Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 134
Filter
1.
Braz. j. biol ; 83: e247562, 2023. tab, graf
Article in English | MEDLINE, LILACS, VETINDEX | ID: biblio-1339410

ABSTRACT

Abstract To investigate the role of cow dung in soil reclamation and bio assimilation along with bio accumulation of heavy metals in earthworm (P. posthuma) (N=900) earthworms were used and treatment groups of CD-soil mixture of different proportion of cow dung were designed. Nonlethal doses of lead acetate and cadmium chloride were added in treatment groups. Mature P. posthuma were released in each experimental pot maintaining the favorable conditions. The pH, carbon, nitrogen, phosphorus, exchangeable cations, and heavy metal level of each mixture was evaluated. The results indicated that bio-assimilation of Pb and Cd by P. posthuma were significantly (P ˂ 0.01) higher in different soil-CD treatments compared to control. Highest bio-assimilation of both metals was observed in T1 of both groups (Pb = 563.8 mg/kg and Cd = 42.95 mg/kg). The contents of both metals were significantly (P ˂ 0.05) lowered in casting. The nutrient concentration in the final castings of all soil-CD treatments were also equally transformed from less or insoluble to more soluble and available for plants, except for carbon level which increased with CD proportion. It is concluded that cow dung as organic matter has a positive effect on soil reclamation and bio-assimilation of metals by P. posthuma.


RESUMO Para investigar o papel do esterco de vaca na recuperação do solo e bioassimilação, juntamente com a bioacumulação de metais pesados ​​em minhocas (P. posthuma) (N = 900), minhocas foram usadas e grupos de tratamento de mistura CD-solo de diferentes proporções de esterco de vaca foram projetados. Doses não letais de acetato de chumbo e cloreto de cádmio foram adicionadas aos grupos de tratamento. P. posthuma maduros foram liberados em cada vaso experimental, mantendo as condições favoráveis. Foram avaliados o pH, carbono, nitrogênio, fósforo, cátions trocáveis ​​e nível de metais pesados ​​de cada mistura. Os resultados indicaram que a bioassimilação de Pb e Cd por P. posthuma foi significativamente (P ˂ 0,01) maior em diferentes tratamentos de solo-CD em relação ao controle. A maior bioassimilação de ambos os metais foi observada em T1 de ambos os grupos (Pb = 563,8 mg / kg e Cd = 42,95 mg / kg). O conteúdo de ambos os metais foi significativamente (P ˂ 0,05) reduzido na fundição. A concentração de nutrientes nas fundições finais de todos os tratamentos de solo-CD também foi igualmente transformada de menos ou insolúvel para mais solúvel e disponível para as plantas, exceto o nível de carbono que aumenta com a proporção de CD. Conclui-se que o esterco de vaca como matéria orgânica tem um efeito positivo na recuperação do solo e na bioassimilação de metais por P. posthuma.


Subject(s)
Animals , Female , Oligochaeta , Soil Pollutants , Metals, Heavy/analysis , Soil , Cadmium , Cattle , Bioaccumulation
2.
Braz. j. biol ; 83: e249641, 2023. tab, graf
Article in English | MEDLINE, LILACS, VETINDEX | ID: biblio-1339363

ABSTRACT

Abstract Estuaries receive daily inputs of chemical elements which can impact the quality of water and sediment, as well as the health of biota. In addition to the sediment, bivalve mollusks have been used in the chemical monitoring of these systems. This study investigated the presence and contents of As, Ba, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn in superficial sediment and in bivalves (Crassostrea gasar, C. rhizophorae and Mytella guyanensis) from estuaries in the south / extreme south of Bahia State, northeast Brazil. The samples were evaluated with inductively coupled plasma optical emission spectrometry (ICP-OES, Varian 710). Except for Cd, all other elements were found in the samples, being that Co was exclusive in the sediment. The estuaries equivalent to sampling stations #1 - Valença, #2 - Taperoá, #3 - Ilhéus and #4 - Belmonte showed levels of metals compatibles with those established by the Brazilian legislation, however, the #5 - Santa Cruz Cabrália, in addition to the presence of As, presented a high level of Pb and Cu in C. gasar, which was attributed to the impacts of nautical activities in that locality.


Resumo Estuários recebem entradas diárias de elementos químicos, que podem impactar a qualidade de água e do sedimento, assim como a saúde da biota. Além do sedimento, moluscos bivalves têm sido utilizados no monitoramento químico desses sistemas. Neste estudo investigou-se a presença e os teores de As, Ba, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb e Zn no sedimento superficial e em bivalves (Crassostrea gasar, C. rhizophorae e Mytella guyanensis) de estuários do sul / extremo sul do estado da Bahia, Nordeste do Brasil. As amostras foram avaliadas por espectrometria de emissão óptica de plasma indutivamente acoplado (ICP-OES, Varian 710). Exceto Cd, todos os demais elementos foram encontrados nas amostras, sendo que Co foi exclusivo no sedimento. Os estuários equivalentes às estações amostrais #1 - Valença, #2 - Taperoá, #3 - Ilhéus e #4 - Belmonte mostraram níveis de metais compatíveis com os estabelecidos pela legislação brasileira, porém, a #5 - Santa Cruz Cabrália, além da presença de As, apresentou alto nível de Pb e de Cu em C. gasar, o que foi atribuído aos impactos por atividades náuticas nesse local.


Subject(s)
Animals , Water Pollutants, Chemical/analysis , Bivalvia , Metals, Heavy/analysis , Brazil , Environmental Monitoring , Estuaries , Geologic Sediments
3.
Braz. j. biol ; 82: e237604, 2022. tab, graf
Article in English | MEDLINE, LILACS, VETINDEX | ID: biblio-1285586

