Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 20
Filtrar
Mais filtros










Intervalo de ano de publicação
1.
Chemosphere ; 349: 140878, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38061563

RESUMO

Bees play a crucial role as natural pollinators, ensuring the maintenance and stability of the world's biodiversity and agricultural crops. Native bees in neotropical regions belong to the Meliponini tribe, a larger group that differs significantly in behavior and biology from honeybees (e.g., Apis mellifera) and solitary bees (e.g., Osmia spp.). Hence, the exposure and effects of pesticides is also likely to vary among these different species. The aim of this study was to develop an analytical method to determine the presence of the neonicotinoid clothianidin in the Brazilian native stingless bee Tetragonisca angustula (local common name: Jataí). The method used for the chemical analysis involved a QuEChERS technique combined with UHPLC-MS/MS analysis. The developed method was subsequently used to analyze collected field samples. In addition, the acute toxicity of the pesticide to T. angustula was evaluated in a laboratory bioassay evaluating both lethal and sublethal endpoints. The analytical method was successfully developed with detection and quantification limits of 1.55 and 5 µg L-1, respectively, along with a linear range of 1-5 ng mL-1. Clothianidin was detected in environmental samples (9.2-32.9 ng g-1), and the exposure experiments demonstrated acute oral toxicity to adults of T. angustula, (24 h-LD50 of 0.16 ng a.i./bee), as well as no significative interference in acetylcholinesterase activity. Considering the obtained toxicity endpoints for T. angustula and those reported in the literature for other bee species, this study revealed that T. angustula is more (lethally) sensitive to clothianidin than other bee species, including those commonly used in environmental risk assessment studies. This thus also supports the call for using native test species in (regional) risk assessment evaluations.


Assuntos
Inseticidas , Praguicidas , Abelhas , Animais , Acetilcolinesterase , Espectrometria de Massas em Tandem , Neonicotinoides/toxicidade , Tiazóis/toxicidade , Inseticidas/toxicidade
2.
Bull Environ Contam Toxicol ; 112(1): 3, 2023 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-38017221

RESUMO

Parabens, a group of preservatives with a wide industrial range, threaten human and aquatic biota health due to their toxicity and endocrine disruption potential. As conventional wastewater treatment may not be enough to keep natural environments safe, toxicity studies are useful tools for supporting ecological risk assessments. Here, we focused on assessing ethylparaben's, one of the most common kinds of paraben, toxicity in the cladocerans Daphnia similis and Ceriodaphnia silvestrii. The EC50 sensitivity for D. similis and C. silvestrii was 24 (21-28) mg L- 1 and 25 (19-33) mg L- 1, respectively. Inhibition of reproduction and late development of females were observed in C. silvestrii exposed to 8 mg L- 1. Furthermore, species sensitivity distribution was used to assess ecological risk, and ethylparaben demonstrated low potential risk for aquatic biota.


Assuntos
Cladocera , Poluentes Químicos da Água , Animais , Feminino , Humanos , Daphnia , Parabenos/toxicidade , Reprodução , Poluentes Químicos da Água/toxicidade
3.
Environ Sci Pollut Res Int ; 30(24): 65401-65411, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-37084054

RESUMO

The increase in agricultural productivity associated with the emergence and the extensive use of pesticides is undeniable. However, strong evidence indicates that this continuous demand is causing serious environmental impacts and bringing toxic effects to associated biota as pollinating insects. The present work aims the determination of the insecticide abamectin (ABA) and the fungicide difenoconazole (DIF) in strawberry flowers (Fragaria x ananassa DUCH.) and pollen sampled from beehives of the stingless bee Tetragonisca angustula Latreille (Hymenoptera: Apidae) located nearby strawberry fields. For analysis, QuEChERS method was optimized, and the analytical performance of those two pesticides was verified. Then, the method was applied to strawberry flowers and the pollen was sampled during three field campaigns. While abamectin was not detected, the systemic fungicide difenoconazole was determined in almost all flowers and pollen samples, demonstrating the major persistence of this pesticide in investigated matrices. The results were then discussed about the difenoconazole application rate and transport to colonies to estimate a preliminary environmental risk assessment for stingless native bees. All calculations were proceeded considering exposure rates and toxicity data from the literature, adapted from Apis mellifera studies. In this sense, the determination, application, and discussion about risk assessment figure out as an important tool to the knowledge about the preliminary risks of native bees exposed to pesticides.


