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.

Lead poisoning associated with the use of Ayurvedic metal-mineral tonics.

OBJECTIVE: The aim of this study was to confirm the connection between lead poisoning and the use of traditional Ayurvedic metal mineral tonics. METHODS: The study group comprised 29 subjects (26 adults and three children) who had previously taken Ayurvedic metal mineral tonics. All subjects were tested for lead absorption by blood lead, erythrocyte delta-aminolevulinic acid dehydratase activity and erythrocyte protoporphyrin. RESULTS: Eighteen samples of Ayurvedic preparations were obtained from 15 subjects and analyzed for lead content. Five adult subjects with established lead poisoning received chelation therapy. In Ayurvedic preparations a wide range of lead content was found (0.9-72,990 micrograms Pb/g; 0.35-29,900 micrograms Pb/capsule or tablet). The blood lead, erythrocyte delta-aminolevulinic acid dehydratase and erythrocyte protoporphyrin of the subjects, grouped according to the remedies used, correlated with the lead content in the preparations (p < 0.001). Chelation therapy was successful in normalization of laboratory findings and clinical recovery. CONCLUSION: Ayurvedic metal-mineral tonics are again identified as a potential source of high lead. The import of such tonics should be strictly controlled.

Visual evoked potentials in individuals exposed to long-term low concentrations of toluene.

An investigation of visual evoked potentials was carried out in two groups of subjects; 49 workers employed in a printing-prss where toluene has been used exclusively as an organic solvent for the last 30 years, and 59 workers not occupationally exposed to any known neurotoxic substances. The average length of work service in the printing-press was 21.4 years. The level of exposure was assessed by determination of the concentration of toluene in peripheral blood, the concentration of hippuric acid and ortho-cresol in urine in subgroups of subjects chosen at random from both groups. N75, P100 and N145 waves of the pattern reversal visual evoked potentials were analyzed. In the group of exposed subjects, significantly greater amplitudes were found in all waves, with significantly longer latency of the P100 wave.

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)

Assessment of exposure to trichloroethylene and tetrachloroethylene in the population of Zagreb, Croatia.

Human exposure to trichloroethylene (TRI) and tetrachloroethylene (perchloroethylene, PER) through air, food and drinking water was assessed by biological monitoring. By stratified sampling 39 subjects with no known solvent exposure were selected from the residents of the city of Zagreb (the capital of the Republic of Croatia). TRI and PER were determined in blood and their metabolites trichloroethanol (TCE) and trichloroacetic acid (TCA) in plasma and urine. Drinking water samples were also taken for TRI and PER determination. TRI was present in measurable concentrations in 22 subjects (range: 0.026-0.090 micrograms/l) and PER in 31 subjects (range: 0.031-2.540 micrograms/l). TCE was not detected in any of the samples, while TCA was determined in all plasma (range: 13.54-160.42 micrograms/l) and urine samples (range: 1.64-291.76 micrograms/24h). In drinking water samples TRI and PER values were also in a very wide range: 0.69-35.90 micrograms/l and 0.36-7.80 micrograms/l, respectively. The variation of all results presented is most probably a reflection of the different environmental contamination with TRI and PER in the different city areas.

A follow-up study in a lead smelter community following the introduction of an effective pollution control system.

A follow-up study using biological and environmental monitoring was performed in a lead smelter community to assess the health risk of inhabitants and to establish how long it takes after the introduction of an effective emission control system to declare a lead-contaminated area safe for normal living. In specific population groups (mothers and children) biological indicators of lead exposure and lead effect on hemoglobin synthesis were determined 2 years before and 11 consecutive years after the installation of bag filters. At the same time lead was monitored in the airborne and deposited particulates, in household dust and in soil. The results clearly show that the process of normalization is rather slow. The difference in blood lead and erythrocyte delta-aminolevulinic acid dehydratase between the exposed and control groups, even 12 years after bag filters installation, was still remarkable. It appears that soil, contaminated with lead from past exposure, is a major source of increased lead absorption in a population for many years.

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.

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.

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.

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.

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.

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.

Metabolic activity of antipyrine in workers occupationally exposed to trichloroethylene.

In order to investigate possible effects of occupational exposure to trichloroethylene (TRI) on the liver cytochrome P-450 dependent monooxygenases, the metabolic activity of salivary antipyrine was determined in workers (I; N = 32) employed in dry-cleaning shops (I-1; N = 17) and in an industrial metal degreasing process (I-2; N = 15). The studies were performed twice: (a) during the working period, (b) and after at least three weeks free of exposure. The control group (II) consisted of 29 subjects with no known exposure to chemicals. Analyses of the solvents used (TRI) showed them to be mixtures. Statistically significant differences were found (P less than 0.01) in antipyrine t1/2 and clearance within the exposed group (Ia:Ib), but not between the exposed (I) and control (II) group. A breakdown of antipyrine pharmacokinetic data by I-1 and I-2 subgroups demonstrated a statistically significant difference in t1/2 (P less than 0.02) and clearance (P less than 0.05) within I-1 subgroup (a:b), in contrast to the I-2 subgroup (a:b). The difference in antipyrine t1/2 between I-1,a and the control group (II) was also statistically significant (P less than 0.05). Although there was no difference in TRI exposure between I-1 and I-2 based on the biological parameters of TRI absorption, the TRI used in I-2 was of higher grade of purity. It can therefore be concluded that TRI itself is not an inducer of liver monooxygenases and that the monooxygenase induction in subgroup I-1 of TRI exposed workers could be due to TRI impurities.

Occupational exposure to benzene in the shoe industry.

In order to determine the possible actual exposure to benzene in the shoe industry from industrially used solvents, glues, and paints containing benzene as a nondeclared constituent, phenol in urine and benzene in blood, as indices of internal exposure to benzene, were measured in workers (N = 33). Since toluene, in contrast to benzene, is declared as a constituent in several glues, toluene in the blood of workers was also analysed. All analyses were performed using gas chromatography. Urine samples were collected on Monday morning (MI) before work and on Wednesday (WI) before and (WII) after work. Venous blood samples were taken on Wednesday only, 1/2 hour after work. There was no difference in the phenol concentrations of MI and WI, while the phenol concentration of WII was about twice as high as that in WI. In all blood samples, benzene was found, as well as toluene, which was about four times higher in comparison with benzene. A correlation (r = 0.465; p less than .01) was found between the difference in pre- and postshift phenol concentrations (WII-WI) in urine and the benzene concentrations in blood. The results presented show that a trace amount of benzene, which is often not declared as a constitutent in industrially used chemicals, could be a source of marked exposure to benzene. It can also be concluded that changes in phenol in urine (if preshift and postshift samples are taken) might be a sufficiently sensitive parameter to assess exposure to benzene even when other data concerning the presence of benzene in the working atmosphere are not available.

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.