ABSTRACT

Abstract This study goal to evaluate the effects of different concentrations of lead (Pb) and silver (Ag) on germination, initial growth and anatomical alterations of Lactuca sativa L. Plants use various mechanisms to reduce the impacts caused by anthropic action, such as xenobiotic elements of soils and water contaminated by heavy metals. These metals were supplied as lead nitrate and silver nitrate and the following treatments were established: control for both metals, maximum dose of heavy metals, for arable soils, allowed by the National Council of the Environment (Ag = 25 mg. Kg-1, Pb = 180 mg. Kg-1), double (Ag = 50 mg. Kg-1, Pb = 360 mg. Kg-1) and triple (Ag = 75 mg. Kg-1, Pb = 540 mg. Kg -1) of this dosage. Vigor and germination tests of the seeds and possible anatomical changes in the leaves and roots of lettuce plants were performed. The species showed a high capacity to germinate under Pb and Ag stress, and the germination was never completely inhibited; however, the germination decreased with increasing Pb concentrations, but not under Ag stress. The use of increasing doses of metals reduced seed vigor and increased chlorophyll content. An increase in biomass was also observed in plants from treatments submitted to Pb. The phytotoxic effects of metals were more pronounced at 15 days after sowing. Anatomically, L. sativa was influenced by metal concentrations, and had a reduction of up to 79.9% in root epidermis thickness at the highest Pb concentration, although some structures did not suffer significant changes. The results suggest that L. sativa presents tolerance to high concentrations of heavy metals, showing possible mechanisms to overcome the stress caused by these metals. In this research lettuce possibly used the mechanism of exclusion of metals retaining Pb and Ag in the roots preserving the photosynthetic apparatus in the aerial part of the plants. In general, the chemical element Pb was more toxic than Ag, in these experimental conditions.


Resumo Este estudo teve como objetivo avaliar os efeitos de diferentes concentrações de chumbo (Pb) e prata (Ag) na germinação, crescimento inicial e alterações anatômicas de Lactuca sativa L. As plantas utilizam vários mecanismos para reduzir os impactos causados pela ação antrópica, como elementos xenobióticos de solos e água contaminada por metais pesados. Esses metais foram fornecidos como nitrato de chumbo e nitrato de prata e foram estabelecidos os seguintes tratamentos: controle para ambos os metais, dose máxima de metais pesados, para solos cultiváveis, permitida pelo Conselho Nacional do Meio Ambiente (Ag = 25 mg.Kg-1, Pb = 180 mg.Kg-1), dobro (Ag = 50 mg.Kg-1, Pb = 360 mg.Kg-1) e triplo (Ag = 75 mg.Kg-1, Pb = 540 mg.Kg -1) desta dosagem. Foram realizados testes de vigor e germinação das sementes e possíveis alterações anatômicas nas folhas e raízes das plantas de alface. A espécie apresentou alta capacidade de germinar sob estresse de Ag e Pb, e a germinação nunca foi completamente inibida; entretanto, a germinação diminuiu com o aumento das concentrações de Pb, mas não sob estresse de Ag. O uso de doses crescentes dos metais, reduziu o vigor das sementes e aumentou o teor de clorofila. Também foi observado aumento da biomassa nas plantas a partir dos tratamentos submetidos ao Pb. Os efeitos fitotóxicos dos metais foram mais acentuados aos 15 dias após a semeadura. Anatomicamente, L. sativa foi influenciada pelas concentrações de metais, e teve uma redução de até 79,9% na espessura da epiderme radicular na maior concentração de Pb, embora algumas estruturas não tenham sofrido alterações significativas. Os resultados sugerem que L. sativa apresenta tolerância a altas concentrações de metais pesados, mostrando possíveis mecanismos para superar o estresse causado por esses metais. Nesta pesquisa a alface possivelmente utilizou o mecanismo de exclusão de metais retendo Pb e Ag nas raízes preservando o aparato fotossintético na parte aérea das plantas. De forma geral o elemento químico Pb se mostrou mais tóxico que Ag, nestas condições experimentais.


Subject(s)
Soil Pollutants/toxicity , Metals, Heavy/analysis , Metals, Heavy/toxicity , Silver Nitrate , Soil , Lettuce , Lead/toxicity , Nitrates/toxicity
4.
Braz. j. biol ; 82: e246979, 2022. tab, graf
Article in English | MEDLINE, LILACS, VETINDEX | ID: biblio-1278466

ABSTRACT

Abstract The influence of pharmaceutical residues and heavy metals on living organisms has received global attention. The present study assessed the interactive effect of antibiotic residues and heavy metals in soil, as contaminated food with cadmium (Cd) and oxytetracycline (OTC) on the isopod Porcellio leavis. It was fed on fresh plant leaves contaminated with different concentrations of cadmium, Cd+OTC1000 ppm, Cd+OTC2000 ppm and Cd+OTC3000 ppm for 4 weeks. The changes in the feeding patterns, protein, lipid peroxidation (LPO), catalase activity (CAT), and total free amino acids (TFAA) were recorded. There were significant differences in the obtained results where Cd reduced the egestion ratio (ER) however, OTC enhanced this ratio. Biochemical analysis illustrated that combination between OTC and Cd inhibits the toxic effects of Cd at low concentration (1000 ppm), while at high concentration (3000 ppm) raise the toxicity. Detailed studies are required for further understanding of the interaction between OTC and heavy metals, and also its impact on soil animals and for improving soil risk evaluation.


Resumo A influência de resíduos farmacêuticos e metais pesados ​​em organismos vivos tem recebido atenção global. O presente estudo avaliou o efeito de resíduos de antibióticos e metais pesados ​​no solo, como alimentos contaminados com cádmio (Cd) e oxitetraciclina (OTC), sobre o isópode Porcellio laevis, o qual foi alimentado com folhas frescas de plantas contaminadas com diferentes concentrações de cádmio, Cd + OTC1000 ppm, Cd + OTC2000 ppm e Cd + OTC3000 ppm, por quatro semanas. As mudanças nos padrões de alimentação, proteína, peroxidação lipídica (LPO), atividade da catalase (CAT) e aminoácidos livres totais (TFAA) foram registradas. Houve diferenças significativas nos resultados obtidos, em que o Cd reduziu a taxa de excreção (ER), no entanto o OTC aumentou essa proporção. A análise bioquímica mostrou que a combinação entre OTC e Cd inibe os efeitos tóxicos do Cd em baixa concentração (1.000 ppm), enquanto, em alta concentração (3.000 ppm), aumenta a toxicidade. Estudos detalhados são necessários para uma maior compreensão da interação entre OTC e metais pesados, e seu impacto sobre os animais do solo, bem como para melhorar a avaliação de risco do solo.


