[The umbilical blood levels of lead and some other toxic metals as a biomarker of environment-induced exposure]

Groups of pregnant women, which made up in Revda, Pervouralsk, Krasnouralsk, and Verkh-Isetsky District of Yekaterinburg, were studied. Tests of umbilical blood samples (UB) for the levels of calcium, iron, chromium, manganese, zinc, nickel, cadmium, lead, arsenic, copper, and mercury have established that the mean concentration of lead and the proportion of samples with elevated UB lead concentrations depend on how close the residential area is located to the major industrial source of emission of this toxic metal into ambient air. This correlation is less marked for other metals or it is not found. The particular position of lead is likely to be explained by the fact that it is entirely foreign to an organism and by the comparative unimportance of a contribution of the sources of exposure to this metal, which are unassociated with man-caused environmental and food pollution. As far as other metals are concerned, the situation is complicated by the fact that they are not only toxic, but when upon minor exposures, also essential biotrace elements with controlled and interdependent toxic kinetics. It is also shown that when a pregnant woman takes a complex of biological protectors promoting a reduction in her body's levels of lead, its concentrations in her body, its UB concentration is much lower than such a bioprophylactic effect is absent.

[Providing safe environment for health of population living near aluminium industry enterprises]

Based on studies of environmental objects and of children's health, the authors justified systematic approach to hygienic evaluation of aluminium plant reconstruction stages, for rational management in minimizing risk of environmental pollution and for health preservation.

[Biologic prophylaxis of intoxications with inorganic compounds]

The authors summarize theoretical principles of increasing human resistence to toxic effects of inorganic compounds polluting occupational environment and habitat, exemplify practical use of this prophylactic trend.

[Hygienic regulation of environmental air pollution with consideration of epidemiological data]

The authors hold that the maximum allowable concentrations (MAC) established in Russia for some ambient air pollutants can adversely affect human health and that they are worthy of reconsideration. This opinion is based on the published results of epidemiological studies of Western investigators and on the authors' own data obtained from the analysis by the time series method for a relationship of daily variations of dust or gaseous ambient air pollution to the so-called acute mortality or for that of the variations to respiratory symptoms and to the values of the maximum expiratory flow rate in preschool with or without respiratory abnormalities in their history; from the cross analysis of an association of the characteristics of atmospheric contamination in 13 urban areas with the prevalence of chronic respiratory diseases in junior schoolchildren, which was established by a special questionnaire. Particular emphasis should be laid on the reconsideration of not only established values, but mainly on the principles in laying down MAC for dust particles. The Western practice in measuring and evaluating risks separately for fractions of particles of varying sizes should be assessed for its use in Russian conditions; however, the authors' experience argues for this practice.

[The role of environmental and epidemiological surveys of ambient pollution in the evaluation of a risk for "acute" mortality]

The paper provides evidence that there is a relationship of daily death rates to variations in the concentrations of total dust and some gaseous ambient pollutants. The great advantage of a procedure to analyze temporary variables is that it makes it possible to retrospectively use the available materials of routine monitoring of air pollution and to consider these effects (cases of death in particular). Along with the high informative value of environmental and epidemiological surveys (EES) based on the analysis of time series, this advantage allows one to recommend them for widely use within the sociohygienic monitoring system. At the same time the paper shows it necessary to control the quality of available data and to chose monitoring centers comparable in this regard. Inevitable missing data on the concentrations of different pollutants on days off and on some working days are of particular value under the actual conditions of monitoring of air pollution. The approach applied in this study to the choice of the most effective ways of filling of such gaps may be recommended. Nevertheless, incomplete data and the need for their artificial reproduction should be regarded as a source of uncertainty of specific results of EES of this type. Increments in mortality rates for a certain increase in the concentrations of pollutants may be used in the risk assessment projects when a dose-response relationship is analyzed. The larger number of EES based on the analysis of time series will be conducted in the regions of Russia, the more reliable the use of EES-grounded single risks will be at the regional and federal level.

[Dioxins: facts and conjectures]

Dioxins and dioxin-like substances are highly toxic and extremely dangerous chemical compounds. Dioxins are formed during the thermal process associated with the use of chlorine. 2,3,7,8-tetrachlorodibenzo-1,4-dioxin is the most toxic, the most typical and well-studied agent. The most characteristic and constant indicators of intoxication with dioxin-containing substances are altered body weight, chloracne, hepatic damage, thyroid involution, structural changes in the adrenal cortex, spleen, genitals, immunodeficiency. There is evidence for a role of these agents in the development of infertility and neonatal pathology.

