Persistence of indoor permethrin and estimation of dermal and non-dietary exposure.

Pesticides applied indoors may persist longer than they would in outdoor environments, making people more vulnerable to the risk of exposure. Permethrin is a pyrethroid insecticide used in agricultural, residential, and public health sites, and is commonly detected in indoor environments. The objectives of this study were to evaluate the persistence of permethrin indoors and to estimate the levels of possible dermal and non-dietary exposure to this insecticide. Permethrin was applied on aluminum foil and kept in a glass chamber and a test house for 112 days; its concentration was measured at application and after 28, 56, and 112 days. Permethrin persisted for the entire 112 days in concentrations equal to a maximum of 89.6% of the initial concentration. We observed low levels of human dermal and non-dietary exposure to permethrin.

Rodenticide efficacy in sewers in São Paulo, Brazil.

Rodents infest urban environments, causing damage and acting as vectors for disease transmission. Currently, anticoagulants are the most widely used chemical rodenticides, and their extensive and widespread use can contaminate the environment. To ensure effectiveness and avoid accumulation of rodent baits in the environment, it is important to evaluate how long rodent baits maintain their palatability and efficacy. In rodent control programs, rodent baits are placed in locations such as sewers, but after a few days, baits appear altered, causing doubts about the control efficacy. For this reason, baits are replaced periodically, which increases costs and generation of chemical waste. The objective of this study was to evaluate the palatability and efficacy of commercial paraffin-type rodent bait blocks placed in sewers in São Paulo City over a period of 90 days. Bait blocks were placed in sewers and collected after 30, 60, and 90 days. Additionally, in a laboratory two-choice test, wild-caught urban Norway rats were offered 40-60 g of bait and an equal volume of standard rat pellets. The amount of bait and rat pellet consumed was registered, the palatability was calculated, and the efficacy was measured as the percentage mortality over 14 days. The results showed that, even when they had an altered appearance, bait blocks remained palatable to the rats and were effective after at least 90 days. Leaving bait blocks for longer periods could be an effective strategy for reducing costs and could help to ensure the control of urban rodents in an environmentally sustainable way.

Persistence of malathion used in dengue control on household surfaces / Permanência do malathion usado no controle da dengue em superfícies domiciliares

Dengue is a viral infection transmitted by the mosquito Aedes aegypti. In Brazil, one of the insecticides used to control the mosquito is malathion, which can be diluted in vegetable oil (1:2 v/v). The purpose of this study was to understand the persistence of malathion on different surfaces and soil. Surfaces were contaminated by malathion and then washed with water and soap. The water used to clean the surfaces was extracted and analyzed by gas chromatography with an FID detector. Soil samples received malathion 14C-TG diluted in vegetable oil (1:2 v/v) and were analyzed zero, 3, 7, 18, 32, 60, 120, 240, and 360 days after the application in a liquid scintillation analyzer. Results showed a high persistence of malathion on porous surfaces. Moreover, it did not degrade in the soil for the first 120 days.(AU)

A dengue é uma infecção viral transmitida pelo mosquito Aedes aegypti. No Brasil, um dos inseticidas utilizados para controlar o mosquito é o malathion, que pode ser diluído em óleo vegetal (1:2 v/v). O objetivo deste trabalho foi avaliar a permanência do malathion em diferentes superfícies e no solo. As superfícies foram contaminadas com malathion e depois lavadas com água e sabão. A água utilizada para limpar as superfícies foi extraída e analisada por cromatografia gasosa com detector de ionização de chama. O malathion 14C-GT diluído em óleo vegetal (1:2 v/v) foi aplicado em amostras de solo que foram analisadas nos tempos 0, 3, 7, 18, 32, 60, 120, 240 e 360 dias após a aplicação, em um analisador de cintilação líquida. Os resultados mostraram alta permanência de malathion em superfícies porosas. Além disso, o malathion não se degradou no solo nos primeiros 120 dias.(AU)

Pyrethroid concentrations and persistence following indoor application.

Residential indoor environments are potential sources of exposure to pyrethroids, which have low acute toxicity to humans but are allergenic and suspected endocrine disruptors. The present study evaluated the persistence of the pyrethroids cypermethrin and beta-cyfluthrin on indoor surfaces and in house dust. Cypermethrin and beta-cyfluthrin were applied and maintained on aluminum foils and in dust samples for 112 d under controlled conditions and for 12 mo in a test house; periodically, they were quantified by high-performance liquid chromatography. Cypermethrin and beta-cyfluthrin concentrations showed decreases of 10.1% and 7.7% on aluminum foils, and 12.7% and 16.4% in dust, respectively, at 112 d under controlled conditions. In the test house, cypermethrin and beta-cyfluthrin concentrations decreased by 40.3% and 60.2% on aluminum foils, and 29.6% and 56.2% in dust at the end of the study. The results show the considerable persistence of cypermethrin and beta-cyfluthrin indoors and indicate the risk of exposure to these products. Environ Toxicol Chem 2017;36:2895-2898. © 2017 SETAC.