Subject(s)
Animals , Oxytetracycline/toxicity , Soil Pollutants/toxicity , Metals, Heavy/analysis , Isopoda , Soil , Cadmium/toxicity
5.
Braz. j. biol ; 82: e243633, 2022. tab, graf
Article in English | LILACS | ID: biblio-1249273

ABSTRACT

Abstract Snow trout (Schizothorax plagiostomus) is an economically important freshwater fish, mostly found in northern areas of water reservoirs of Pakistan. The current study was conducted in River Swat to analyze the bioaccumulation of heavy metals (Pb, Cr, Ni, and Zn) in tissues of Schizothorax plagiostomus. Tissues were extracted and dissolved in perchloric acid (HClO4) and nitric acid (HNO3) along with hotplate. The heavy metals, zinc (Zn), lead (Pb), chromium (Cr), and Nickel (Ni) were determined using Perkin Elmer 2380 atomic absorption spectrophotometer. Results shows great variation in the content of the metal related to tissue type and sampling sites. A high concentration of bioaccumulation was reported at Charbagh, whereas lowest at Odigram: Charbagh>Landakai>Odigram. In the same way, Cr was the most accumulated heavy metal followed by lead, nickel, and Zinc:


Resumo A truta das neves (Schizothorax plagiostomus) é um peixe de água doce economicamente importante, encontrado principalmente nas áreas ao norte de reservatórios de água do Paquistão. O presente estudo foi realizado em River Swat para analisar a bioacumulação de metais pesados (Pb, Cr, Ni e Zn) em tecidos de Schizothorax plagiostomus. Os tecidos foram extraídos e dissolvidos em ácido perclórico (HClO4) e ácido nítrico (HNO3) com placa de aquecimento. Os metais pesados zinco (Zn), chumbo (Pb), cromo (Cr) e níquel (Ni) foram determinados usando espectrofotômetro de absorção atômica Perkin Elmer 2380. Os resultados mostram grande variação no conteúdo do metal relacionado ao tipo de tecido e locais de amostragem. Uma alta concentração de bioacumulação foi relatada em Charbagh, enquanto a mais baixa, em Odigram: Charbagh > Landakai > Odigram. Da mesma forma, Cr foi o metal pesado mais acumulado, seguido por Pb, Ni e Zn.


Subject(s)
Animals , Water Pollutants, Chemical/analysis , Cyprinidae , Metals, Heavy/analysis , Pakistan , Environmental Monitoring , Rivers , Bioaccumulation
6.
Braz. j. biol ; 82: e230147, 2022. tab, graf
Article in English | LILACS | ID: biblio-1153479

ABSTRACT

Abstract Metals and agrochemicals are among the main aquatic contaminants, being able to trigger oxidative stress in exposed organisms. The objective of this work was to evaluate the correlation between the level of oxidative stress biomarkers in Aegla crabs (Crustacea, Anomura) with (i) the set of metals present in the streams sediment and (ii) with land uses of three hydrographic basins. The study was carried out in streams (≤ 2nd order) of hydrographic basins in southern Brazil (Basins of Rio Suzana, Rio Ligeirinho-Leãozinho and Rio Dourado). In these streams were quantified the land uses and Cu, Cr, Cd, Fe, Mn and Zn concentrations in the sediment. The enzymes Catalase (CAT) and Glutathione Reductase (GR), as well as the level of membrane lipid peroxidation (TBARS), were analyzed in adult females. The PCA analysis showed that the distribution of metals was different between the basins. Cd, Cr and Fe were correlated positively with CAT and negatively with TBARS and GR. The Dourado basin had the lowest concentrations of these three metals and the highest levels of TBARS. However, in Dourado basin there is predominance of agriculture land use, and TBARS was positively correlated with agricultural land use. Besides in Dourado basin, GR activity was higher than in the others basins, indicating a compensatory response in relation to CAT inhibition. The basins of Suzana and Ligeirinho-Leãozinho rivers had lower TBARS values, which may be due to the induction of CAT in response to metals accumulated in sediment. In summary, this work indicates that in the basins with a higher concentration of toxic metals there is an adaptive response of CAT induction, which reduces TBARS in Aegla. On the other hand, in the basin with lower metallic contamination, TBARS occurrence was primarily influenced by agricultural land use.


Resumo Os metais e agroquímicos estão entre os principais contaminantes aquáticos, podendo desencadear estresse oxidativo em organismos expostos. O objetivo deste trabalho foi avaliar uma possível correlação entre o nível de biomarcadores de estresse oxidativo em Aegla (Crustacea, Anomura) com (i) o conjunto de metais presentes no sedimento e (ii) com os usos da terra, em três bacias hidrográficas distintas. O estudo foi realizado em riachos (≤ 2ª ordem) de bacias hidrográficas do Sul do Brasil (Bacias do Rio Suzana, do Rio Ligeirinho-Leãozinho e do Rio Dourado), as quais foram caracterizadas em função do percentual de usos da terra e do nível de Cu, Cr, Cd, Fe, Mn e Zn no sedimento. As enzimas Catalase (CAT) e Glutationa Redutase (GR), bem como o nível de peroxidação lipídica das membranas (TBARS), foram analisadas em fêmeas adultas. Uma análise de PCA mostrou que a distribuição de metais foi distinta entre as bacias. Cd, Cr e Fe no sedimento correlacionaram positivamente com a CAT e negativamente com TBARS e GR. Entretanto, a bacia do Dourado apresentou os menores níveis destes três metais e os maiores níveis de TBARS, o que pode ser justificado pelo predomínio da agricultura nesta bacia, já que o TBARS correlacionou positivamente com o percentual de uso agrícola. Nesta bacia, a atividade da GR foi mais alta do que nas outras, indicando uma resposta compensatória em relação a inibição da CAT. As bacias do rio Suzana e rio Ligeirinho-Leãozinho apresentaram valores menores de TBARS, o que pode decorrer da indução da CAT em função dos metais acumulados no sedimento. Em síntese, este trabalho indica que nas bacias com maior concentração de metais tóxicos ocorre uma resposta adaptativa de indução da CAT, o que reduz os níveis de TBARS em Aegla. Por outro lado, na bacia com menor contaminação metálica os níveis de TBARS foram primariamente influenciados pelo uso agrícola.