[Ecologo-epidemiologic studies in the social-hygiene monitoring system (experience in the Sverdlovsk region)]

Surveys made in the Sverdlovsk Region suggest that a procedure for evaluating a risk in combination with ecological and epidemiological surveys greatly enhances the potentialities of predicting and detecting human environment-related diseases and both approaches deserve a wide introduction into the socio-sanitary monitoring system.

Some considerations concerning multimedia-multipollutant risk assessment methodology: use of epidemiologic data for non-cancer risk assessment in Russia

The highly industrialized small town of Verkhnyaya Pyshma (in the Urals region of Russia) was chosen as the site of a multimedia-multipollutant risk assessment using the U.S. Environmental Protection Agency methodology. The assessment was based on routine environmental pollution monitoring data for ambient air, soils, drinking water, and food, and the international environmental epidemiology literature. Using an a priori set of the preliminary health-based criteria, we selected nine pollutants for risk assessment: total suspended particles (TSP), sulfur dioxide, nitrogen dioxide, benzo(a)pyrene (BaP), ammonia arsenic, copper, cadmium, and lead. We used dose-response functions derived from epidemiologic studies to assess individual and population risks for TSP, SO2, NO2, As, Cd, and Pb. We assessed both cancer (for BaP, As, and Cd) and non-cancer (for all the chosen pollutants but BaP) responses, but in this paper we discuss only the assessments of noncarcinogenic risks due to TSP, SO2, NO2, Pb, and Cd as examples of how the quantitative estimates of health effects can be produced by using a risk function approach. We also schematically present a modified conceptual model of multimedia-multipollutant risk assessment taking into account the experience gained with this study.

[Some results of the used methodology for the evaluation of risk in the Sverdlovsk region]

The authors represent a scheme of conceptual model for methodology to evaluate health risk caused by environmental pollution. The model is based on analysis of literature and the authors' experience.

[On hygienic standards of the allowable levels of suspended particles in the air]

Elevation of average daily concentrations of suspended particles in air, even being within the MAC, could be associated with higher mortality in general population and deteriorated respiratory symptoms in children, especially in those having chronic respiratory diseases with bronchial obstruction. Discussion on reduction of MAC for suspended particles is expendient with wider practice of fraction measurement their concentrations.

[Impact of short-term increase in air pollution on mortality of the population]

The authors analyzed whether there is an association of mortality with ambient air pollution analyzed in Yekaterinburg and Nizhni Tagil in 1994 to 1997. There was a positive correlation between general mortality and CO or SO2 concentrations, between cardiovascular mortality and dust, NH3 or phenol, between mortality and CO or NH3. An increase of deaths as percents per 10 micrograms/m3 dust was calculated.

[Evaluation of hazards caused by effects of lead on preschool children living near a copper-smelting plant]

The studies conducted in Krasnouralsk (Sverdlovsk region) proved that environmental pollution with lead in the area subjected to releases by copper-melting enterprise creates significant risk of lead accumulation in preschoolers especially prone to unfavorable factors. Considering various environmental lead sources, biokinetic analog formation reliably forecasts serum lead levels. Soil polluted with lead, as the analog considers, is the most important environmental lead source. The authors suggest a system of prophylactic measures based on analysis of children's health risk caused by environmental pollution with lead.

[Late changes in the body function of the inhabitants in the area of the eastern Urals radioactive trace]

Using a mathematical methodology based upon the theory of pattern recognition, the adequacy of this methodology being confirmed by the corroborative results obtained with neuro-net non-parametric methods of analysis, it proved possible to discriminate reliably between generalized organism's statuses, as described with a big number of laboratory indices, of the inhabitants of different areas of a big industrial city which differ in levels of radioactive and non-radioactive environmental pollution.

