Relationships between blood lead and indicators of effect in cows environmentally exposed to lead.

Biological indicators of lead exposure and its effects were measured in 83 cows from a lead-contaminated area in the vicinity of a lead smeltery and in 53 cows from a control area. Differences between the groups were highly significant for blood lead (PbB) content, activity of erythrocyte delta-aminolevulinic acid dehydratase (ALAD) and erythrocyte protoporphyrin (EP) content, but considerably less significant for blood hemoglobin (Hb) content and not significant for hematocrit (Hct). An exponential, rather than linear, characteristic form was observed for the relationships between ALAD activity, EP, Hb and Hct with respect to PbB. This finding supports the hypothesis that lead-induced effects are dependent on the long-term integrated level of lead exposure, rather than the recent lead exposure level as mainly reflected by PbB. The use of ALAD activity and EP as cumulative lead exposure indicators is suggested.

Lead absorption and psychological function in Zagreb (Croatia) school children.

A cross-sectional study was performed on 275 pupils from the third and fourth grade of three elementary schools (three urban areas with different traffic conditions) in Zagreb. Lead exposure was environmental, mostly through leaded gasoline. The difference in traffic density around the schools was consistent with biological indicators of lead absorption. The aim of the study was to clarify the relationship between characteristic biological indicators of lead absorption including indicators of hematological status with some psychological functions. Lead absorption in pupils was relatively low (mean blood lead: 70.8 +/- 17.88 microgram/L). Pupils' socio-economic status was evaluated by parents' education. The results obtained indicate that gender and school were associated with both biological and psychological variables. After adjusting for age, parental education, and gender, lead appears to have no association with cognitive or psycho-motor measures. The nonstandardized regression coefficients for blood lead-as a measure of the size of lead effect on VIQ, NIQ, and IQ-were -0.016, -0.031, and -0.025, respectively, all nonsignificant.

In vitro study on lead and alcohol interaction and the inhibition of erythrocyte delta-aminolevulinic acid dehydratase in man.

The effect of lead (Pb) and ethanol (EtOH) interaction on the inhibition of erythrocyte delta-aminolevulinic acid dehydratase (ALAD) was investigated in human blood in vitro. Two different doses of ethanol (equivalent to 16.28 mmol of EtOH/l of blood and 108.53 mmol of EtOH/l of blood) and lead (equivalent to 2.17 mumol of Pb/l of blood and 4.34 mumol of Pb/l of blood) were examined separately and in combination. The dose-effect (EtOH-ALAD) relationship for a wide range of ethanol concentrations (0-217.06 mmol of EtOH/l of blood) was also investigated. The results obtained indicate that ethanol by itself does not inhibit ALAD, while lead does it readily. Neither ethanol concentrations significantly altered ALAD activity. The dose-effect (EtOH-ALAD) relationship did not reveal any inhibitory effect of ethanol on ALAD either; however, a weak trend towards increased ALAD activity was found. The effect of ethanol combined with lead indicated no significant difference as compared to the effect of the same dose of lead per se; however, a weak trend towards decreased ALAD activity was found. These findings support the hypothesis that the effect of ethanol on the transient inhibition of ALAD activity in vivo does not occur directly, but possibly through the intermediary action of lead from the body lead pool.

In vivo study on lead and alcohol interaction and the inhibition of erythrocyte delta-aminolevulinic acid dehydratase in man.

The effect on alcohol (EtOH) consumption on the inhibition of erythrocyte delta-amino-levulinic acid dehydratase (ALAD) was investigated in 13 male lead workers and 7 "normal" male subjects. Lead and zinc protoporphyrin in blood and lead, delta-aminolevulinic acid, porphobilinogen and coproporphyrin in 24-h urine specimens were also determined. During 1 h the subjects drank 122.8 (SD 18.65) ml of an almost lead-free brandy, ie, a dose of 11.07 mmol/kg of body weight. This dose resulted in a trend toward a parallel decrease in ALAD activity and an increase in lead in blood (PbB), both of which approached the prealcohol value 24 h after the initial alcohol ingestion. A trend toward increased lead excretion in urine (PbU) was observed on the day of alcohol ingestion, as compared to the preceding and succeeding 24-h urine specimens. However, the observed increase in PbB and PbU cannot be attributed to the small amount of lead ingested through the brandy, ie, 7.09 (SD 1.06) nmol. The characteristic dose-effect relationship between PbB and ALAD (examined prior to and 1, 3, 5, and 24 h after the initial alcohol ingestion) reached the highest correlation coefficient 3 h after the initial alcohol ingestion (p less than 0.001). The data obtained appear to support the hypothesis of a possible role for the body lead pool and the lead-mediated influence of alcohol consumption on ALAD activity in man.

