Assessing the impact of different urban morphology scenarios on air pollutant emissions distribution.

As urban areas grow with the increase in population, so do the problems associated with these areas, such as an increase in atmospheric emissions. Since urban morphology has an effect on the environment, it is necessary to design future urban morphologies to accommodate the expected growth and mitigate the associated problems. By employing an emission distribution methodology based on the relationship between land use and emission activity sectors, including transport and road traffic emissions modelling (with PTV-VISUM and TREM, respectively), this study aims to identify urban morphologies that have the potential to minimize atmospheric emissions for future multi-core regions. This study assesses three urban morphology scenarios, focused on Aveiro, Portugal, where two represent urban compaction - Focused City scenario and Independent City scenario -, and one represents an extreme version of the current urban dispersion. The impact of urban scenarios was compared against the current urban morphology. Results indicate that, for the compact urban morphologies, the Focused City scenario showed a small increase in emissions, and the Independent City scenario led to a decrease in emissions, especially for NOx (-16 %), as it is the pollutant most affected by road traffic emissions. As for the Disperse City scenario, it showed the highest overall increase, as it greatly increased the vehicle volume and total distance travelled. These results highlight the need for policy and behavioral changes to accompany the changes to urban morphology, and for special attention to be paid to the location of activity sectors when designing the different urban morphologies. This study contributes novel insights by applying a comprehensive methodology that integrates land use, activity sectors, and road traffic emissions modelling. By assessing the urban morphology's impact on air pollutant emissions, it is possible to inform urban planners of future urban planning strategies.

Impact of forest fire on the mercury stable isotope composition in litter and soil in the Amazon.

Mercury (Hg) emissions from forest fires, especially tropical forests such as the Amazonian forest, were shown to contribute significantly to the atmospheric mercury budget, but new methods are still necessary to improve the traceability and to reduce the great uncertainties related to this emission source. Recent studies have shown that the combustion process can result in Hg stable isotope fractionation that allows tracking coal combustion Hg emissions, as influenced by different factors such as combustion temperature. The main goal of the present study was, therefore, to investigate for the first time the potential of Hg stable isotopes to trace forest fire Hg emissions and pathways. More specifically, small-scale and a large scale prescribed forest fire experiments were conducted in the Brazilian Amazonian forest to study the impact of fire severity on Hg isotopic composition of litter, soil, and ash samples and associated Hg isotope fractionation pathways. In the small-scale experiment, no difference was found in the mercury isotopic composition of the samples collected before and after burning. In contrast, the larger-scale experiment resulted in significant mass dependent fractionation (MDF δ202Hg) in soils and ash suggesting that higher combustion temperature influence Hg isotopic fractionation with the emission of lighter Hg isotopes to the atmosphere and enrichment with heavier Hg in ashes. As for coal combustion, mass independent fractionation was not observed. To our knowledge, these results are the first to highlight the potential of forest fires to cause Hg isotopic fractionation, depending on the fire severity. The results also allowed to establish an isotopic fingerprint for tropical forest fire Hg emissions that corresponds to a mixture of litter and soil Hg isotopic composition (resulting atmospheric δ202Hg, Δ200Hg and Δ199Hg were -1.79 ± 0.24‰, -0.05 ± 0.04‰ and -0.45 ± 0.12‰, respectively).

Civil aviation emissions in Argentina.