Subject(s)
Animals , Female , Water Pollutants, Chemical/analysis , Water Pollutants, Chemical/toxicity , Metals, Heavy/analysis , Anomura , Brazil , Biomarkers/metabolism , Environmental Monitoring , Oxidative Stress , Rivers , Agriculture
7.
Article in Chinese | WPRIM | ID: wpr-921631

ABSTRACT

The effects of four natural organic soil amendments on the quality and pesticide residues of Panax notoginseng were investigated through field experiments and the suitable dosage ratio of each soil amendment was selected to provide a new idea for the pollution-free cultivation of P. notoginseng. The four natural organic soil amendments used in this study were Jishibao, Jihuo, Fudujing, and omnipotent nutrients, which were produced by mixed fermentation of aboveground parts of different plants, biological waste residue, and biochar. During the experiments, only four soil amendments were applied to P. notoginseng instead of any pesticides and fertilizers. The experiment was designed as four factors and three levels. There were three dosage gradients(low, medium, and high) for Jishibao(A), Jihuo(B), Fudujing(C), and omnipotent nutrients(D). When the dosage of one soil amendment changed, the do-sage of the other soil amendments remained medium. There were 10 groups in addition to the soil amendment-free group as control(CK). The results showed that the four soil amendments could significantly improve the growth environment of P. notoginseng and increase the seedling survival rate and saponin content of P. notoginseng. The seedling survival rates of the treatment groups increased by 8.24%-30.05% as compared with the control group. Furthermore, the content of pesticide residues in P. notoginseng was too low to be detected, and that of heavy metals in P. notoginseng was far lower than the specified content in the Chinese Pharmacopoeia(2020). The optimal effect was achieved at medium dosage for all the soil amendments with the highest content of saponins, high seedling survival rate, and significantly reduced heavy metals, such as lead, cadmium, arsenic, and mercury.


Subject(s)
Arsenic , Metals, Heavy/analysis , Panax notoginseng , Soil , Soil Pollutants/analysis
8.
Article in English | WPRIM | ID: wpr-887736

ABSTRACT

Objective@#This study aimed to assess the risk of cumulative exposure to Pb, Cd, Hg, and iAs through aquatic products consumed by Chinese people.@*Methods@#Heavy metal concentration data were obtained from the national food contamination monitoring program during 2013-2017. Consumption data were derived from the China National Food Consumption Survey in 2014 and the relative potency factor (RPF) method was used to estimate cumulative exposure for neurotoxicity and nephrotoxicity.@*Results@#The results demonstrated that the cumulative exposure based on neurotoxicity was below the lower confidence limit on benchmark doses of lead (BMDL @*Conclusion@#The cumulative exposures of the 2-6 year-old group to the four heavy metals did not reach (but came close to) the corresponding safety threshold for both neurotoxicity and nephrotoxicity. Given that there are still other food sources of these four heavy metals, it is necessary to more closely study their cumulative health effects.


Subject(s)
Adolescent , Adult , Aged , Animals , Arsenic/analysis , Child , Child, Preschool , Dietary Exposure/analysis , Environmental Monitoring , Food Contamination/analysis , Humans , Metals, Heavy/analysis , Middle Aged , Risk Assessment , Seafood/analysis , Water Pollutants, Chemical/analysis , Young Adult
9.
Braz. j. biol ; 81(2): 398-405, 2021. tab, graf, ilus
Article in English | MEDLINE, LILACS, VETINDEX | ID: biblio-1153348

ABSTRACT

Continuous occurrence of heavy metals is a major cause of environmental pollution due to its toxic effects. At minimum concentrations, these metals are highly reactive and can gather in the food chains and food web, causing major dangers to public health concerns. Soil samples were collected from Paharang drain, Faisalabad. Cadmium tolerant bacteria were isolated and evaluated for their MIC against Cd. The isolated bacterial strain GCFSD01 showed MIC value upto 30 mM/L. The bacterial strain with the highest resistance against Cd was selected for further study. Molecular characterization of bacterial isolate GCFSD01 was performed by 16S rRNA which confirmed it as Bacillus cereus. Optimum growth conditions of bacterial strain were also evaluated. Strain GCFSD01 showed optimum growth at pH 7 and 37 °C temperature. Our result revealed that B. cereus strain GCFSD01 reduced 61.3% Cd after 48 hrs. Multiple metal tolerance and Cd reduction by B. cereus indicate its potential for further use for decontamination of polluted soil.


A ocorrência contínua de metais pesados é uma das principais causas de poluição ambiental devido aos seus efeitos tóxicos. A contaminação por metais pesados representa um grande risco para todas as formas de vida encontradas no meio ambiente. Em concentrações mínimas, esses metais são altamente reativos e podem se acumular nas cadeias alimentares e na cadeia alimentar, causando grandes perigos às preocupações com a saúde pública. Amostras de solo foram coletadas no esgoto de Paharang, Faisalabad. Bactérias tolerantes ao cádmio foram isoladas da amostra coletada pelo método da placa de ágar. As colônias separadas individuais selecionadas foram avaliadas quanto às suas concentrações inibitórias mínimas contra Cd. A cepa bacteriana isolada GCFSD01 apresentou valores de CIM de 30 mM/L. A colônia bacteriana que apresentou maior resistência contra o Cd foi selecionada para identificação. Após seleção da maior colônia bacteriana resistente ao Cd, coloração de Gram e diferentes testes bioquímicos foram realizados para a caracterização da bactéria isolada. A caracterização molecular do isolado bacteriano GCFSD01 foi realizada por PCR 16S rRNA confirmando a presença de Bacillus cereus. Após a identificação molecular, as condições ótimas de crescimento da cepa bacteriana também foram verificadas. A cepa GCFSD01 apresentou crescimento ótimo em pH 7 e temperatura de 37 °C. Nosso resultado revelou que a cepa de B. cereus GCFSD01 reduziu 61,3% de Cd após 48 horas. A tolerância a múltiplos metais e a redução de Cd por B. cereus indicam seu potencial para uso posterior na descontaminação do solo poluído.


Subject(s)
Soil Pollutants/toxicity , Bacillus cereus/genetics , Cadmium/toxicity , Industrial Effluents/adverse effects , Metals, Heavy/analysis , Soil , Soil Microbiology , Biodegradation, Environmental , RNA, Ribosomal, 16S/genetics
10.
Braz. j. biol ; 80(4): 823-828, Oct.-Dec. 2020. tab
Article in English | LILACS | ID: biblio-1142532

ABSTRACT

Abstract This study was conducted to assess water pollution by examining DNA fragmentation in selected fish organs (kidney, liver, gills, and muscle tissue) from Wallago attu, Sperata sarwari, Vulgaris vulgaris, and Labeo rohita collected from a known polluted section of the Chenab River, Pakistan, and from a control site. The fish were caught using a gill net and were assigned to three different weight groups (W1, W2, and W3) to study the degree of variation in DNA fragmentation in relation to body weight. In fish from the polluted site, DNA fragmentation was higher in kidney, liver, gills, and muscles, compared to the control. No significant DNA fragmentation was observed in fish collected from the control site. Highly significant (P < 0.01) relationship between body weight and DNA fragmentation was found in the organs of fish procured at the contaminated site. DNA fragmentation in body organs was found to be affected by the concentrations of lead, copper, nickel, and cadmium in W. attu, S. sarwari, L. rohita, and V. vulgarus harvested from Chenab River. DNA fragmentation in different freshwater fish species is therefore a reliable biomarker of water pollution.


