Environmental contamination by heavy metals is a common fact in Central Asia. In the present study two sampling procedures were achieved: (i) Sampling of fodder, camel raw milk and shubat (fermented camel milk) in 8 farms closed to pollution sources from the South of Kazakhstan for copper, iron, manganese, zinc, arsenic and lead analysis, (ii) sampling of camel milk in 4 regions of Kazakhstan (63 samples) analyzed for lead, chrome and zinc contamination. In first sampling, camel milk contained 0.07 ± 0.04, 1.48 ± 0.53, 0.08 ± 0.03, 5.16 ± 2.17, <0.1 and 0.025 ± 0.02 ppm respectively for Cu, Fe, Mn, Zn, As and Pb. In shubat (fermented milk) the mean content was 0.163 ± 0.164, 1.57 ± 0.46, 0.088 ± 0.02, 7.217 ± 2.55 and 0.007 ppm respectively. Arsenic was detected in some samples of milk and shubat only. The trace elements concentration increase in shubat compared to milk but lead concentration decreased. No clear correlation was observed with fodder composition. In second sampling, the lead content was on average 250 ± 56 ppb in the camel milk with no significant differences between regions. The maximum value was observed at Atyrau (532 ppb). Zinc content in milk (5.42 ± 0.2 ppm) did not change significantly between regions. In reverse, chrome (59.5 ± 45.4 ppb) was higher in Shymkent region compared to others. These values were discussed according to the proximity of pollution sources. Specially, higher concentrations were experienced in fodder from pastures close to some industrial sites or high traffic road. (Résumé d'auteur)

Transfer parameters are key inputs for modeling radionuclide transfer in the environment and estimating risk to humans and wildlife. However, there are no data for many radionuclide-foodstuff/wildlife species combinations. The use of parameters derived from stable element data when data for radionuclides are lacking is increasingly common. But, do radionuclides and stable elements behave in a sufficiently similar way in the environment? To answer this question, at least for soil to plant transfer, sampling was conducted in four different countries (England, Kazakhstan, Spain and Ukraine) affected by different anthropogenic radionuclide source terms (in chronological order: global fallout, Semipalatinsk Test Site, the 1957 Windscale accident and the 1986 Chernobyl accident) together with a bibliographical review. Soil to grass transfer parameters (ratio between dry matter concentrations in plant and soil), Fᵥ, for ¹³⁷Cs and ⁹⁰Sr were significantly higher than those for stable elements, suggesting that the use of the latter could lead to underestimating radionuclide concentrations in plant samples Transfer parameters for ¹³⁷Cs and stable Cs were linearly correlated, with a slope of 1.54. No such correlation was observed for ⁹⁰Sr and stable Sr, the mean value of the ⁹⁰Sr:Sr ratio was 35 ranging (0.33–126); few data were available for the Sr comparison. The use of radionuclide transfer parameters, whenever possible, is recommended over derivation from stable element concentrations. However, we acknowledge that for many radionuclides there will be few or no radionuclide data from environmental studies. From analyses of the data collated there is evidence of a decreasing trend in the Fᵥ(¹³⁷Cs)/Fᵥ(Cs) ratio with time from the Chernobyl accident.

Trace elements (TEs) in the insoluble particles of surface snow are less affected by melting processes and can be used as environmental proxies to reveal natural and anthropogenic emissions. Here the first comprehensive study of the 16 TEs (Al, As, Ba, Bi, Cr, Cu, Fe, Mn, Ni, Pb, Sn, Sr, Ti, U, V, and Zn) in insoluble particles (>0.45 μm) from surface snow samples collected at Urumqi Glacier No. 1 (UG1), Eastern Tien Shan, China, from February 2008 to January 2010 were presented. Results show that concentrations of most insoluble particulate TEs (TEs ᵢₙₛₒₗ) in the snow were higher in summer while lower in winter, due to the increasing particle inputs and melting processes. The abundances of As, Cr, Cu, Ni, Pb, and Zn in some samples were higher than those in surrounding urban soils, which might due to these TEs have further anthropogenic input beyond the already contaminated re-suspended urban soil particles and TEs were mainly enriched in particles with small grain size. Based on enrichment factor (EF) and principal component analysis (PCA), our results suggest that eight TEs (Al, Fe, Ti, Ba, Mn, Sr, U, and V) mainly came from mineral dust, while the remaining eight TEs (As, Bi, Cr, Cu, Ni, Pb, Sn, and Zn) were affected by coal combustion, mining and smelting of non-ferrous metals, traffic emissions, and the steel industry. The Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model suggests that pollutants might originate from Xinjiang province, Kazakhstan, and Kyrgyzstan. Moreover, UG1 received more significant inputs of particle-bound pollutants in summer than in winter due to the stronger convection and the prevailing valley wind that transports pollutants from the city of Urumqi.

