Background
The growth of industry in northern Mexico has created
the potential for severe environmental problems. Yet,
attention to environmental controls has lagged behind
the pace of industrialization. Industrial sites such as ore
smelters are often located in residential areas, where
exposure to heavy metals through inhalation and ingestion
of contaminated soil and dust is possible [1].
Lead has long been established as a health threat to
people living in communities surrounding ore smelters
and refineries [2]. In 1999, the Benin group [1], analyzed
dust samples obtained from residential neighborhoods
around metallurgic industries in Monterrey, Chihuahua
and Torreon, Mexico. Dust concentrations of all heavy
metals were significantly higher around the active smelter
in Torreon, where more than 90% of samples
exceeded Superfund cleanup goals of 400 μg/g for lead
in soil [3]. The dust samples in Torreon had a median