicou que DCOIT e SiNC-DCOIT tem capacidade de biomagnificação. VI) avaliou os efeitos subletais de curto e longo prazo de formas nanoestruturadas de biocidas (DCOIT; Ag; SiNC-DCOIT; SiNC-DCOIT Ag) e a nanocápsula “vazia” (SiNC) em juvenis de Crassostrea gigas após 96 h e 14 dias de exposição, indicando que o SiNC-DCOIT apresentou um perfil de toxicidade inferior ao biocida livre. No geral, nossos resultados geraram dados ecotoxicológicos importantes para um contexto que permitirá previsões mais precisas de risco para o ambiente marinho. Os resultados também indicou que as áreas costeiras próximas a portos e marinas são hotspots de contaminação de antiincrustantes sendo considerados os locais mais ameaçados, exigindo, portanto, um controle rigoroso das taxas de liberação e regulamentação rigorosa sobre essas áreas
After the ban on the tributyltin-based antifouling paints, DCOIT (4,5-Dichloro-2- octylisothiazol-3(2H)-one) has become one of the most used antifouling biocide. Besides being considered a pseudo persistent contaminant in areas with Hight traffic of vessels and toxic to non-target species, the bioaccumulation and trophic transfer of DCOIT in marine organisms remains unknown. The present study is divided into three chapters which: I) presented, as a critical review, a comprehensive compilation of toxicological and environmental data of the more commons biocides, and further used such information in an ecological risk assessment (ERA) of the 11 EU approved antifouling biocides (PT21), which indicated that DCOIT, diuron, dichlofluanid, chlorothalonil, CuSCN, Cu2O, medetomidine, and zineb pose risk for the coastal ecosystems. II) evaluated the degradation of DCOIT, Irgarol, Diuron, and Dichlofluanid during a sediment spiking equilibrium phase of 24 hours in three different time points and concentrations through kinetic degradation models, resulting in the following half-lives: DCOIT and Diuron: < 5 h; dichlofluanid < 2 h; and Irgarol < 6h. The results also indicated that apart from dichlofluanid, the antifouling biocides have shown that in 6 hours of equilibrium the rate of degradation is reduced dramatically. III) Investigated the sublethal effects (biochemical, cellular, and histopathological) of environmentally relevant concentrations of DCOIT on the neotropical oyster Crassostrea brasiliana exposed to increasing concentrations of DCOIT. This study showed that DCOIT causes negative effects on C. brasiliana at all analyzed levels of biological organization. IV) Evaluated the water and whole sediment toxicity of DCOIT in the following species: Perna perna (bivalve), Echinometra lucunter (sea-urchin) Artemia sp (crustacean), Nitrocra sp (copepod) and Tiburonella viscanna (amphipod). The toxicity data were used to calculate endpoints of environmental hazard and risk which were compared to values obtained for temperate species, revealing that tropical pelagic organisms were in avarage 1.7-fold more sensitive to DCOIT compared to non-tropical species. For sediment, based on the environmental concentrations and toxic thresholds, DCOIT possibly presents environmental risk in Korea, Japan, Spain, Malaysia, Indonesia, Vietnam, and Brazil. V) Investigated the bioaccumulation, biomagnification, and trophic transfer of DCOIT and SiNC-DCOIT (a nanoengineered and environmentally friendly alternative of DCOIT) from the marine microalgae Tetraselmis chuii to the mussel Mytilus galloprovincialis during uptake of 24h and depuration of 72h, which showed that the mussels rapidly internalized and metabolized both DCOIT and SiNC-DCOIT, being considered non-bioaccumulative. Yet, food exposure treatment indicated that DCOIT and SiNC-DCOIT can transfer up a food chain with biomagnification capabilities. VI) assessed short and long-term sub-lethal effects of nanostructured and soluble forms of AF biocides (DCOIT; Ag; SiNC-DCOIT; SiNC-DCOIT Ag) and the “empty” nanocapsule (SiNC) on juveniles of Crassostrea gigas after 96 h and 14 days of exposure, indicating that the SiNC-DCOIT presented a lower toxicity profile compared to the free biocide. Overall our results generated important ecotoxicological data for regulatory context that will enable more accurate predictions of risk to the marine environment. The results also indicated that coastal areas close to ports and marinas are hotspots of antifouling contamination being considered the most threatened locations, thus requiring rigorous control of the release rates and strict regulation on these areas
