A fluorometric high-performance liquid chromatographic (HPLC) method was developed for the highly sensitive measurement of delta-aminolevulinic acid (ALA) in biological materials. By using this method, we determined ALA in the plasma and urine of 418 workers occupationally exposed to lead and in the plasma and urine of 227 controls. The concentrations of ALA in the plasma and urine of lead workers were significantly elevated as compared with those of the controls. The concentration of ALA in plasma and urine was highly correlated with that of lead in blood in lead workers. It was found that the correlation (r = 0.742) between log of plasma ALA concentrations and blood lead concentrations in lead workers was similar to that (r = 0.711) between log of urine ALA concentrations and blood lead concentrations. These results demonstrated that the measurement of ALA in plasma or in urine using a fluorometric HPLC method was useful for the biological monitoring of lead workers.

To clarify the effects of lead on autonomic and central nervous system functions, electrocardiographic R-R interval variability (CVRR) as well as visual and brainstem auditory evoked potentials (VEP and BAEP) were measured in 36 female workers exposed to lead (exposed group) and in 15 female textile workers (unexposed group). The C-CVLF, C-CVHF (two component CVs of the CVRR reflecting sympathetic and parasympathetic activities, respectively), and LF/HF ratio (indicator of sympatho-vagal balance) were also computed from component spectral powers by means of autoregressive spectral and component analyses. The exposed group had engaged in glass work for 2-17 (mean 7.8) years. Blood lead (BPb) concentrations were 25.8-79.3 (mean 55.6) micrograms/dl in the exposed group and 4.7-8.6 (mean 6.3) micrograms/dl in the unexposed group. The CVRR, C-CVLF, C-CVHF, and LF/HF ratio in the exposed group were significantly lower than those in the unexposed group. Also, the exposed group had more complaints of subjective symptoms and signs than did the unexposed group. On the other hand, no significant differences in either VEP or BAEP latencies were found between the two groups. It is suggested that autonomic nervous function is more susceptible to lead than visual and auditory nervous functions; lead affects sympathetic activity more strongly than parasympathetic activity.

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Aims: Although lead exposure has, in the absence of mathematical modelling, been believed to elevate blood pressure in females, it is necessary to clarify the relation between lead and blood pressure by eliminating confounding factors in the analysis. Methods: Blood lead was measured in 193 female workers, including 123 lead exposed workers. Possible confounding factors were controlled by multiple regression analyses. Results and Conclusion: Blood lead above 40 µg/dl was found to be the most potent factor for elevating systolic/diastolic blood pressure. Aging, urine protein, and plasma triglyceride also contributed to systolic/diastolic/pulse pressure increase, but hypertensive heredity did not. Data suggested that lead induced changes in lipoprotein metabolism may play an important role in the lead induced blood pressure increase in female workers. Blood pressure is believed to become increased among residents exposed to lead, such as that emitted from house paint, gasoline, and other sources. Several reports are available concerning the lead-blood pressure relation in which confounding factors (age, sex, hypertensive heredity, nutrition, lead exposure level, etc) were adjusted by mathematical modelling.1-7 Harlan and colleagues 8 described a close association between blood lead and systolic or diastolic blood pressure, based on the Second National Health and Nutrition Examination Survey data (NHANES II). We have also applied mathematical modelling to our survey data on 220 male workers, and found that diastolic blood pressure was increased in male workers with blood lead concentrations above 40 µg/dl.9 On the other hand, Harlan 10 indicated that blood lead was closely related to systolic and diastolic pressures in males but not in females, based on multiple regression analysis. Female workers were normally not included or exposed to lower concentrations of lead, and no consensus for the relation between lead exposure and blood lead has been established.We therefore examined the lead induced increase of blood pressure in female workers by the use of mathematical modelling. METHODS Study populationThe study population consisted of 127 female crystal toy making workers (age range 17-44 years, mean (SD) 27.3 (5.4) years; duration of employment 0.8-25.0 years, mean 7.2 (4.6) years) and 70 female sewing workers (age range 16-58 years, mean 24.2 (6.4) years; duration of employment 0.1-11.4 years, mean 2.2 (2.2) years). All female workers were examined in each factory. Both factories were located in Beijing City, China. The working environment of the crystal toy making factory was contaminated with lead dust at concentrations of 0.39-1.91 mg/m 3 (mean 0.92 (0.42)) that were much higher than the occupational exposure limit of 0.05 mg/m 3 recommended by the American Conference of Governmental Industrial Hygienists.11 The suburban environment, the target site, was also seriously polluted with lead from automobile exhaust gases, although no precise data were available for the target site at the time of our survey. Table 1...

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