Persistence of chlorpyrifos in greenhouse air / Persistência do inseticida clorpirifós no ar em casa de vegetação

Organophosphate pesticides are among those with the highest acute toxicity and are available on the market and used in several regions of Brazil. The concentration and residence time of the organophosphate pesticide, chlorpyrifos, in the air after application in a greenhouse were investigated. For more than 24 h, the chlorpyrifos remained in the greenhouse air at concentrations three times above the occupational exposure limit and was still detectable four days later.(AU)

Os inseticidas organofosforados estão entre os agrotóxicos de maior toxicidade aguda disponíveis no mercado e são usados em várias regiões do Brasil. Avaliaram-se a concentração e o tempo de permanência do inseticida organofosforado clorpirifós no ar, após aplicação em uma casa de vegetação. O clorpirifós permaneceu no ar da casa de vegetação em concentração três vezes acima do limite de exposição ocupacional por mais de 24 horas, e ainda foi detectado após quatro dias.(AU)

Bioavailability and influence of ¹4C-carbofuran on Eisenia andrei avoidance, growth and reproduction in treated natural tropical soils.

The bioavailability of carbofuran to the compost worms Eisenia andrei and the influence of its residual amounts on the avoidance, reproduction and growth of this species were studied in two natural tropical soils: a Typic Humaquept (GM) and a Typic Hapludox (LVD), as indicated by the Brazilian environmental authorities for ecotoxicological tests. The worms avoided the soil LVD treated with different doses of carbofuran. The pesticide also affected the production of juvenile specimens in both soils, but cocoon production was reduced only in the GM soil. The earthworms' growth and weight loss were affected by carbofuran (2,2-dimethyl-2,3-dihydro-1-1-benzofuran-7-yl methylcarbamate. CAS number 1563-66-2) only in the LVD and the mortality detected at 56 days of contact with the treated soils was not statistically significant in both of them. Fourteen days after the soil treatment with(14) c-carbofuran, most residues detected in the soils were bound residues (approximately 36% and 30% in the GM and LVD, respectively) and neither mortality nor bioaccumulation was detected in the earthworms, even with absorptions of 13% and 43%, respectively. The LVD soil has lower organic matter content, and the effects of carbofuran on different aspects of the earthworms' life were more pronounced in this soil, most likely due to the higher bioavailability of the pesticide in the soil solution. The results for carbofuran clearly demonstrate that even small quantities of residues do not assure lack of toxicity. They also make evident the necessity of studying the effects of pesticides in natural agricultural soils. Furthermore, as the bound residues and the earthworm contamination are not detected by conventional techniques, they are not taken into account and may be underestimated on environmental risk assessments.

Palatability and efficacy of bromadiolone rodenticide block bait previously exposed to environmental conditions.

BACKGROUND: In São Paulo city, rodent infestation is considered to be a serious public health problem and is the object of a municipal rodent control programme. One of the most important routine methods involves baiting in sewers, using bromadiolone block bait in a pulsed baiting strategy. It has been observed that, after each pulse, bait is not always consumed, and its appearance is altered, which has led to concerns about efficacy. We assessed whether exposure to sewer conditions influences the palatability and efficacy of rodenticide baits to Norway rats (Rattus norvegicus). Baits containing bromadiolone as active ingredient were placed in sewers, removed after 30 days and offered to rats in a two-choice food trial and a no-choice food trial. RESULTS: The appearance of the rodenticide baits changed after 30 days exposure to sewer conditions, but they continued to be palatable and effective against rats. The level of mortality was considered to be satisfactory, 75% in the two-choice food trial and 100% in the no-choice food trial. CONCLUSION: Results support the reuse of rodenticide block bait in rodent control. It seems to be justified to continue using/reuse baits even when their appearance has changed after 30 days exposure in sewer systems.