Assuntos
Fragaria , Fungicidas Industriais , Himenópteros , Praguicidas , Urticária , Abelhas , Animais , Pólen
4.
Environ Toxicol Chem ; 41(10): 2365-2374, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-35770720

RESUMO

In the present study, a method for the determination of residues of the neonicotinoid insecticides thiamethoxam and imidacloprid in the stingless bee Melipona scutellaris Latreille (1811) was optimized through a factorial design, tested using green metrics, and then applied to exposed bees. It combines the extraction with a modified quick, easy, cheap, effective, rugged, and safe method and the determination by liquid chromatography-tandem mass spectrometry analysis. Different parameters such as the mass of the sample, dispersive sorbents, and elution solvents were assessed. Method validation parameters were checked and include sensitivity, specificity, and linearity. The limit of quantification of 0.0025 µg g-1 was obtained for both insecticides, where accuracy was 94%-100% with satisfactory intraday and interday precisions (relative standard deviation <10%). The qualified method was applied to orally and topically exposed bee samples, and the results indicated that it is suitable for the determination and quantification of neonicotinoid pesticide residues in this species. Moreover, green analytical metrics like the National Environmental Methods Index, Eco Scale score, high-performance liquid chromatography with an environmental assessment tool (HPLC-EAT), waste generation, and amount of sample were compared with methods described in the literature involving neonicotinoid analysis in honeybees. As a result, the present study displayed the highest Eco Scale score and HPLC-EAT score and the second smallest amount of sample and waste generated. Thus, the method meets green analytical metrics more than other methods. In this sense, besides the application, the multicriteria decision analysis tool employed suggests that this is a good option as a green analytical method. Environ Toxicol Chem 2022;41:2365-2374. © 2022 SETAC.


Assuntos
Inseticidas , Resíduos de Praguicidas , Animais , Abelhas , Benchmarking , Inseticidas/análise , Neonicotinoides/análise , Nitrocompostos , Resíduos de Praguicidas/análise , Solventes , Tiametoxam/análise
5.
J Environ Sci Health B ; 57(4): 252-262, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35264079

RESUMO

A miniaturized QuEChERS extraction method followed by ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) was developed to analyze thiamethoxam and imidacloprid in 0.3 g of lyophilized Africanized honey bees (Apis mellifera L.). The work aimed to estimate honey bees' exposure to pesticides at the nanogram/gram (ng g-1) levels, using small sample and reagent quantities. Low amounts of solvents and salts were employed - 15× less than used in traditional methods. Average recoveries ranged from 64.5% to 99.7%, with repeatability below 20% for samples spiked at 3 and 167 ng g-1. LOD and LOQ were 0.7, and 3 ng g-1 for both pesticides. Applying the proposed approach, honey bee samples from different apiaries from the State of São Paulo (Brazil) were analyzed. The pesticides were detected in concentrations between 7.0 and 27.0 ng g-1. Thus, the proposed method can be used as a greener alternative to analyze the two neonicotinoids at trace levels in small quantities of bees, consequently saving chemicals and waste.


Assuntos
Inseticidas , Praguicidas , Animais , Abelhas , Brasil , Cromatografia Líquida de Alta Pressão , Cromatografia Líquida , Inseticidas/análise , Inseticidas/toxicidade , Neonicotinoides , Nitrocompostos/toxicidade , Praguicidas/análise , Espectrometria de Massas em Tandem
6.
Sci Total Environ ; 822: 153401, 2022 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-35114242

RESUMO

An attractive alternative for drinking water production is ecological filtration. Previous studies have reported high removal levels of pharmaceutical and personal care products (PPCPs) by this technology. Algae and cyanobacteria play an important role in the biological activity of ecological filters. The aim of this study was to characterize and identify the community of algae and cyanobacteria in relation to its composition, density and biovolume from 22 ecological filters that received spikings of 2 µg L-1 PPCPs. For algae and cyanobacteria species, triplicate samples were collected before and 96 h after each spiking from the interface between the top sand layer of the ecological filters and the supernatant water. Results show that Chlorophyceae and Cyanobacteria were present in high numbers of taxa and abundance. The specie Lepocinclis cf. ovum (Euglenophyceae) had the highest percentage occurrence/abundance and frequency into the filters, indicating a possible tolerance by Lepocinclis cf. ovum to the concentration of selected PPCPs. Although the concentration of PPCPs did not affect the treated water quality, they did affect the algae and cyanobacteria community. No differences were detected between filters that received a single PPCP and filters that received a mixture of the six compounds. Also, changes in the composition of algae and cyanobacteria communities were observed before and 96 h after the spikings.