Resumo Este estudo foi conduzido para avaliar a poluição da água examinando a fragmentação do DNA em órgãos de peixes selecionados (rim, fígado, brânquias e tecido muscular) de Wallago attu, Sperata sarwari, Vulgaris vulgaris e Labeo rohita coletados de uma conhecida área poluída do rio Chenab, Paquistão e de um local de controle. Os peixes foram capturados usando uma rede branquial e foram divididos em três grupos de pesos diferentes (W1, W2 e W3) para estudar o grau de variação na fragmentação do DNA em relação ao peso corporal. Nos peixes do local poluído, a fragmentação do DNA foi maior nos rins, fígado, brânquias e músculos, em comparação ao controle. Não foi observada fragmentação significativa do DNA em peixes coletados no local de controle. Relação altamente significativa (P <0,01) entre o peso corporal e a fragmentação do DNA foi encontrada nos órgãos dos peixes adquiridos no local contaminado. Verificou-se que a fragmentação do DNA nos órgãos do corpo é afetada pelas concentrações de chumbo, cobre, níquel e cádmio em W. attu, S. sarwari, L. rohita e V. vulgarus colhidos no rio Chenab. A fragmentação do DNA em diferentes espécies de peixes de água doce é, portanto, um biomarcador confiável da poluição da água.


Subject(s)
Animals , Water Pollutants, Chemical/analysis , Water Pollutants, Chemical/toxicity , Metals, Heavy/analysis , Pakistan , Environmental Monitoring , Rivers , DNA Fragmentation , Gills
11.
Braz. j. biol ; 79(4): 659-664, Nov. 2019. tab, graf
Article in English | LILACS | ID: biblio-1001473

ABSTRACT

Abstract The Doce River basin has suffered the largest environmental accident ever occurred in Brazil with the influx of tailings from Fundão and Santarém, belonging to Samarco mining company, due to the disaster in Mariana. A spill between 50 and 60 million m3 of tailings was estimated by the company. According to Samarco, the wastewater was composed mainly of clay, silt and heavy metals like iron, copper and manganese. Thereby, the objective of the present study was evaluated the genotoxic damage in juvenile of Geophagus brasiliensis (Quoy e Gaimard, 1824) exposed to Doce river water before (DRWBA - Doce River water before acident) and after (DRWAA - Doce River water after acident) the influx of tailings from the Germano and Santarém Dam disasters in Mariana, MG, Brazil. For this, 24 individuals of the species G. brasiliensis (obtained on IFES/ALEGRE fish culture) were submitted to a bioassay with three treatments and eight replicates. The treatments were: 1) Control water (water from the urban water supply system, filtered with a 0.45 µm membrane), 2) DRBA and 3) DRAA. After 96 h, these fishes were anesthetized to remove blood for evaluation of genotoxic damage (micronucleus and comet). For the bioassay, a total of 80 L of The Doce River water were collected before the influx of tailings and after the influx and then submitted to metal quantification analysis. Fish exposed to DRWBA and DRWAA treatments showed a significant increase in both the number of erythrocyte micronuclei and the DNA damage index in relation to the control fish; however, they did not present any differences between the two treatments. The results demonstrate that the DRWBA treatment was already genotoxic for the fish, mainly due to dissolved Cu concentrations in the water. The DRWAA treatment probably presented genotoxicity due to the increase in the dissolved fraction and synergistic effects of several metals found in the tailings of the Mariana accident.


Resumo A bacia do Rio Doce sofreu o maior acidente ambiental com o influxo de rejeitos de Fundão e Santarém, pertencentes à empresa de mineração Samarco, devido ao desastre em Mariana. Um derramamento entre 50 e 60 milhões de m3 de rejeitos foi estimado pela empresa. De acordo com a Samarco, o rejeito despejado era composto principalmente de argila, silte e alguns metais pesados como ferro, cobre e manganês. Com isso, o presente estudo teve como objetivo avaliar os danos genotóxicos em juvenis de Geophagus brasilienses expostos a água do rio Doce antes (DRWAA - água do Rio Doce antes do acidente) e depois (DRWBA- água do Rio Doce depois do acidente) da chegada dos rejeitos do rompimento das barragens de Germano e Santarém em Mariana, MG, Brasil. Para isso, 24 indivíduos da espécie G. brasilienses (obtidos na piscicultura do IFES/ALEGRE) foram submetidos a um bioensaio com três tratamentos e oito réplicas. Os tratamentos eram: 1) Controle (com água do abastecimento urbano, filtrada com filtro analítico de 0,45 µm); 2) DRWBA e 3) DRWAA. Após um período de 96 h, esses peixes foram anestesiados para retirada de sangue para avaliação dos danos genotóxicos (micronúcleo e cometa). Para a realização do bioensaio, um total de 80 L de água do Rio Doce foram coletados antes da chegada dos rejeitos e outros 80 L foram coletados depois da chegada dos rejeitos e ambas foram submetidas a análises de quantificação de metal. Os peixes expostos ao DRWBA e ao DRWAA apresentaram um aumento significativo na quantidade de micronúcleos eritrocitários e no índice de danos do DNA em relação aos peixes controle, no entanto não apresentaram diferenças entre si. Os resultados obtidos demonstram que a DRWBA já era genotóxica para os peixes, principalmente, em função das concentrações de Cu dissolvido na água. A DRWAA apresentou genotixicidade, provavelmente, em função do aumento da fração dissolvida e do efeito sinérgico de diversos metais presentes nos rejeitos do acidente de Mariana.


