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[en] ASEAN Network on Nuclear Power Safety Research (ASEAN NPSR) has been working since 2017 on the atmospheric dispersion benchmark problem to support capacity building in emergency preparedness and response (EPR) in ASEAN. Its project named Enhancing ASEAN Research Competency in Nuclear Emergency Preparedness and Response is being funded under the ASEAN Science, Technology and Innovation Funds (ASTIF). Atmospheric dispersion characteristics of a hypothetical release from nuclear power plants (NPP) are assessed with different meteorological conditions, calculation codes and assessors, and the results are compared and discussed. The project started with the assessment of the proposed Ninh Thuan 1 Nuclear Power Plant, and later shifted to Fangchenggang Nuclear Power Plant. Source term data is adopted from the station blackout scenario in the SOARCA report. Three different sets of meteorological data are used for the calculation to cover dry and wet conditions. The benchmark problem is assessed by three member states: Singapore, Vietnam and Thailand, using four calculation codes: ARGOS, Flexpart, JRODOS and NACAC. The dispersion patterns of ARGOS and JRODOS are almost identical, while those of Flexpart and NACAC are quite different. It was found that air concentration and ground concentration calculated by ARGOS and JRODOS are within the same ranges (differences are less than an order of magnitude), though ARGOS delivers much smaller total effective dose equivalents (TEDEs) for dry deposition, and much larger TEDEs for wet deposition. The results are being investigated to find the root causes to these differences, and to summarize recommendations to the users of these calculation codes when the codes are applied to transboundary atmospheric dispersion calculation. (author)
[en] Reviewed the question of influence of the Rivno nuclear power plant on tritium contamination of the Stir river as a result of discharge of debalance waters. The preliminary prognosis of change of tritium activity in the Stir River on a border with Belarus is given. (authors)
[en] The occurrence of POPs in remote areas, such as Antarctica, is the result of their ability to udergo Long Range Transport (LRT) in the atmosphere, precipitation and cold condensation. In this study, both recent levels of various POPs in Trematomus bernacchii and their changes in roughly three decades were determined in order to evaluate trends of POPs in Antarctic benthic seawaters. In fact, Trematomus bernacchii is considered a good sentinel bio-indicator for monitoring not only the extent of contamination by POPs in the Antarctic aquatic ecosystem, but also changes in Antarctic ecosystem quality and trends. A slight decreasing PCB trend was detected during 30-years time span (from early 1980's to 2010) in the circumantarctic seawaters. Two higher peaks of concentrations were reported in 2001 and 2005 in the Ross Sea and they may reflect the ice melting of icebergs. Because fire risk is very high in Antarctica due to the very dry air, a large use of flame retardants in buildings and furniture of stations is highly probable; moreover, many stations were built when there were no restrictions on flame retardants use. The PBDE levels in the T. bernacchii from 2001 to 2011 ranged 0.05–0.35 pg/g and were of the same order of magnitude in 2001/2011 and in 2002/2005, with a maximum value in 2005 (0.35 pg/g). Comparable concentrations of HCB, HCHs PCDDs and PCDFs are available only for few seasons: all these compounds showed a decreasing temporal trends and their concentrations were one or more order of magnitude lower in 2000s–2010s. - Trematomus bernacchii was used to evaluate the POP temporal trend in Antarctic benthic seawaters: some POPs showed a decreasing trend and for others the tendencies are uncertain.
