Natalya Romanova

Blood lead and cadmium and birth weight among sub-arctic and arctic populations of Norway and Russia

BACKGROUND Delivering women and their newborns in the Kola Peninsula of Russia and the neighboring arctic area of Norway were studied to explore relationships between maternal cadmium and lead status and birth weight as a pregnancy outcome. METHODS Life-style information, maternal blood and cord blood specimens were collected from 50 consecutive mother-infant pairs from hospital delivery departments in three Russian and three Norwegian communities. Pregnancy outcomes were verified by consulting medical records. Lead and cadmium were determined in the blood samples by electrothermal atomic absorption spectrometry. RESULTS The median blood-cadmium concentration for the Russian mothers was 2.2 nmol/L (n = 148) versus 1.8 nmol/L in the Norwegian group (n = 114, p = 0.55). A weak association was observed between maternal cadmium and amount smoked (r = 0.30, p<0.001); no correlation was found between maternal blood cadmium and birth weight. The corresponding maternal lead values were 0.14 (Russia) and 0.06 micromol/L (Norway), p<0.001. The latter lead concentration constitutes one of the lowest adult population values reported to date. Maternal and cord blood lead levels were strongly correlated (r = 0.88, p<0.001). In a multivariate linear regression model, maternal blood lead was recognized as a negative explanatory variable (p<0.05) for birth weight and childs body mass index (BMIC), with or without adjustment for gestational age. A similar association was suggested by ANOVA-analysis of maternal blood lead by quartiles. CONCLUSION Maternal blood-lead level as an environmental factor is an apparent predictor of low birth weight and BMIC. It reduced substantially the contribution of a country factor in explaining the observed differences in birth weight.

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.

Reduction of Background Absorption in the Measurement of Cadmium, Lead and Selenium in Whole Blood Using Iridium-sputtered Graphite Tubes in Electrothermal Atomic Absorption Spectrometry

The thermal behaviour during pyrolysis and of the vapour phase during atomization for Cd, Pb and Se in acid-digested whole blood using Ir-sputtered tubes is described. The performance of Ir as a permanent modifier was affected unfavourably by the complex matrix compared with conventional modifiers. Background absorption was measured using an atomic absorption spectrometer in addition to a diode-array spectrometer and compared with the background obtained in pyrolytic graphite-coated graphite tubes. Both methods of measurement indicated that the background was much reduced in the Ir-sputtered tubes. The decrease in background absorption improves conditions for the measurement of these elements. Background molecular absorption was also measured as a function of time. Molecular species such as NO were detected in the vapour phase using pyrolytic graphite-coated tubes, whereas CS and CO were detected using Ir-sputtered tubes.

Urinary nickel concentrations and selected pregnancy outcomes in delivering women and their newborns among arctic populations of Norway and Russia

The two objectives of this study were to compare urinary nickel excretion in pregnant women and their newborns living in the Murmansk and Arkhangelsk Counties of Russia with that in comparable Norwegian populations living in Finnmark and the city of Bergen and to assess the influence on pregnancy outcome of different risk variables, specifically urinary nickel concentrations and questionnaire-based anamnestic information. Life-style information and urine samples were collected from 50 consecutive mother-infant pairs from hospital delivery departments in three Russian and three Norwegian communities. Pregnancy outcomes were verified from medical records. Urinary nickel excretion was significantly higher in the Russian communities, independent of the presence of a nickel refinery as a local environmental source. The birth weight and mean body mass index of the newborn children (BMIC) were significantly lower (p < 0.001) in the Russian groups, with or without adjustment for gestational age. A multivariate linear regression analysis indicated that maternal urinary nickel concentration had no impact on birth weight. The maternal body mass index (BMI) and maternal height were positive explanatory variables; maternal urinary creatinine is suggested as a weak negative factor. Smoking was shown to be a strong negative predictor only in the Norwegian group among whom there was a significantly higher smoking frequency (p = 0.005). The significant contribution of a country factor in the predictive model is interpreted to indicate that a number of important risk factors for low birth weight were not identified.

Evaluation of internal standardisation in electrothermal atomic absorption spectrometry

Significantly improved performance in electrothermal atomic absorption spectrometry is possible using an internal standardisation technique. A Perkin-Elmer SIMAA 6000 simultaneous multielement spectrometer was used to study the correlation between two integrated absorbance signals. The behaviour of Pb (analyte) in different urine, blood and placenta samples was compared to that of Bi or Tl used as the internal standards. All samples were spiked with known amounts of Pb and Bi or Tl. A satisfactory signal correlation (r = 0.94) between the integrated absorbances for spikes of the analyte and internal standard was observed with Bi as the internal standard. After signal correction, the relative standard deviation of the integrated absorbance for Pb spikes reduced from 29 to 7% for urine, from 19 to 2% for blood and from 22 to 4% for placenta. The mean difference between Pb concentration found in analysed samples by the method of additions and using an internal standard was 10%.

