Are there any risks of the disposal of pesticide effluents in soils? Biobed system meets ecotoxicology ensuring safety to soil fauna.

The biobed is a purification system, which reduces soil pollution for receiving pesticide residues from handling and washing machinery in agricultural areas. The aims of this study were (1) to assess ecotoxicity effects over time to soil fauna, posed by Lorsban® 480 BR (Chlorpyrifos) and Dithane® NT (Mancozeb) residues when disposed of in a biobed system compared with two subtropical soils, and (2) to assess ecotoxicity effects over time to soil fauna simulating an accidental spillage with Lorsban® 480 BR at the biobed. A semi-field experiment was conducted for 420 days in southern Brazil, testing continuous disposal of washing pulverization tanks in biobeds, Typic Haploperox or Typic Hapludults. In addition, different biobeds received a single dose (1 L) of Lorsban® 480 BR to simulate an accidental spillage. Chronic ecotoxicity tests were performed using Folsomia candida, Eisenia andrei, and Enchytraeus crypticus in different sampling times for both experiments. F. candida was the most sensitive species. The biobed system was able to eliminate effects from residues of both pesticides over time in all species, which did not happen in both natural soils. In accidental spillage simulation, even 420 days after contamination, F. candida did not show reproduction. The biobeds can be a feasible alternative for the disposal and treatment residues of pesticides, also for handling and washing pesticides activities. The system was efficient in promoting degradation and reducing ecotoxicity effects posed by Lorsban® 480 BR and Dithane® NT for soil fauna. It is a safe alternative to avoid soil contamination.

Destination of pesticide residues on biobeds: State of the art and future perspectives in Latin America.

Land-use intensification with a high demand for pesticides is a consequence of human population increase. Feasible alternatives for correct concentrated residues discharge are necessary to avoid soil and water resources contamination. Biobeds are in situ bioreactors for treating pesticide residues, used by several European and American countries due to its low cost and simple construction, whose efficiency has been scientifically proved for over 20 years. This review presents the state of the art of biobeds in Latin America (LA), identifying advances and future research needs. Factors affecting the efficiency of biobeds are discussed, like ideal temperature, moisture, and microbial communities, followed by methods for evaluating the bioreactor's efficiency. It was necessary to adapt this technology to the climatic and economic conditions of Latin-American countries, due to its European origins. Guatemala is the LA country that uses biobeds as official technology. Brazil, Argentina, Costa Rica and Chile are examples of countries that are actively investigating new substrates and pursuing legal aspects for the establishment of the biobeds. Robust scientific evidences may enable farmers start using this technology, which is an environmentally safe system to protect water resources.

New analytical method for chlorpyrifos determination in biobeds constructed in Brazil: Development and validation.

A quick and efficient method was optimized and validated to determine chlorpyrifos in biobeds using ultra-performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS). Chlorpyrifos was extracted from the matrix with 30 mL of a mixture of acetone, phosphoric acid and water 98:1:1 (v/v/v). After homogenization, centrifugation and filtration, 125 µL of the extract was evaporated and reconstituted in 5 mL of methanol acidified with 0.1% acetic acid. Validation was performed by studying analytical curve linearity (r2), estimated instrument and method limits of detection and limits of quantification (LODi, LODm, LOQi and LOQm, respectively), accuracy, precision (expressed as relative standard deviation, RSD), and matrix effect. Accuracy and precision were determined from the amount of pesticide recovered from biobed blank samples (i.e. without pesticide residue) spiked with chlorpyrifos at three different concentrations (2, 10 and 50 mg kg-1), with seven replicates at each concentration. For all three concentrations studied, the average recovery values obtained were between 96 and 115% with RSD values lower than 20%. The validated LOQ obtained was 2 mg kg-1 (from recovery studies) and the matrix effect observed was lower than ±20%, which demonstrated that there was neither considerable suppression nor enhancement of the analyte signal. The biobed system efficiently degraded chlorpyrifos in both 1) simulation of accidental spillage and 2) application of diluted pesticide solution. In the latter case, all the values obtained at the final sampling time (14 months) were below the validated LOQm.

The fungicide mancozeb affects soil invertebrates in two subtropical Brazilian soils.

Mancozeb is a dithiocarbamate non-systemic fungicide widely used to control fungal diseases of plants, commonly applied in apple orchards in Brazil. Instead of its common use, there are no reports about the risk to non-target organisms in Brazilian soils. We studied the risk of Mancozeb (in the commercial formulation Dithane® NT) for standard invertebrate species (Folsomia candida, Eisenia andrei and Enchytraeus crypticus) in two subtropical Brazilian soils, Oxisol and Ultisol, which are representative of apple production areas in Brazil. Reproduction and survival tests were carried out following ISO guidelines. Results showed that Mancozeb in Oxisol reduced the survival and reproduction of collembolans (LC50 54.43 and EC50 2.72 mg a.i. kg-1) and enchytraeids (LC50 6.97 and EC50 3.56 mg a.i. kg-1), in lowest values than those observed in Ultisol (F. candida LC50 > 1000 and EC50 > 100 mg a.i. kg-1; E. crypticus LC50 280.21 and EC50 29.67). Effects to E. andrei were similar in both soils and indicated a lower sensitivity of this species to Mancozeb. The species F. candida and E. crypticus were more sensitive than E. andrei. These results reinforce the need to include other soil organisms besides earthworms, using chronical endpoints and considering different types of soils, to better predict the risk of pesticides for subtropical soils.

