Solange Papini

OPTIMIZING MICROWAVE-ASSISTED SOLVENT EXTRACTION (MASE) OF PESTICIDES FROM SOIL

Microwave-assisted solvent extraction (MASE) was investigated as an alternative for extraction of parathion (O,O-diethyl O-4-nitrophenyl phosphorothioate), methyl parathion (O,O-dimethyl O-4-nitrophenyl phosphorothioate), p,p′-DDE [1,1′-dichloro-2,2-bis(4-chlorophenyl)ethane], hexachloro-benzene (HCB), simazine (6-chloro-N 2,N 4-diethyl-1,3,5-triazine-2,4-diamine) and paraquat dichoride (1,1′-dimethyl-4,4′-bipyridinium) from two different soils and from an earthworm-growing substrate. The matrices were fortified with 14C-radiolabeled pesticides and extracted with various solvent systems under different microwave conditions. Recoveries of more than 80% could be obtained depending on the used microwave conditions and solvent, except for paraquat whose recovery was generally less efficient. Thus, MASE can be successfully used to extract pesticides from environmental and biological samples and could be a viable alternative to conventional extraction methods. The technique uses smaller amounts of organic solvents, thereby minimizing the costs of the analysis and the disposal of waste solvent.

Degradação acelerada do metalaxil em solos agricultáveis do Estado de São Paulo

This work investigated the effect of repeated applications on enhanced degradation of metalaxyl in two different agricultural soils used for cultivation of orange and lemon from Casa Branca and Itapetininga districts of Sao Paulo State, Brazil. Soil samples were collected from areas repeatedly treated with commercial ridomil 50GR for six successive years, and from other areas never exposed to this fungicide. At the laboratory, soil samples received a 14C-metalaxyl solution and its degradation was studied through radiometric techniques to measure biomineralization and recovery of extractable- and soil-bound products. Enhanced degradation was verified only in one soil, although partial degradation and mineralization of the fungicide were detected in both soils. The different rates and patterns of metalaxyl degradation in the soils were probably due to their different physical, chemical, and biological characteristics.

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

Abstract 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-N 2 -N 4 -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.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.

Glyphosate: influência na bioatividade do solo e ação de minhocas sobre sua dissipação em terra agrícola

The widespread usage of pesticides leads to the need of improving the knowledge on their environmental behaviour in order to decrease the risks to biota, as well as the water, soil, and food contamination. The influence of the earthworms Eisenia foetida on the dissipation of glyphosate, the herbicide bioaccumulation in the worms and the influence of the herbicide on the endogeneous microbial bioactivity were evaluated in an agricultural soil sample treated with aqueous solution of 14C-glyphosate. The studies were performed in systems maintained for 2 or 4 months containing soil samples treated with three different concentrations of 14C-glyphosate and containing or not the earthworms. After these periods, soil samples and the earthworms were extracted and combusted for radiocarbon quantification by liquid scintillation counting (ECL). The microbial bioactivity was evaluated through the activity of the dehydrogenase enzyme. Results showed that earthworms did not influence the soil dissipation of glyphosate, independently of the contact period, although they bioaccumulated glyphosate residues, proportionally to the contact period. The higher period favoured the 14C-non-extractable or bound residues production. Soil bioactivity was not altered, neither by the earthworms, nor by the treatments or time after treatments.

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 μg 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.

Avaliação da vestimenta utilizada como equipamento de proteção individual pelos aplicadores de malationa no controle da dengue em São Paulo, Brasil

O inseticida malationa em calda oleosa e utilizado no controle do Aedes aegypti e a sua aplicacao e feita por meio de nebulizacao. Essa atividade exige o uso de equipamento de protecao individual (EPI) pelos aplicadores. Este trabalho avaliou a capacidade de retencao do inseticida malationa nas vestimentas do EPI apos nebulizacao em campo. Foram acompanhadas nebulizacoes em campo, realizadas pelos agentes de zoonoses, na cidade de Sao Paulo, Brasil. Antes de cada nebulizacao eram colocados absorventes sob e sobre a vestimenta do EPI no torax, na face superior da parede toracica (costas) e nos antebracos. Apos cada aplicacao, os absorventes eram retirados, identificados e submetidos a extracao sob agitacao mecânica. Os extratos foram analisados por cromatografia a gas com detector de ionizacao de chama. Observou-se a presenca de malationa nos absorventes sob as vestimentas do EPI ja na primeira aplicacao, antes da lavagem. Os resultados indicam que os agentes, nas condicoes avaliadas, estao 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.

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.

Evaluation of personal protective equipment used by malathion sprayers in dengue control in São Paulo, Brazil

O inseticida malationa em calda oleosa e utilizado no controle do Aedes aegypti e a sua aplicacao e feita por meio de nebulizacao. Essa atividade exige o uso de equipamento de protecao individual (EPI) pelos aplicadores. Este trabalho avaliou a capacidade de retencao do inseticida malationa nas vestimentas do EPI apos nebulizacao em campo. Foram acompanhadas nebulizacoes em campo, realizadas pelos agentes de zoonoses, na cidade de Sao Paulo, Brasil. Antes de cada nebulizacao eram colocados absorventes sob e sobre a vestimenta do EPI no torax, na face superior da parede toracica (costas) e nos antebracos. Apos cada aplicacao, os absorventes eram retirados, identificados e submetidos a extracao sob agitacao mecânica. Os extratos foram analisados por cromatografia a gas com detector de ionizacao de chama. Observou-se a presenca de malationa nos absorventes sob as vestimentas do EPI ja na primeira aplicacao, antes da lavagem. Os resultados indicam que os agentes, nas condicoes avaliadas, estao 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.

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.

Persistência do inseticida clorpirifós no ar em casa de vegetação

Arq. Inst. Biol., v.83, 1-4, e1052014, 2016 RESUMO: 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.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.