Factor analysis of essential and toxic elements in human placentas from deliveries in arctic and subarctic areas of Russia and Norway

Concentrations in human placenta of 11 essential elements (P, Ca, Mg, Cu, S, Na, Fe, Zn, K, Se, Mn) and 5 toxic elements (Ba, Sr, Pb, Ni, Cd) are compared for each of two arctic communities in eastern Norway and western Russia, and for another in each country located at more southerly latitudes. All but Mg, Fe, P and K were present in higher concentrations in the Russian study group. The observed inter-element correlations are reflected by the four major factors identified in a principal component analysis. The total variation explained was 67.3%, of which more than half (35.3%) was contributed by Factor 1. P, Ca, Mg, Ba, Sr, Pb, and Ni were major contributors to this factor. The placental concentrations of these elements depended strongly on gestational age, increasing from about week 35 and peaking near weeks 39 and 40, and exhibited skewed frequency distributions and a dependence on maternal smoking. The gestational-dependent mineralization of the placenta is interpreted to reflect the deposition of metal phosphates coinciding with smoking-induced tissue damage. The loadings of the remaining three factors are reviewed in the context of common uptake mechanisms, similar biochemistries and unique transport pathways. The inter-element relationships and grouping of the elements observed should constitute a scientific base for the use of placenta composition in environmental monitoring and epidemiological studies.     

Multi-component assessment of worker exposures in a copper refinery. Part 2. Biological exposure indices for copper, nickel and cobalt

Urinary copper (Cu), nickel (Ni) and cobalt (Co) concentrations were determined for 127 Cu refinery workers (40 females, 87 males), with values of the 95% upper confidence interval of the geometric mean in nmol per mmol creatinine of 89 (Ni), 42 (Cu) and 3.4 (Co) for electrorefinery workers. In the pyrometallurgical departments, the corresponding concentrations were 37 (Ni), 99 (Cu) and 11 (Co). Female workers had higher Co urinary concentrations than males (p< or = 0.05) while no gender difference was observed for Cu and Ni. Inter-elemental correlations were moderate to weak. Based on the inhalable aerosol levels reported previously for the same workers, the observed urinary Cu concentrations were considerably lower than expected, relative to Co and Ni. This is interpreted in terms of the current understanding of Cu homeostasis.     

Ultrafine particles at workplaces of a primary aluminium smelter

The number concentration and size distribution of ultrafine particles in a S?derberg and a prebake potroom of an aluminium primary smelter have been measured using a scanning mobility particle spectrometer. The particle morphology was studied by transmission electron microscopy (TEM). The study shows the existence of elevated number concentrations of ultrafine particles in both potrooms. The main source of these particles is likely to be the process of anode changing. The ultrafine particles were measured directly at the source but could also be identified as episodes of high number concentrations in the general background air. Unlike the larger particles belonging to the 50-100 nm mode, the nanoparticle mode could not be detected in the TEM indicating that they may not be stable under the applied sampling conditions and/or the high vacuum in the instrument.     

Aluminium metabolism in chronic renat failure: Environmental influences and regional differences in Norway

