Eficácia biológica e feitos tóxicos de fontes de cobre e diquat para organismos aquáticos
Carregando...
Data
2016-04-01
Autores
Malaspina, Igor Cruz [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Estadual Paulista (Unesp)
Resumo
As macrófitas aquáticas possuem papel fundamental nos ecossistemas aquáticos participando dos processos de ciclagem de nutrientes, além de servirem como abrigo e alimento para muitas espécies de peixes e outros organismos. Dentre os principais métodos de controle de macrófitas está o controle químico com o uso de herbicidas. O objetivo deste estudo foi realizar o controle químico da macrófita Hydrilla verticillata com a aplicação isolada de diquat e hidróxido de cobre, e da mistura de diquat + 1% de hidróxido de cobre. O primeiro experimento para o controle da H. verticillata e da microalga Ankistrodesmus gracilis foi realizado em sala de bioensaio em recipientes plásticos de 1,5 litros, sendo todos os tratamentos testados eficientes no controle da macrófita e da microalga. Posteriormente, foram realizados experimentos em condições de microcosmos de concreto de 600 litros e em mesocosmos de concreto de 1200 litros, com o monitoramento de variáveis da qualidade da água (temperatura, oxigênio dissolvido, condutividade elétrica e pH), teor de clorofila a, demanda biológica de oxigênio (DBO) e demanda química de oxigênio (DQO) por um período de sessenta dias após a aplicação dos tratamentos. A mistura de diquat + 1% de hidróxido de cobre foi o tratamento mais eficaz no controle da macrófita Hydrilla verticillata para a maioria dos parâmetros analisados, havendo alteração nas variáveis de qualidade da água. Foram também realizados experimentos ecotoxicológicos para organismos não-alvo (Hyphessobrycon eques, Pomacea canaliculata, Lemna minor e Azolla caroliniana) com diquat, oxicloreto e hidróxido de cobre, onde a mistura de diquat + 1% de oxicloreto de cobre foi a mais tóxica para os organismos bioindicadores e a macrófita Lemna minor foi o bioindicador que apresentou a maior sensibilidade aos agroquímicos testados.
The macrophytes have a fundamental role in aquatic ecosystems participating in nutrient cycling processes, as well as serving as shelter and food for many species of fish and other organisms. Among the main weeds control methods is chemical control using herbicides. The aim of this study was the chemical control of the macrophyte Hydrilla verticillata with isolated application of diquat and copper hydroxide, and the mixture of diquat + 1% copper hydroxide. The first experiment for the control of H. verticillata and microalgae Ankistrodesmus gracilis was held in bioassay room in plastic containers of 1.5 liters, with all treatments tested effective in controlling macrophyte and microalgae. Subsequently, experiments were carried out under conditions of 600 liters concrete microcosms and in 1200 liters concrete mesocosms, with the monitoring of water quality variables (temperature, dissolved oxygen, electrical conductivity and pH), content chlorophyll a, demand biological oxygen (BOD) and chemical oxygen demand (COD) for a period of sixty days after the application of treatments. The mixture diquat + 1% copper hydroxide was the most effective treatment in Hydrilla verticillata of weed control for the majority of parameters, with change in water quality variables. Ecotoxicological experiments were also carried out for non-target organisms (Hyphessobrycon eques, Pomacea canaliculata, Lemna minor and Azolla caroliniana) with diquat, oxychloride and copper hydroxide, wherein the mixture of diquat + 1% copper oxychloride is more toxic to bioindicators organisms and macrophyte Lemna minor was bioindicador with the highest sensitivity to the tested pesticides.
The macrophytes have a fundamental role in aquatic ecosystems participating in nutrient cycling processes, as well as serving as shelter and food for many species of fish and other organisms. Among the main weeds control methods is chemical control using herbicides. The aim of this study was the chemical control of the macrophyte Hydrilla verticillata with isolated application of diquat and copper hydroxide, and the mixture of diquat + 1% copper hydroxide. The first experiment for the control of H. verticillata and microalgae Ankistrodesmus gracilis was held in bioassay room in plastic containers of 1.5 liters, with all treatments tested effective in controlling macrophyte and microalgae. Subsequently, experiments were carried out under conditions of 600 liters concrete microcosms and in 1200 liters concrete mesocosms, with the monitoring of water quality variables (temperature, dissolved oxygen, electrical conductivity and pH), content chlorophyll a, demand biological oxygen (BOD) and chemical oxygen demand (COD) for a period of sixty days after the application of treatments. The mixture diquat + 1% copper hydroxide was the most effective treatment in Hydrilla verticillata of weed control for the majority of parameters, with change in water quality variables. Ecotoxicological experiments were also carried out for non-target organisms (Hyphessobrycon eques, Pomacea canaliculata, Lemna minor and Azolla caroliniana) with diquat, oxychloride and copper hydroxide, wherein the mixture of diquat + 1% copper oxychloride is more toxic to bioindicators organisms and macrophyte Lemna minor was bioindicador with the highest sensitivity to the tested pesticides.
Descrição
Palavras-chave
Hydrilla verticillata, Ecotoxicologia, Macrófita, Ecotoxicologyen, Hydrilla verticillata, Macrophyte