Analytical method validation to evaluate dithiocarbamates degradation in biobeds in South of Brazil.

In order to evaluate the efficiency of biobeds on DTC degradation, the aim of this study was to apply, optimize and validate a method to determine dithiocarbamate (mancozeb) in biobeds using gas chromatography-tandem mass spectrometry (GC-MS). The DTC pesticide mancozeb was hydrolysed in a tin (II) chloride solution at 1.5% in HCl (4 mol L-1), during 1 h in a water bath at 80 °C, and the CS2 formed was extracted in isooctane. After cooling, 1 mL of the organic layer was transferred to an auto sampler vial and analyzed by GC-MS. A complete validation study was performed and the following parameters were assessed: linearity of the analytical curve (r2), estimated method and instrument limits of detection and limits of quantification (LODm, LODi, LOQm and LOQi, respectively), accuracy (recovery%), precision (RSD%) and matrix effects. Recovery experiments were carried out with a standard spiking solution of the DTC pesticide thiram. Blank biobed (biomixture) samples were spiked at the three levels corresponding to the CS2 concentrations of 1, 3 and 5 mg kg-1, with seven replicates each (n = 7). The method presented satisfactory accuracy, with recoveries within the range of 89-96% and RSD ≤ 11%. The analytical curves were linear in the concentration range of 0.05-10 µg CS2 mL-1 (r2 > 0.9946). LODm and LOQm were 0.1 and 0.5 mg CS2 kg-1, respectively, and the calculated matrix effects were not significant (≤ 20%). The validated method was applied to 80 samples (biomixture), from sixteen different biobeds (collected at five sampling times) during fourteen months. Ten percent of samples presented CS2 concentration below the LOD (0.1 mg CS2 kg-1) and 49% of them showed results below the LOQ (0.5 mg CS2 kg-1), which demonstrates the biobeds capability to degrade DTC.

Correlation between vegetation indexes generated at Vitis Vinifera L. and soil, plant and production parameters for emergency application in decision making / Correlação entre indices de vegetação gerados em Vitis Vinifera L. e parâmetros de solo, planta e produção para aplicação emergencial na tomada de decisão

Correlation between proximal sensing techniques and laboratory results of qualitative variables plus agronomic attributes was evaluated of a 3,0 ha vineyard in the county of Muitos Capões, Northeast of Rio Grande do Sul State, Brazil, in Vitis vinifera L. at 2017/2018 harvest, aiming to evaluate the replacement of conventional laboratory analysis in viticulture by Vegetation Indexes, at situations were laboratory access are unavailable. Based on bibliographic research, looking for vegetative indexes developed or used for canopy reflectance analysis on grapevines and whose working bands were within the spectral range provided by the equipment used, a total of 17 viable candidates were obtained. These chosen vegetation indices were correlated, through Pearson (5%), with agronomic soil attributes (apparent electrical conductivity, clay, pH in H2O, phosphorus, potassium, organic matter, aluminum, calcium, magnesium, effective CTC, CTC at pH 7.0, zinc, copper, sulfur and boron) for depths 0 -20 cm and 20-40 cm, and plant tissue (Nitrogen, phosphorus, potassium, calcium, magnesium, sulfur, copper, zinc, iron, manganese and boron) , in addition to some key oenological and phytotechnical parameters for the quantification of wine production and quality. One hundred and thirty ninesignificant correlations were obtained from this cross, with 36 moderate coefficients between 19 parameter variables versus 12 of the indexes. We concluded that in cases where access or availability of laboratory analyzes is difficult or impracticable, the use of vegetation indices is possible if the correlation coefficients reach, at least, the moderate magnitude, serving as a support to decision making until the lack analytical structure to be remedied.