Acute intermittent porphyria and hormone disbalance.

A study of acute intermittent porphyria (AIP) in three female patients indicates the necessity of stressing that in cases of clinical and laboratory exacerbation of the disease in patients of reproductive age the possibility of the existence of pathological changes in the ovaries (polycystic ovary, anovulatory cycle) should be taken into consideration. By examination of patients' endocrinological status and on the basis of the experience of clinicians it can be concluded that in such cases of exacerbation of the disease, apart from conventional therapy with glucose, Panhematin, electrolyte correction and other symptomatic therapy, coexisting steroid deficiency should be corrected.

Biological monitoring of lead effects in a smelter community before and after emission control.

Biological monitoring of lead effects in specific population groups living in the vicinity of a lead smelter has been followed up after effective emission control, in order to estimate the length of time necessary before the characteristic indicators of increased lead absorption normalize. The period established could be a realistic basis for predicting the time necessary to elapse before a lead contaminated area can be proclaimed as safe for normal living. Three groups of subjects were examined: preschool children, school children and mothers. The biological monitoring included the measurement of delta-aminolevulinic acid dehydratase activity (ALAD) and the concentration of zinc-protoporphyrin (ZPP), blood lead (Pb-B) and hemoglobin (Hb). The results obtained demonstrated a gradual normalization of the characteristic indicators of lead absorption, although they were still outside corresponding values in the control group even four years after the installation of effective emission control. These findings emphasize the advantages of biological monitoring over environmental for objective assessment of internal and external lead exposure following effective engineering control of the emission source.

Dietary calcium and blood lead levels in women.

Nutritional factors are known to influence metabolism and toxicity of several metals in animal experiments, but relevant human data are scarce and inconclusive. In this work, we tested the hypothesis that dietary calcium influences lead metabolism in humans. Blood lead concentrations were used as indicators of lead exposure and metabolism. Two groups of peasant women living in similar conditions in two different regions in Yugoslavia (100 in each) were chosen as subjects for this purpose. In region A, the dietary calcium intake was about 940 mg, and in region B about two times lower, i.e., 450 mg/day. The average blood lead concentration was significantly lower in women from region A (69 micrograms/L) than from region B (83 micrograms/L). Our results support the assumption that adequate calcium intake might be one of the preventive measures for decreasing lead absorption. This new evidence, sought for some time by nutritionists and toxicologists, needs further international confirmation.

A comparative study of human levels of trichloroethylene and tetrachloroethylene after occupational exposure.

The rate of trichloroethylene (TRI) and perchloroethylene (PER) absorption was investigated in workers who were (1) occupationally exposed to TRI in four dry-cleaning shops (Group 1, n = 10) and (2) occupationally exposed to PER in one dry-cleaning shop (Group 2, n = 18). Concentrations of TRI and PER in blood were analyzed, and concentrations of trichloroethanol (TCE) and trichloroacetic acid (TCA) in blood and urine were analyzed. Results varied widely: PER was found in the blood of workers in group 1, but TRI was not detected in blood from any worker in group 2; most blood samples from group 2 workers did not contain a detectable quantity of TCE, and urine TCE concentrations in this group were very low. During the work week, a significant difference was found in group 1 for TRI in blood and TCE in blood and urine. In group 2, however, the only significant difference during the work week was for PER in blood. Therefore, the most reliable biological indicators for TRI and PER exposure are TCE in blood and PER in blood, respectively.

Assessment of urban population exposure to trichloroethylene and tetrachloroethylene by means of biological monitoring.