Assuntos
Cosméticos , Cianobactérias , Água Potável , Poluentes Químicos da Água , Purificação da Água , Cosméticos/análise , Preparações Farmacêuticas , Poluentes Químicos da Água/análise , Purificação da Água/métodos
7.
Environ Sci Pollut Res Int ; 29(6): 8816-8830, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34491494

RESUMO

Parabens are preservatives widely used by industry since these compounds have antifungal properties, relative low cost, and stability over a wide pH range. This study aims to quantify and assess the environmental risks of methylparaben (MP), ethylparaben (EP), propylparaben (PP), and butylparaben (BP) in surface water from a Brazilian River, Mogi Guaçu. The State of São Paulo, including the Mogi Guaçu River region, suffered from a period of intense drought and high temperatures, which caused anomalies in river flows and water supply problems. The water samples were collected from 14 locations, along 300 km of river extension, at four different seasons. Samples were previously extracted and pre-concentrated by dispersive liquid-liquid microextraction (DLLME) and later analyzed by ultra-performance liquid chromatography coupled with electrospray ionization in tandem with mass spectrometry (UPLC-ESI-MS/MS) detector. During the sampling period, PP was detected in 89.3% of the water samples, MP in 87.5%, EP in 73.2%, and BP in 48.2%. The sum of parabens' average levels was 42.2 µg L-1 in Winter, 41.5 µg L-1 in Summer, 36.6 µg L-1 in Autumn, and 31.5 µg L-1 in Spring. These levels can be attributed to the smaller dilution effect caused by the drought period. Also, ecological risk assessment indicated that parabens could take a low, medium, and high risk for target organisms in the measured aquatic environments, especially considering Pimephales promelas where 15% of the samples do not present potential risk, 84% of samples can present medium risk and only 1% have low risk. Besides, the risks for BP are also considerably higher, when almost 40% presents for high risks and 60% for medium risks. The present study indicates worrisome threats to the water source and to allegedly protected biodiversity and, therefore, urgent actions are needed to effectively protect.


Assuntos
Parabenos , Rios , Brasil , Parabenos/análise , Medição de Risco , Espectrometria de Massas em Tandem , Água
8.
Environ Res ; 204(Pt A): 111988, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-34480948

RESUMO

The historic contamination of water and soils by arsenic (As) is an extremely alarming environmental and public health issue worldwide. This study investigated the relationship between As sorption and physicochemical properties of composts and biochars derived from the organic fraction of municipal solid wastes (OFMSW) towards the development of promising sorbents with value-added solid wastes management solutions. The sorbents were characterized and their effectiveness on the As sorption was tested. Several isothermal and kinetic sorption models were used for the prediction of sorption. Composts did not show promising sorption capacities, and in some cases, the As immobilization was practically null. In contrast, biochars achieved higher sorption performance, and the experimental data fitted well on Dubinin-Rabushkevich and Langmuir models, with higher R2 values. The maximum sorption capacities of BC700 estimated by such models were 6.495 and 170.252 mg g-1, respectively, whereas those of BC500 estimated by D-R and Langmuir models were only 0.066 and 0.070 mg g-1, respectively. In sorption kinetics, As was retained onto biochars at a faster first stage, reaching equilibrium after approximately 1 h and 2 h for initial concentrations of 10 and 100 mg L-1. The pseudo-second-order, Ritchie's second-order, Ritchie's, and Elovich models more adequately described the sorption kinetics of As onto biochars with high R2 values. Overall, the complexation and precipitation were predominant mechanisms for As sorption by OFMSW-derived biochars. Furthermore, the mathematical models indicated contributions arise from physisorption and external and internal diffusion mechanisms. Although BC700 can immobilize large As amounts, the gastric phase of the oral bioaccessibility test revealed more than 80% of the sorbed As could be released under conditions similar to a human stomach (pH~1.2). Such conclusions have given important insights about the refining of effective and eco-friendly remediation technologies for the management and rehabilitation of As-contaminated soil and water, particularly in developing countries.


