Heavy metal contamination levels, source distribution, and risk assessment in fine sand of urban surface deposited sediments of Ekaterinburg, Russia.

Urban surface deposited sediments (USDS) are unique indicators of local pollution that pose a potential threat to the living environment and human health. Ekaterinburg is a highly populated metropolitan area in Russia with rapid urbanization and industrialization activities. In Ekaterinburg's residential areas, about 35, 12, and 16 samples are represented by green zones, roads, driveways, and sidewalks, respectively. The total concentrations of heavy metals was detected using a chemical analyzer inductively coupled plasma mass spectrometry (ICP-MS). Zn, Sn, Sb, and Pb have the highest concentrations in the green zone, while V, Fe, Co, and Cu represent the utmost values on roads. Moreover, Mn and Ni are the prevailing metals in the fine sand fraction of driveways along with sidewalks. Broadly, the high pollution in the studied zones is generated by anthropogenic activities and traffic emissions. The potential ecological risk (RI) was observed in high risk (IR > 600), even though the results of all heavy metals reveal no adverse health effects from the considered noncarcinogenic metal for adults and children by different exposure pathways except the children's exposure to Co in case of the dermal contact, where the HI values of Co for children in the studied zones are higher than the proposed level (> 1). In all urban zones, the total carcinogenic risk (TLCR) values are predicted as a high potential inhalation exposure.

Potentially harmful elements in urban surface deposited sediment of Ekaterinburg, Russia: Occurrence, source appointment and risk assessment.

In this study, the human health risks of potentially harmful elements (PHEs) in urban surface deposited sediments (USDS) were examined by collecting urban dust samples, measuring their PHE concentrations, and using index evaluation. About 35, 12 and 16 samples are represented a green zones, roads, driveways and sidewalks in residential areas of Ekaterinburg, respectively. The dust fraction (0.002-0.1 mm) was obtained by sieving, filtration, and decantation process. Total concentrations of 10 PHEs were measured using inductively coupled plasma mass spectrometry. The highest concentrations of Pb were found in USDS from green zones, while Fe, V, Mn, Co, Ni, Sn, and Sb on roads, Cu and Zn on driveways and sidewalks. The contamination levels in the investigated land-use areas were studied, where the highest contamination was contributed from Sb in the driveways and sidewalk. Moreover, the pollution in the studied zones was a high load, contributing to anthropogenic activities and traffic emissions. No non-cancerogenic risk was attributed from the PHEs based on the results of health indices (HI < 1) for both adult and children, except Co and Ni which has HI > 1 for children. The total carcinogenic risk (TLCR) in all urban landscape areas is defined as a high potential inhalation exposure and a low potential ingestion and dermal exposure.

Radon concentration in conventional and new energy efficient multi-storey apartment houses: results of survey in four Russian cities.

During last decades, energy saving in new buildings became relevant within the energy efficiency strategies in various countries. Such energy efficient building characteristics as air tightening and low ventilation can compromise indoor air quality, in particular, increase radon concentration. In Russia, a significant part of the new buildings is the energy efficient multi-storey apartment houses. The aim of this study is to assess the significance of possible radon concentration increase in new energy efficient buildings in comparison with typical conventional multi-storey houses of previous periods. Radon surveys were conducted in Russian cities Ekaterinburg, Chelyabinsk, Saint-Petersburg and Krasnodar. The radon measurements were carried out in 478 flats using CR-39 nuclear track detectors. Energy efficiency index (EEI) was assigned to each house. All buildings were divided into six main categories. The smallest average radon concentration was observed in panel and brick houses built according to standard projects of 1970-1990 (four-city average 21 Bq/m3). The highest average radon concentration and EEI were observed in new energy efficient buildings (49 Bq/m3). The trend of radon increase in buildings ranked with high EEI index is observed in all cities. The potential increase of radiation exposure in energy-efficient buildings should be analyzed taking into account the principles of radiological protection.