Subject(s)
Animals , DNA Damage/drug effects , Metals, Heavy/analysis , Metals, Heavy/classification , Cichlids/physiology , Cichlids/genetics , Disasters , Water Pollutants, Chemical/analysis , Water Pollutants, Chemical/classification , Water Pollutants, Chemical/toxicity , Brazil , Environmental Monitoring/methods , Metals, Heavy/toxicity , Rivers/chemistry , Fresh Water/chemistry , Mining
12.
Braz. arch. biol. technol ; 62: e19180211, 2019. tab, graf
Article in English | LILACS | ID: biblio-1039127

ABSTRACT

Abstract Mangroves are tropical and subtropical flooded forests that generally develop in estuarine areas over unstable sediments protected from the action of waves in the intertidal zone with an environment characterized by a great diversity of fauna and flora. Thus, the present study aimed to evaluate the levels of heavy metals that are absorbed by mangrove oysters, in estuarine systems in the Alagoas coast by determining the concentrations of Fe, Cu, Mn, Zn, Cd and Cr. Two areas, which consisted of both a collection during the rainy season and the dry season, were selected for sampling of mangrove oysters. In each collection, seven samples were collected, at seven different points, where each sample contained four oysters. In the laboratory the oysters were dried at 105°C for 72 hours and then macerated. It was then digested with 10 ml of a solution comprising a combination of 4:1 nitric acid and hydrochloric acid, initially in 1h at 40°C, followed by 3 hours at 140°C. In General, the medians followed the order Zn > Fe > Mn > Cu > Cr > Cd in MMELC and Zn > Cu > Fe > Mn > Cr > Cd in Meirim River. It is concluded that the Crassostrea rhizophorae oysters from the studied environments presented concentrations of all the metals proposed in the research and demonstrates its accumulating and bioindicator character.


Subject(s)
Ostreidae , Metals, Heavy/analysis , Wetlands , Brazil
13.
Braz. j. microbiol ; 49(1): 29-37, Jan.-Mar. 2018. tab, graf
Article in English | LILACS | ID: biblio-889196

ABSTRACT

ABSTRACT Increased environmental pollution has necessitated the need for eco-friendly clean-up strategies. Filamentous fungal species from gold and gemstone mine site soils were isolated, identified and assessed for their tolerance to varied heavy metal concentrations of cadmium (Cd), copper (Cu), lead (Pb), arsenic (As) and iron (Fe). The identities of the fungal strains were determined based on the internal transcribed spacer 1 and 2 (ITS 1 and ITS 2) regions. Mycelia growth of the fungal strains were subjected to a range of (0-100 Cd), (0-1000 Cu), (0-400 Pb), (0-500 As) and (0-800 Fe) concentrations (mgkg-1) incorporated into malt extract agar (MEA) in triplicates. Fungal radial growths were recorded every three days over a 13-days' incubation period. Fungal strains were identified as Fomitopsis meliae, Trichoderma ghanense and Rhizopus microsporus. All test fungal exhibited tolerance to Cu, Pb, and Fe at all test concentrations (400-1000 mgkg-1), not differing significantly (p > 0.05) from the controls and with tolerance index >1. T. ghanense and R. microsporus demonstrated exceptional capacity for Cd and As concentrations, while showing no significant (p > 0.05) difference compared to the controls and with a tolerance index >1 at 25 mgkg-1 Cd and 125 mgkg-1 As. Remarkably, these fungal strains showed tolerance to metal concentrations exceeding globally permissible limits for contaminated soils. It is envisaged that this metal tolerance trait exhibited by these fungal strains may indicate their potentials as effective agents for bioremediative clean-up of heavy metal polluted environments.


Subject(s)
Fungi/isolation & purification , Fungi/metabolism , Metals, Heavy/metabolism , Soil Pollutants/metabolism , Cadmium/analysis , Cadmium/metabolism , Copper/analysis , Copper/metabolism , Fungi/classification , Fungi/genetics , Gold/analysis , Gold/metabolism , Metals, Heavy/analysis , Mining , Phylogeny , Soil Pollutants/analysis
14.
Braz. j. microbiol ; 49(1): 7-9, Jan.-Mar. 2018.
Article in English | LILACS | ID: biblio-889192

ABSTRACT

ABSTRACT In this report, we present a draft genome of 2,886,173 bp of an Exiguobacterium aurantiacum strain PN47 isolate from the sediment of a saline pond named "Salar del Huasco" in the Altiplano in the North of Chile. Strain PN47 encodes adaptive characteristics enabling survival in extreme environmental conditions of high heavy metal and salt concentrations and high alkalinity.


Subject(s)
Bacillaceae/isolation & purification , Bacillaceae/genetics , Ponds/microbiology , Genome, Bacterial , Phylogeny , Bacillaceae/classification , Bacillaceae/metabolism , DNA, Bacterial/genetics , Base Sequence , Sodium Chloride/analysis , Sodium Chloride/metabolism , Ponds/chemistry , Chile , Metals, Heavy/analysis , Metals, Heavy/metabolism
15.
Braz. arch. biol. technol ; 61: e18160777, 2018. tab, graf
Article in English | LILACS | ID: biblio-974113

ABSTRACT

ABSTRACT This study aims to specify the amount of ten heavy metals (Al, Cr, Mn, Ni, Cu, Zn, As, Cd, Hg, Pb) in water, sediment and Enteromorpha intestinalis samples gathered from Kadin Creek in seasonal periods in 2011 and 2012 and to reveal bioaccumulation capability of this macrophytic algae. In this regard, heavy metal concentrations in the gathered samples were determined first with mineralization and then via inductively coupled plasma mass spectroscopy (ICP-MS) method. Findings suggested that algae could be used as an indicator in freshwater ecosystems in terms of studied heavy metals. With regard to bioconcentration factor values, in terms of water, algae accumulated aluminum the most and cadmium the least (Al > Cu > As > Zn > Cr > Mn > Ni > Pb > Hg > Cd), in terms of sediment, it accumulated mercury the most and aluminum the least (Hg > Cd > As > Zn > Pb > Mn > Ni > Cr > Cu > Al). The highest rate of heavy metal concentration in algae was observed in summer when contaminants in water and dynamics of plant development increased. It was also observed that the mean mercury and cadmium concentrations exceeded the maximum residue limit values.