[en] The paper reports on the study of the radiation situation and the degree of contamination with natural radionuclides and toxic elements of 11 transboundary rivers and the Big Chu Channel at the points of their inflow into Kazakhstan from Kyrgyzstan. The methods of radiometry, IGS, XRF, MS-ICP, OES-ICP, RChA were used. It was established that the radiation background in the examined areas is high, but does not pose a risk to human health. In the majority of the transboundary watercourses, the chemical toxicity of waters exceeds for 2-12 times the regulatory value set in the Republic of Kazakhstan for drinking water. Uranium contributes 37% to this indicator. (author)
[en] The Ordos region of Inner Mongolia is rapidly developing and suffers from poor air quality and unhealthy levels of fine particulate matter. PM2.5 concentrations in the Ordos region were found to exceed 75 μg/m3 on average, annually, with peak pollution days in excess of 350 μg/m3, but local air pollution emissions from surrounding sources are not sufficient to drive pollution levels to these concentrations. The current study was designed to quantify sources of PM2.5 and assess the local source contributions and effects of regional transport on local pollution. The results show that the Ordos region is primarily impacted by regional long-range transport of pollutants from anthropogenic sources located outside of the Inner Mongolia in Shanxi province areas but is also largely affected by regional dust transported from the deserts located in western Inner Mongolia. The analysis proved that approximately 77% of PM2.5 mass is transported long-range from the sites exterior to the study area and contributes 59.32 μg/m3 on average, annually, while the local sources contribute 17.41 μg/m3 (23%) on annual average to the PM2.5 mass in the study area. High spatial correlation coefficients (R2 > 0.6) were observed for most of the factors pointing to the transport of external emissions into the area. Spatial correlation analysis, bivariate polar plots and hybrid trajectory models for industrial and secondary inorganic factors provide evidence for the impact of long-range transport from Shanxi province areas. In addition, the deserts in western Inner Mongolia were found to be the source regions for dust. Finally, our analysis shows that the source of oil combustion and mobile factors are impacted by local sources in the Ordos region; however, some regional impacts from other regions were also observed for mobile source in the area. - Dominance of the regional long-range transport of PM2.5 sources in the Ordos region. Around 77% of PM2.5 mass is transported long-range from the sites exterior to the Inner Mongolia.
[en] Antibiotic resistance is a worsening global concern, and the environmental behaviors and migration patterns of antibiotic resistance genes (ARGs) have attracted considerable interest. Understanding the long-range transport of ARG pollution is crucial. In this study, we characterized the dynamics of ARG changes after their release into aquatic environments and demonstrated the importance of traditional chemical contaminants in the transmission mechanisms of ARGs. We hypothesized that the main route of ARG proliferation switches from active transmission to passive transmission. This antibiotic-dominated switch is motivated and affected by non-corresponding contaminants. The effect of anthropogenic activities gradually weakens from inland aquatic environments to ocean environments; however, the effect of changes in environmental conditions is enhanced along this gradient. The insights discussed in this study will help to improve the understanding of the distribution and migration of ARG pollution in various aquatic environments, and provide a modern perspective to reveal the effect of corresponding contaminants and non-corresponding contaminants in the process of antibiotic resistance proliferation. - Highlights: • Process of ARGs flow through WWTPs, rivers, estuaries and ocean to implement global proliferation and commutation. • The diversity and concentrations of ARGs progressively decrease during dynamic long-range migration processes. • The main route of ARG proliferation switches from active transmission to passive transmission from inland to ocean. - The diversity and concentrations of antibiotic resistance genes progressively decrease during dynamic long-range migration processes.
[en] Highlights: • Comparison of production-based and consumption-based accounting of CO2 emissions. • Longitudinal analysis of the newest data for 110 countries for the last 15 years. • Results show only small differences between PBA and CBA. • Countries with large imports have higher CBA/PBA ratios. • The CBA/PBA ratio is positive for countries with high energy efficiency. - Abstract: Lately, a controversial debate has evolved regarding consumption-based accounting (CBA) versus production-based accounting (PBA) of CO2 emissions. So far, the debate has been predominately theoretical and has inspired only a few empirical studies. In this article, we compare production-based versus consumption-based emissions, and for the first time analyze reasons for the differences. In particular, we focus on whether there is evidence for carbon leakage from developed to developing countries. We use the newest available data for 110 countries and analyze whether there are differences between OECD and non-OECD members. Furthermore, we compare the within-country differences for the time span of 1997 to 2011 via fixed effects panel regression models in order to investigate whether increases in GDP per capita result in higher imported emissions. The results suggest that for most countries the differences depending on accounting schemes are small. Furthermore, we find no evidence for carbon leakages. In particular, the ratio of CBA to PBA is not driven by OECD membership or GDP per capita. Instead, the ratio is greater for countries with high energy efficiency and high import rates. Given the small differences between PBA and CBA, we suggest keeping the production-based accounting of CO2 emissions.
