Environmental Assessment and Evaluation of Oxidative Stress and Genotoxicity Biomarkers Related to Chronic Occupational Exposure to Benzene.

Environmental and occupational exposure to benzene from fuels is a major cause for concern for national and international authorities, as benzene is a known carcinogen in humans and there is no safe limit for exposure to carcinogens. The objective of this study was to evaluate the genotoxic effects of chronic occupational exposure to benzene among two groups of workers: filling station workers (Group I) and security guards working at vehicles entrances (Group II), both on the same busy highway in Rio de Janeiro, Brazil. Sociodemographic data on the workers were evaluated; the concentration of benzene/toluene (B/T) in atmospheric air and individual trans,trans-muconic acid (ttMA) and S-phenylmercapturic acid (S-PMA) were measured; oxidative stress was analyzed by catalase (CAT), glutathione S-transferase (GST), superoxide dismutase (SOD), thiol groups (THIOL) and malondialdehyde (MDA); genotoxicity was measured by metaphases with chromosomal abnormalities (MCA) and nuclear abnormalities, comet assay using the enzyme formamidopyrimidine DNA glycosylase (C-FPG), and methylation of repetitive element LINE-1, CDKN2B and KLF6 genes. Eighty-six workers participated: 51 from Group I and 35 from Group II. The B/T ratio was similar for both groups, but Group I had greater oscillation of benzene concentrations because of their work activities. No differences in ttMA and S-PMA, and no clinical changes were found between both groups, but linearity was observed between leukocyte count and ttMA; and 15% of workers had leukocyte counts less than 4.5 × 109 cells L-1, demanding close worker's attention. No differences were observed between the two groups for THIOL, MDA, MCA, or nuclear abnormalities. A multiple linear relationship was obtained for the biomarkers MCA and C-FPG. A significant correlation was found between length of time in current job and the biomarkers C-FPG, MCA, GST, and MDA. Although both populations had chronic exposure to benzene, the filling station workers were exposed to higher concentrations of benzene during their work activities, indicating an increased risk of DNA damage.

The role of chemical interactions between thorium, cerium, and lanthanum in lymphocyte toxicity.

Thorium, cerium, and lanthanum are metals present in several types of minerals, the most common of which is monazite. Cerium and lanthanum are elements in the lanthanides series. Thorium, an actinide metal, is a hazardous element due to its radioactive characteristics. There is a lack of information describing the possible chemical interactions among these elements and the effects they may have on humans. Toxicological analyses were performed using cell viability, cell death, and DNA damage assays. Chemical interactions were evaluated based on the Loewe additivity model. The results indicate that thorium and cerium individually have no toxic effects on lymphocytes. However, thorium associated with lanthanum increases the toxicity of this element, thereby reducing the viability of lymphocytes at low concentrations of metals in the mixture.

Elevated manganese and cognitive performance in school-aged children and their mothers.

BACKGROUND: Growing evidence suggests that excess manganese (Mn) in children is associated with neurobehavioral impairments. In Brazil, elevated hair Mn concentrations were reported in children living near a ferro-manganese alloy plant. OBJECTIVES: We investigated these children's and caregivers' cognitive function in relation to bioindicators of Mn exposure. METHODS: In this cross-sectional study, the WISC-III was administered to 83 children aged between 6 and 12 years; the Raven Progressive Matrix was administered to the primary caregivers (94% mothers), who likewise responded to a questionnaire on socio demographics and birth history. Mn in hair (MnH) and blood (MnB) and blood lead (PbB) were measured by graphite furnace atomic absorption spectrometry (GFAAS). RESULTS: Children's mean MnB and MnH were 8.2 µg/L (2.7-23.4) and 5.83 µg/g (0.1-86.68), respectively. Mean maternal MnH was 3.50 µg/g (0.10-77.45) and correlated to children's MnH (rho=0.294, p=0.010). Children's MnH was negatively related to Full-Scale Intelligence Quotient (IQ) and Verbal IQ; ß coefficients for MnH were -5.78 (95% CI -10.71 to -0.21) and -6.72 (-11.81 to -0.63), adjusted for maternal education and nutritional status. Maternal MnH was negatively associated with performance on the Raven's (ß=-2.69, 95% CI -5.43 to 0.05), adjusted for education years, family income and age. CONCLUSIONS: These findings confirm that high MnH in children is associated with poorer cognitive performance, especially in the verbal domain. Primary caregiver's IQ is likewise associated to Mn exposure, suggesting that, in this situation, children's cognition may be affected directly and indirectly by Mn exposure.

High levels of hair manganese in children living in the vicinity of a ferro-manganese alloy production plant.

