Prediction of a low-risk concentration of diflubenzuron to aquatic organisms and evaluation of clay and gravel in reducing the toxicity.

Resumo: Predição da concentração de baixo risco de diflubenzuron para organismos aquáticos e avaliação da argila e brita na redução da toxicidade. O diflubenzuron é um inseticida que além de ser usado agricultura, tem sido amplamente empregado na piscicultura, apesar do seu uso ser proibido nesta atividade. Este composto não consta na lista da legislação brasileira que estabelece limites máximos permissíveis em corpos de água para a proteção das comunidades aquáticas. No presente trabalho, a partir da toxicidade do diflubenzuron em organismos não-alvo, foi calculada a concentração de risco para somente 5% das espécies (HC5). O valor deste parâmetro foi estimado em aproximadamente 7 x 10-6 mg L-1 . Este baixo valor é devido à extremamente alta toxicidade do diflubenzuron para dafnídeos e à grande variação de sensibilidade entre as espécies testadas. Dois matérias de relativamente baixo custo se mostraram eficientes na remoção da toxicidade do diflubenzuron de soluções contendo este composto. Dentre esses materiais, a argila expandida promoveu a redução em aproximadamente 50% da toxicidade de uma solução contendo diflubenzuron. Os resultados podem contribuir para políticas públicas no Brasil relacionadas ao estabelecimento de limites máximos permissíveis de xenobióticos no compartimento aquático. Também, para a pesquisa de matérias inertes e de baixo custo com potencial de remoção de xenobióticos presentes em efluentes da aquicultura ou da agricultura. Abstract: Diflubenzuron is an insecticide that, besides being used in the agriculture, has been widely used in fish farming. However, its use is prohibited in this activity. Diflubenzuron is not in the list of Brazilian legislation establishing maximum permissible limits in water bodies for the protection of aquatic communities. In this paper, according toxicity data of diflubenzuron in non-target organisms, it was calculated an hazardous concentration for only 5% of the species (HC5) of the aquatic community. This parameter value was estimated to be about 7 x 10 -6 mg L -1 . The low value is due to the extreme high toxicity of diflubenzuron to daphnids and to the large variation in sensitivity among the species tested. Two relatively low cost and inert materials were efficient in removing the diflubenzuron from solutions containing this compound. Among these materials, expanded clay shown to promote reduction of approximately 50% of the toxicity of a solution containing diflubenzuron. The results may contribute to the establishment of public policies in Brazil associated to the definition of maximum permissible limits of xenobiotics in the aquatic compartment. This study is also relevant to the search of low cost and inert materials for xenobiotics removal from aquaculture or agricultural effluents.

Metals and linear alkylbenzene sulphonate as inhibitors of the algae Pseudokirchneriella subcapitata acid phosphatase activity.

Sewage sludge applied to soils as a fertilizer often contains metals and linear alkylbenzene sulphonate (LAS) as contaminants. These pollutants can be transported to the aquatic environment where they can alter the phosphatase activity in living organisms. The acid phosphatase of algae plays important roles in metabolism such as decomposing organic phosphate into free phosphate and autophagic digestive processes. The order of in vitro inhi- bition of Pseudokirchneriella subcapitata acid phosphatase at the highest concentration tested was LAS[Hg2? = Al 3?[Se4? = Pb2?[Cd2?. A non-competitive inhibi- tion mechanism was obtained for Hg2? (Ki = 0.040 mM) and a competitive inhibition for LAS (Ki = 0.007 mM). In vivo studies with treated algae cultures showed that the inhibition of specific activity was observed in algae exposed during 7 days, in contrast to short term (24 h) treatments with both these chemicals. Our results suggest that the inhibition parameters in vitro did not markedly differ between the two chemicals. On the other hand, in vivo evaluations showed strong differences between both pollu- tants regarding the concentration values and the degree of response.

Macroinvertebrados aquáticos como bioindicadores no processo de licenciamento ambiental no Brasil

