Investigations on neurotoxicity of chemical substances at the workplace

Summary A cross-sectional study was performed in order to investigate the influence of chronic lead-exposure on the peripheral nervous system. We examined 148 male workers of a storage battery manufacturing plant, who had been exposed to lead metal and inorganic lead compounds for 1 to 28 years (mean 11 years). Fifteen workers with non-occupational risks of peripheral neuropathy (former diseases, alcohol abuse, medication) were excluded from the study. The investigation program comprised: case history, physical examination, analyses of blood- and urine-samples and determination of maximal motor, mixed and sensory conduction velocity (NCV) of the ulnar and median nerve of the right forearm. Objectively no worker showed any signs of health effects related to lead exposure. The Biological Monitoring included the determination of (1) Blood-lead level (Pb-B), (2) Free erythrocyte porphyrins (FEP), (3) -Aminolevulinic acid dehydratase (ALA-D) and (4) -Aminolevulinic acid in urine (ALA-U). Further time-weighted-average (TWA)-values of Pb-B were calculated on the basis of several determinations over the period 1975–1981. The following actual (TWA) median values resulted: Pb-B 53 g/dl (54 g/dl), ALA-U 5.6 mg/l (8.4 mg/l), FEP 2.0 mg/l (2.0 mg/l). The Biologischer Arbeitsstoff Toleranz Wert (BAT) of 70 g//dl for Pb-B was exceeded in 15 workers (11%), and of 15 mg/l for ALA-U in 30 cases (23%). In comparison with age-matched controls, the lead workers showed a mild slowing of NCV with mean values between 0.8 and 2.0 m/s. Multiple stepwise regression analyses revealed statistically significant correlations between the four NCV and age as well as Pb-B. There were better correlations by using TWA than actual data of Pb-B. Consideration of the results of the regression analyses, together with an evaluation of the individual neurophysiological status as a function of internal lead exposure, a dose-effect-relationship was found only in the case of Pb-B exceeding 70 g/dl. From our study it is concluded that chronic lead exposure resulting in blood-lead levels of below 70 g/dl is no occupational risk causing a functionally significant slowing of nerve conduction velocities.With Grants from the Deutsche Forschungsgemeinschaft, Bonn (Project no. Va 23/19-1)     

Lead in deciduous teeth of children living in a non-ferrous smelter area and a rural area of the FRG

Summary Lead concentrations were measured in the deciduous teeth (incisors) of 302 children living in a lead-smelter area in the FRG (Stolberg, Rheinland) and of 86 children living in a nonpolluted rural area (Gummersbach, Bergisches Land). Blood lead levels were determined in 83 of the children living in the lead smelter area. On average, tooth lead levels of children living in the smelter area (mean: 6.0 g/g; range: 1.49–38.5 g/g) were significantly higher than those of children living in the rural area (mean: 3.9 g/g; range: 1.6–9.4 g/g). Blood lead levels were 6.8–33.8 g/100 ml (mean: 14.3 g/100 ml). Children of lead workers had on average higher tooth lead and blood lead levels than children of people who were not lead-workers. Tooth lead levels increased with increasing duration of residence in the lead-smelter area and with the degree of local environmental pollution by lead, as indicated by the lead content of the atmospheric dust fall-out around the children's homes. The correlation coefficient of tooth lead vs blood lead was 0.47. The intra-individual variability of tooth lead levels was low (r=0.86), and tooth lead levels of brothers and sisters were similar (r=0.75), suggesting that tooth lead may be used as a representative and reliable indicator of long-term lead exposure.This study was carried out at the request and with support of the Ministerium für Arbeit, Gesundheit und Soziales NW, Düsseldorf     

Blood lead levels in the general population of Taiwan,Republic of China

The purpose of this study was to investigate the environmental lead exposure of the general population in Taiwan. A total of 2919 residents of Taiwan were selected by multistage sampling methods. The participants were characterized by questionnaires and 10 ml venous blood was collected for blood lead measurement. A quality assurance/quality control program was designed during the analysis of blood lead levels. The mean blood lead level of 2719 residents without occupational lead exposure was 8.29 ± 5.92 g/dl. After adjustment for age and sex distribution to the Taiwan general population, the mean blood lead level was 8.10 g/dl. Adjusted for an 11% underestimation of blood lead levels among the six laboratories, the mean blood lead level was estimated to be 8.99 g/dl. This study also found that blood lead levels were associated with personal characteristics, i.e., gender, ethnic group, education level; lifestyle factors, i.e., smoking, alcohol consumption, sources of drinking water; and residential location, i.e., levels of urbanization, distance of house from the road. However, age, floor of residence, milk consumption, betel nut consumption, and Chinese herbal drug consumption were not found to be associated with blood lead levels. These results show that blood lead levels in Taiwan residents were not higher than in most developed and developing countries. Environmental lead pollution does not seem to be a serious problem in Taiwan.     