Manganese (Mn) is an essential element, but an effective toxic at high concentrations. While there is an extensive literature on occupational exposure, few studies have examined adults and children living near important sources of airborne Mn. The objective of this study was to analyze hair Mn of children living in the vicinity of a ferro-manganese alloy production plant in the Great Salvador region, State of Bahia, Brazil and examine factors that influence this bioindicator of exposure. We examined 109 children in the age range of 1-10 years, living near the plant. Four separate housing areas were identified a priori on the bases of proximity to the emission sources and downwind location. A non-exposed group (n=43) of similar socio-economic status was also evaluated. Mn hair (MnH) concentration was measured by graphite atomic absorption spectrometry (GFAAS). Possible confounding hematological parameters were also assessed. Mean MnH concentration was 15.20 microg/g (1.10-95.50 microg/g) for the exposed children and 1.37 microg/g (0.39-5.58 microg/g) for the non-exposed. For the former, MnH concentrations were 7.95+/-1.40 microg/g (farthest from the plant), 11.81+/-1.11 microg/g (mid-region), 34.43+/-8.66 microg/g (closest to the plant) and 34.22+/-9.15 microg/g (directly downwind). Multiple regression analysis on log transformed MnH concentrations for the exposed children derived a model that explained 36.8% of the variability. In order of importance, area of children's residence, gender (girls>boys) and time of mother's residence in the area at the birth of the child, were significantly associated with MnH. Post hoc analyses indicated two groupings for exposure areas, with those living closest to and downwind of the plant displaying higher MnH concentrations compared to the others. The contribution of the time the mother lived in the community prior to the child's birth to the children's current MnH suggests that in utero exposure may play a role. A study of neurobehavioral performance with respect to Mn exposure in these children is currently underway.

DDT and its metabolites in breast milk from the Madeira River basin in the Amazon, Brazil.

Until the 1990s the 1,1,1-trichloro-bis-2,2'-(4chlorophenyl) ethane (DDT) was sprayed in the walls of the house along the Madeira River basin, Brazilian Amazon, a region well known for its large number of malaria cases. In 1910, Oswaldo Cruz described the presence of malaria in 100% of the population living in some localities from the Madeira River basin. Data available in the literature point to the DDT contamination in fishes captured in Madeira River region. Fish is the major source of dietary protein to these people. DDT tends to accumulate in lipid rich tissues and is being eliminated by different events, including lactation. Considering the importance of feeding breast milk to the children, the associated risks of DDT exposure via breast milk intake to children must be assessed. This is the main objective of this work: to analyse the presence of the p,p'-DDT and its metabolites p,p'-DDE and p,p'-DDD in 69 human milk samples and to estimate the intake of DDT and its metabolite in terms of total DDT (total DDT=p,p'-DDE+p,p'-DDD+p,p'-DDT). All the samples showed contamination with DDT and its metabolites ranging from 25.4 to 9361.9 ng of total DDT/g of lipid (median=369.6 ng of total DDT/g of lipid) and 8.7% of the estimated daily intake (EDI), in terms of total DDT, which was higher than the acceptable daily intake proposed by the WHO.

Age related effects of pesticide exposure on neurobehavioral performance of adolescent farm workers in Brazil.

Adolescents (10 to 18 years old) from a rural area in the state of Rio de Janeiro, Brazil were tested using the Behavioral Assessment and Research System (BARS) to evaluate their performance. Participants were drawn from two areas--a school serving farm children (rural N=38) and a school serving children from a city within this area (urban N=28). These children were drawn from an ongoing study being carried out by Fundação Oswaldo Cruz where rural and urban participants were matched for age, sex, and level in school. For this ongoing study, the participants had been interviewed to determine their occupational history, especially their activities that might involve exposure to pesticides. Interview responses were used to assign an exposure index to each participant. While a few BARS performance measures suggested behavioral impairments for the rural versus the urban participants, a stronger and more consistent association between BARS measures (especially impairment of tapping, digit span, and selective attention) and level of exposure to pesticides was noted when the exposure index was entered into a multiple linear regression analysis. Exposure appeared to be especially strong for the youngest participants (10-11 years old). The relationship between these behaviors and the exposure index was stronger than the relationship between behaviors and either age or sex.

Dietary and reproductive determinants of plasma organochlorine levels in pregnant women in Rio de Janeiro.