Resumo: Licenciamento ambiental no Brasil é um procedimento com vários níveis e etapas, concebido como ferramenta preventiva aos potenciais danos ambientais causados pela implantação de empreendimentos. Embora este procedimento seja obrigatório desde meados da década de 1980, ainda é limitado no que diz respeito ao uso de informações biológicas para a avaliação e o monitoramento de ambientes aquáticos. Neste processo, o órgão licenciador (federal, estadual ou municipal) define as variáveis a serem medidas, tendo como referência o tipo e a magnitude do empreendimento e as características específicas do local proposto para sua instalação. Respostas biológicas devem ser usadas para medir os impactos sobre ecossistemas aquáticos e os macroinvertebrados constituem um grupo que apresenta vantagens como bioindicadores, sendo os mais utilizados para este fim. Em 2011, o Grupo de Trabalho Intersetorial em Biomonitoramento foi criado para discutir o uso de macroinvertebrados em programas de monitoramento. Este trabalho apresenta as reflexões e propostas deste grupo e fornece subsídios para a inclusão destes organismos nos termos de referência a serem aplicados nos processos de licenciamento ambiental no Brasil. Abstract: In Brazil, the environmental licensing process has many stages, and it was designed as a tool to identify the potential and to prevent environmental damages caused by enterprises. Although this procedure is required since the mid-1980s, it is still limited regarding the use of bioassessment and biomonitoring of aquatic ecosystems. In this process, the agency responsible for the licensing (federal, state or local) is the responsible for defining the parameters to be measured. Those parameters are required based on the type and magnitude of the project, and the specific environment and location proposed for its installation. We recommend that biological responses should be used to assess and monitor stressors on aquatic ecosystems. Macroinvertebrates have been used worldwide as bioindicators because they have some advantages over other biological groups for this purpose. In 2011, the ?Intersectoral Working Group on Biomonitoring? was created to discuss the use of macroinvertebrates in biomonitoring programs. This paper presents proposals and recommendations aiming to stimulate and provide guidance for the use of this group in the context of the environmental licensing process in Brazil. Resumen: En Brasil, el proceso de licenciamiento ambiental tiene varios niveles y etapas. Fue diseñado como una herramienta de prevención de posibles daños ambientales causados por la ejecución de proyectos. Aunque este procedimiento exista desde la década de 1980, siegue con limitaciones en relación al uso de la información biológica para la evaluación y control de los ecosistemas acuáticos. En este proceso, la agencia de licenciamiento (federal, estadual o local) es la que define las variables a mensurar en función del tipo y la magnitud del proyecto y las características específicas del lugar propuesto para su instalación. Las respuestas biológicas deben ser utilizadas para evaluar los impactos a los ambientes acuáticos, y el grupo de los macroinvertebrados tienen ventajas sobre otros grupos biológicos y son los más utilizados para este fin. En 2011, el ?Grupo de Trabajo Intersectorial de Biomonitoreo? fue creado para discutir el uso de los macro-invertebrados en los programas de monitoreo ambiental. Este artículo presenta reflexiones y propuestas de este grupo y ofrece subsidios para la inclusión de estos organismos en los términos de referencia que serán aplicados en el proceso de licenciamiento ambiental en Brasil.

Assessing the safety of Pseudomonas putida introduction in the environment: an overview of ecotoxicological tests.

Risk assessment guidelines for the environmental release of microbial agents are performed in a tiered sequence which includes evaluation of exposure effects on non target organisms. However, it becomes important to verify whether environmental risk assessment from temperate studies is applicable to tropical countries, as Brazil. Pseudomonas putida is a bacteria showing potential to be used for environmental applications as bioremediation and plant disease control. This study investigates the effects of this bacteria exposure on rodents and aquatic organisms (Daphnia similes) that are recommended to be used as non-target organism in environmental risk assessments. Also, the microbial activity in three different soils under P. putida exposure was evaluated. Rats did not show clinical alterations, although the agent was recovered 16 h after the exposure in lung homogenates. The bacteria did not reduce significantly the reproduction and survival of D. similis. The soil enzymatic activities presented fluctuating values after inoculation with bacteria. The measurement of perturbations in soil biochemical characteristics is presented as an alternative way of monitoring the overall effects of the microbial agent to be introduced even in first stage (Tier I) of the risk assessment in tropical ecosystems.

Influence of Baculovirus anticarsia on the growth rate and survival of some nontarget aquatic organisms.

Recently, microbial pest control agents (MPCAs) have been worldwide used to reduce chemical pesticide use and to diminish the high risk of those compounds in the environment. Among various MPCAs, the nuclear polyhedrosis virus Baculovirus anticarsia is widely used in Brazil in the biological control of the velvet bean caterpillar. Although literature data do not show adverse effects of baculoviruses to nontarget organisms, it is necessary to evaluate their toxicity or patogenicity in order to study th environmental risk of those products and to register the formulations in the Brazilian Environmental Regularory Agency - IBAMA. In the presente work, the influence of a Baculovirus anticarsia formulation was evaluted to measure the consequences in the growth rateof the green algae Selenastrum capricornutum, the duckweed Lemna valdiviana and the microcrustacean Daphnia similis. The survival of the fish Hyphessobrycon scholzei exposed during 28 days was also evaluated. No significative adverse effects (P > 0.05) were observed in the test organisms which were exposed to 1-1000 times the maximum calculated pesticide concentration following a direct application to 15 cm layer of water.