The impact of aviation on climate change is reflected in increasing emissions of CO2 and other pollutants from fuel burning emitted at high altitudes, representing 2.9 % of total Greenhouse gases (GHG) emissions in 2019. However, mitigations options for decarbonization of aviation are difficult to implement given operational safety, technology maturity, energy density and other constraints. One alternative for mitigation is the use of certified sustainable aviation fuel (SAF) with lower carbon intensity than conventional jet fuel (CJF). This research presents an inventory of Argentine civil aviation emissions for its domestic and international flights, and analyzes the possibility of supplying SAF as a mitigation strategy given its abundant biomass production. Argentine aviation activity is presented as a monthly 4D (latitude, longitude, altitude and time) spatial inventory for the interval 2001-2021, based on origin and destination city pairs, aircraft types and airlines. Fuel consumption and pollutant emissions were calculated for landing-and-take-off and cruise phases. Monthly domestic ranged from 67 to 179 kt CO2eq (2001-2019). Annual peak values occurred in 2019 consuming 560 kt CJF and direct emitting of 1.77 Mt CO2eq. While Revenue-Passenger-Kilometer (RPK) grew almost 4 times (4.18 × 109 in 2001 to 16.42 × 109 in 2019), the number of flights changed only 1.5 times (from 98,000 in 2002 to 152,000 in 2019). The main efficiency indexes varied from 97 t CJF/RPK, 308 gCO2eq/RPK to 34 t CJF/RPK, 107 gCO2eq/RPK between 2001 and 2019, respectively, showing an average annual improvement of 3.5 % due to partial fleet renewal, especially from 2015 onwards. Emissions of other pollutants for 2019 reached total values of CO 14.14 kt; NOx 6.77 kt; PM tot 55.12 kt. For the period 2001-2019, international aviation consumed between 1 Mt - 1.5 Mt CJF, directly emitting between 3.30 and 4.80 Mt of CO2eq; RPKs went from 6.234 × 109 to 20.524 × 109; the efficiency indices ranged from 529 to 240 gCO2eq/RPK. The most important changes occurred with an optimization of routes and number of flights and the replacement of the four-engines (B747, A380) by more efficient twin-engines (B777, A330) aircraft. Argentina is not required to any offsetting regulatory program due to its small aviation market (approx. 0.22 % global market in 2019), nor has to date certified SAF production pathways, nevertheless it has potential for SAF availability based on actual biofuels production (ethanol, biodiesel and soybean oil) and biomass feedstock's existences. In this sense this studies proposes that 2019 domestic fuel consumption could be supplied using 79 % exportable amounts of sugarcane ethanol (257 ± 53 kt) (by Ethanol to Jet ETJ) and 34 % of exportable soybean oil (1079 ± 160 kt) (by hydroprocessed esters and fatty acids- HEFA) pathways. For this scenario average GHG emissions reached 1.321 ± 0.115 Mt CO2eq; which would imply a 62 % of the current emission value using CJF (2.17Mt CO2eq), or savings of about 838 kt CO2eq (38 %). At the 2019 level of harvest and biofuel production, up to 1.4 Mt of SAF could be produced from sugarcane ethanol/ETJ and soybean oil/HEFA mitigating up to 1.8 MtCO2eq. A 35 kt CO2eq annual sectoral national mitigation strategy could be reached by using 14 kt of SAF.

An integrated analysis of COVID-19 impacts on energy and environment: Lessons learnt.

Carbon neutrality, sustainable development and reducing our impact on the environment is the top priority in future measures. The COVID-19 pandemic brought challenges to every sector at a global scale but can provide valuable insight to reach these goals. The main objective of this work is to provide an integrated analysis of the impact of the COVID-19 pandemic, focused on energy and its related aspects, i.e., environment and costs. Mainland Portugal was used as a case study and two years were analysed, one pre pandemic (2019) and another post pandemic (2020). In 2020, the majority of sectors - Transport, Services, Industry and Agriculture & Fisheries - show a reduction of energy consumption, atmospheric emissions, carbon footprint and related monetary and social costs. In contrast, the Domestic sector presents an overall increase, with maximums of 25.4% in electricity consumption (during Spring), 0.72% in the PM10 (particulate matter) and NOx (nitrogen dioxides) emissions (in Summer), and 2.9% in carbon footprint (in Spring). The integrated analysis proposed in this work was crucial to identify the paths to a post pandemic world focused on the different aspects of sustainability - new concepts of mobility and workplace, as well as increased investment in energy performance and renewable energy sources. This study showed that changing our energy consumption patterns could significantly affect future greenhouse gas emissions, and contribute to the sustainable growth of the economy, while maintaining good progress towards climate-neutral goals.

Health care in rural areas: proposal of a new telemedicine program assisted from the reference health centers, for a sustainable digitization and its contribution to the carbon footprint reduction.