After the ban on the tributyltin-based antifouling paints, DCOIT (4,5-Dichloro-2- octylisothiazol-3(2H)-one) has become one of the most used antifouling biocide. Besides being considered a pseudo persistent contaminant in areas with Hight traffic of vessels and toxic to non-target species, the bioaccumulation and trophic transfer of DCOIT in marine organisms remains unknown. The present study is divided into three chapters which: I) presented, as a critical review, a comprehensive compilation of toxicological and environmental data of the more commons biocides, and further used such information in an ecological risk assessment (ERA) of the 11 EU approved antifouling biocides (PT21), which indicated that DCOIT, diuron, dichlofluanid, chlorothalonil, CuSCN, Cu2O, medetomidine, and zineb pose risk for the coastal ecosystems. II) evaluated the degradation of DCOIT, Irgarol, Diuron, and Dichlofluanid during a sediment spiking equilibrium phase of 24 hours in three different time points and concentrations through kinetic degradation models, resulting in the following half-lives: DCOIT and Diuron: < 5 h; dichlofluanid < 2 h; and Irgarol < 6h. The results also indicated that apart from dichlofluanid, the antifouling biocides have shown that in 6 hours of equilibrium the rate of degradation is reduced dramatically. III) Investigated the sublethal effects (biochemical, cellular, and histopathological) of environmentally relevant concentrations of DCOIT on the neotropical oyster Crassostrea brasiliana exposed to increasing concentrations of DCOIT. This study showed that DCOIT causes negative effects on C. brasiliana at all analyzed levels of biological organization. IV) Evaluated the water and whole sediment toxicity of DCOIT in the following species: Perna perna (bivalve), Echinometra lucunter (sea-urchin) Artemia sp (crustacean), Nitrocra sp (copepod) and Tiburonella viscanna (amphipod). The toxicity data were used to calculate endpoints of environmental hazard and risk which were compared to values obtained for temperate species, revealing that tropical pelagic organisms were in avarage 1.7-fold more sensitive to DCOIT compared to non-tropical species. For sediment, based on the environmental concentrations and toxic thresholds, DCOIT possibly presents environmental risk in Korea, Japan, Spain, Malaysia, Indonesia, Vietnam, and Brazil. V) Investigated the bioaccumulation, biomagnification, and trophic transfer of DCOIT and SiNC-DCOIT (a nanoengineered and environmentally friendly alternative of DCOIT) from the marine microalgae Tetraselmis chuii to the mussel Mytilus galloprovincialis during uptake of 24h and depuration of 72h, which showed that the mussels rapidly internalized and metabolized both DCOIT and SiNC-DCOIT, being considered non-bioaccumulative. Yet, food exposure treatment indicated that DCOIT and SiNC-DCOIT can transfer up a food chain with biomagnification capabilities. VI) assessed short and long-term sub-lethal effects of nanostructured and soluble forms of AF biocides (DCOIT; Ag; SiNC-DCOIT; SiNC-DCOIT Ag) and the “empty” nanocapsule (SiNC) on juveniles of Crassostrea gigas after 96 h and 14 days of exposure, indicating that the SiNC-DCOIT presented a lower toxicity profile compared to the free biocide. Overall our results generated important ecotoxicological data for regulatory context that will enable more accurate predictions of risk to the marine environment. The results also indicated that coastal areas close to ports and marinas are hotspots of antifouling contamination being considered the most threatened locations, thus requiring rigorous control of the release rates and strict regulation on these areas
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Palavras-chave
DCOIT, Antifouliing, Biocides, Biaccumulation, Toxiciy, ERA, Hazzard