On the relationship between activation and breakdown of macrophages in the pathogenesis of silicosis (an overview)

Silica particles cause considerable damage to macrophages resulting in their eventual breakdown. At the same time, the development of silicosis involves a number of mechanisms associated with the activation of macrophages. In suggesting schemes for the pathogenesis of this disease many authors associate the central part with activation, completely neglecting damage to cells. Our experiments have shown, however, that much of the activation phenomena could be reproduced in vitro or in vivo by exposing macrophages to macrophage breakdown products. Alternatively, the secondary character of activation is demonstrated by the fact that it reveals itself only at silica doses which cause part of the cells to lose their viability in the same culture. Our data show that the range of macrophage activation phenomena which could be considered as secondary with respect to the breakdown of cells includes the production of neutrophil attractants, enhanced co-operation with T lymphocytes, increase in phagocytic activity, enhancement of cellular O2 consumption and peroxidation, an increase in the activity of dehydrogenases, reduction in the activity of 5'-nucleotidase, and some other effects. Although not denying that small silica doses may be able to exert a direct activating influence upon the macrophage we do, however, believe that the most important and primary role in the pathogenesis of silicosis is played by the damage to and the breakdown of this cell.

An approach to detecting delayed effects of radioactive contamination on industrial-urban-area dwellers

Detecting changes in humans that result from radioactive contamination of the area of residence many years after an incident (i.e., when the radiation has substantially decayed) presents a difficult epidemiological problem. Problems of this kind are even more complicated ina areas where the population is continually exposed to other harmful man-made factors. The city of Kamensk-Uralsky (Sverdlovsk region, Russia) is a good case in point. In 1957, part of Kamensk-Uralsky was contaminated as the result of an accident at the Kyshtym nuclear plant. In addition, the population of the contaminated area is being exposed to atmospheric emissions from several industrial enterprises. Two comparable groups of residents were formed: one in the contaminated are and another in a control area within the same city characterized by similar levels of chemical pollution but substantially lower radioactive contamination. The groups were composed of only those people who had been living in these areas continually since time of the accident and who were under 15 years of age at the time of the accident. The groups were matched by sex, age, and socio-occupational characteristics. For each subject, data were gathered on more than 50 parameters including hematological, immunological, and biochemical indices of the health status. All these data were obtained from blood tests taken in the fall of 1992. Data processing was carried out with the help of a computerized mathematical pattern recognition methodology, which ensured reliable discrimination between the generalized health status in the areas under study. We found that the health status of inhabitants of the area more contaminated with radioactive fallouts was adversely affected by radiation.

Prediction of the comparative intensity of pneumoconiotic changes caused by chronic inhalation exposure to dusts of different cytotoxicity by means of a mathematical model

A multicompartmental mathematical model has been used to simulate variations in the cytotoxicity of dusts in the kinetics of the retention, in the pulmonary region and tracheobronchial lymph nodes, of practically insoluble quartzite and titanium dioxide dust particles deposited on the free surfaces of the acini from alveolar air. Experiments with these dusts were conducted on rats exposed to virtually the same dust concentrations in the air for an experimental period of 20 weeks and a period of 10 weeks after exposure. Satisfactory approximation to the experimental data on the retention of these dusts is obtained by using the model parameters that depend either on damage to lung macrophages by phagocytosed particles or on the response of the host organism to this damage by enhanced recruitment of neutrophilic leucocytes; all the other variables of the model being unchanged. The values of the "action integral" computed from this model and multiplied by the index of comparative cytotoxicity of particles in vitro satisfactorily approximate to quantitative differences in the intensity of pneumoconioses caused by the dusts under study by the end of the experimental period. On the whole, the results of the mathematical model agree with the hypothesis that the cytotoxicity of particles plays a key part in both the process of retention of dust in the lung parenchyma and lung associated lymph nodes, and the pathological process caused by the retained dust. Thus given the factors and conditions on which the deposition of practically insoluble dusts in the pulmonary region depends, it is necessary to take into account the multiplicative nature of these two effects of cytotoxicity when predicting the comparative risk of pneumoconiosis.

[Significance of short-term cytotoxicity tests for hygienic assessment of industrial aerosols]

The evaluation of low-soluble particles toxicity for human phagocytes (primarily, for macrophages) was proved to have advantages in predicting their effects on the human body and in rapid toxico-hygienic regulation. The preference is given to tests "in vitro". If comparative toxicities of substances in group are discordant according to different "in vitro" tests the decision must be made after the "in vivo" evaluation of cytotoxicity: in 24 hours after the intratracheal administration of small doses of these low-soluble particles the bronchoalveolar lavage is examined cytologically. Reliable neutrophilia in lavage is of great value.