Introduction: This paper studies and quantifies the environmental benefits of implementing a new telemedicine service for users of the public health system in a rural area of Alicante (Spain). The proposed telemedicine service is based on carrying out 20% of the follow-on consultations with a specialist virtually from the Reference Health Centres with the support of qualified staff. This way of providing medical care remotely will be a good transition to fully online medical services, especially for the elderly. The proposed model avoids the displacement of users to the Alcoy Hospital, reducing the distances to be travelled, which will be directly reflected in a reduction of the emission of pollutants (carbon footprint) generated by patients' vehicles. Methods: Data from the Alcoy Health Department were used for 2019, the last year of normal activity of the health centres before Covid-19. Using data from the Department's health management report and the emission factors of the vehicles, we calculated the distances, hours, litres of fuel saved, as well as the tonnes of CO2 equivalent, CO2, CH4 and N2O. Results: With the implementation of this type of telemedicine, journeys would be avoided, saving 447,279 km, 7,580 h and 38,019 L of fuel. The emission into the atmosphere of 79.26 metric tons of CO2, 74.5 kg of CH4 and 487.28 kg of N2O per year would be avoided. Conclusions: The implementation of this telemedicine service contributes to a high degree to: (a) increasing the environmental sustainability of the rural health sector thanks to the reduction of traffic emissions (saving 9% of pollutants compared to the current system), (b) decongesting the health system by reducing face-to-face visits to specialists, (c) increasing the quality of life of patients by avoiding road travel (d) promoting the digitalisation of the rural population.

Human metabolic emissions of carbon dioxide and methane and their implications for carbon emissions.

Carbon dioxide (CO2) and methane (CH4) are important greenhouse gases in the atmosphere and have large impacts on Earth's radiative forcing and climate. Their natural and anthropogenic emissions have often been in focus, while the role of human metabolic emissions has received less attention. In this study, exhaled, dermal and whole-body CO2 and CH4 emission rates from a total of 20 volunteers were quantified under various controlled environmental conditions in a climate chamber. The whole-body CO2 emissions increased with temperature. Individual differences were the most important factor for the whole-body CH4 emissions. Dermal emissions of CO2 and CH4 only contributed ~3.5% and ~5.5% to the whole-body emissions, respectively. Breath measurements conducted on 24 volunteers in a companion study identified one third of the volunteers as CH4 producers (exhaled CH4 exceeded 1 ppm above ambient level). The exhaled CH4 emission rate of these CH4 producers (4.03 ± 0.71 mg/h/person, mean ± one standard deviation) was ten times higher than that of the rest of the volunteers (non-CH4 producers; 0.41 ± 0.45 mg/h/person). With increasing global population and the expected large reduction in global anthropogenic carbon emissions in the next decades, metabolic emissions of CH4 (although not CO2) from humans may play an increasing role in regional and global carbon budgets.

Mass flow, enrichment and potential environmental impacts of mercury in a preheater-precalciner cement plant using multiple mining and industrial wastes.

Cement plants (CPs) are one of the most important anthropogenic sources of mercury (Hg) emissions in China. Over 1000 cement production lines operate in China and use various raw materials; however, little data on Hg emissions is recorded on site. This study investigated a CP in Guizhou Province that uses multiple mining and industrial wastes as part of the circular economy policy. Among the various raw materials, carbide slag had the highest Hg content (2.6 mg/kg) and contributed half of the Hg input. High Hg concentration (27 mg/kg) in the kiln tail dust and a strong Hg enrichment factor (39) was found, which was determined as the ratio of total Hg accumulated within the clinker production process to the daily Hg input from raw materials and fuel. The clinker had negligible Hg (0.001 mg/kg), while the Hg in cement products (0.04 mg/kg) mostly came from additives and retarders. The estimated atmospheric emission factor of Hg from this CP was 161.5 mg Hg/t clinker, which was much higher than those of other CPs in Guizhou that employ low-Hg raw materials. A five-step sequential extraction experiment with kiln tail dust indicates that Hg mainly existed in fraction of F4 (73-96% of the total Hg, possibly as Hg2Cl2) and that some samples had high proportions of water-soluble Hg (up to 21% of the total), which may be easily released into surrounding water bodies and pose high environmental risks. Using low-Hg raw (or alternative raw) materials and conducting proper disposal of kiln tail dust will reduce the environmental risk of Hg from CPs.