[en] Here, the Arctic is warming at an alarming rate, yet the processes that contribute to the enhanced warming are not well understood. Arctic aerosols have been targeted in studies for decades due to their consequential impacts on the energy budget, both directly and indirectly through their ability to modulate cloud microphysics. Even with the breadth of knowledge afforded from these previous studies, aerosols and their effects remain poorly quantified, especially in the rapidly changing Arctic. Additionally, many previous studies involved use of ground-based measurements, and due to the frequent stratified nature of the Arctic atmosphere, brings into question the representativeness of these datasets aloft. Here, we report on airborne observations from the US Department of Energy Atmospheric Radiation Measurement (ARM) program's Fifth Airborne Carbon Measurements (ACME-V) field campaign along the North Slope of Alaska during the summer of 2015. Contrary to previous evidence that the Alaskan Arctic summertime air is relatively pristine, we show how local oil extraction activities, 2015's central Alaskan wildfires, and, to a lesser extent, long-range transport introduce aerosols and trace gases higher in concentration than previously reported in Arctic haze measurements to the North Slope. Although these sources were either episodic or localized, they serve as abundant aerosol sources that have the potential to impact a larger spatial scale after emission.
[en] Highlights: • Convergence in CO2 emissions per capita is studied in a global sample of countries during 1970– 2014. • A Spatial Green Solow model is developed to accommodate spatial dependence in emissions data. • A convergence equation which has the form of a Dynamic Spatial Durbin model is estimated. • Spatial multi-regime panel data models are developed to study heterogeneous convergence dynamics • Spatial non-parametric techniques are used to analyze convergence dynamics across clubs. - Abstract: This research analyzes the evolution of CO2 emissions per capita in a sample of 141 countries during the period 1970–2014. The study develops a spatially augmented Green Solow model by taking into consideration technological externalities and interdependence in the process of production, which ultimately implies that CO2 emissions in an economy are affected by the economic characteristics in neighboring countries. The empirical model predicts convergence in CO2 emissions among countries which is examined by means of modern dynamic spatial panel econometric techniques. The multimodal distribution of the CO2 emissions is consistent with the existence of three spatial clubs. The space-time dynamics of the three clubs are analyzed by means of the Local Directional Moran Scatterplot and spatial panel model with heterogeneous parameters. Our analysis reveals the hypothesis of spatial convergence clubs is more consistent with the data than the hypothesis of conditional convergence.
[en] A period of elevated surface concentrations of airborne particulate matter (PM) in the UK in spring 2014 was widely associated in the UK media with a Saharan dust plume. This might have led to over-emphasis on a natural phenomenon and consequently to a missed opportunity to inform the public and provide robust evidence for policy-makers about the observed characteristics and causes of this pollution event. In this work, the EMEP4UK regional atmospheric chemistry transport model (ACTM) was used in conjunction with speciated PM measurements to investigate the sources and long-range transport (including vertical) processes contributing to the chemical components of the elevated surface PM. It is shown that the elevated PM during this period was mainly driven by ammonium nitrate, much of which was derived from emissions outside the UK. In the early part of the episode, Saharan dust remained aloft above the UK; we show that a significant contribution of Saharan dust at surface level was restricted only to the latter part of the elevated PM period and to a relatively small geographic area in the southern part of the UK. The analyses presented in this paper illustrate the capability of advanced ACTMs, corroborated with chemically-speciated measurements, to identify the underlying causes of complex PM air pollution episodes. Specifically, the analyses highlight the substantial contribution of secondary inorganic ammonium nitrate PM, with agricultural ammonia emissions in continental Europe presenting a major driver. The findings suggest that more emphasis on reducing emissions in Europe would have marked benefits in reducing episodic PM_2_._5 concentrations in the UK. (letter)