Current status of rodenticide intoxication in Brazil: a preliminary survey from 2009 to 2011

The chemical control of rodents with anticoagulant products, especially derivatives of the coumarin chemical group, is legally authorised in Brazil. These products provide effective control and are safe for humans. However, the use of illegal 'rodenticides' has increased in many Brazilian cities recently, accompanied by increased numbers of suicides, homicides, and intoxications. The National Toxicology Information System (Sinitox) registers the number of rodenticide intoxications, including suicides, but does not differentiate between the legal and illegal rodenticides. Intoxications by rodenticides outnumber those by illicit drugs and pesticides. A survey of data from 2005-2011 revealed an average of about 3,800 intoxications per year, about 60% of which were suicides. Many of these intoxications probably involved illegal rodenticides, some with unknown chemical compositions, which confound the data on rodenticide intoxication. This evaluation of Sinitox data highlighted the need to ensure the proper use of the term 'rodenticide' when registering intoxication cases. Intoxication by-products that are not rodenticides, but are erroneously used for this purpose, should be classified separately to improve the quality of information.

[Evaluation of personal protective equipment used by malathion sprayers in dengue control in São Paulo, Brazil]. / Avaliação da vestimenta utilizada como equipamento de proteção individual pelos aplicadores de malationa no controle da dengue em São Paulo, Brasil.

Malathion insecticide in vegetable oil is used to control Aedes aegypti and is applied by spraying, which requires the use of personal protective equipment (PPE). The current study assessed the capacity of PPE suits to retain malathion. The study monitored field spraying in São Paulo, Brazil. Before each spraying, feminine sanitary napkins were placed under and upon the PPE suit in the chest, back, and forearms. After spraying, the sanitary napkins were removed, labeled, and submitted to extraction under mechanical agitation. The extracts were analyzed by gas chromatography with a flame ionization detector. Presence of malathion in sanitary napkins under PPE suits was observed after spraying and before washing the suits. The findings indicate that sprayers are exposed to malathion, even when they use new PPE suits.

Avaliação da vestimenta utilizada como equipamento de proteção individual pelos aplicadores de malationa no controle da dengue em São Paulo, Brasil / Evaluation of personal protective equipment used by malathion sprayers in dengue control in São Paulo, Brazil / Evaluación de la vestimenta utilizada como equipo de protección personal por los fumigadores de malathion en el control del dengue en São Paulo, Brasil

O inseticida malationa em calda oleosa é utilizado no controle do Aedes aegypti e a sua aplicação é feita por meio de nebulização. Essa atividade exige o uso de equipamento de proteção individual (EPI) pelos aplicadores. Este trabalho avaliou a capacidade de retenção do inseticida malationa nas vestimentas do EPI após nebulização em campo. Foram acompanhadas nebulizações em campo, realizadas pelos agentes de zoonoses, na cidade de São Paulo, Brasil. Antes de cada nebulização eram colocados absorventes sob e sobre a vestimenta do EPI no tórax, na face superior da parede torácica (costas) e nos antebraços. Após cada aplicação, os absorventes eram retirados, identificados e submetidos à extração sob agitação mecânica. Os extratos foram analisados por cromatografia a gás com detector de ionização de chama. Observou-se a presença de malationa nos absorventes sob as vestimentas do EPI já na primeira aplicação, antes da lavagem. Os resultados indicam que os agentes, nas condições avaliadas, estão expostos ao malationa, mesmo com uso de vestimentas de EPI novos.

Malathion insecticide in vegetable oil is used to control Aedes aegypti and is applied by spraying, which requires the use of personal protective equipment (PPE). The current study assessed the capacity of PPE suits to retain malathion. The study monitored field spraying in São Paulo, Brazil. Before each spraying, feminine sanitary napkins were placed under and upon the PPE suit in the chest, back, and forearms. After spraying, the sanitary napkins were removed, labeled, and submitted to extraction under mechanical agitation. The extracts were analyzed by gas chromatography with a flame ionization detector. Presence of malathion in sanitary napkins under PPE suits was observed after spraying and before washing the suits. The findings indicate that sprayers are exposed to malathion, even when they use new PPE suits.

El insecticida malathion en jarabe aceitoso se utiliza en el control del Aedes aegypti y su aplicación se realiza través de un nebulizador. Esta actividad requiere el uso de un equipo de protección personal (PPE) para los fumigadores. Este estudio evaluó la capacidad de retención del insecticida malathion en la vestimenta del PPE. Se acompañó durante el proceso de nebulización en el campo a los agentes responsables de zoonosis en la ciudad de São Paulo, Brasil. Antes de cada nebulización se colocaron absorbentes debajo y encima de la ropa del PPE en el pecho, en la espalda y antebrazos. Después de cada aplicación, los absorbentes fueron identificados y sometidos a una extracción con agitación mecánica. Los extractos se analizaron por cromatografía de gases con detector de ionización de llama. Se observó la presencia de malathion en los absorbentes internos del PPE de la primera fumigación, antes de ser lavados. Los resultados indican que los agentes, en las condiciones evaluadas, están expuestos al malathion, incluso tras el uso de un PPE nuevo.