Are green roofs the path to clean air and low carbon cities?

Green roofs, as part of urban green structures, have been pointed out as the solution to pursuit the goal of healthy cities. This study aims to investigate the direct, focused on meteorological changes, and indirect, related to both meteorological and emissions changes, impacts of green roofs on air quality (PM10, NO2 and O3). For that, the numerical modelling system composed by the WRF-SLUCM-CHIMERE models was applied to a 1-year period (2017), having as case study the Porto urban area. The EnergyPlus model was also applied to estimate the green roofs impacts on the building's energy needs and related impacts on air quality and atmospheric emissions. The analysis of the direct impacts showed that green roofs promote a temperature increase during the autumn and winter seasons and a temperature decrease during the spring and summer seasons. Both negative - concentrations increase - and positive - concentrations decrease - impacts were obtained for the primary, PM10 and NO2, and secondary, O3, air pollutants, respectively, due to changes in the dynamical structure of the urban boundary layer. The indirect effects of green roofs showed their potential to enhance the buildings energy efficiency, reducing the cooling and heating needs. These changes in energy consumption promoted an overall decrease of the environmental and economic indicators. Regarding air quality, the impact was negligible. The obtained results highlight the need for a multipurpose evaluation of the impacts of green roofs, with the different effects having to be traded off against each other to better support the decision-making process.

Soil and ambient air mercury as an indicator of coal-fired power plant emissions: a case study in North China.

Coal-fired power plants (CFPPs) are an important anthropogenic mercury (Hg) source in China, and it is crucial to understand the environmental impacts of this detrimental element emitted from this source. In the present study, field experiments were conducted for measuring Hg in ambient atmosphere and upland agricultural soils within a radius of 10 km surrounding a large scale coal-fired power plant (1550 MW) in Tangshan, Hebei province. Short-term (20 min) average of gaseous elemental mercury (GEM or Hg0) in ambient air varying from 1.5 to 9.0 ng/m3 and total Hg (THg) in surface agricultural soil (0-20 cm) varying from 9.2 to 43.5 µg/kg at different sites were observed. THg in two soil cores decreased with depth, with concentrations being 2-2.5 times higher in the surface layer than that in the deep layer (50-60 cm), indicating the possibility of the atmospheric input of Hg. Based on the information of the total atmospheric Hg emission since this CFPP's operation in 1970s and the increased THg in nearby soils, it was estimated that about 3.9% discharged Hg has accumulated in the nearby agricultural soils. The low retention rate of the total emitted Hg by soils is a result of high proportion of Hg0 (79.5%) in stack gas emission and potential loss of Hg from soil surface reemission. The positive shifting (~ 0.5‰) of Hg isotopic signature (δ202Hg) from deep soil to surface soil reflected Hg deposition from nearby CFPP emissions that are featured with much heavier Hg isotopic signatures inherited from feed coal (δ202Hg: -0.50‰) and different combustion products (δ202Hg: -0.95 to 3.71‰) compared with that in deep soil layer (δ202Hg: ca -1.50‰). Overall, this study demonstrated that this CFPP has a slight but distinguishable effect on the elevation of ambient GEM and agricultural soil THg in the local environment.

Análise do monitoramento ambiental da incineração de resíduos sólidos urbanos na Europa e a necessidade de alterações na legislação brasileira / Environmental monitoring analysis of municipal solid waste incineration in Europe and the needs for changes in brazilian legislation

