Risk analysis of a residential area close to the tailing dams of an ex-foundry



Several old mining sites in Latin America are unexpectedly turning into residential areas, posing a high health risk for its residents. Hence, we address the case of an old mineral processing plant and foundry, located in Chihuahua, Mexico. This study comprised site sampling, determination of Pb contents in the soil, and a risk analysis of the exposed child population via the Integrated Exposure Uptake Biokinetic Model (IEUBK, USEPA model). Three exposure scenarios were derived from the Pb concentrations found in soil and were classified as: maximum (A), average (B), and minimum (C). The IEUBK considered two amounts of soil intake: (350 mg/day) for areas without paved streets and (200 mg/day) for paved streets. Results show that 62% of the samples exceed the maximum permissible level recommended for lixiviates, which indicates the solubility and possible dispersion of metal contents. 90% of the samples exceed the permissible contents of Pb for residential use and 85% are above guidelines for industrial use. Results from the IEUBK model, considering unpaved streets, show that the average concentration of Pb in blood in scenarios A, B, and C were 79.94, 16.58, and 9.25 μg/dL, respectively. For communities with paved streets and under the same conditions, the amounts of Pb in blood decreased to 57.75, 11.57, and 4.18 μg/dL respectively. In both cases, the maximum permissible concentration of Pb in children's blood is exceeded. It is imperative to take the appropriate remediation measures in this site to reduce the Pb contents in the soil and to minimize the public health risk. © 2012 American Institute of Chemical Engineers Environ Prog, 32: 1150–1154, 2013