Many aspects of Al metabolism in chronic renal failure are poorly understood. A longitudinal study of serum Al concentrations in predialysis patients and healthy control subjects revealed very high values during the autumn of 1984 and 1985. Renal Al clearance was low during the autumnal spike in serum Al but increased substantially when the serum Al concentration declined. A second study confirmed that by using citric acid as a chelator, the gastrointestinal absorption of Al from Al(OH)₃ may be considerably augmented as reflected by increases in both serum Al concentrations and renal Al clearance. The individual differences in Al absorption in this study were large.The first study suggests the existence of an unidentified environmental factor, possibly water borne, with profound effects on Al absorption and excretion. The citric acid/Al(OH)₃ experiment suggests that the existence of such a factor is likely. The implications of these results are not known.A histomorphometric study of bone biopsies from 138 hemodialysis and 66 predialysis patients without clinical evidence of Al related disease, revealed Al deposits after staining with aurin tricarboxylic acid in 78% of the biopsies from the former and 24% of the latter patients. Serum Al concentrations did not differ between predialysis and hemodialysis patients with Al positive biopsies. Stratification of the hemodialysis patients, who came from all parts of Norway, revealed that patients living in regions with slightly Al contaminated drinking water (Al <30 g/L) had lower serum Al concentrations than patients from regions with highly contaminated water (Al >100 g/L). The prevalence of Al-positive biopsies was the same in both regions. Patients with Al-positive biopsies did not differ in serum Al level from those with Al-negative biopsies within the same region. Predialysis patients with Al-positive biopsies had significantly higher serum Al levels than predialysis patients with Al negative biopsies.Stainable Al deposits are commonly found in the bone of patients with chronic renal failure. Cross-sectionally obtained serum Al concentrations do not reflect the prevalence of stainable bone Al in renal patients but are related to the degree of Al contamination of water of the region.     

Characterisation of workers' exposure in a Russian nickel refinery

In support of a feasibility study of reproductive and developmental health among females employed in the Monchegorsk (Russia) nickel refinery, personal exposure and biological monitoring assessments were conducted. The inhalable aerosol fraction was measured and characterised by chemical speciation and particle-size distribution measurements. Unexpected findings were that: (i), pyrometallurgical working environments had significant levels of water-soluble nickel; (ii), significant exposure to cobalt occurred for the nickel workers; (iii), particles of size corresponding to the thoracic and respirable fractions appeared to be virtually absent in most of the areas surveyed. The water-soluble fraction is judged to be primarily responsible for the observed urinary nickel and cobalt concentrations. It is concluded relative to current international occupational-exposure limits for nickel in air, and because of the high nickel concentrations observed in urine, that the Monchegorsk nickel workers are heavily exposed. The implication of this finding for follow-up epidemiological work is alluded to.     

Occupational exposure to fluorinated hydrocarbons during refrigeration repair work

This study describes refrigeration repair workers' occupational exposures to halogenated refrigerants, focusing on difluorochloromethane (HCFC 22), tetrafluoroethane (HFC 134a) and a mixture of tri-, tetra- and pentafluoroethane (R404A) in 30 work operations. Unlike earlier reported studies, the present study includes working procedures involving welding in order to measure possible occupational exposure to decomposition products. The measurements included hydrogen fluoride (HF), hydrogen chloride (HCl), phosgene (COCl2) and volatile organic compounds (VOC). The exposures were assessed during work operations on small-scale cooling installations like refrigerators and freezers. The repair workers' occupational exposures to refrigerants were moderate, and the major part of the exposures were associated with specific working procedures lasting for relatively short periods of time (<20 min). During these exposure events the concentrations were occasionally high (up to 42434 mg m(-3)). Although welding operations lasted only for short periods of time, HF was detected in 9 out of 15 samples when HCFC 22, HFC 134a or R404A had been used. Hydrogen chloride was detected in 3 out of 5 samples in air polluted with HCFC 22. Phosgene was not detected. A large number of VOCs in various concentrations were found during welding. Except for the applied refrigerants, halogenated compounds were only found in one sample.     

Chemical composition of individual aerosol particles from working areas in a nickel refinery

Individual aerosol particles (n = 1170) collected at work stations in a nickel refinery were analyzed by wavelength-dispersive electron-probe microanalysis. By placing arbitrary restrictions on the contents of sulfur and silicon, the particles could be divided into four main groups. Scanning electron images indicated that most of the particles examined were relatively small (< or = 2 microm, equivalent projected area diameter), and that their morphology suggested formation from a melt. There was an absence of well-defined phases and simple stoichiometries, indicating that exposures to pure substances such as nickel subsulfide or specific oxides appeared not to occur. Although the elemental composition of particles varied greatly, a rough association was evident with the known elemental content of the refinery intermediates. The implications of the findings for aerosol speciation measurements, toxicological studies and interpretation of adverse health effects are explored.