14 research outputs found
A compilation of field surveys on gaseous elemental mercury (GEM) from contrasting environmental settings in Europe, South America, South Africa and China: separating fads from facts
Mercury is transported globally in the atmosphere
mostly in gaseous elemental form (GEM, Hg0
gas),
but still few worldwide studies taking into account
different and contrasted environmental settings are
available in a single publication. This work presents
and discusses data from Argentina, Bolivia, Bosnia
and Herzegovina, Brazil, Chile, China, Croatia, Finland,
Italy, Russia, South Africa, Spain, Slovenia and
Venezuela. We classified the information in four
groups: (1) mining districts where this contaminant
poses or has posed a risk for human populations and/or
ecosystems; (2) cities, where the concentration ofatmospheric mercury could be higher than normal due
to the burning of fossil fuels and industrial activities;
(3) areas with natural emissions from volcanoes; and
(4) pristine areas where no anthropogenic influence
was apparent. All the surveys were performed using
portable LUMEX RA-915 series atomic absorption
spectrometers. The results for cities fall within a low
GEM concentration range that rarely exceeds 30 ng m-3,
that is, 6.6 times lower than the restrictive ATSDR
threshold (200 ng m-3) for chronic exposure to this
pollutant. We also observed this behavior in the former
mercury mining districts, where few data were above
200 ng m-3.We noted that high concentrations of GEM
are localized phenomena that fade away in short
distances. However, this does not imply that they do not
pose a risk for those working in close proximity to the
source. This is the case of the artisanal gold miners that
heat the Au–Hg amalgam to vaporize mercury. In this
respect, while GEM can be truly regarded as a hazard,
because of possible physical–chemical transformations
into other species, it is only under these localized
conditions, implying exposure to high GEM concentrations,
which it becomes a direct risk for humans.Grants
CGL2009-13171 and CTM2012-33918 from the Spanish
Ministry of Economy and Competitiveness and PII1I09-0142-
4389 from theCastilla-LaMancha (Spain)RegionalGovernment.Published713-7346A. Monitoraggio ambientale, sicurezza e territorioJCR Journalrestricte
Carcinogenic organic content of particulate matter at urban locations with different pollution sources
Polycyclic aromatic hydrocarbons (PAHs) are compounds known for their adverse effects on human health. Many of them are proven carcinogens, especially those with 5 and 6 aromatic rings, which under normal tropospheric conditions are found in the particle-phase. Benzo(a)pyrene (BaP) is often measured as their general representative. Sarajevo, the capital of Bosnia and Herzegovina, is among the European cities with the poorest air quality. However, in Sarajevo PAHs are neither routinely measured within the air quality monitoring network nor have been a subject of extended, continuous field studies during the most polluted cold periods of the year. The capital of Croatia, Zagreb, is located approximately 300 km air distance north-west from Sarajevo. PAH mass concentrations in Zagreb have been measured continuously since 1994 within air quality monitoring networks. During winter 2017/2018, the SAFICA project (Sarajevo Canton Winter Field Campaign 2018) was carried out in order to characterize the chemical composition of organic and inorganic aerosol in the Sarajevo Canton. This paper presents the results of PAH measurements in the cities of Sarajevo and Zagreb at one urban location per city. Daily (24 h), continuous samples of PM10 (particulate matter with aerodynamic diameters ≤10 μm) were collected during heating season, from December 27, 2017 to February 27, 2018. Mass concentrations of eleven particle-phase PAHs in Sarajevo and Zagreb from filter samples collected during the same period were compared. The average BaP ambient mass concentrations in Sarajevo and Zagreb were 6.93 ng m−3 and 3.11 ng m−3, respectively. The contribution of BaP to the total PAH mass concentration was similar at both locations (11%). However, much higher contributions of particle-phase fluoranthene and pyrene were found in Sarajevo. Contributions of individual PAH, diagnostic ratios and factor analysis indicate that combustion of gasoline and diesel from vehicle traffic are a potential source of PAHs at both locations, as well as combustion of other liquid fossil fuels (petroleum and fuel oil). Wood burning was occasionally indicated as a PAH emission source in Zagreb, while in Sarajevo the contribution of PAHs from wood and coal combustion was more evident. Calculated value for total carcinogenic potency (TCP) of PAHs, which was estimated using toxic equivalence factors from the literature, in PM10 samples collected in Sarajevo was more than twice higher than in Zagreb (10.6 ng m−3 and 4.7 ng m−3, respectively). BaP had the highest contribution to the TCP at both locations (69 and 67%)
On the horizon European refugees and migrants advice and guidance into employment
Report of the European Union Employment-Horizon Project 1995-1997Available from British Library Document Supply Centre-DSC:m02/38599 / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo
Analysis of PM10, Pb, Cd, and Ni atmospheric concentrations during domestic heating season in Sarajevo, Bosnia and Herzegovina, from 2010 to 2019
