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1.
Heliyon ; 5(8): e02237, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31440593

RESUMO

The practice of intensive herbicide use in the sugarcane industry has a high risk of compromising the quality of the water and the organisms that live there due to losses through runoff, leaching and other processes. In this work, the dynamics of four herbicides present in three different mixtures were evaluated through their incorporation and elimination in the muscle tissue of tilapia (Oreochromis niloticus). The highest mean values of bioconcentration factors were 1.730 for ametryn, 0.891 for tebuthiuron, 0.322 for hexazinone and 4.783 for diuron. Diuron presented the highest risk regarding the consumption of tilapia fillets by the population. However, considering that the fish would reach maximum levels of diuron when exposed to extremely high concentrations, an individual weighing 70 kg would need to ingest approximately 1.5 kg of this food product to surpass the acceptable daily intake of 0.007 mg kg-1 body weight. It was concluded that the risk of injury to the population consuming tilapia fillets from fish exposed to herbicides in water arising from sugarcane activities is very low. According to the risk estimation performed in this work, which is substantiated by the assumptions of the World Health Organization and the International Life Sciences Institute, there is a low risk of injury to the population consuming tilapia fillets from fish exposed to water containing herbicides in concentrations arising from sugarcane activities. However, as the risk was estimated from laboratory conditions, caution should be taken where herbicide applications are carried out with high frequency near water bodies, as the consumption of fish from these areas is quite common.

2.
Bull Environ Contam Toxicol ; 93(3): 360-4, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25008796

RESUMO

At least 52 % of the planted rice area in Rio Grande do Sul, a major rice producing state in Brazil, employs Clearfield(®) production system, corresponding to 580,000 ha of cultivated area. To grow rice with Clearfield(®) technology, producers combine imazethapyr and imazapic herbicides. However, these herbicides leave residual activity in soil; consequently, the repeated application of imazethapyr and imazapic on Brazilian Clearfield(®) rice fields has increased these herbicides persistence in treated soils. In this study, a method has been developed for removal and quantification of imazethapyr and imazapic residues in soil through ultrasonic assisted extraction using methanol-phosphoric acid aqueous solution (pH 2.0). The detected response was linear for both herbicides within the range of 0.25-5 ng mL(-1) with correlations coefficients >0.99. The quantification limit was limit of quantification 0.2 µg Kg(-1) for both pesticides. The good recovery rate from all pesticides, which ranges between 70 % and 120 %, demonstrates the method's validity.


Assuntos
Herbicidas/análise , Imidazóis/análise , Extração Líquido-Líquido/métodos , Ácidos Nicotínicos/análise , Poluentes do Solo/análise , Brasil , Cromatografia Líquida de Alta Pressão , Espectrometria de Massas , Oryza , Solo/química , Ultrassom
3.
J AOAC Int ; 95(3): 913-22, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22816282

RESUMO

A simple method using LC/MS/MS was developed and validated to determine residues of malachite green (MG) and leucomalachite green (LMG) in fish fillet. A modified QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) technique was used to perform the sample preparation. The optimal extraction and cleanup conditions were established using an experimental design. The validation parameters obtained to determine both MG and LMG complied with the requirements established by regulatory agencies for the presence of such substances in fish, which establish that the method must attain, at least, a minimum required performance limit of 2 ng/g. The accuracy values ranged between 95 and 107%, and the precision values were lower than 11.2%. The method was used in the analysis of tilapia samples (n = 20) commercialized in Campinas, SP, Brazil. None of the samples presented detectable levels of MG or LMG residues.


Assuntos
Cromatografia Líquida/métodos , Contaminação de Alimentos/análise , Corantes de Rosanilina/análise , Alimentos Marinhos/análise , Espectrometria de Massas em Tandem/métodos , Animais , Peixes , Corantes de Rosanilina/isolamento & purificação
4.
J Environ Sci Health B ; 45(1): 89-94, 2010 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-20390936

RESUMO

Several different Advanced Oxidation Processes (AOPs) including ozonation at pH 6.5 and 10, photolysis and heterogeneous photocatalysis using TiO(2) as semiconductor and dissolved oxygen as electron acceptor were applied to study the degradation of glyphosate (N-phosphonomethyl glycine) in water. The degree of glyphosate degradation, the reactions kinetic and the formation of the major metabolite, aminomethyl phosphonic acid (AMPA), were evaluated. Ozonation at pH 10 resulted in the maximum mineralization of glyphosate. It was observed that under the experimental conditions used in this study the degradation of glyphosate followed the first-order kinetics. The half-life obtained for glyphosate degradation in the O(3)/pH 10 process was 1.8 minutes.