Avaliou-se a correlação entre as técnicas de sensoriamento proximal e os resultados laboratoriais de variáveis qualitativas, mais os atributos agronômicos do solo de um vinhedo de 3,0 ha no município de Muitos Capões, região nordeste do estado do Rio Grande do Sul, Brasil, na safra 2017/2018. Objetivou avaliar a substituição das análises laboratoriais convencionais em viticultura por Índices de Vegetação, em situações de indisponibilidade de acesso ao laboratório. Com base em pesquisa bibliográfica, buscaram-se índices vegetativos desenvolvidos ou utilizados para análise de refletância de dossel em videiras e cujas bandas de trabalho estavam dentro do intervalo espectral fornecido pelo equipamento utilizado, obtendo-se um total de 17 candidatos viáveis. Esses índices de vegetação escolhidos foram correlacionados, por meio de Pearson (5%), com atributos agronômicos do solo (condutividade elétrica aparente, argila, pH em H2O, fósforo, potássio, matéria orgânica, alumínio, cálcio, magnésio, CTC efetivo, CTC em pH 7,0, zinco, cobre, enxofre e boro) para profundidades de 0 - 20 cm e 20 - 40 cm, e tecido vegetal (nitrogênio, fósforo, potássio, cálcio, magnésio, enxofre, cobre, zinco, ferro, manganês e boro), além de alguns parâmetros enológicos e fitotécnicos essenciais para a quantificação da produção e qualidade do vinho. Deste cruzamento foram obtidas 139 correlações significativas, resultando 36 coeficientes moderados entre 19 variáveis de parâmetros versus 12 dos índices. Concluímos que nos casos em que o acesso ou disponibilidade de análises laboratoriais é difícil ou impraticável, a utilização de índices de vegetação é possível, desde que os coeficientes de correlação atinjam, pelo menos, a magnitude moderada, servindo como suporte para a tomada de decisão até a falta de estrutura analítica ser remediada.

Transferência superficial de fósforo reativo potencialmente contaminante por chuvas simuladas intensas / Superficial loss of reactive phosphorus potentially contaminant by intense rainfall simulation

O fósforo naturalmente presente ou adicionado ao solo, dependendo da conjunção de fatores, pode desencadear uma situação de alto risco ambiental para os recursos hídricos de bacias hidrográficas. O objetivo deste trabalho foi quantificar a transferência na superfície do solo de algumas formas de fósforo reativo, originário da adubação fosfatada em solo sem cultivo e descoberto, transportado pelo escoamento superficial da água de chuvas. O experimento foi executado em Lages, SC, com duas repetições de campo, sob regime de chuvas intensas simuladas (64 mm h−1 durante 50 minutos). Os resultados apontam que o fósforo pode representar sério risco ambiental aos recursos hídricos das bacias, em diferentes escalas no tempo e no espaço, através das formas reativas de fósforo e suas diferentes maneiras de transporte.

Phosphorus is naturally present or added to the soil and, depending on the mix of factors, may trigger a high environmental risk to water resources in river basins. The aim of this study was to quantify the transfer for soil surface of some forms of reactive phosphorus originating from phosphorus fertilization on bare soil, carried by the runoff. The experiment was carried out in Lages, SC, Brazil, with two replications in the field under intense simulated rainfall (64 mm h−1 for 50 minutes). The results indicate that phosphorus may represent a serious environmental risk to water resources of basins at different scales in time and space, through the reactive forms of phosphorus and their different ways of transportation.

Introduzindo critérios de risco em modelos de contaminação pontual para locais de carga de agrotóxicos / Introducing risk criteria into models of point source contamination in pesticide load pads

O objetivo deste trabalho foi propor a adaptação do modelo de risconão pontual “Environmental Risk Index” (ERI), de Alister e Kogan(2006), mediante criação e aplicação de fatores de risco pontualderivados do manejo dos produtos nos locais de abastecimentode pulverizadores de agrotóxicos, gerando o modelo “índice deRisco pontual” (IRAp). O trabalho de campo foi executado nasdependências da Estação de Fruticultura de Clima Temperado(EFCT), da Embrapa Uva e Vinho, em Vacaria (RS), onde foramcoletados os dados acerca da infl uência humana sobre o fator derisco ambiental do agrotóxico no momento do preenchimento dopulverizador. A fase de geração do modelo de simulação ocorreuna EFCT e na sede do centro da Embrapa Uva e Vinho, medianteadaptação do fator Dose (D) do ERI, transformando-o no Índicede Dose Pontual (iDp) e pela adequação matemática do fatorLixiviação (L) ao aproximar o comportamento dos 30 agrotóxicosteste expressos no modelo GUS para o modelo LIX. A introduçãode critérios de risco envolvendo fatores humanos em casosde contaminação pontual por agrotóxicos provocou diferençassignifi cativas em relação aos modelos destinados à avaliação decontaminação não pontual, e o Índice de Risco Ambiental pontual(IRAp) reproduziu os resultados de campo nas simulações. O IRApdemonstrou grande potencial para a análise preliminar (“screenning”)dos riscos envolvidos nas repetidas operações de carga e limpezade pulverizadores de agrotóxicos, permitindo o planejamento delongo prazo da escolha de produtos a serem utilizados na atividade,segundo a necessidade de segurança toxicológica do trabalhador edo ambiente ou o conjunto de ambas.