RESUMO A incineração é uma tecnologia de tratamento térmico de resíduos sólidos cujo principal objetivo é a redução do volume e da massa dos resíduos a serem depositados em aterros. Os incineradores construídos nas últimas décadas trazem a possibilidade de recuperação energética dos resíduos, na forma de vapor e/ou energia elétrica, entretanto essa tecnologia ainda gera questionamentos sobre possíveis impactos ambientais relacionados às suas emissões. A incineração é regulada na Europa por legislação específica que, entre outras questões, obriga a divulgação de dados de monitoramento ambiental de incineradores. No presente trabalho, são analisados dados de emissões atmosféricas de incineradores associados à Confederation of European Waste-to-Energy Plants (CEWEP), por meio de buscas nos websites dos respectivos incineradores, em artigos científicos e relatórios técnicos. Foram examinados dados de monitoramento de todos os poluentes de medição contínua e periódica definidos na legislação da UE, em séries temporais de 2010 a 2017. Todos os valores médios anuais de emissões nos incineradores analisados estiveram abaixo dos limites definidos pela diretiva europeia, com pequena variação ao longo dos anos observados. A comparação dos padrões de emissão europeus com os brasileiros mostra a necessidade de mudança na legislação local referente à incineração para que, caso essa tecnologia seja implementada no Brasil, ela possa operar respeitando limites seguros, com garantia de minimização de impactos ao ambiente e às populações do entorno.

Abstract Incineration is a solid waste treatment technology whose main purpose is to reduce the volume and mass of the waste to be disposed of in landfills. The incinerators built in the last decades bring the possibility of energy recovery from waste, in the form of steam and/or electric energy. However, this technology still raises questions about possible environmental impacts related to its emissions. Incineration is regulated in Europe through specific legislation which, among other issues, requires the disclosure of environmental monitoring data for incinerators. In the present work, atmospheric emissions data from incinerators associated with the Confederation of European Waste-to-Energy Plants (CEWEP) are analyzed by searching the websites of the respective incinerators, scientific articles and technical reports. Monitoring data on all continuous and periodic measured pollutants defined in the legislation in time series from 2010 to 2017 were analyzed. All annual average emission values of the incinerators analyzed were below the limits defined by the European Union's Directive, with little variation over the observed years. The comparison of European with Brazilian emission standards shows the need for a change in local legislation on incineration so that, if this technology is implemented in Brazil, it will operate within safe limits, with a guarantee of minimizing impacts on the environment and surrounding populations.

Inventory of Pb emissions from one of the largest historic Pb smelter worldwide: 118-year legacy of Pb pollution in northern Mexico.

The atmospheric Pb emissions (1901-2019), from one of the world's largest non-ferrous metallurgical complexes (Met-Mex in Torreón, México), were estimated based on historical records of modifications in the design, processes, and production volumes. Eight historical periods, with differing amounts of Pb emissions, were distinguished: (1) Essentially no controls (1901-1960); (2) migration to limited controls (1961-1972) by conversion to a Pb-Zn smelter-refining complex and installation of SO2 collectors in 1961-1963; (3) completion to limited control (1973-1977) by the installation of a third H2SO4 collector and a low-efficiency filtration system; (4) maintenance of limited control with no changes (1978-1987); (5) migration to strict control (1988 to 1998) by updating H2SO4 collectors and installation of fertilizer and SO2 liquid extraction plants; (6) completion to strict control (1999-2000) by the installation of state-art technology filtration systems and roofing working areas; (7) migration to abatement (2001-2003) by implantation of good management practices; and (8) maintenance of abatement following good management practices (2004-2019). Based on differences between those periods, we reconstructed the evolution of the Pb emission reduction efficiency (ER in %) and Pb emission factors (EF in gram/ton) for the Torreón complex. Pb emitted by the complex over the past 118 years totaled 23,350-27,580 t, with most of it (63-75%) occurring when emission controls were negligible (pre-1960 period). In comparisons with other facilities worldwide (e.g., the USA, Canada, and Europa), the modification in Met-Mex for control the Pb emission occurred several years. Emissions from the primary Pb-Zn smelter-refining are released mostly to the atmosphere from the sintering, smelting, drossing, and refining. While Pb emissions from the facility have declined by over an order of magnitude to contemporary levels (≤ 12.6 t/year), the current Pb rates still account for atmospheric Pb levels that are 2-3 times higher the USEPA standard and still constitutes a major health threat in Torreón.

An increasing role for solvent emissions and implications for future measurements of volatile organic compounds.