Subject(s)
Seaweed , Water Samples , Metals, Heavy/analysis , Bioaccumulation
16.
Braz. j. biol ; 76(4): 967-974, Oct.-Dec. 2016. tab, graf
Article in English | LILACS | ID: biblio-828099

ABSTRACT

Abstract In this study we determined the concentration of metals (Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn) in the water lower São Francisco River basin, to evaluate the influence of urbanization and industrialization on environmental changes in the water resource. All samples were analyzed using the IUPAC adapted method and processed in an atomic absorption spectrophotometer. The sampling stations located near the industrial areas were influenced by industrialization because they presented higher concentrations of Cd, Cr, Ni and Cu. The other sampled locations showed changes with regard the trace elements probably originating in the soil, like Fe, Zn and Pb. There was a gradual increase in the concentrations of metals, in general, in the period of highest rainfall of the hydrographic network. Overall, except for Zn and Mn, the trace elements exceeded the maximum allowed value established by national legislation (CONAMA). Lower São Francisco River basin has suffered interference from urbanization and industrialization, so awareness programs should be developed so as to control and lessen future problems.


Resumo Neste trabalho foi determinada a concentração dos metais (Cd, Cr, Cu, Fe, Mn, Ni, Pb e Zn) na água do submédio Rio São Francisco para avaliar a influência da urbanização e da industrialização nas modificações ambientais do recurso hídrico. Todas as amostras foram analisadas usando o método IUPAC adaptado e processados em um espectrofotômetro de absorção atômica. As estações de amostragem localizadas próximas às áreas industriais sofreram influência da industrialização por apresentarem concentrações mais elevadas de Cd, Cr, Ni e Cu. Os demais locais amostrados apresentaram modificações com relação aos elementos traços de provável origem sedimentar como Fe, Zn e Pb. Houve aumento gradativo nas concentrações dos metais, de forma geral, no período de maior pluviosidade da rede hidrográfica. Em geral, com exceção do Zn e Mn, os elementos traços ultrapassaram o valor máximo permitido, estabelecido pela legislação nacional (CONAMA). O submédio Rio São Francisco tem sofrido interferência da urbanização e industrialização, por isso, é preciso que, programas de conscientização sejam estabelecidos, para controlar e amenizar problemas futuros.


Subject(s)
Seasons , Metals, Heavy/analysis , Rivers/chemistry , Spectrophotometry, Atomic , Trace Elements/analysis , Urbanization , Brazil , Environmental Monitoring , Industrial Development
17.
Acta cir. bras ; 31(7): 490-497, tab, graf
Article in English | LILACS | ID: lil-787266

ABSTRACT

ABSTRACT PURPOSE: To evaluate the contamination index of metals and pesticides in pregnant women, and to relate this to perinatal outcomes. METHODS: Descriptive, retrospective, exploratory study, developed from existing secondary data analyses at Level III maternity center. A total of 40 mothers with their newborns (NB), living in a rural area in Botucatu- Brazil and surrounding region. Blood samples from mothers and newborn were collected to determine the total contamination index for metals and pesticides. The concentrations of each metal and each pesticide were determined in blood samples of mothers and their newborns by Rudge's results. After obtaining these concentrations, the total contamination index in mother and NB was calculated, along with its correlation with clinical parameters of NB. RESULTS: There was no correlation (p> 0.05) between maternal contamination index with NB clinical parameters, and NB contamination index versus NB clinical parameters. CONCLUSION: The maternal contamination index of metals and pesticides was not related to perinatal outcomes, but it could be used as baseline parameter in future toxicological studies, regarding to long-term toxic characteristics as persistent organic pollutants, its long half-lives, bioacumulative, and expected to impose serious health effects on humans.


Subject(s)
Humans , Female , Infant, Newborn , Adult , Young Adult , Pesticides/blood , Birth Weight , Metals, Heavy/blood , Fetal Blood/chemistry , Pesticides/analysis , Rural Population/statistics & numerical data , Socioeconomic Factors , Brazil , Pregnancy , Hazardous Substances/analysis , Hazardous Substances/blood , Retrospective Studies , Maternal Exposure/adverse effects , Metals, Heavy/analysis
18.
Rev. biol. trop ; 64(2): 779-789, abr.-jun. 2016. tab, ilus
Article in English | LILACS | ID: biblio-843312

ABSTRACT

AbstractThe use of direct response of animals to environmental challenges by production of biomarkers is a better tool to assess environmental pollution than the conventional methods. This study aimed to measure Glutathione-S-transferase (GST) in earthworms as tools for assessing heavy metal pollution in abattoir soil. Five (5) replicates each of earthworm species (Libyodrilus violaceous, Eudrilus eugeniae and Alma millsoni), soil and rumen waste samples were collected from three (3) abattoir sites (Lafenwa, Gbonogun and Madojutimi abattoirs), and a control site located within Federal University of Agriculture Abeokuta, beside an undisturbed stream with no rumen waste. Heavy metal (Cu, Zn, Pb, Cd, Co, Cr, Ni and Mn) concentrations in rumen waste, abattoir soils and earthworm tissues were determined using Atomic Absorption Spectrophotometer. The pH and organic matter (OM) concentrations of the rumen waste and abattoir soils were determined by standard methods. GST activities in the earthworm tissues were determined through the conjugation of 1 mM reduced glutathione (GSH) with 1 mM 1-chloro-2,4-dinitrobenzene (CDNB). The rumen waste recorded significantly higher (p ≤ 0.05) % OM, heavy metal concentrations and pH level than in their respective abattoir soils. The mean heavy metal concentrations of Cu, Zn, Pb, Cd and Mn were highest in the tissue of earthworm species obtained from Lafenwa abattoir. A significantly (p ≤ 0.05) higher GST activities were recorded in the tissue of earthworm species obtained from Lafenwa and Gbonogun abattoirs. Libyodrilous violaceus obtained from Lafenwa abattoir recorded the highest GST activity (8.47±1.39) in their tissue followed by the ones from Gbonogun abattoir (8.21±0.85). A significant (p ≤ 0.05) positive correlations was observed between GST activities in earthworm tissues and heavy metal concentrations. GST activities can therefore be used to assess the level of heavy metal pollution in abattoir soils. Rev. Biol. Trop. 64 (2): 779-789. Epub 2016 June 01.


