Lead Exposure and Indicators of Biological Effect

Abstract

ISEE-193 Objective: The medical literature shows that both occupational and environmental exposure to lead affect the human health. Clinical manifestations appear when the absorbed lead is higher than the eliminated lead, generating the acute or chronic intoxication. The aim of this study was to analyze comparatively, using some specific and precocious affected biological indicators, 2 groups of people occupationally and environmentally exposed to lead. Material and Methods: We investigated 195 workers from a nonferrous metallurgical plant (mean = 31.81 ± 8.19 years and meantime of exposure = 9.03 ± 6.67 years), and 255 people who live in the proximity (mean = 35.66 ± 8.49 years and meantime of exposure = 7.73 ± 6.16 years). We carried out clinical, neurological, and psychological examinations, biotoxicologic investigations, urinary delta amino levulinic acid (ALA-u), zinc protoporphyrin (ZPP), and standard questionnaires regarding the effects of lead on the human organism. The air lead exceeded 71.3 times the maximum accepted values. Results: We found high values of ZPP (over 10 μg/L) in 78.6% of exposed workers and 28.2% of people from the environmental group. In the environmental group, aged 20 to 35 years and length of service under 5 years, 19.1% had ZPP over 10 μg/L. High values of ALA-u (over 10 mg/L) were found in 68.1% of exposed workers and 27.4% from the environmental group. In the group aged 20 to 35 years and had length of service under 5 years, 62.9% workers and 16.6% controls had values over 10 mg/L. There were concordance between ZPP and ALA-u values (r = 0.567, P < 0.001). Conclusions: There were significant differences between the exposed and environmental group regarding the values of the intoxication marker ZPP (P < 0.001) and the values of ALA-u, which is specific for the lead intoxication (P < 0.001). There were also significant differences regarding ZPP and ALA-u values between the 2 groups (aged 20–35 years and working length under 5 years) (P < 0.001). The most affected were the younger people. The general and professional morbidity correspond with the clinical and toxicologic data.