Blood lead levels in children of S.W. Sardinia

The purpose of the present study was to make a preliminary evaluation of blood lead levels in school-aged children from three towns of southwestern Sardinia, Portoscuso, S. Antioco and Calasetta, the first of which is very close to a large industrial complex. Blood lead concentration was determined in venous blood samples by graphite furnace atomic absorption spectrophotometry. The survey revealed that children residing in the town of Portoscuso had higher mean blood lead levels (12.7 g/dl) than children of the same age residing in S. Antioco and Calasetta (8.3 and 8.4 g/ dl respectively) and that levels were slightly higher in males than in females. This difference is suggested to be a result of the greater fallout of industrial pollutants in the area of Portoscuso.Corresponding author.     

Assessment of thyroid,testes, kidney and autonomic nervous system function in lead-exposed workers

Summary The objective of the study was to assess whether moderate occupational exposure to lead may be associated with early changes in potential target organs (thyroid, testes, kidney, autonomic nervous system). Workers exposed to lead in a lead acid battery factory (n = 98; mean blood lead 51 g/dl, range 40–75 g/dl) and 85 control workers were examined. None of the indicators of kidney function (in urine: retinol-binding protein, ₂-microglobulin, albumin,N-acetyl--d-glucosaminidase; in serum: creatinine, ₂-microglobulin), endocrine function (follicle-stimulating hormone, luteinizing hormone, thyroid-stimulating hormone, thyroxine, triiodothyronine) and autonomic nervous system (R-R interval variations on the electrocardiogram) were correlated with lead exposure (blood lead or duration of exposure) or showed significantly different mean values between the exposed group and controls. These results and an assessment of the published data suggest that compliance with the Directive of the Council of the European Communities on lead exposure (health surveillance in workers whose lead in blood exceeds 40 g/dl and removal from exposure when blood lead exceeds 70–80 g/dl) would prevent the occurrence of significant biological changes in the majority of lead-exposed workers.     

Studies on erythrocyte pyrimidine 5′-nucleotidase (P5N) test and its evaluation in workers occupationally exposed to lead

Summary An erythrocyte pyrimidine 5-nucleotidase (P5N) test was performed for 171 workers occupationally exposed to lead. Erythrocyte P5N activity was markedly inhibited by exposure to lead. Among several biological indicators (erythrocyte P5N, -aminolevulinic acid dehydratase (ALAD), protoporphyrin (PROTO), urinary -aminolevulinic acid (ALA), coproporphyrin (COPRO)), the P5N activity had the highest correlation with the concentration of lead in blood (r = – 0.77). A significant inhibition of erythrocyte P5N was found in groups of lead workers with blood-lead levels of more than 10 to 19 g/dl. This P5N inhibition started before any changes occurred in urinary ALA and COPRO. A 45 to 50% inhibition of P5N corresponded to the blood-lead value (50 g/dl) of the BEI recommended by ACGIH. In some lead workers, erythrocyte nucleotides (mainly CTP and UTP) were determined. The data indicated that a marked accumulation of these nucleotides had occurred, and their levels correlated negatively with P5N activity and positively with blood lead.     

Ultraviolet and volatility loss of herbicides

Herbicide 2,4-D formulated as a urea-type polymer was readily destroyed by long-wave uv (356-nm) irradiation, whereas conventional 2,4-D was more resistant. The opposite relationship was noted for polymeric and conventional formulations of dicamba. Polymerized 2,4-D was more resistant to thermal degradation (60°C) than non-polymerized formulations. Ultraviolet degradation of polymerized 2,4-D was eliminated by the incorporation of RYLEX-H and UVINUL D-50, industrial uv absorbers. Exposure of polymeric dicamba to 60°C heat, followed by trapping of the volatile component, indicated that 21 percent was lost by thermal degradation and 46.6 percent by volatilization. Comparable values for non-polymerized dicamba were 37.9 and 60.1 percent.     