Assuntos
Arsênio , Compostagem , Adsorção , Carvão Vegetal , Humanos , Cinética , Resíduos Sólidos
9.
Environ Pollut ; 265(Pt B): 114313, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32806434

RESUMO

Bees are considered as important providers of ecosystem services, acting via pollination process in crops and native plants, and contributing significantly to the maintenance of biodiversity. However, the decrease of bee's population has been observed worldwide and besides other factors, this collapse is also related to the extensive use of pesticides. In this sense, studies involving the assessment of adverse effects and the uptake of pesticides by bees are of great concern. This work presents an analytical method for the determination of the insecticide abamectin and the fungicide difenoconazole in the stingless bee Melipona scutellaris exposed via oral and topic to endpoints concentrations of active ingredients (a.i.) alone and in commercial formulations and the discussion about its mortality and uptake. For this purpose, QuEChERS (Quick, Easy, Cheap, Efficient, Rugged and Safe) acetate modified method was used for extraction and pesticides were determined by LC-MS/MS. The validation parameters have included: a linear range between 0.01 and 1.00 µg mL-1; and LOD and LOQ of 0.038 and 0.076 µg g-1 for abamectin and difenoconazole, respectively. The uptake of tested pesticides via oral and topic was verified by the accumulation in adult forager bees, mainly when the commercial product was tested. Mortality was observed to be higher in oral exposure than in topic tests for both pesticides. For abamectin in a commercial formulation (a.i.) no differences were observed for oral or topic exposure. On the other hand, for difenoconazole, topic exposure had demonstrated higher accumulation in bees, according to the increase of received dose. Through the results, uptake and the possible consequences of bioaccumulated pesticides are also discussed and can contribute to the knowledge about the risks involving the exposure of bees to these compounds.


Assuntos
Ecossistema , Espectrometria de Massas em Tandem , Animais , Abelhas , Cromatografia Líquida , Dioxolanos , Ivermectina/análogos & derivados , Triazóis
10.
Chemosphere ; 226: 210-219, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30927673

RESUMO

The presence of PPCPs (Pharmaceuticals and Personal Care Products) in water sources and drinking water has concerned researchers in recent times. This study was carried out to evaluate the occurrence of 6 PPCPs (namely paracetamol, diclofenac, naproxen, ibuprofen, benzophenone-3 and methylparaben) in the Lobo reservoir, their degradation products, and how efficiently they were removed by 22 ecological filters, considering individual and mixture of compounds. There were 3 spiking events of PPCPs (2 µg L-1) in the ecological filter influents conducted with a lag period of 15 days between spikes. Water samples were collected from the influent and effluent of the filters at 3, 6 and 24 h after each spiking event. All target PPCPs were identified in the Lobo reservoir water in the range of µg L-1. The personal care products were detected with 100% frequency in the samples, and in higher concentrations compared to the pharmaceuticals. Degradation products of diclofenac and benzophenone-3 were identified in the water samples. Results of this investigation show that ecological filtration was an effective process (70-99%) to remove 2 µg L-1 of the selected PPCPs, and demonstrated that the filters were resilient to individual compounds and to their mixtures.


Assuntos
Filtração/métodos , Preparações Farmacêuticas/isolamento & purificação , Poluentes Químicos da Água/isolamento & purificação , Purificação da Água/métodos , Benzofenonas/análise , Brasil , Cosméticos/análise , Diclofenaco/análise , Preparações Farmacêuticas/análise , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/análise
11.
Drug Chem Toxicol ; 41(4): 449-458, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-29115172

RESUMO

Toxicities of bisphenol A (BPA) and nonylphenol (NP) to the neotropical freshwater cladocerans Ceriodaphnia silvestrii and Daphnia similis were studied under laboratory conditions. Acute exposures to BPA generated mean 48-h EC50 values of 14.44 (6.02-22.85) mg L-1 for C. silvestrii and 12.05 (1.73-22.37) mg L-1 for D. similis. When the organisms were exposed to acute doses of NP, mean 48-h EC50 values were 0.055 (0.047-0.064) mg L-1 (C. silvestrii) and 0.133 (0.067-0.200) mg L-1 (D. similis). Ceriodaphnia silvestrii was also tested in chronic bioassays, which resulted in mean 8-d IC25 values of 2.43 (2.16-2.69) mg L-1 BPA [no observed effect concentration (NOEC): 1.38 mg L-1] and 0.020 (0.015-0.026) mg L-1 NP (NOEC: 0.015 mg L-1). These laboratory tests are valuable to broaden the understanding of the environmental threat posed by BPA and NP in aquatic ecosystems, and to increase the knowledge about the sensitivity of neotropical indigenous species to these contaminants. In addition to the laboratory bioassays, species sensitivity distributions were used to suggest protective concentrations of BPA and NP to prevent adverse effects on freshwater organisms. According to the obtained results, concentrations lower than 36.47 µg L-1 BPA and 1.39 µg L-1 NP are not expected to adversely impact aquatic organisms in natural ecosystems.


