Lead concentrations in whole blood, serum, saliva and house dust in samples collected at two time points (12 months apart) in Santo Amaro, BA, Brazil.

UNLABELLED: Whole Blood Lead Level (BLL) is the main marker used to verify lead contamination. The present study explores how BLL is associated with lead concentrations in serum, saliva and house dust. Samples were collected twice from Santo Amaro, BA, Brazil, a region that was contaminated by a lead smelter in the past; a time interval of 12 months was allowed between the two collections. It is noteworthy that the following measures have recently been taken to diminish exposure of the population to lead: streets have been paved with asphalt, and educational campaigns have been launched to reduce exposure to contaminated dust. RESULTS: Compared with the first time point, all the samples collected at the second time point contained lower lead concentration (p<0.05), which suggested that the adopted measures effectively reduced exposure of the population to lead present in contaminated soil and dust. Statistically significant correlations only existed between lead in blood collected in the first year and lead in blood collected in the second year (Spearman's r=0.55; p<0.0001; n=62), and lead in house dust collected in the first year and lead in house dust collected in the second year (Spearman's r=0.5; p<0.0001; n=59). CONCLUSIONS: Results support the validity of lead determination in blood and in house dust to assess lead exposure over time. However, lead in blood and lead in dust did not correlate with lead in serum or lead in saliva.

Avaliação da exposição ao Pb e Cd em crianças de 0 a 17 anos por consumo de alimentos vegetais cultivados em solos contaminados no município de Santo Amaro (BA) / Evaluation of Pb and Cd exposure in children 0 to 17 years of age by consumption of vegetable food cultivated in soils contaminated in Santo Amaro (BA)

O objetivo do presente trabalho foi estimar as doses de exposição aos contaminantes chumbo (Pb) e cádmio (Cd) em crianças de 0 a 17 anos de idade via consumo de alimentos vegetais cultivados em quintais contaminados, localizados no entorno de uma metalúrgica desativada, no município de Santo Amaro, Estado da Bahia. Para a estimativa das doses foi utilizada a metodologia de avaliação de riscos sobre a saúde humana, especificamente a etapa de análise da exposição, determinando as concentrações dos metais e variáveis sociodemográficas das crianças. As doses de exposição estimadas para ambos os contaminantes superaram os valores recomendados pela Organização Mundial da Saúde (OMS), atingindo valores máximos de exposição de 166,9 μg.kg−1 dia−1 e 2,95 μg.kg−1 dia−1 para o Pb e o Cd, respectivamente, por consumo de frutas. Os resultados comprovam que o consumo de alimentos vegetais cultivados em quintais pela população residente próxima à antiga fábrica é uma importante rota de exposição atual aos metais, representando um risco para a saúde da população.

This paper aims to estimate the exposure of children between 0 to 17 years old to lead (Pb) and cadmium (Cd) via ingestion of vegetables cultivated in contaminated backyards located in the surroundings of a deactivated lead metallurgy in Santo Amaro, Bahia, Brazil. For the estimation of the exposure doses, the risk assessment on human health methodology, exposure analysis, was used, determining the concentrations of metals and socio-demographic variables of children. The estimated doses for both contaminants exceeded the values recommended by the World Health Organization (WHO). Maximum obtained values were 166.9 μg.kg−1 day−1 and 2.95 μg.kg−1 day−1 for Cd and Pb, respectively, due to fruits consumption. The results show that the consumption of vegetables cultivated in the backyards by the population living near the deactivated metallurgical plant plays an important role in the exposition of the population to metals.

A study of the routes of contamination by lead and cadmium in Santo Amaro, Brazil.

The problem of contamination by cadmium and lead in Santo Amaro, Brazil, has been studied since 1970 and the severity of this contamination case has been demonstrated by many authors. This study evaluates the persistence of the superficial soil contamination around the metallurgical plant and attempts to correlate the lead and cadmium concentrations to the past atmospheric emissions from the lead plant and with the presence of lead debris under urban road surface and in the backyards of homes. Past emissions still play an important role in soil contamination. In areas without debris, about 30% of the soil samples had lead concentrations above the agricultural use limit of 180 parts per million (ppm) (according to CONAMA 420, 2009), 20% of the samples had concentrations above 300 ppm (maximum for residential use) and 9.6% of the samples had concentrations above 900 ppm (maximum for industrial use). These concentrations are higher cldse to the chimney of the metallurgical plant. An average lead concentration of 1316 ppm was found in the backyard samples. About 80% of the houses had lead concentrations above 300 ppm and about 50% of the samples had values above 900 ppm, indicating the importance of the lead debris in the contamination scenario. Although a matter of concern, the cadmium concentrations seem to be less problematic than lead at the present time, probably due to the higher mobility of cadmium. The cadmium concentrations in the atmospheric dispersion and backyard samples showed similar trends, while the influence of the lead debris on the soil contamination is less evident.