Exposure of the general population to trichloroethylene and tetrachloroethylene under normal environmental conditions, achieved with biological monitoring, was assessed, and the possible influence of these compounds via drinking water on the body burden was revealed. A total of 79 subjects with no known solvent exposure was selected, by stratified sampling, from the residents of the city of Zagreb. Trichloroethylene and tetrachloroethylene were determined in blood, and trichloroethanol and trichloroacetic acid were determined in plasma and urine. Drinking water samples were also analyzed for trichloroethylene and tetrachloroethylene. Concentrations of trichloroethylene and tetrachloroethylene in blood, trichloroacetic acid in plasma, trichloroacetic acid in urine, trichloroethylene in drinking water, and tetrachloroethylene in drinking water were as follows: < 0.015 to 0.090 micrograms/l, < 0.010 to 0.239 micrograms/l, 8.6 to 148.1 micrograms/l, 1.67 to 102.3 micrograms/24 h, < 0.05 to 22.93 micrograms/l, and 0.21 to 7.80 micrograms/l, respectively. The variation in all results presented is probably a reflection of different environmental contamination with trichloroethylene and tetrachloroethylene in the different city areas. Correlation analyses revealed significant relationships between trichloroethylene and tetrachloroethylene in blood (r = .402, p = .0004); trichloroacetic acid in urine and in plasma (r = .522, p = .0000); and trichloroethylene and tetrachloroethylene in drinking water (r = .800, p = .0000). A division of all parameters into a subgroup (n = 58), taking drinking water concentrations of trichloroethylene above 3 micrograms/l as a basis, demonstrated the same significant relationships as mentioned above.(ABSTRACT TRUNCATED AT 250 WORDS)

Relationship between the levels of biological indicators of lead exposure in children and their mothers environmentally exposed to lead.

From a follow-up study (1976-1985) on lead exposure in population groups living in the vicinity of a lead smeltery, and those from a control area, data were selected on 222 simultaneous measurements of biological indicators of effective lead exposure (absorption) in the blood of children and their mothers. The range of lead exposure levels in both the children and the mothers was very wide (from "normal" to largely excessive lead exposure) as indicated by blood lead (PbB), activity of delta-aminolaevulinic acid dehydratase (ALAD) and erythrocyte zinc-protoporphyrin (ZnPP). A highly significant (P less than 0.001) exponential decrease in ALAD with respect to PbB, as well as an exponential increase in ZnPP with respect to PbB, was found in children and their mothers. Highly significant (P less than 0.001) relationships were found between the levels of PbB, ALAD, and ZnPP in the children with respect to those found in their mothers, indicating the relevant influence of a similar microenvironment (e.g. lead in indoor air and in household dust) and life-style (e.g. household hygiene habits and food preferences) on the level of effective individual lead exposure. Although these relationships have indicated generally higher levels of lead in children with respect to their mothers, the hypothesis of a relatively higher absorption and retention of lead in children of a lower age than that in children of a higher age could not be confirmed, which is in agreement with our previous observations. However, when the three subgroups according to the age of the children were compared (i.e. 0.3-4.5 years, 5-10 years, and 10.5-15 years), it appeared that children aged 0.3-4.5 years had the lowest lead absorption and those aged 5-10 years the highest in relation to their mothers. Within each of these subgroups, a tendency towards relatively higher effective lead exposure in children (i.e. the child/mother ratio of PbB, ALAD and ZnPP levels) with respect to an increase in environmental lead exposure level has been observed.

Assessment of exposure to lead and cadmium through air and food in inhabitants of Zagreb.

Exposure to lead and cadmium was monitored in a group of 17 non-smoking women in Zagreb. The monitoring included measurement of the intake of the two metals via air and the diet during a period of seven days. Duplicate daily diets and air filter samples were collected for analysis of lead and cadmium. To check the intake of lead and cadmium with the daily diet, faeces were collected and analysed. The mean gastrointestinal absorption was estimated to be 4.9 micrograms/day for lead and 0.75 micrograms/day for cadmium. These values were derived from faecal data which were assumed to be more reliable. The daily absorption through inhalation estimated on the basis of air analysis was 2.7 micrograms for lead and 0.03 micrograms for cadmium.