Screening epidemiological study: Blood lead levels in the vicinity of a lead smelter

Abstract

The private sector lead smelting industry in Cairo has traditionally been located in a northern suburb, Shoubra el-Kheima. Originally an industrial zone, over time residential blocks have filled in the neighborhood, until now it is one of the country's most densely populated areas. The largest of these smelters is the Awadallah Secondary Lead Smelter, which began operation in 1979, and ceased smelting activities in 2001 as the Government of Egypt (GOE) encouraged smelters to move to new industrial zones and install up-to-date technology to reduce harmful emissions from the smelting process. Since 2001, the smelter facility has been used to refine and manufacture lead products. Knowing the 'state of the site', however, is only one part of the picture. It is also necessary to ascertain that the smelter imposed no adverse health effects on the people living in proximity to the smelter due to the high levels of lead contamination that exists in the study area. A screening epidemiological study determining blood lead levels - the best available index of body lead load - was conducted to provide further information on the potential impacts of lead contamination in the vicinity of the Awadallah Smelter. This allowed determination of the effect of environmental lead on the blood lead levels of children younger than 7 years of age (the most vulnerable to the harmful effects of lead), on females of reproductive age and on adult males. The study investigated the relationship between the blood lead levels of the target population with lead contamination of the indoor environment - household dust, drinking water, and interior paint. It was found that the outdoor environment, especially lead contamination of the soil, was the primary cause of elevated blood lead levels in residents. The lead levels of the test group varied from one zone to another, depending on soil lead levels. Another study was done three years after shutting down the smelter and cleaning a children's school situated in the study area, it was found that the blood lead level for most of the children in the school was within the allowable limit.