Perfil de exposição ao chumbo em crianças escolares da rede municipal da cidade do Rio de Janeiro, Brasil / The lead exposure profile of municipal public schoolchildren in the city of Rio de Janeiro, Brazil

Descrever os níveis de exposição ambiental ao chumbo entre criancas de duas escolas localizadas em regiões com características socioambientais distintas no município do Rio de Janeiro. Métodos: estudo piloto em amostra de conveniência com 270 estudantes. A análise das amostras de sangue capilar foi realizada usando o método de Espectrometria de Massa Acoplado a Plasma Indutivo (ICP-MS). A exposição ao chumbo entre as crianças foi estimada através de comportamentos e habitos diarios e presença de fontes de chumbo no domicilio ou entorno. Resultados: a concentração média do chumbo no sangue capilar foi 3,59 μg/dL ± 2,25. Cinco crianças (1,85 por cento) apresentaram concentrações acima de 10 μg/dL. Observou-se uma diferença estatisticamente significativa na concentração média de chumbo em sangue capilar nas variáveis idade (p=0,034), renda per capita (p=0,005) e exposição a chumbo (p=0,044). As variáveis renda média familiar per capita e idade mostraram-se inversamente proporcionais à concentração de chumbo e o status de exposição diretamente proporcional. As escolas apresentaram diferença estatisticamente significativa (p=0,004) quanto à prevalência de crianças expostas ao chumbo. Conclusões: embora a variável escola não tenha sido boa preditora da concentração capilar de chumbo, a maior prevalência de crianças expostas a chumbo se encontra na escola localizada na área mais poluída...

To describe the levels of environmental exposure to lead among children from two schools in regions with distinct social and environmental features in the municipality of Rio de Janeiro. Methods: a pilot study was carried out in a convenience sample of 270 students. Analysis of capillary blood samples was conducted using the Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Lead exposure among the children was estimated on the basis of the their daily habits and behavior patterns and the presence of sources of lead in the household or surrounding area. Results: the mean concentration of lead in capillary blood was 3.59 μg/dL ± 2.25. Five children (1.85 percent) had concentrations higher than 10 μg/dL. A statistically significant difference was found in the mean concentration of lead in capillary blood for the variables age (p=0.034), per capita income (p=0.005) and exposure to lead (p=0.044). The variables mean household per capita income and age were inversely proportional to the concentration of lead and exposure status directly proportional. There was a statistically significant difference between the schools (p=0.004) in terms of the prevalence of children exposed to lead. Conclusions: although the school variable was not a good predictor of capillary concentrations of lead, the higher prevalence of children exposed to lead was found in the school situated in the most polluted area...

Assessment of heavy metal residues in Brazilian poultry and swine tissue / Avaliação de resíduos de metais pesados em tecidos de aves e suínos

The aim of this study was to investigate the presence of arsenic, lead and cadmium residues in samples of liver, kidney and muscle of poultry and swine during the years from 2002 to 2008. A total of 1978 samples were analyzed: 1031 of poultry and 947 of swine from Brazilian slaughterhouses. The samples were analyzed at the National Agricultural Laboratory using the atomic absorption spectrometry technique. In poultry, the arsenic residues were detected in 53.6% of liver samples, although no results have exceeded the MRL. In kidneys, 39.7% of the samples showed measurable residues and there was no violation of the limits. Regarding lead, there were 5 contaminated liver samples and 24 contaminated kidney samples (1.5 and 3.6% respectively). In muscle tissue there was only one sample with residues...

Objetivou-se investigar a presença de resíduos de arsênico, chumbo e cádmio em amostras de fígado, rins e músculo de aves e suínos, durante os anos de 2002 a 2008. Um total de 1.978 amostras foi analisado: 1031 de aves e 947 de suínos provenientes de matadouros brasileiros. As amostras foram analisadas no Laboratório Nacional Agropecuário (Lanagro), sendo utilizada a técnica de espectrometria de absorção atômica. Em aves, os resíduos de arsênico foram detectados em 53,6% das amostras de fígado, embora sem exceder o LMR. Nos rins, 39,7% das amostras mostraram resíduos mensuráveis e não houve violação dos limites. Em relação ao chumbo, cinco amostras de fígado e 24 de amostras de rins estavam contaminadas (1,5 e 3,6%, respectivamente). No tecido muscular, houve apenas uma amostra com resíduos. Para o cádmio, 3,8% das amostras apresentavam valores abaixo do LMR. Resíduos de cádmio foram encontrados em 110 amostras de rins (16,3% testados), mas apenas uma ultrapassou o limite máximo permitido pela legislação nacional. Em suínos, resíduos de arsênico foram detectados em 15,3% das amostras de fígado, sem exceder o LMR. Nos rins, 14,2% das amostras apresentaram resíduos mensuráveis...

Flocculation of Cu, Mn, Ni, Pb, and Zn during estuarine mixing [Caspian Sea]

During estuarine mixing of fresh water with saline water and due to the flocculation process, a portion of dissolved metals come into particulate phase, and the dissolved load decreases. This process plays an important role in self-purification of heavy metals in rivers. In this study, flocculation of Cu, Mn, Ni, Pb and Zn during mixing of Cheshme-Kileh River water with Caspian Sea water has been investigated. Salinity and electrical conductivity are the governing factors for the flocculation of Mn and Cu. Zn and Ni are governed by pH. Dissolved oxygen is a governing factor for the flocculation of Pb. Rapid flocculation occurs in the earlier stages of mixing. The final flocculation rates of metals are in the following order: Mn [68.79%] > Pb [45.45%] > Ni [26.32%] > Cu [23.08%] > Zn [21.21%]. In addition, electro-flocculation [EF] is investigated. The results reveal that EF had adverse effect on flocculation rates of heavy metals. General pattern of EF of metals is like the following: Mn [57.89%] > Pb [40.9%] > Cu [23.08% > Ni [22.37%] > Zn [15.15%]. Furthermore, the effect of decreasing pH level on flocculation of heavy metals is studied. Except for Mn, decreasing the pH increased the flocculation rates of heavy metals. Maximum flocculation of Ni, Cu, Pb, and Zn occur at pH about 7.5. Due to the flocculation of trace metals during the estuarine mixing about 51.6, 7.8, 5.5, 3.9, and 3.6 ton/year of Mn, Ni, Zn, Pb, and Cu, respectively, are removed from the river water

Equilibrium sorption isotherm studies of Cd(II), Pb(II) and Zn(II) ions detoxification from waste water using unmodified and EDTA-modified maize husk

The mobilization of heavy metals in the environment due to industrial activities is of serious concern due to the toxicity of these metals in humans and other forms of life. The equilibrium adsorption isotherms of Cd(II), Pb(II) and Zn(II) ions, detoxification from waste water using unmodified and EDTA-modified maize husk have been studied. Maize husk was found to be an excellent adsorbent for the removal of these metal ions. The amount of these metal ions adsorbed increased as the initial concentration increased. Also, EDTA-modification enhanced the adsorption capacity of maize husk due to the chelating ability of ethylenediamine tetra acetic acid (EDTA). Among the three adsorption isotherms tested, Dubinin-Radushkevich isotherm gave the best fit with R² value ranging from 0.7646 to 0.9988 and an average value of 0.9321. This is followed by Freundlich and then Langmiur isotherms. The sorption process was found to be mostly a physiosorption process as seen from the apparent energy of adsorption which ranged from 1.03 KJ/mol to 12.91 KJ/mol. Therefore, this study demonstrates that maize husk which is an environmental pollutant could be used to adsorb heavy metals and achieve environmental cleanliness.