This paper examines atmospheric concentrations of particulate matter with an aerodynamic diameter smaller than 10 μm (PM10) and related particle-phase toxic heavy metals Cd, Ni, and Pb during domestic heating seasons from 2010 to 2019 in Sarajevo, Bosnia and Herzegovina. In total, 242 daily PM10 samples were collected usingmediumand high volume air samplers. Themean daily PM10 mass concentration for all measurements is 75.16 μg/m3 (with the range of 28.77–149.00 μg/m3). Variation of ambient PM10 was observed throughout the study in different years. Hourly values for PM10 measurements during two heating seasons are also presented. Metal concentrations in PM10 were analyzed by electrothermal atomic absorption spectrometry (ETAAS). Quantities of atmospheric mass concentrations of studied trace metals were observed in the following order: Pb > Ni > Cd. The mean concentrations of metals varied with Pb showing the highest concentration (ranging from 1.38 to 234.00 ng/ m3), Ni ranging from 0.87 to 42.43 ng/m3, and Cd showing the lowest concentration ranging from 0.26 to 10.09 ng/m3. The concentration of Pb and Cd in PM10 was strongly correlated, suggesting a common source or dependence of these metals in PM10 in Sarajevo. Bioaccessibility of metals in the synthetic gastric juice was also estimated. The quantities of average bioaccessible metal fractions in PM10 samples showed the following trend: Cd > Pb > Ni. The health risk assessment shows that the population of Sarajevo is at increased lifetime risk of experiencing cancer because of exposure to these Cd concentrations in PM10. In addition, parallel PM10 sampling on two samplers showed that obtained results are highly comparable
Rent Seeking and Power Hierarchies: A Noncooperative Model of Network Formation with Antagonistic Links
Network structure has a significant role in determining the outcomes of many socioeconomic relationships, including the antagonistic ones. In this paper we study a situation in which agents, embedded in a network, simultaneously play interrelated bilateral contest games with their neighbors. Interrelatedness of contests induces complex local and global network effects. We first characterize the equilibrium of a game on an arbitrary fixed network. Then we study a dynamic network formation model, introducing a novel but intuitive link formation protocol. As links represent antagonistic relationships, link formation is unilateral while link destruction is bilateral. A complete k-partite network is the unique stable network topology. As a result, the model provides a micro-foundation for the structural balance concept in social psychology, and the main results go in line with theoretical and empirical findings from other disciplines, including international relations, sociology and biology
A compilation of field surveys on gaseous elemental mercury (GEM) from contrasting environmental settings in Europe, South America, South Africa and China: separating fads from facts
Mercury is transported globally in the atmosphere
mostly in gaseous elemental form (GEM, Hg0
gas),
but still few worldwide studies taking into account
different and contrasted environmental settings are
available in a single publication. This work presents
and discusses data from Argentina, Bolivia, Bosnia
and Herzegovina, Brazil, Chile, China, Croatia, Finland,
Italy, Russia, South Africa, Spain, Slovenia and
Venezuela. We classified the information in four
groups: (1) mining districts where this contaminant
poses or has posed a risk for human populations and/or
ecosystems; (2) cities, where the concentration ofatmospheric mercury could be higher than normal due
to the burning of fossil fuels and industrial activities;
(3) areas with natural emissions from volcanoes; and
(4) pristine areas where no anthropogenic influence
was apparent. All the surveys were performed using
portable LUMEX RA-915 series atomic absorption
spectrometers. The results for cities fall within a low
GEM concentration range that rarely exceeds 30 ng m-3,
that is, 6.6 times lower than the restrictive ATSDR
threshold (200 ng m-3) for chronic exposure to this
pollutant. We also observed this behavior in the former
mercury mining districts, where few data were above
200 ng m-3.We noted that high concentrations of GEM
are localized phenomena that fade away in short
distances. However, this does not imply that they do not
pose a risk for those working in close proximity to the
source. This is the case of the artisanal gold miners that
heat the Au–Hg amalgam to vaporize mercury. In this
respect, while GEM can be truly regarded as a hazard,
because of possible physical–chemical transformations
into other species, it is only under these localized
conditions, implying exposure to high GEM concentrations,
which it becomes a direct risk for humans
PAHs in the urban air of Sarajevo: levels, sources, day/night variation, and human inhalation risk
Polycyclic aromatic hydrocarbons (PAHs)
are organic pollutants derived from pyrolysis and
pyrosynthesis processes. Industrial activity,motor vehicle
emission, and domestic combustion are the main sources
of PAHs in the urban atmosphere. In this work, samples
collected during the day and night in the urban area of
Sarajevo are analyzed separately for gaseous and particlebound
PAHs; the possible origin of PAHs at the receptor
site was suggested using different methods applied to the
solid phase and to the total PAHs (gaseous + particulate
phase). Finally, the risk level in Sarajevo associated to the
carcinogenic character of the studied PAHs has been
assessed. The result of this study suggests that (a) the
total PAH concentrations were higher than those reported
in other European cities; (b) the PAH daytime concentrations
are higher than nocturnal concentrations: the sum of
the PAH day/night ratios is 1.52 (gas) and 1.45 (particle
phase); (c) stationary combustion and traffic were suggested
to be the main sources of PAHs; (d) the average
particle-bound benzo(a)pyrene (BaP) concentration
(5.4 ng/m3) is higher than EU target annual value
(1 ng/m3); and (e) PAH cancer risk exceeds the carcinogenic
benchmark level recommended by the EPA mainly
due to BaP during both the day and night periods