Assuntos
Compostos Benzidrílicos/toxicidade , Cladocera/efeitos dos fármacos , Daphnia/efeitos dos fármacos , Fenóis/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Ecossistema , Feminino , Água Doce , Especificidade da Espécie
12.
Environ Technol ; 34(13-16): 2317-26, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24350487

RESUMO

An old landfill leachate was pre-treated in a pilot-scale aerated packed tower operated in batch mode for total ammoniacal nitrogen (TAN) removal. The stripped ammonia was recovered with a 0.4 mol L(-1) H2SO4 solution, deionized water and tap water. Ca(OH)2 (95% purity) or commercial hydrated lime was added to the raw leachate to adjust its pH to 11, causing removal of colour (82%) and heavy metals (70-90% for Zn, Fe and Mn). The 0.4 molL(-1) H2SO4 solution was able to neutralize 80% of the stripped ammonia removed from 12 L of leachate. The effectiveness of the neutralization of ammonia with deionized water was 75%. Treating 100 L of leachate, the air stripping tower removed 88% of TAN after 72 h of aeration, and 87% of the stripped ammonia was recovered in two 31 L pilot-scale absorption units filled with 20 L of tap water.


Assuntos
Amônia/isolamento & purificação , Recuperação e Remediação Ambiental/instrumentação , Recuperação e Remediação Ambiental/métodos , Poluentes Químicos da Água/química , Absorção , Ar , Amônia/análise , Amônia/química , Hidróxido de Cálcio/química , Sulfeto de Hidrogênio , Concentração de Íons de Hidrogênio , Metais Pesados
13.
Eng. sanit. ambient ; 18(3): 215-222, July-Sept/2013. tab, graf
Artigo em Português | LILACS | ID: lil-690018

RESUMO

O objetivo do estudo foi avaliar a degradação do hormônio 17β-estradiol com doses de cloro e tempos de contato comumente utilizados em estações de tratamento de água. A aplicação de cloro levou a pequenas alterações na maioria das variáveis analisadas. A concentração inicial de 17β-estradiol influenciou a remoção pelo cloro, e observou-se que o aumento da dose de cloro aumentou a remoção do 17β-estradiol até a dose de 2 mg.L-1. A maior remoção de hormônio obtida foi de 99%, e a inativação dos microrganismos indicadores, E. coli e coliformes totais foi de até 5,6 log para valores de CT maiores que 14 mg.min.L-1 .


The purpose of this study was to evaluate the degradation of the estrogen 17β-estradiol at doses of chlorine and contact times commonly used in water treatment plants. The application of chlorine led to minor changes in most parameters examined. The initial concentration of the hormone affected the removal by chlorine and was observed that increasing the dose of chlorine increased the removal of 17β-estradiol until the dose of 2 mg.L-1. The highest removal of hormone obtained was 99%, and inactivation of the indicator microorganisms, E. coli and total coliform was up to 5.6 log for values of CT greater than 14 mg.min.L-1 .

