Perna perna e crassostrea brasiliana como sentinelas da contaminação por microplásticos em zonas costeiras
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Data
2022-10-31
Autores
Ribeiro, Victor Vasques [UNIFESP]
Orientadores
Castro, Ítalo Braga [UNIFESP]
Tipo
Dissertação de mestrado
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Resumo
A poluição marinha é um importante problema ambiental na atualidade, tendo as atividades antropogênicas como fontes histórias de substâncias e materiais potencialmente danosos para o ambiente. Resíduos sólidos, principalmente os plásticos, geram impactos aos ecossistemas, e estudos sobre o tema têm aumentado nos últimos anos. Estima-se que em 2050 haverá mais plástico que peixes nos oceanos, devido a lenta degradabilidade que lhes garante vasta distribuição, até em locais remotos. Microplásticos (MPs) são partículas plásticas com tamanho entre 1 µm e 5 mm, resultantes do processo de degradação de partículas maiores, ou já produzidas nesta faixa de tamanho. De fato, MPs têm sido encontrados associados à tecidos de várias espécies de organismos aquáticos. Nesse sentido, bivalves filtradores são particularmente suscetíveis a acumulá-los em seus tecidos. Dessa forma, ostras e mexilhões parecem ser boas sentinelas da contaminação por MPs, por serem sésseis, apresentarem ampla distribuição geográfica, e responderem fisiologicamente à exposição a contaminantes ambientais. Apesar disso, poucos estudos realizados até o momento avaliaram comparativamente a performance de diferentes espécies de bivalves no que tange a seu emprego em monitoramentos ambientais. O Sistema Estuarino de Santos (SES) está sob a influência de aportes de resíduos oriundos de diversas indústrias, além de abrigar um relevante complexo portuário para a América Latina. Costões rochosos do SES abrigam bancos naturais de Perna perna e Crassostrea brasiliana, cronicamente expostos a um gradiente de contaminação. Com base neste cenário, hipotetizamos que diferenças qualitativas e quantitativas no acúmulo de MPs podem ser detectadas entre estas espécies. Assim, o presente estudo avaliou comparativamente o acúmulo de MPs considerando as concentrações totais, forma, tamanho e composição polimérica em ostras e mexilhões expostos à diferentes níveis de contaminação no SES. Foram encontrados 2.534 MPs associadas ao tecido dos bivalves C. brasiliana e P. perna no SES. Os organismos obtidos no ponto mais contaminado (S1) foram os que apresentaram os piores estados de nutrição e saúde. Além disso, a concentração de MPs em bivalves de S1 estão entre os mais altos já reportados para moluscos até o presente momento (até 44,1 itens.g -1). Os MPs amostrados eram compostos principalmente de Celulose e polimetilmetacrilato (PMMA). Além disso, MPs foram principalmente < 1.000 µm (67,6%), fibras (97,3%) e sem coloração (87%). A avaliação espacial da distribuição de MPs em ostras e mexilhões do SES confirmou a presença de um gradiente de contaminação que já fora identificado por outros estudos de monitoramento da contaminação ambiental. As ostras apresentaram estado de nutrição e saúde mais consistente ao longo do gradiente de contaminação, além de acumularem uma maior diversidade de polímeros e mais MPs em pontos de amostragem sob menor pressão antropogênica. Entretanto, as duas espécies foram igualmente capazes de diagnosticar diferenças espaciais na concentração de MPs assim como os tipos mais frequentes de polímeros, classes de tamanho, forma e cor. Portanto, as duas espécies apresentam alto nível de equivalência quando usadas como sentinelas da contaminação por MP, apesar de algumas diferenças interespecíficas. Nossa abordagem pode servir como um guia valioso para selecionar espécies com bom desempenho para serem utilizadas em programas de monitoramento ambiental nas perspectivas local e global.