Assuntos
Glicina/análogos & derivados , Herbicidas/química , Titânio/química , Poluentes Químicos da Água/química , Catálise , Recuperação e Remediação Ambiental , Glicina/química , Concentração de Íons de Hidrogênio , Cinética , Oxirredução , Ozônio/química , Processos Fotoquímicos , Fotólise , Glifosato
5.
J Environ Sci Health B ; 42(6): 635-9, 2007 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-17701698

RESUMO

This study was undertaken to evaluate the degradation and mobility of the herbicide tebuthiuron (N-[5-(1,1-dimethylethyl)-1,3,4-thiadiazol-2-yl]-N,N'-dimethylurea) in soil under field conditions, and its potential for leaching and groundwater contamination. A watershed, Espraiado, located over a recharge area in Brazil, was chosen for soil and water studies. At Espraiado, water samples were collected from seven wells at intervals of three months from March 2004 to June 2006 and analyzed for tebuthiuron. Other samples were taken from city wells located outside of the recharge area. To assess the potential movement to the aquifer, tebuthiuron was also applied to trial plots at the recommended label rate of 1.0 kg/ha a.i. in May of 2004, with and without sugarcane coverage, on sandy soil. Soil samples were collected during the years of 2004 and 2005, at depths intervals of 20 cm from soil surface down to 120 cm and analyzed for tebuthiuron at zero, 3, 30, 60, 90, 120, 150, 180, 240, and 300 days after application. There was no clear effect of sugarcane coverage on the tebuthiuron degradation in soils, but it moved faster into the soil where there was no cover. After 180 days there were no measurable residues in the soil, and tebuthiuron was not found below 40 cm depth in any time. Tebuthiuron had a half-life of 20 days under those conditions. No tebuthiuron residue was found in ground water samples at any sampling time.


Assuntos
Herbicidas/análise , Compostos de Metilureia/análise , Poluentes do Solo/análise , Poluentes Químicos da Água/análise , Poluição Química da Água/prevenção & controle , Abastecimento de Água/normas , Brasil , Monitoramento Ambiental/métodos , Sedimentos Geológicos/química , Meia-Vida , Herbicidas/química , Compostos de Metilureia/química , Medição de Risco , Saccharum/química , Solubilidade , Movimentos da Água , Poluição Química da Água/análise
6.
Pesticidas ; 11: 1-16, jan.-dez. 2001. tab
Artigo em Português | LILACS | ID: lil-306781

RESUMO

Analisou-se o potencial de contaminaçäo das águas subterrâneas e superficiais do Submédio do Rio Säo Francisco por pesticidas aplicados nas culturas de manga e uva, mediante critérios da Environmental Protection Agency, do índice de GUS e critérios propostos por Goss. Todos os critérios utilizados levam em consideraçäo as propriedades dos produtos aplicados, näo demandado custos elevados nem muito tempo para o levantamento das informaçöes e para a avaliaçäo do potencial de contaminaçäo. Os resultados obtidos reforçam a importância de disponibilizar informaçöes sobre as propriedades físico-químicas dos pesticidas, principalmente o coeficiente de adsorçäo, cujo valor permite a previsäo da mobilidade do composto no solo. Este fator, integrado ao conhecimento do tempo de degradaçäo do produto até a metade de sua concentraçäo inicial (meia-vida) no solo, fornece informaçöes sobre a sua influência no potencial de contaminaçäo das águas. Os resultados deste trabalho propiciam o conhecimento dos pesticidas com maior potencial de contaminaçäo dos recursos hídricos, os quais devem ser priorizados no monitoramento "in loco"


Assuntos
Água Subterrânea , Meio Ambiente , Saúde Ambiental , Monitoramento Ambiental , Águas Superficiais , Riscos Ambientais , Frutas , Praguicidas , Monitoramento da Água , Poluição da Água , Qualidade da Água
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