Number-Between g-Type Statistical Quality Control Charts for Monitoring Adverse Events

Alternate Shewhart-type statistical control charts, called g and h charts, are developed and evaluated for monitoring the number of cases between hospital-acquired infections and other adverse events, such as heart surgery complications, catheter-related infections, surgical site infections, contaminated needle sticks, and other iatrically induced outcomes. These new charts, based on inverse sampling from geometric and negative binomial distributions, are simple to use and can exhibit significantly greater detection power over conventional binomial-based approaches, particularly for infrequent events and low defect rates. A companion article illustrates several interesting properties of these charts and design modifications that significantly can improve their statistical properties, operating characteristics, and sensitivity.     

Exposure to lead of the Belgian population

Summary According to the Council Directive of 29 March 1977 on biological screening of the population for lead, the blood-lead levels (PbB) were determined in samples of the Belgian population not occupationally exposed to this metal. Two campaigns of sampling were performed: the first one in 1979 (1678 samples analysed) and the second in 1981 (1000 samples analysed). Sampling was done in urban and industrial zones, as well as in areas where lead risk could be present. Concerning the urban and industrial areas, the results obtained seem to indicate that a particular lead risk does not exist for the adult population if we consider the reference levels of the CEE Directive. Moreover, the results of the second campaign of sampling showed a decreasing trend: the median PbB values dropped from 183 to 156 g/l in Brussels and from 192 to 139 g/l in Liège. This could be partly due to the limitation of the lead content of gazoline. On the other hand, the results of the surveys clearly demonstrated the existence of two areas where an obvious lead risk exists. In one of those, the lead risk is of industrial origin (lead smelter) and concerns mainly children: median PbB value 260 g/l, percentile 90 and 98 respectively 390 and 430 g/l. In the other one, the lead risk is from a hydric source and concerns adults and children: median PbB value 258 g/l, percentile 90 and 98 respectively 370 and 520 g/l.     

Isomer-specific analysis and toxic evaluation of polychlorinated biphenyls in striped dolphins affected by an epizootic in the western Mediterranean sea

Isomer-specific concentrations of polychlorinated biphenyls (PCBs) including planar, mono- and di-ortho congeners and concentrations of DDT were determined in striped dolphins affected by a morbillivirus epizootic in the western Mediterranean in 1990. Extremely high concentrations of PCBs ranging from 94 to 670 g/g (wet wt) were detected in the blubber. Similarly, DDT concentrations were high, between 22 and 230 g/g (wet wt). The concentrations of three non-ortho coplanar PCBs were 43 (3,3,4,4-T₄CB), 6.8 (3,3,4,4,5-P₅CB), and 7.8 (3,3,4,4,5,5-H₆CB) ng/g (wet wt), respectively, the highest residue levels reported to date. The estimated 2,3,7,8-TCDD toxic equivalents of non-, mono- and di-ortho PCB congeners in striped dolphins were several times higher than those observed for other marine mammals and humans. Mono-ortho congeners contributed greater 2,3,7,8-TCDD toxic equivalents than non-ortho members. The higher ratio of 3,3,4,4,5,5-H₆CB/3,3,4,4,5-P₅CB (IUPAC 169/126) suggested a strong induction of mixed function oxidase enzymes and highlighted the possibility of using this ratio as an index for risk assessment of PCB contamination in marine mammals. Elevated concentrations of PCBs may have played a role in the immune depression in striped dolphins, ultimately leading to the development of morbillivirus disease.     

DDT Residues in samples of human milk,and in mothers' and cord blood serum,in a continental town in Croatia (Yugoslavia)*

Summary Concentrations of p,p'-DDE, p,p-DDD, and p,p-DDT were determined in 34 samples of human milk obtained 3–5 days after delivery and in 37 samples obtained at later times of lactation (up to 55 weeks). All samples contained p,p-DDE, but only several contained p,p-DDD and p,p-DDT. The concentrations of p,p-DDE were 31 g/l in the beginning of lactation and 53 g/l at later time intervals. The concentration ranges in both groups overlap almost completely and the difference in the mean values is not significant.Serum samples from 35 mothers and cord blood were also analyzed. All samples contained p,p-DDE, the concentrations being 18 g/l and 6.8 g/l in the mothers' and cord blood serum, respectively. Serum samples of 24 nonpregnant women contained the same amount of p,p-DDE (20 pg/1) as mothers' sera.All samples were collected in a continental town of Croatia (Yugoslavia) between 1977 and 1979. The concentrations of DDT residues were determined by gas chromatography, and two methods for extraction from milk were used and compared.This work was supported in part by the Environmental Protection Agency (USA) and the World Health Organization (Geneva)     