Currently marine pollution is an important environmental issue, with anthropogenic activities and historical sources of residues and contaminants potentially harmful to natural areas. Solid waste, especially plastics, generate impacts on ecosystems, and studies on the subject have increased in recent years. It is estimated that by 2050 there will be more plastic than fish in the oceans, due to the slow degradability contributing to their wide distribution, even in remote zones. Microplastics (MPs) are plastic particles measuring between 1 µm and 5 mm, resulting from the degradation process of larger particles, or already produced in this size range. In fact, MPs has been found associated to tissues ofseveral species of aquatic organisms. In this sense, filter-feeding bivalves are particularly sensitive to accumulating them in their tissues. Thus, oysters and mussels seem to be good sentinels of MPs contamination, as they are sessile, have a wide geographic distribution, and respond physiologically to exposure to environmental contaminants. Despite this, few studies carried out to date have comparatively evaluated the performance of different species of bivalves in terms of their use in environmental monitoring. The Santos Estuarine System (SES) is under the influence of inputs of waste from various industries, in addition to housing a relevant port complex for Latin America. Rocky shores of the SES harbor natural banks of Perna perna and Crassostrea brasiliana, chronically exposed to a contamination gradient. Based on this scenario, we hypothesized that qualitative and quantitative differences in MPs accumulation can be detected in these species. Thus, the present study comparatively evaluated the MPs accumulation considering the total concentrations, shape, size and polymeric composition in oysters and mussels exposed to different levels of contamination in SES. We found 2,534 MPs associated to tissue of C. braziliana and P. perna. The organisms obtained at the most contaminated site (S1) presented the worst nutritional and health conditions. Furthermore, the MPs concentration in bivalves from S1 are among the highest ever reported for molluscs to date (up to 44.1 particles.g -1). The MPs found were mainly composed of Cellulose and polymethyl methacrylate (PMMA). In addition, MPs were mostly < 1,000 µm (67.6%), fiber (97.3%) and colorless (87%). The spatial assessment of the MPs distribution in the SES confirmed the presence of a contamination gradient that had already been identified by previous environmental monitoring studies. The oysters showed more consistent nutrition and health status along the contamination gradient, in addition to accumulating a greater diversity of polymers and more MPs at sampling sites under lower anthropogenic pressure. However, the two species were equally able of diagnosing spatial differences in the MPs concentration and the most common types of polymers and size, shape and color classes. Therefore, a high level of equivalence between oysters and mussels can be expected in monitoring studies of MPs contamination, despite some interspecific differences. Our approach can serve as a valuable guide for selecting well-performing species for use in environmental monitoring programs from local and global perspective.
Currently marine pollution is an important environmental issue, with anthropogenic activities and historical sources of residues and contaminants potentially harmful to natural areas. Solid waste, especially plastics, generate impacts on ecosystems, and studies on the subject have increased in recent years. It is estimated that by 2050 there will be more plastic than fish in the oceans, due to the slow degradability contributing to their wide distribution, even in remote zones. Microplastics (MPs) are plastic particles measuring between 1 µm and 5 mm, resulting from the degradation process of larger particles, or already produced in this size range. In fact, MPs has been found associated to tissues ofseveral species of aquatic organisms. In this sense, filter-feeding bivalves are particularly sensitive to accumulating them in their tissues. Thus, oysters and mussels seem to be good sentinels of MPs contamination, as they are sessile, have a wide geographic distribution, and respond physiologically to exposure to environmental contaminants. Despite this, few studies carried out to date have comparatively evaluated the performance of different species of bivalves in terms of their use in environmental monitoring. The Santos Estuarine System (SES) is under the influence of inputs of waste from various industries, in addition to housing a relevant port complex for Latin America. Rocky shores of the SES harbor natural banks of Perna perna and Crassostrea brasiliana, chronically exposed to a contamination gradient. Based on this scenario, we hypothesized that qualitative and quantitative differences in MPs accumulation can be detected in these species. Thus, the present study comparatively evaluated the MPs accumulation considering the total concentrations, shape, size and polymeric composition in oysters and mussels exposed to different levels of contamination in SES. We found 2,534 MPs associated to tissue of C. braziliana and P. perna. The organisms obtained at the most contaminated site (S1) presented the worst nutritional and health conditions. Furthermore, the MPs concentration in bivalves from S1 are among the highest ever reported for molluscs to date (up to 44.1 particles.g -1). The MPs found were mainly composed of Cellulose and polymethyl methacrylate (PMMA). In addition, MPs were mostly < 1,000 µm (67.6%), fiber (97.3%) and colorless (87%). The spatial assessment of the MPs distribution in the SES confirmed the presence of a contamination gradient that had already been identified by previous environmental monitoring studies. The oysters showed more consistent nutrition and health status along the contamination gradient, in addition to accumulating a greater diversity of polymers and more MPs at sampling sites under lower anthropogenic pressure. However, the two species were equally able of diagnosing spatial differences in the MPs concentration and the most common types of polymers and size, shape and color classes. Therefore, a high level of equivalence between oysters and mussels can be expected in monitoring studies of MPs contamination, despite some interspecific differences. Our approach can serve as a valuable guide for selecting well-performing species for use in environmental monitoring programs from local and global perspective.
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Citação
RIBEIRO, Victor Vasques. Perna perna e crassostrea brasiliana como sentinelas da contaminação por microplásticos em zonas costeiras. 2022. 56 f. Dissertação (Mestrado em Biodiversidade Marinha e Costeira) - Instituto do Mar, Universidade Federal de São Paulo, Santos, 2022.