Condições urbanas e exposição dos trabalhadores sob aplicação de malationa 12 / Urban conditions and exposure of workers under malathion application

A cidade de São Paulo caracteriza-se pelo acentuado crescimento, o que favoreceu a formação de áreas com diferentes condições sociais, econômicas e ambientais. Várias doenças transmitidas por vetores apresentam frequências diferentes nos diversos sítios da cidade, mas o programa de controle de vetores é o mesmo para todos os locais. O controle do Aedes aegypti, mosquito vetor da dengue, envolve entre outras ações a realização de nebulização de malationa GT 96% em óleo de soja (1:2, v/v) quando há casos confirmados da doença. Durante o procedimento dois ou mais funcionários (batedores) informam os munícipes para sair de suas casas e retornarem após 15 minutos do término do procedimento e, então, o aplicador acompanhado do funcionário que atua como apoio entra nas residências e aplicam o inseticida. O produto é aplicado dentro da residência do caso positivo, na sua área externa e nas residências do entorno. Embora os locais sejam diferentes e o procedimento de nebulização seja o mesmo, não se sabe se as características urbanas podem influenciar a exposição dos funcionários. Assim, este trabalho avaliou a presença de malationa sobre as vestimentas dos funcionários em três diferentes locais. A área A era um local de baixo poder aquisitivo com casas pequenas ou assobradas com pouca ou nenhuma área externa. A área B se constituía em condomínios com prédios de até cinco andares onde foi nebulizado somente a garagem e o saguão do primeiro andar. E a área C era uma favela com edificações improvisadas e pequenas vielas.A e B eram áreas regulares com sistema viário e calçadas, mas C era um aglomerado de construções e barracos de madeira permeados por vielas. Em todas as áreas a atividade foi realizada em seis dias sob as mesmas condições climáticas Para avaliar a quantidade de malationa recebido durante a nebulização, oito absorventes higiênicos femininos foram colocados sobre a vestimenta do equipamento de proteção individual de cada funcionário. Após a nebulização, cada absorvente era removido e submetido à extração com 60 mL de hexano sob agitação mecânica por 30 min e os extratos analisados por cromatografia gasosa para detecção e quantificação do malationa. Nas áreas A e C não se observou diferença na quantidade de malationa nos absorventes do aplicador e do apoio, mas em B a quantidade de malationa foi maior. Por outro lado observou-se maior quantidade de malationa nos batedores no sítio. Os resultados permitiram concluir que as condições ambientais podem influenciar o grau de exposição dos funcionários.

Condições urbanas e exposição dos trabalhadores sob aplicação de malationa 12 / Urban conditions and exposure of workers under malathion application

A cidade de São Paulo caracteriza-se pelo acentuado crescimento, o que favoreceu a formação de áreas com diferentes condições sociais, econômicas e ambientais. Várias doenças transmitidas por vetores apresentam frequências diferentes nos diversos sítios da cidade, mas o programa de controle de vetores é o mesmo para todos os locais. O controle do Aedes aegypti, mosquito vetor da dengue, envolve entre outras ações a realização de nebulização de malationa GT 96% em óleo de soja (1:2, v/v) quando há casos confirmados da doença. Durante o procedimento dois ou mais funcionários (batedores) informam os munícipes para sair de suas casas e retornarem após 15 minutos do término do procedimento e, então, o aplicador acompanhado do funcionário que atua como apoio entra nas residências e aplicam o inseticida. O produto é aplicado dentro da residência do caso positivo, na sua área externa e nas residências do entorno. Embora os locais sejam diferentes e o procedimento de nebulização seja o mesmo, não se sabe se as características urbanas podem influenciar a exposição dos funcionários. Assim, este trabalho avaliou a presença de malationa sobre as vestimentas dos funcionários em três diferentes locais. A área A era um local de baixo poder aquisitivo com casas pequenas ou assobradas com pouca ou nenhuma área externa. A área B se constituía em condomínios com prédios de até cinco andares onde foi nebulizado somente a garagem e o saguão do primeiro andar. E a área C era uma favela com edificações improvisadas e pequenas vielas.A e B eram áreas regulares com sistema viário e calçadas, mas C era um aglomerado de construções e barracos de madeira permeados por vielas. Em todas as áreas a atividade foi realizada em seis dias sob as mesmas condições climáticas Para avaliar a quantidade de malationa recebido durante a nebulização, oito absorventes higiênicos femininos foram colocados sobre a vestimenta do equipamento de proteção individual de cada funcionário. Após a nebulização, cada absorvente era removido e submetido à extração com 60 mL de hexano sob agitação mecânica por 30 min e os extratos analisados por cromatografia gasosa para detecção e quantificação do malationa. Nas áreas A e C não se observou diferença na quantidade de malationa nos absorventes do aplicador e do apoio, mas em B a quantidade de malationa foi maior. Por outro lado observou-se maior quantidade de malationa nos batedores no sítio. Os resultados permitiram concluir que as condições ambientais podem influenciar o grau de exposição dos funcionários.