Volatile organic compounds (VOCs) are a broad class of air pollutants which act as precursors to tropospheric ozone and secondary organic aerosols. Total UK emissions of anthropogenic VOCs peaked in 1990 at 2,840 kt yr-1 and then declined to approximately 810 kt yr-1 in 2017 with large reductions in road transport and fugitive fuel emissions. The atmospheric concentrations of many non-methane hydrocarbons (NMHC) in the UK have been observed to fall over this period in broadly similar proportions. The relative contribution to emissions from solvents and industrial processes is estimated to have increased from approximately 35% in 1990 to approximately 63% in 2017. In 1992, UK national monitoring quantified 19 of the 20 most abundant individual anthropogenic VOCs emitted (all were NMHCs), but by 2017 monitoring captured only 13 of the top 20 emitted VOCs. Ethanol is now estimated to be the most important VOC emitted by mass (in 2017 approx. 136 kt yr-1 and approx. 16.8% of total emissions) followed by n-butane (52.4 kt yr-1) and methanol (33.2 kt yr-1). Alcohols have grown in significance representing approximately 10% of emissions in 1990 rising to approximately 30% in 2017. The increased role of solvent emissions should now be reflected in European monitoring strategies to verify total VOC emission reduction obligations in the National Emissions Ceiling Directive. Adding ethanol, methanol, formaldehyde, acetone, 2-butanone and 2-propanol to the existing NMHC measurements would provide full coverage of the 20 most significant VOCs emitted on an annual mass basis. This article is part of a discussion meeting issue 'Air quality, past present and future'.

Short-Term Responses of Air Quality to Changes in Emissions under the Representative Concentration Pathway 4.5 Scenario over Brazil.

Brazil, one of the world's fastest-growing economies, is the fifth most populous country and is experiencing accelerated urbanization. This combination of factors causes an increase in urban population that is exposed to poor air quality, leading to public health burdens. In this work, the Weather Research and Forecasting Model with Chemistry is applied to simulate air quality over Brazil for a short time period under three future emission scenarios, including current legislation (CLE), mitigation scenario (MIT), and maximum feasible reduction (MFR) under the Representative Concentration Pathway 4.5 (RCP4.5), which is a climate change scenario under which radiative forcing of greenhouse gases (GHGs) reach 4.5 W m-2 by 2100. The main objective of this study is to determine the sensitivity of the concentrations of ozone (O3) and particulate matter with aerodynamic diameter 2.5 µm or less (PM2.5) to changes in emissions under these emission scenarios and to determine the signal and spatial patterns of these changes for Brazil. The model is evaluated with observations and shows reasonably good agreement. The MFR scenario leads to a reduction of 3% and 75% for O3 and PM2.5 respectively, considering the average of grid cells within Brazil, whereas the CLE scenario leads to an increase of 1% and 11% for O3 and PM2.5 respectively, concentrated near urban centers. These results indicate that of the three emission control scenarios, the CLE leads to poor air quality, while the MFR scenario leads to the maximum improvement in air quality. To the best of our knowledge, this work is the first to investigate the responses of air quality to changes in emissions under these emission scenarios for Brazil. The results shed light on the linkage between changes of emissions and air quality.

Data analysis of atmospheric emission from geothermal power plants in Italy.

Electric production from geothermal energy is still little exploited compared to its large potential and to the World renewable energy production from other sources. Some countries have exploited this energy source in order to enhance their transition to renewables. Today the largest geothermal energy producers in the world are New Zealand, U.S.A, Mexico, Philippines, Italy, Iceland, and, more recently, Turkey (Geothermal, 2012). Differently from other renewable sources, geothermal energy produces impacts on the environment that are very site-specific because of the nature of the resource and its geological characteristics Bravi et al.,2010; Parisi et al.,2013. In the same way, the atmospheric emissions associated to the activity of geothermal power plants for electric or heat production (mainly CO2, H2S, NH3, Hg, CH4) are also site-specific. In fact, due to technological and geographical differences among the geothermal installations operating all over the World, it is quite impossible to identify and attribute typical emission patterns, to perform forecasts valid for multiple sites or to collect universal data. Furthermore, it is virtually impossible the comparison among technologies located in different regions or countries. Definitively, inventories of primary data, as accurate and complete as possible, are essential to correctly evaluate the peculiarities of geo-thermoelectric energy production Parisi et al.,2018. Data reported here try to fill the gap in respect to the Italian situation. To this end, a complete survey of the atmospheric emissions from all the geothermal power plants in operation in the Tuscany Region is performed. In addition to data reporting, also some statistical analysis is performed to process data and to operate a further level of simplification which averages the emissions on the basis of geothermal sub-areas. The data collected is related to the research article "Life cycle assessment of atmospheric emission profiles of the Italian geothermal power plants" Parisi et al.,2019.