Beta radioactivity of urban surface-deposited sediment in three Russian cities.

Study of gross beta activity was conducted in Russian cities Ekaterinburg, Rostov-on-Don, and Nizhny Novgorod. The cities were characterized by continental climate, although they are located in different geographical zones. The bulk urban samples were fractionated with three size fractions: dust (0.002-0.1 mm), fine sand (0.1-1 mm), and coarse sand (> 1 mm). Measurement setup equipped with beta radiometer BDPB-01 was designed to measure the low levels of gross beta-activity in a small amount of the obtained size-fractionated samples. According to the results of the study, the gross beta activity depends on the size fraction and the city. The highest beta activity concentration was found in the dust fraction which is about the same in all cities 0.8-0.9 Bq g-1. In size fractions of fine sand and coarse sand, the beta activity depends on the city. Among other cities, the highest average beta concentration was found in Ekaterinburg (0.8 and 0.6 Bq g-1 in fine and coarse sand fractions, respectively), while the lowest is 0.28 and 0.44 Bq g-1, respectively. The relationship of beta activity concentration with mineral and chemical composition is studied. Average beta activity in the different fractions of the surface-deposited sediment correlates with uranium, thorium, and organic matter concentration. The gross beta activity may be considered an indicator of high contribution of dust and high pollution with Pb, Cu, and Zn in the urban environment.

Urban geochemical changes and pollution with potentially harmful elements in seven Russian cities.

This paper presents results of an analysis of potentially harmful elements (PHEs, Pb, Zn and Cu) and conservative element (CE, Fe) concentrations in urban surface deposited sediment (USDS). The study was conducted in seven large Russian cities located in different geographic and climatic zones, and in territories with different geology and anthropogenic pressures: Chelyabinsk, Magnitogorsk, Nizhniy Novgorod, Nizhniy Tagil, Rostov-on-Don, Tyumen, and Ufa. The initial geochemical baseline relationships between PHEs and CE concentrations in the USDS were reconstructed for each city applying an approach based on linear weighted fitting of PHE as a function of CE with lower weights assigned to more polluted samples. The reconstructed average initial baseline Pb, Cu, and Zn concentrations varied between 17-52, 25-196, and 91-413 mg kg-1, respectively. Several new criteria for assessing the degree of geochemical transformation and pollution of the urban environment, such as the percentage of polluted samples, average pollutant concentration in polluted samples, and weighting degree index δ, were suggested and compared with common criteria, such as the PHE concentration and the geo-accumulation index. The environmental rank of a city significantly differed depending on whether the criterion for ranking was total PHE pollution or changes in comparison with the initial geochemical baseline.

Snow-dirt sludge as an indicator of environmental and sedimentation processes in the urban environment.

The formation of snow-dirt sludge (SDS) via the mixing of snow and surface-deposited sediment by vehicles and pedestrians is one of the least studied sedimentation processes in urban areas. The aim of this study was to analyse the material, mineral, particle size, and chemical compositions of the SDS solid phase. The study was conducted using Ekaterinburg, Russia, as an example city with an intense anthropogenic impact and a long cold snowy period. The average content of the SDS solid phase was approximately 35 g L-1 of meltwater on heavy traffic roads, of which the dust fraction (<0.1 mm) accounted for 23 g L-1. On driveways and lawns, the contents of the SDS solid phase were 12 and 6.6 g L-1, respectively. The mineral composition of the SDS solid phase was generally similar to the geology of the surrounding area, which is composed of a mosaicked combination of felsic and mafic complexes. The presence of building material fragments and other anthropogenic particles confirms the significant anthropogenic impact. The chemical composition contained major and minor elements specific to the minerals and materials that constitute the SDS solid phase. There was significant variability in the concentrations of Pb, Cu, and Zn in the granulometric fractions, indicating pollution. Intensive melting of SDS with a high particulate matter (PM) content is an important factor influencing the environmental quality of the urban environment.