Effect of lead on cardiac parasympathetic function

Summary A cross-sectional survey was performed on 172 male, lead exposed workers to clarify the effects of lead on the cardiac autonomic nervous system expressed as the decrease of R-R interval variation on an electrocardiogram and to obviate the dose-effect relationship between blood-lead level (Pb-B) and the degree of the decrease. For 132 workers who were exposed to lead for more than one year and whose Pb-B levels were relatively stable (Pb-B variation less than 20 g/dl during recent one year), a significant dose-related decrease of R-R interval variation during deep breathing was observed. Age-adjusted R-R interval variation during deep breathing in those whose Pb-B were 30 g/dl or above was significantly decreased compared with those whose Pb-B levels were 20 g/dl or below. This decrease was observed more clearly in younger workers. These results suggest that an effect on autonomic nervous system expressed as decrease of R-R interval variation during deep breathing might be one of the earliest effects of lead exposure.     

Belgian collaborative study of the in-vitro susceptibility of the Bacteroides fragilis group

The antimicrobial susceptibility of clinical isolates of the Bacteroides fragilis group obtained from nine large Belgian university and community hospitals was studied. Of the -lactam antibiotics tested, none were active against 100% of the isolates. Piperacillin was active against 93% of the strains at a breakpoint of 64 lag/ml. The percentage of isolates inhibited at 16 g/ml (and 32 g/ml) for the 7-alpha-methoxy antibiotics was: cefoxitin 84 [94]; latamoxef 87 [93]; and cefotetan 64 [79]. B. fragilis tended to be more susceptible to all -lactams than the other members of the group.Among the non -lactam antibiotics, the resistance rate for minocycline, doxycycline, clindamycin and erythromycin (at a breakpoint of 4 g/ml) were l%, 4%, 14% and 34%, respectively. Like the -lactams, clindamycin was less active against non B. fragilis species of the group.Chloramphenicol, metronidazole and tinidazole were still active against 100% of the isolates at their breakpoint values (8 lag/ml).     

Relationship of air lead and blood lead for workers at an automobile battery factory

Summary Air lead and blood lead data, recorded over a period of 3 years for 972 employees at an automobile battery factory as part of a lead control program, were summarized and statistically analyzed. The air lead values were measured by mobile area samplers for approximately 2 years and then by personal samplers for approximately 1 year. Blood lead analyses were usually performed once a month for most of the workers.The trend in air lead levels was significantly upward in the 1st year and significantly downward in the 2nd year while the trend in blood lead levels was significantly downward in the 1st year and in the 3rd year. There were no other significant trends.To assess the relationship between air lead and blood lead, data were used whenever an air lead obtained by personal sampler was followed within 1 month by a blood lead on the same worker. The variables age, job tenure, and department identity were included in an analysis of covariance. Only air lead and departments were significant, accounting for 9% and 13% of the variance in blood lead, respectively. From these data 95% confidence limits were calculated for predicting blood leads from given air leads for an individual worker. These were 30–68 g/100 ml at 200 g/m³; 25–62 g/ 100 ml at 100 g/m³, and 22–60 g/100 ml at 50 g/m³.     

Managing for health: why health care?

Health and health care are increasingly big business. The challenge is to apply our knowledge and skills to meet people's needs, if not their demands as efficiently, effectively and beneficially as possible. Value for money is the slogan. For those who deliver the goods as required, the converse, money for value should equally apply, and not only in a market driven system. This paper offers a very personal view of these issues in the light of recent UK policy developments.     

Dimensionen der Zufriedenheit im Alter

Zusammenfassung In einer Interview-Studie von 480 Betagten in städtischen Verhältnissen wurden neben anderen Fragen auch solche zur Zufriedenheit gestellt. Eine Faktoranalyse der Antworten erlaubt die Unterscheidung eines Faktors Depressivität von einem Faktor Zufriedenheit mit Sozial-kontakten und einer gesundheitlichen Dimension.

---

Dimensions of satisfaction among old people

Summary In an interview study of 480 aged persons, questions on satisfaction with several aspects of life were included. A factor analysis allows to distinguish a factor relating to depressivity from a factor satisfaction with social contacts and a health-related dimension.

---

Dimensions de la satisfaction des personnes âgées

Résumé Das une enquête d'un échantillon de 480 personnes âgées, des questions concernant leur satisfaction ont été inclues dans l'interview. Une analyse factorielle permet de distinguer un facteur associé à la dépressivité d'un facteur satisfaction avec les contactes sociaux et d'une dimension santé.