In the present study, the daily dose in terms of particle surface area received by citizens living in different low- and middle-income countries, characterized by different lifestyles, habits, and climates, was evaluated. The level of exposure to submicron particles and the dose received by the populations of Accra (Ghana), Cairo (Egypt), Florianopolis (Brazil), and Nur-Sultan (Kazakhstan) were analyzed. A direct exposure assessment approach was adopted to measure the submicron particle concentration levels of volunteers at a personal scale during their daily activities. Non-smoking adult volunteers performing non-industrial jobs were considered. Exposure data were combined with time-activity pattern data (characteristic of each population) and the inhalation rates to estimate the daily dose in terms of particle surface area.The received dose of the populations under investigation varied from 450 mm² (Florianopolis, Brazil) to 1300 mm² (Cairo, Egypt). This work highlights the different contributions of the microenvironments to the daily dose with respect to high-income western populations. It was evident that the contribution of the Cooking & Eating microenvironment to the total exposure (which was previously proven to be one of the main exposure routes for western populations) was only 8%–14% for low- and middle-income populations. In contrast, significant contributions were estimated for Outdoor day and Transport microenvironments (up to 20% for Cairo, Egypt) and the Sleeping & Resting microenvironment (up to 28% for Accra, Ghana), highlighting the effects of different site-specific lifestyles (e.g. time-activity patterns), habits, socioeconomic conditions, climates, and outdoor air quality.

Using a global database of contaminated sites, toxic hotspots in eight former Soviet countries were analyzed to identify the prevalence, types and sources of toxic pollution, as well as their associated potential public health impacts. For this analysis, polluted sites in Armenia, Azerbaijan, Kazakhstan, Kyrgyzstan, Russia, Tajikistan, Ukraine, and Uzbekistan were compiled and analyzed. The levels of contamination of seven key pollutants were assessed in each country. 424 contaminated sites were identified using data from Blacksmith Institute. Pesticides, lead (Pb), radioactive metals, arsenic (As), mercury (Hg), chromium (Cr), and cadmium (Cd) were the most commonly identified key pollutants. Collectively, these sites pose health risks to an estimated 6.2 million residents. The existing data on toxic hotspots in former Soviet countries likely captures only a small percentage of actual contaminated sites, but suggests potentially severe public health consequences. Additional assessments are needed to understand the risks posed by toxic pollution in the region.

In this paper, we briefly described the ecological consequences of six space rocket accidents launched from the Baikonur Cosmodrome between 1999 and 2018 and focused on an assessment of efficiency of soil remediation following the accidental crash of launch vehicle Proton-M on July 2, 2013, which resulted in the severest environmental impact in the modern Russian space industry. On the day after the accident, the content of carcinogenic unsymmetrical dimethylhydrazine and nitrosodimethylamine, as well as nitrate in soils of the crash site exceeded their maximal permissible concentrations by 8900, 6100 and 85 times, respectively. Mitigation measures included soil detoxication by a solution of 10% H₂O₂ and 1% iron complexonate, soil excavation and ploughing. Two years later (in April 2015), both unsymmetrical dimethylhydrazine and nitrosodimethylamine concentrations were below 0.05 mg/kg and nitrate concentration did not exceed 3.9 g/kg. As compared to background sites, soils of the crash site had significantly (P-value<0.05) lower values of pH and the content of total organic carbon, basicity from soda and carbonates and higher total nitrogen and soluble salt contents. Soil microbial communities were the most vulnerable component of the disturbed arid ecosystems, as their suppressed condition was indicated by a low biochemical oxygen demand and a very low cellulase activity.

The water quality of the northern Caspian Sea has not been well-known, and its contamination can adversely affect the health of swimmers and seashore residents. The study sought to determine the contamination state of the Caspian Sea in Kazakhstan and quantify human health risks coming from the existing heavy metals concentration. The Caspian Sea was found to be “fairly to marginally” contaminated (24 < CCME-WQI < 64), with Cd influencing the index significantly. Concentrations of Cd and Pb increase over time (seasonal Kendall test, p-values = 2–4 %) in sites near oil fields and ports, suggesting the significant role of anthropogenic sources in causing diverse pollution events. Pb demonstrated the highest variability and number of outliers (4.3 % of all samples with coefficients of variation reaching up to 175 %). The principal component analysis further revealed that various discharges from oilfields and upstream transport could contribute to the contamination by heavy metals and their concentrations. Contamination is associated with up to 6 % cancer risk for adults. The long exposure duration of swimmers in water increases risks by up to 18 %, indicating the local population is at a higher risk. In conclusion, statistical tests and analysis indicate the presence of anthropogenic sources, and risk assessment reveals swimming can contribute to cancer risk.