EFFECTIVE DOSES ESTIMATED FROM THE RESULTS OF DIRECT RADON AND THORON PROGENY SENSORS (DRPS/DTPS), EXPOSED IN SELECTED REGIONS OF BALKANS.

The main contribution to population exposure is due to radon and thoron progenies and not radon itself. The aim of this study was therefore to estimate annual effective dose using the results of Direct Radon and Thoron Progeny Sensors were exposed in 69 selected schools and 319 dwellings in several regions of Balkans: in Serbia: regions of Sokobanja and Kosovo and Metohija, Republic of Macedonia, Republic of Srpska and Slovenia. Obtained average total effective doses are in the range from 0.22 mSv a-1 (schools in Republic of Srpska) to 2.5 mSv a-1 (dwellings in Kosovo) and are below the reference level of 10 mSv a-1 recommended by International Commission on Radiological Protection.

Meta-analysis of case-control studies on the relationship between lung cancer and indoor radon exposure.

Indoor exposure to natural radon is a factor that influences lung cancer risk worldwide. The present study includes a meta-analysis of epidemiological data on the relationship between lung cancer and indoor radon. Altogether, 31 case-control studies with 20,703 cases, 34,518 controls and 140 individual odds ratio (OR) estimates are included in the meta-analysis. Weighted median OR was calculated for five radon intervals. The following parameters were used for the weighting: standard error of OR, duration of radon concentration measurement, and relative number of controls in reference intervals. The dependence of the weighted median OR on the radon concentration was estimated applying linear non-threshold and threshold models. The results obtained suggest a significant linear no-threshold exposure-effect relationship for radon concentrations above 100 Bq/m3, with a slope of 0.14 (95% confidence interval 0.08-0.21) per 100 Bq/m3.

Radon, smoking and HPV as lung cancer risk factors in ecological studies.

OBJECTIVES: Cohen's ecological analyses revealed negative correlation between the lung cancer mortality and average indoor radon concentration in the US counties, that contradicts to linear non-threshold (LNT) model and is inconsistent with results of case-control studies. The aim of this study was to analyze dependence between radon exposure and lung cancer mortality rate taking into account more complete data on smoking and new findings on association of the lung cancer with human papillomavirus (HPV) infection. MATERIALS AND METHODS: Information on the cancer rates in the US counties and Russian oblasts, smoking prevalence and indoor radon concentration was found in literature. The cervix cancer incidence rate was used as surrogate of the HPV infection prevalence. The analysis included calculation of the coefficients of linear dependence between radon exposure and lung cancer mortality rate with adjustment to smoking and HPV infection prevalence. RESULTS: After adjustment for the most relevant data on smoking and HPV infection, correlation between the lung cancer mortality and indoor radon was found to be consistent with results of the case control studies. CONCLUSIONS: Analysis of geographically aggregated data on the lung cancer mortality and radon concentration in dwellings with adjustment to the significant risk factors confirms both the linear non-threshold dependency and results obtained in studies with individual accounting for the smoking and radon.

Strontium biokinetic model for mouse-like rodent.

Model describing the biokinetics of strontium for murine rodent is suggested. The model represents modification of the ICRP model for reference human with reduced number of compartments: Blood, Gastrointestinal tract, Soft tissues, Skeleton, Urinary bladder. To estimate transfer rates of the model the published experimental data on strontium retention in body of laboratory and wild mice were analyzed. A set of eleven transfer rates suggested for the strontium biokinetic model for murine rodent satisfactorily describes both the laboratory experiments (relative standard error of 9.5%) and data on radiostrontium content available for wild animals. Application of the model allows estimation of strontium distribution by organs and tissues both in the cases of acute and chronic exposure with assessment of strontium activity in organs with time since beginning of exposure. The developed strontium biokinetic model will be used for internal dose assessment for murine rodents inhabiting East-Ural Radioactive Trace, where (90)Sr intake is a significant source of contemporary internal exposure.