     

Psychological performance of workers with blood-lead concentration below the current threshold limit value

Summary The effects of lead exposure on psychological test performance and subjective feelings of well-being were investigated in 40 exposed workers whose PbB levels had never exceeded 60 g/100 ml and in 20 controls matched for sex, age and educational level. The exposed workers were divided into two groups of 20, with recent PbB levels in the range 45–60 g/100 ml or below 35 g/100 ml. The group of workers with the higher PbB levels showed significantly poorer performance and reported more physical symptoms than the other two groups. These differences were unrelated to socio-demographic and personality characteristics. A principal component analysis suggested that the poorer performance was mainly due to an impairment of general functioning and only to some extent to a deterioration in specific functions, such as verbal reasoning and abstraction. Higher lead concentrations were correlated with poorer performance and a higher number of physical complaints. These results indicate that in exposed workers the threshold for impaired performance lies below the blood-lead concentration of 60 g/100 ml, which is the current threshold limit value (TLV).This study was supported by the Consiglio Nazionale delle Ricerche (CNR, Roma), Gruppo Nazionale Scienze del Comportamento (Grant no. 81.00083.04 and no. 82.02117.04)     

Occupational lead exposure and pituitary function

Summary Twenty-five moderately exposed lead workers (mean blood-lead level 1.9 mol/l) had lower plasma levels of follicle stimulating hormone than 25 individually matched controls without occupational lead exposure (blood-lead level 0.2 mol/l). In addition, the ten most heavily exposed individuals had higher levels of thyroid stimulating hormone, and the 14 workers under the age of 40 had decreased plasma levels of luteinizing hormone and serum levels of cortisol, as compared to the controls. All values were within normal reference limits. There was no significant change of the plasma testosterone level. These data indicate a complex effect on the endocrine system by moderate lead exposure, possibly mediated by changes at the hypothalamic-pituitary level. Besides the effect on hormone levels, there was also a decrease in plasma selenium level for the lead exposed workers.     

Effects of lead on red blood cell membrane proteins

Summary The effects of lead on red blood cell (RBC) membrane proteins were studied in two groups of workers with different lead exposure levels: Group 1 (6 subjects employed in a battery plant) with a mean blood lead of 40.1 (SD = 3.7) g/100 ml; Group II(5 workers employed in different industries) with a mean blood lead of 60.6 (SD = 8.0) g/100 ml, compared with a control group with mean blood lead of 15.6 (SD = 9.3) g/100 ml. The analysis of RBC membrane polypeptides was carried out by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and by using a densitometer for percentage measurement of the bands corresponding to protein fractions. The results show a very significant decrease in Band 3 (anion channel) and 4.1 in more exposed workers (Group II) only. The effects of lead on RBC membrane proteins seem to be evident at blood-lead levels higher (> 50 g/100 ml) than those previously reported in literature. These results confirm the effects of lead on membrane proteins, even if the exact mechanism, particularly the influence of proteolysis and the meaning of the interference, still needs to be investigated thoroughly.     

Organochlorine chemicals in skin lipids as an index of their accumulation in the human body

Application of a noninvasive method of analyzing skin lipids was considered as a means of monitoring human exposure to organochlorine pesticides. Skin lipids were collected by wiping the face with cotton and purified by gel permeation chromatography and treatment with H₂SO₄. Organochlorine chemicals were determined by electron capture gas chromatography with a fused silica capillary column.p,p-DDE, -HCH and chemicals related to chlordane were detected in the skin lipids. Residue levels ofp,p-DDE, -HCH and oxychlordane in the skin lipids correlated with those in the adipose tissue; correlation coefficients forp,p-DDE, -HCH and oxychlordane were 0.93, 0.92, and 0.68, respectively. The correlation between skin lipids and adipose tissue for trans-nonachlor was poor ( = 0.46). The component pattern of chlordanes in skin lipids was similar to that of technical chlordane. The results suggested that chemicals in the skin lipids reflected both their accumulation in the body burden and dermal exposure.Skin lipids collected during 1986 to 1988 in Japan were determined forp,p-DDE, -HCH and the chlordanes. Residue levels ofp,p-DDE and -HCH in the aged were high compared with those in the young (=0.31–0.45). Chlordanes were detected from inhabitants in the southern area of Japan where chlordane had been used for termite control.