Subject(s)
Animals , Oligochaeta/enzymology , Soil Pollutants/analysis , Metals, Heavy/analysis , Environmental Biomarkers , Glutathione Transferase/biosynthesis , China , Environmental Monitoring , Abattoirs
19.
Rev. bras. plantas med ; 18(2,supl.1): 613-620, 2016. tab, graf
Article in English | LILACS | ID: biblio-830060

ABSTRACT

ABSTRACT Zinc (Zn) participates of numerous metabolic processes in plants. However, it can become toxic to plants in excessive concentrations in the soil. Pfaffia glomerata is a Brazilian medicinal species that has stood out because of its numerous chemical and functional properties, mainly by the triterpene saponins and ecdysteroids accumulated in its roots. This study aimed to evaluate the effects of zinc excess on many root morphological parameters of Pfaffia glomerata. A 4 x 3 factorial design was employed in a completely randomized scheme with 3 replicates. The treatments consisted of four concentrations of Zn (2, 100, 200, and 300 µM) and three accessions of P. glomerata (BRA, GD, and JB) grown in a hydroponic system for 7 and 14 days. Differences in root morphology and dry mass production were observed among the three accessions in response to excessive Zn. Some growth parameters of GD accession increased with the addition of Zn, ranging from 36 to 79 µM. However, the GD and JB accessions presented reduction in dry mass production, root area, length, and volume with increasing Zn levels. The BRA accession, which had the lowest growth among accessions, presented chlorotic leaves. The shoot/root dry mass ratio and root diameter increased linearly for BRA and GD accessions at 7 days. Based on the evaluated parameters, we observed the following order of Zn excess tolerance in P. glomerata accessions: GD> JB> BRA.


RESUMO O zinco (Zn) participa de numerosos processos metabólicos nas plantas. No entanto, em concentrações excessivas no solo pode tornar-se tóxico para os vegetais. Pfaffia glomerata é uma espécie medicinal brasileira que tem se destacado devido as suas inúmeras propriedades químicas e funcionais, devido principalmente às saponinas triterpênicas e ecdisteróides acumuladas em suas raízes. O objetivo do presente trabalho foi avaliar os efeitos do excesso de Zn sobre vários parâmetros morfológicos radiculares de Pfaffia glomerata. O delineamento experimental utilizado foi o inteiramente casualizado com três repetições, dispostos em um arranjo fatorial (4 x 3). Os tratamentos consistiram em quatro níveis de Zn (2, 100, 200 e 300µM) e três acessos (BRA, GD e JB) de P. glomerata cultivados em sistema hidropônico em casa de vegetação por 7 e 14 dias. Diferenças na morfologia radicular e na produção de material seca foram observadas entre os três acessos em resposta ao excesso de Zn. Alguns parâmetros de crescimento do acesso GD aumentaram sob a adição de Zn variando entre 36 e 79 µM. No entanto, os acessos GD e JB apresentaram redução na matéria seca, bem como na área de superfície, comprimento e volume radicular com o aumento dos níveis de Zn. O acesso BRA, que teve o menor crescimento entre os acessos, apresentou folhas cloróticas. A razão entre matéria seca da parte aérea e raízes e o diâmetro radicular aumentou linearmente para os acessos BRA e GD aos 7 dias de cultivo. Baseando-se nos parâmetros avaliados foi observada a seguinte ordem de tolerância ao excesso de Zn: GD> JB> BRA.


Subject(s)
Amaranthaceae , Panax , Zinc/analysis , Growth , Metals, Heavy/analysis
20.
Bol. Acad. Nac. Med. B.Aires ; 93(2): 217-231, jul.-dic. 2015. tab
Article in Spanish | LILACS | ID: biblio-997159

ABSTRACT

El cabello y especialmente el localizado en la cabeza provee importante información sobre posibles exposiciones ambientales y/o laborales a diferentes elementos. El pelo puede ser considerado como un producto excretor, y su estudio reflejaría el metabolismo de minerales en el cuerpo. Nuestro propósito en el presente estudio es conocer si datos existentes dan información poblacional sobre la presencia de elementos tóxicos o no a través del análisis del cabello humano. RESULTADOS: Fue analizada la información proveniente de 241 muestras de cabello, de los cuales 163 (67,6%) corresponden al sexo femenino y 78 (32,4%) al masculino. Fueron analizados 22 elementos esenciales y 17 elementos de tóxicos. Entre los elementos esenciales presentaron resultados elevados Calcio (Ca), Magnesio (Mg), Manganeso (Mn), Molibdeno (Mo), Vanadio (V), Estroncio (Sr) y Circonio (Zr); entre los elementos tóxicos tuvieron valores elevados Aluminio (Al), Arsénico (As), Bario (Ba), Bismuto (Bi), Cadmio (Cd), Níquel (Ni), Plomo (Pb), Mercurio (Mg), Plata (Ag), Estaño (Sn). CONCLUSIÓN. Nuestro estudio muestra a nivel poblacional, no individual, puntos de alerta por la carencia o exceso de algunos elementos analizados debiéndose continuar con estudios locales interdisciplinarios en los cuales exista información sobre enfermedades, hábitos alimentarios, hábitos tóxicos, actividad laboral y exposición ambiental a los diferentes elementos. (AU)


Hair, especially localized in the head, provides important information on possible environmental and/or labor exposures to different elements. Hair can be considered as an excretory product, and its study would reflect the metabolism of minerals in the body. Our purpose in this study was to determine whether existing population data provide information on the presence of toxic and non-toxic elements by analizing human hair. RESULTS: We analyzed information from 241 hair samples, of which 163 (67.6%) are from females and 78 (32.4%) are from males. There were analyzed 22 essential elements and 17 toxic elements. Among the essential elements that had elevated results there were: Calcium (CA), magnesium (Mg), manganese (Mn), molybdenum (Mo), vanadium (V), strontium (Sr) and zirconium (Zr); among the toxic elements, those with higher values were: Aluminum (Al), arsenic (As), barium (BA), bismuth (Bi), Cadmium (Cd), Nickel (Ni), lead (Pb), Mercury (Mg), silver (Ag), tin (Sn). CONCLUSION. Our study shows at population level, not individual, warning points due to the lack or excess of some elements analyzed. It is reccommended to continue the research with local interdisciplinary studies which include information on diseases, eating habits, toxic habits, work activity and environmental exposure to different elements. (AU)


Subject(s)
Humans , Male , Female , Metals, Heavy/analysis , Metals, Heavy/chemistry , Hair/chemistry , Minerals/analysis , Minerals/chemistry , Epidemiology, Descriptive , Retrospective Studies , Observational Study
SELECTION OF CITATIONS
SEARCH DETAIL