International audience | The environmental situation concerning pollution by (eco)toxic and persistent trace elements in Kazakhstan has been investigated by analytical reviews of scientific studies published over the past 20 years reporting concentrations of 10 toxic trace elements (TTE) observed in soil, sediments or surface water. A database of 62 articles published in Kazakh, Russian or English covered the majority of the territory of the country for soil and water samples but to a lesser extent for sediments. Reported concentrations were summarized using statistical parameters, then spatialized and finally classified in contamination classes according to local legislation. This analysis revealed some hotspots of TTE in surface waters (Cd and Pb), soil (As) and sediments (Cd and As). Hotspots of less toxic Cu, Zn and Mn were also detected. Spatialization of results allowed localization of these hotspots close to industrial sites, such as smelters or mining and metallurgic combines. Others have been shown to be close to disused mining sites or landfills with municipal waste. Methodological improvements for further studies have been suggested, such as to integrate more West Kazakhstan or remote areas in sampling campaigns, but also to describe more exhaustively the used analytical methods and to be more attentive to the speciation of the analyzed form of the element. Finally, a management strategy to strengthen a sustainable food policy has been proposed: to reduce emissions by modernization of industrial facilities and better waste management, to organize land use depending on the contamination levels and to reduce the bioavailability of the toxic elements.

Quantification of grassland carbon (C) variations is necessary for understanding how grazing and climate change interact to regulate carbon capture and release. Central Asia (CA) has the largest temperate grassland belt in the world and unique temperate dryland ecosystems, which experienced severe climate change and grazing-induced disturbances. However, the impact of grazing on C dynamics is highly uncertain owing to climate variations. Here, an arid ecosystem model (AEM) supplemented with a grazing module that specifically addressed physiological and ecological characteristics of dryland vegetation was developed to quantitatively simulate grassland C dynamics in response to changes in precipitation, temperature, grazing intensity, and CO₂ level in the past decades. The regional simulation results showed that net primary productivity (NPP) was affected mainly by precipitation (in 59% of the studied area). Grazing had a negative effect on NPP and C stocks, whereas overcompensation occurred in 25.71% of the studied area, mainly in the dry western parts. The complex interaction effects of climate, CO₂, and grazing negatively affected productivity, with a grassland NPP decrease of − 1.14 g C/m²/a and high interannual variability. We found that the temporal pattern of cumulative C sequestration, especially total C and vegetation C (VEGC), closely followed the annual fluctuations of precipitation. VEGC stocks decreased from 182.22 to 177.82 g C/m², with a very low value between 1998 and 2008, when precipitation significantly decreased. The results indicate that southern Xinjiang and the Turgay Plateau of Kazakhstan are ecologically fragile areas due to grassland degradation.

Extended stochastic impact by regression on population, affluence, and technology model incorporating ridge regression was used to analyze the driving mechanism of energy-related CO₂ emissions in Kazakhstan during 1992–2014. The research period was divided into two stages based on GDP of Kazakhstan in 1991 (85.70 × 10⁹ dollars), the first stage (1992–2002), GDP < 85.70 × 10⁹ dollars, the stage of economic recovery; the second stage (2003–2014), GDP > 85.70 × 10⁹ dollars, the stable economic development stage. The results demonstrated that (1) population scale and the technological improvement were the dominant contributors to promote the growth of the CO₂ emissions during 1992–2014 in Kazakhstan. (2) Economic growth and industrialization played more positive effect on the increase of the CO₂ emissions in the stable economic development stage (2003–2014) than those in the stage of economic recovery (1992–2002). The proportion of the tertiary industry, the trade openness, and foreign direct investment were transformed from negative factors into positive factors in the stable economic development stage (2003–2014). (3) Due to the over-urbanization of Kazakhstan before the independence, the level of urbanization continued to decline, urbanization was the first factor to curb CO₂ emissions during 1992–2014. Finally, some policy recommendations are put forward to reduce energy-related carbon emissions.