14.
Chemosphere ; 92(2): 184-91, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23540811

RESUMO

This study was carried out to evaluate the efficiency of conventional drinking water treatment processes with and without pre-oxidation with chlorine and chlorine dioxide and the use of granular activated carbon (GAC) filtration for the removal of diclofenac (DCF). Water treatment was performed using the Jar test with filters on a lab scale, employing nonchlorinated artesian well water prepared with aquatic humic substances to yield 20HU true color, kaolin turbidity of 70 NTU and 1mgL(-1) DCF. For the quantification of DCF in water samples, solid phase extraction and HPLC-DAD methods were developed and validated. There was no removal of DCF in coagulation with aluminum sulfate (3.47mgAlL(-1) and pH=6.5), flocculation, sedimentation and sand filtration. In the treatment with pre-oxidation and disinfection, DCF was partially removed, but the concentration of dissolved organic carbon (DOC) was unchanged and byproducts of DCF were observed. Chlorine dioxide was more effective than chorine in oxidizing DCF. In conclusion, the identification of DCF and DOC in finished water indicated the incomplete elimination of DCF through conventional treatments. Nevertheless, conventional drinking water treatment followed by GAC filtration was effective in removing DCF (⩾99.7%). In the oxidation with chlorine, three byproducts were tentatively identified, corresponding to a hydroxylation, aromatic substitution of one hydrogen by chlorine and a decarboxylation/hydroxylation. Oxidation with chlorine dioxide resulted in only one byproduct (hydroxylation).


Assuntos
Diclofenaco/química , Purificação da Água/métodos , Carvão Vegetal , Cloro/química , Compostos Clorados/química , Cromatografia Líquida de Alta Pressão/métodos , Diclofenaco/isolamento & purificação , Desinfecção , Filtração/métodos , Substâncias Húmicas , Hidroxilação , Oxirredução , Óxidos/química , Espectrometria de Massas por Ionização por Electrospray
15.
Artigo em Português | LILACS | ID: lil-655386

RESUMO

As cianobactérias constituem um grupo de micro-organismos procariontes encontrado em ambientes aquáticos, os quais vêm sendo pesquisado devido à capacidade de produzir toxinas que causam grandes impactos à saúde pública e ambiental. A ocorrência de florações desses micro-organismos em reservatórios de água utilizada para abastecimento público tem sido frequente e prejudicado os usos múltiplos da água. Algumas cepas produzem florações nocivas liberando compostos neurotóxicos, hepatotóxicos ou irritantes à pele de seres humanos e animais, podendo ocasionar intoxicação e morte. A literatura reporta a ocorrência de um acidente em Caruaru, Pernambuco, onde faleceram 65 pacientes que faziam hemodiálise, devido à presença de microcistina-LR na água que consumiram. Esse estudo objetivou realizar uma revisão sobre a presença da toxina microcistina em água, os impactos e medidas de controle. Foram relatados os principais métodos utilizados para a remoção e quantificação da microcistina em água, bem como sua relação com a saúde humana.


Cyanobacteria are a group of prokaryotic microorganisms found in aquatic environments, which have been researched because of the ability to produce toxins that cause major public health impacts and environmental. The occurrence of seaweed buddings in reservoirs used for public supplying has been frequent, and has affected the multiple uses of the drinking water. Some strains of seaweed, in special the cyanobacterial, can produce toxins as the microcystins, which are responsible for the intoxication and death of animals and humans.The literature reports the occurrence of an accident in Caruaru, Pernambuco, where he died 65 hemodialysis patients who were due to the presence of microcystin-LR in water. This study aimed to perform a review of the presence of the toxin microcystin in water, impacts and control measures. Reported were the main methods used for the removal and quantification of microcystins in water and its relation to human health.


Assuntos
Cianobactérias/patogenicidade , Microcistinas/intoxicação , Saúde Pública
16.
Chemosphere ; 86(1): 36-40, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21955349

RESUMO

Abamectin is used as an acaricide and insecticide for fruits, vegetables and ornamental plants, as well as a parasiticide for animals. One of the major problems of applying pesticides to crops is the likelihood of contaminating aquatic ecosystems by drift or runoff. Therefore, toxicity tests in the laboratory are important tools to predict the effects of chemical substances in aquatic ecosystems. The aim of this study was to assess the potential hazards of abamectin to the freshwater biota and consequently the possible losses of ecological services in contaminated water bodies. For this purpose, we identified the toxicity of abamectin on daphnids, insects and fish. Abamectin was highly toxic, with an EC(50) 48 h for Daphnia similis of 5.1 ng L(-1), LC(50) 96 h for Chironomus xanthus of 2.67 µg L(-1) and LC(50) 48 h for Danio rerio of 33 µg L(-1).