Avaliação da dissipação no ambiente do raticida Brodifacum formulado como bloco parafinado / Evaluation of the dissipation in the environment of rodenticide Brodifacoum formulated as paraffined block

Para o controle químico de roedores na cidade de São Paulo, principalmente ratazanas, são colocados blocos parafinados contendo o ingrediente ativo ( i.a) brodifacum em bueiros sujeitos à ação das intempéries que podem acarretar alterações no i.a. e sua transferência para outros ambientes. Visando verificar essa possibilidade foram montados sistemas experimentais com blocos parafinados, simulando as condições de campo. Também foram colocados 100 blocos em bueiros monitorados semanalmente. Três blocos dos sistemas e dos bueiros foram coletados semanalmente , durante 10 semanas, e analisados por cromatografia a líquido de alta eficiência. Os dados obtidos foram utilizados para a avaliação da dissipação do i.a. Os resultados evidenciaram a estabilidade da molécula sob condições ambientais reais de aplicação, pois 100 por cento do i.a. foram recuperados após a exposição do bloco. Já, nos sistemas experimentais, cerca de 50 por cento dos blocos se soltaram do arame de fixação até a quinta semana de exposição e a recuperação do i.a. diminuiu gradativamente ao longo das 10 semanas de estudo, chegando a 50 por cento da concentração total.

Influence of substrate on bioaccumulation of 14C-paraquat in compost worms Eisenia foetida.

Contamination of soil with pesticides can be evaluated using toxicity tests with worms because their ecological niche makes them good bioindicators. Bioaccumulation in compost worms of [methyl-14C] paraquat (1,1'-dimethyl-4,4'-bipyridinium dichloride) was measured after three-month exposure in two substrates with differing physicochemical characteristics, in particular their organic matter and clay contents. The treatments were 1.2, 12, and 120 microg paraquat g(-1) substrate. The action of the worms did not influence the loss of 14C from the substrates, as the 14C-recovered was essentially quantitative at the end of the study in both the presence and absence of the worms. The organic matter and clay contents of the substrates determined the extent of the paraquat uptake by the worms; worms from the substrate with smaller amounts of clay and organic matter had the higher values of the bioconcentration factor (BCF), these being about 5 (fresh-weight basis) and independent of the application rate. The BCF values in the substrate containing more organic matter and clay were smaller but increased from 1.1 to 3.8 with the increasing rates of application. However, in both substrates the amounts of paraquat bioaccumulated in the worms was always less than 1% of that applied, indicating the very strong binding of paraquat to the substrates and hence low availability to the worms.

Influence of soil properties on bioaccumulation of 14C-simazine in earthworms Eisenia foetida.

The toxicity of pesticides has been evaluated by several methods including tests with earthworms in both artificial and natural soils treated with the compounds. The ecological niches of earthworms make them good bioindicators of soil contamination. The bioaccumulation of 14C-simazine (6-chloro-N2-N4-diethyl- 1,3,5-triazine-2,4-diamine) was evaluated in earthworms (Eisenia foetida) maintained during three months in two substrates with different physical-chemical characteristics. The substrates were treated with 3.0 mg and 330 kBq of 14C-simazine kg(-1) substrate. Results indicated that worms did not influence simazine dissipation in both substrates as indicated by similar recoveries and with no statistical differences with and without earthworms. The radiocarbon recoveries were 86.8 and 95.3%, respectively in the substrates with lower and higher organic matter contents with earthworms, and 91.0 and 107.4% in the same substrates without worms. However, in earthworms the recoveries were statistically higher when they were maintained in the substrate with lower amount of organic matter (0.89%) than from the higher one (0.33%). Consequently, 14C-simazine bioconcentration factor (BCF) was also greater in the substrate with lower organic matter (6.89+/-1.55) than in the substrate with higher organic matter content (0.88+/-0.06). The results suggest that the higher soil organic matter content will cause lower probability of contamination of soil organisms with simazine.