Elements in placenta and pregnancy outcome in arctic and subarctic areas

Objectives. This paper describes a comprehensive assessment of the association of concentrations of essential and toxic elements in maternal and neonatal body fluids and the placenta as predictors of birth weight and newborn body mass index (BMIC) for deliveries in northern Norway and Russia. Study design. A prospective cross-sectional study of delivering women and their outcomes from different locations in Russian and Norwegian arctic and sub-arctic areas. Methods. Life-style information, blood, urine and placenta specimens were collected for 50 consecutive mother-infant pairs from hospital delivery departments in a total of six communities located in Finnmark, Norway, or the western arctic/subarctic regions of Russia. Questionnaire information was collected by individual interviews performed by trained health personnel. Pregnancy outcomes were verified by consulting medical records. Cadmium, copper, iron (as ferritin), nickel, lead, selenium and zinc were measured in maternal blood, serum or maternal urine; and in cord blood, or neonatal urine and placental tissue. Univariate and multivariate linear regression analysis and ANOVA were employed to explore associations between these clinical chemistry outcomes and birth weight and BMIC. Results. A number of significant relationships were evident between: placental and maternal blood cadmium (p < 0.005); cord and maternal blood lead (p < 0.001); placental and maternal blood lead (p < 0.001); placental and cord-blood lead (p < 0.001); placental and maternal serum, or blood, selenium (p < 0.001); and placental and maternal serum copper (p < 0.001). Maternal body mass index (BMI), maternal age, placental lead, or maternal blood lead, and smoking were retained as predictors of birth weight and BMIC in the multivariate modelling. Birth weights in both countries were normally distributed. Conclusions. Maternal age and BMI as positive predictors of birth weight, and cigarette smoking and lead exposure as negative determinants, are discussed in terms of established evidence and recognized confounders, including maternal genetic factors, socio-economic status, socio-political change, life-style issues, prenatal care and nutrition. It is recommended that future work in societies undergoing socio-economic transition might best focus on preventive measures to improve neonatal health and development. (Int J Circumpolar Health 2004; 63(2):169–187)

Concentrations of essential trace elements in maternal serum and the effect on birth weight and newborn body mass index in sub‐arctic and arctic populations of Norway and Russia

BACKGROUND This project is part of an assessment of the impact of environmental factors on human health in the Kola Peninsula of Russia and the neighboring arctic area of Norway. Pregnant women and their newborns were studied to explore a relationship between maternal status of essential metals and birth weight. METHODS Life-style information and serum specimens were collected from at least 50 consecutive mother-infant pairs from hospital delivery departments in three Russian and three Norwegian communities (N=151 and 167, respectively). Pregnancy outcomes were verified by consulting medical records. Copper, selenium and zinc in serum were determined by atomic absorption spectrometry and ferritin by an automated analyzer method. RESULTS Mean birth weight and childs body mass index (BMIC) were significantly lower in the Russian group (p<0.001), with or without adjustment for gestational age. Copper, iron (as ferritin) and selenium serum concentrations were in the normal range, while zinc levels in both countries were mostly below the lower limit (10.8 micromol/L) of reported reference intervals. A positive correlation between zinc and birth weight or BMIC was only observed for concentrations exceeding 10.8 micromol/L. Analysis by quartiles showed that maternal urinary creatinine and birth weight were negatively correlated (p=0.001). The influence of the different elements on BMIC, grouped by quartiles, was significantly positive only for selenium (p=0.03) and ferritin (p=0.02), while there was no significant relationship for copper or zinc. Adjustment of birth weight and BMIC for gestational age did not alter substantially the various associations indicated. CONCLUSIONS With the exception of zinc, the mineral status of delivering women in arctic and sub-arctic regions of Norway and western Russia appears to be adequate. The significantly lower BMIC for the Russian group suggests the likely occurrence of nutritional deficiencies during pregnancy in Russia. However, the significant contribution of a country factor in the predictive model implies that the maternal serum trace-element concentrations explored in this study are incomplete indicators of fetal undernourishment.

Factor analysis of essential and toxic elementsin human placentas from deliveries in artic and subarctic areas of Russiaand 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.

Intercommunity and temporal variation of eleven essential and five toxic elements in human placentas from deliveries in thirteen arctic and sub-arctic areas of Russia and Norway

Research is described that constitutes an extension of an earlier paper (J. Environ. Monit., 2001, 3, 177-184), in which concentrations were measured in 263 human placentas of 11 essential elements (P, Ca, Mg, Cu, S, Na, Fe, Zn, K, Se, Mn) and 5 toxic elements (Ba, Sr, Pb, Ni, Cd). The additional data considered derive from earlier visits to 4 of the original 6 communities and 3 others, all but one of which are located in northern Norway and neighbouring areas of Russia. This more than doubled the number of placental samples available (263 to 571). Unfortunately, the personal, life-style and morphometric information obtained for the first study group was not available for the additional mothers. Country differences were evident for all elements except Ba, Fe and Zn; Cd, Cu, Mn, Na, Se, Ni, Pb, Sr and S were higher and K, P, Ca and Mg were lower in Russia (p < 0.03). Not unexpectedly, the highest median lead concentration was observed for the largest city in the western arctic region of Russia, namely Murmansk. Similarly, the higher median nickel level observed for Russia reflects the established observation that urinary nickel concentrations are higher in the Russian than in the Norwegian communities. Even though sampling was performed at different times of the year and before and after a 3-year interval in four centres, inter-collection differences were of relatively small magnitude and appear not to be linked to seasonal or temporal changes. Principal component analysis (PCA) confirmed the prominence of Factor 1, which grouped those metals that are known to form insoluble phosphate complexes and whose concentrations showed a dependence on gestational age and maternal smoking in the earlier study. It is concluded that PCA is a powerful statistical tool for exploring and identifying fundamental pathways and processes involved in governing the inorganic elemental composition of placental tissue. It also has the potential of identifying study limitations and quality assurance shortfalls. Further our findings show promise that placental concentrations of toxic elements may serve as an index of exposure and of nutritional intake for selected essential micro-elements.

Multi-component assessment of worker exposures in a copper refinery

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.