Assuntos
Chironomidae/efeitos dos fármacos , Daphnia/efeitos dos fármacos , Ivermectina/análogos & derivados , Poluentes Químicos da Água/toxicidade , Peixe-Zebra/metabolismo , Acaricidas/análise , Acaricidas/toxicidade , Animais , Anti-Helmínticos/análise , Anti-Helmínticos/toxicidade , Cromatografia Líquida de Alta Pressão/veterinária , Fluorometria/veterinária , Inseticidas/análise , Inseticidas/toxicidade , Ivermectina/análise , Ivermectina/toxicidade , Dose Letal Mediana , Testes de Toxicidade Aguda , Poluentes Químicos da Água/análise
17.
Environ Technol ; 33(19-21): 2299-304, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-23393971

RESUMO

To boost crop yield, sugarcane growers are using increasing amounts of pesticides to combat insects and weeds. But residues of these compounds can pollute water resources, such as lakes, rivers and aquifers. The present paper reports the results of a study of water samples from the Feijão River, which is the source of drinking water for the city of São Carlos, São Paulo, Brazil. The samples were evaluated for the presence of four leading pesticides--ametryn, atrazine, diuron and fipronil--used on sugarcane, the dominant culture in the region. The samples were obtained from three points along the river: the headwaters, along the middle course of the river and just before the municipal water intake station. The pesticides were extracted from the water samples by solid-phase extraction (SPE) and then analyzed by liquid chromatography with diode array detection (LC-DAD). The analytical method was validated by traditional methods, obtaining recovery values between 90 and 95%, with precision deviations inferior to 2.56%, correlation coefficients above 0.99 and detection and quantification limits varying from 0.02 to 0.05 mg L(-1) and 0.07 to 0.17 mg L(-1), respectively. No presence of residues of the pesticides was detected in the samples, considering the detection limits of the method employed.


Assuntos
Praguicidas/análise , Poluentes Químicos da Água/análise , Cromatografia Líquida de Alta Pressão , Rios/química , Extração em Fase Sólida , Água/análise
18.
Environ Technol ; 33(15-16): 1767-77, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22439564

RESUMO

This study aims to verify the influence of the apparent molecular size of aquatic humic substances (AHSs) on the effectiveness of coagulation with aluminium sulphate and ferric chloride. Coagulation-filtration tests using the jar test and bench-scale sand filters were carried out with water samples having a true colour of approximately 100 Hazen units and prepared with AHSs of different molecular sizes. Stability diagrams are presented showing regions of > or = 90% and > or = 95% apparent colour removal delineated for each water sample using plots of total metal ion concentration (Al3+ and Fe3+) versus coagulation pH. To achieve the same degree of colour removal, the water samples with smaller apparent molecular sizes and a higher percentage of fulvic acids required higher dosages of both aluminium sulphate and ferric chloride.


Assuntos
Substâncias Húmicas/análise , Eliminação de Resíduos Líquidos/métodos , Compostos de Alúmen/química , Benzopiranos/análise , Cloretos/química , Compostos Férricos/química , Filtração , Peso Molecular , Espectrofotometria Ultravioleta
19.
J Chromatogr Sci ; 47(9): 785-8, 2009 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-19835689

RESUMO

A simple and efficient new procedure is presented for the analysis of diflubenzuron (DFB) accumulation in tilapia (Oreochromis niloticus) filet. A liquid-chromatography (LC) with diode array detection method with C(18) solid-phase extraction clean-up was employed. The methods exhibit no significant matrix effect as verified by the recovery efficiency. The limits of detection and quantification were 32 microg/kg and 110 microg/kg, respectively. LC-tandem mass spectrometry analysis confirmed the presence of DFB in filet of tilapia exposed to this pesticide. The method was successfully applied for the analyses of fish captured in three different fee-fishing farms during two seasons and for the analyses of fish from an experimental pond (subjected to Dimilin exposition) and depuration tank during different time intervals.

20.
Pesticidas ; 13: 53-58, jan.-dez. 2003. ilus, graf
Artigo em Português | LILACS | ID: lil-387514

RESUMO

Efetuou-se revisão de literatura sobre os principais tipos de pesticidas, bem como suas toxicidades e riscos associados contaminação da água e do meio ambiente. Os pesticidas podem ser bastante úteis na produção agrícola, especialmente quando o clima favorece o desenvolvimento de pragas. Contudo, o seus uso deve ser corretamente orientado por profissionais e a saúde da população. Para esses fins, as pesquisas na área de pesticidas vêm caminhando na direção da obtenção de compostos cada vez menos tóxicos para os seres vivos


Assuntos
Praguicidas , Poluentes da Água , Poluição da Água
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...