Organochlorine (OC) plasma levels and their dietary and reproductive determinants were investigated in 64 pregnant women from Rio de Janeiro, Brazil. Prenatal exposure of newborns was evaluated in a subset of these women in which umbilical cord blood was analyzed. To assess the influence of dietary factors on OC levels, a semiquantitative food frequency questionnaire was completed by participants. Nondietary determinants were investigated through a general questionnaire that addressed reproductive history, lifestyle, and social-demographic characteristics. Both women and their newborns had detectable but low levels of OCs. The most frequently detected compound was p,p'-DDE, the main metabolite of p,p'-DDT. This compound was found in 97% of the women who participated in the study and in 67% of the umbilical cord blood samples, with levels ranging from 0.161 to 8.03ppb and from 0.320 to 1.06ppb, respectively. Among the OCs detected, only p,p'-DDE showed any correlation with dietary and nondietary factors. There was a positive correlation between maternal p,p'-DDE and the consumption of fish (Pearson r=0.38,P=0.002) and chicken (Pearson r=0.26, P=0.042). The correlation between pork consumption and p,p'-DDE exhibited an inverse relationship (Pearson r=-0.25,P=0.052). Parity was the only nondietary factor that showed a significant correlation (Pearson r=-0.36,P=0.004). The main determinants of p,p'-DDE levels in this group of women were fish consumption and parity, together explaining 28% of the variance (P<001), in a multivariate model.

Avaliação integrada do impacto do uso de agrotóxicos sobre a saúde humana em uma comunidade agrícola de Nova Friburgo, RJ / Integrated evaluation of the health impact of pesticide use in a community at Nova Friburgo, RJ

O impacto do uso de agrotóxicos sobre a saúde humana é um problema que tem merecido atenção da comunidade científica em todo o mundo, sobretudo nos países em desenvolvimento. O consumo de agrotóxicos na região sudeste do Brasil está estimado em 12kg de agrotóxico/trabalhador/ano. Em algumas áreas agrícolas do Estado do Rio de Janeiro, como na região da Microbacia do Córrego de São Lourenço, Nova Friburgo, o consumo de agrotóxico foi estimado em 56kg de agrotóxico/trabalhador/ano. Elevados níveis de contaminação humana e ambiental foram encontrados nesta região, como decorrência do uso extensivo destes agentes químicos. A avaliação do impacto sobre a saúde humana implica o conhecimento e a visualização da importância/magnitude relativa de cada uma das vias de contaminação. Inúmeros fatores, que, em geral, encontram-se inter-relacionados, contribuem para a situação encontrada na Microbacia do Córrego de São Lourenço e a forma mais adequada de se avaliar toda a dimensão deste problema é o uso de uma abordagem integrada.

Estaräo alguns grupos populacionais brasileiros sujeitos à açäo de disruptores endócrinos? / Are some Brazilian population groups subject to endocrine disrupters?

Várias substâncias químicas com atividade sobre o sistema endócrino têm sido amplamente utilizadas no Brasil tanto em atividades industriais quanto em outros ramos, como por exemplo, na agricultura. Alguns dados mostrando a contaminaçäo de grupos populacionais brasileiros por substâncias supostamente possuidoras destas propriedades säo apresentados. Entretanto, muito pouco, ou mesmo nada, se sabe sobre os efeitos que as mesmas têm sobre a saúde destas populaçöes expostas, mostrando claramente a necessidade urgente de implementaçäo de um programa destinado a esta finalidade.

Cancer cluster among young Indian adults living near power transmission lines in Bom Jesus do Tocantis, Pará, Brazil

Avaliou a ocorrência de um agrupamento de casos de câncer em 1992, que se verificou em adultos jovens indígenas vivendo em aldeia na Amazônia, situada nas proximidades de duas linhas de transmissäo de 500 kV, as quais começaram a operar em 1982. Determinou-se os níveis sangüíneos atuais de DDT e pesticidas organofosforados, assim como a presença de metais em amostras de cabelo. A exposiçäo a campos eletromagnéticos de freqüência extremamente baixa foi determinada durante diversas atividades diárias desenvolvidas pelos indígenas. Considerando-se a incidência de câncer em diferentes cidades brasileiras, a probabilidade de ocorrência ao acaso deste agrupamento de casos foi considerada remota (p<0,03, distribuiçäo de Poisson). Níveis elevados de p.p'-DDT (mediana variando entre 26 e 58 ppb) foram observados nas amostras estudadas. A exposiçäo contínua aos campos eletromagnéticos de freqüência extremamente baixa, a qual atingiu 95 mG abaixo das linhas de transmissäo, foi observada em diversas oportunidades durante atividades diárias desenvolvidas pelos índigenas. Estudos observacionais futuros deveriam analisar a interaçäo da exposiçäo aos campos eletromagnéticos de freqüência extremamente baixa (50-60 Hz) subseqüente à exposiçäo a agentes de iniciaçäo tumoral no desenvolvimento de neoplasias.