How closely do mercury trends in fish and other aquatic wildlife track those in the atmosphere? - Implications for evaluating the effectiveness of the Minamata Convention.

The Minamata Convention to reduce anthropogenic mercury (Hg) emissions entered into force in 2017, and attention is now focused on how to best monitor its effectiveness at reducing Hg exposure to humans. A key question is how closely Hg concentrations in the human food chain, especially in fish and other aquatic wildlife, will track the changes in atmospheric Hg that are expected to occur following anthropogenic emission reductions. We investigated this question by evaluating several regional groups of case studies where Hg concentrations in aquatic biota have been monitored continuously or intermittently for several decades. Our analysis shows that in most cases Hg time trends in biota did not agree with concurrent Hg trends in atmospheric deposition or concentrations, and the divergence between the two trends has become more apparent over the past two decades. An over-arching general explanation for these results is that the impact of changing atmospheric inputs on biotic Hg is masked by two factors: 1) The aquatic environment contains a large inventory of legacy emitted Hg that remains available for bio-uptake leading to a substantial lag in biotic response time to a change in external inputs; and 2) Biotic Hg trends reflect the dominant effects of changes in multi-causal, local and regional processes (e.g., aquatic or terrestrial biogeochemical processes, feeding ecology, climate) that control the speciation, bioavailability, and bio-uptake of both present-day and legacy emitted Hg. Globally, climate change has become the most prevalent contributor to the divergence. A wide range of biotic Hg outcomes can thus be expected as anthropogenic atmospheric Hg emissions decline, depending on how these processes operate on specific regions and specific organisms. Therefore, evaluating the effectiveness of the Minamata Convention will require biomonitoring of multiple species that represent different trophic and ecological niches in multiple regions of the world.

Pb-210 and Po-210 atmospheric releases via fly ash from oil shale-fired power plants.

During high temperature processes in the furnace volatile and semi-volatile elements and radionuclides are partially emitted to the environment, depending on their chemical form in the original fuel, the technological set-up of the combustion system, and the prevailing combustion conditions. Two of the world's largest oil shale-fired power plants (PPs) have been operational in Estonia from the 1960s, during which time creation of significant environmental emissions and waste containing naturally occurring radionuclides has occurred. Pb-210 and 210Po are considered natural radionuclides with the highest emission rates from PPs and possess elevated potential radiation exposure risks to humans and the environment. These radionuclides have the highest activity concentration values in fine ash fractions, especially in fractions remaining below 2.5 µm. To determine the activity concentrations of 210Pb and 210Po in the PPs' outlet, sampling was conducted from boilers operating on pulverized fuel (PF) technology with novel integrated desulphurization (NID) system and bag filters as well as with electrostatic precipitators (ESPs). The 210Pb and 210Po activity concentrations remained around 300 Bq kg-1 for the NID system compared to 60-80 Bq kg-1 in the ESP system. The dominant ash fraction in both systems was PM2.5, constituting over 50% of the fly ash mass collected from the outlet. The authors estimate that the total atmospherically emitted activity for the modernized PPs remains dominantly below 1% of the activity that is inserted via fuel. The implementation of higher efficiency purifications systems has significantly reduced the negative effect of these PPs. Based on annually emitted fly ash and boilers' working hours, the 210Pb and 210Po activity released relative to energy production were up to 68.3 kBq GWhel-1 for 210Pb and 64.6 kBq GWhel-1 for 210Po. These values are 1 to 2 orders of magnitude lower compared to the situation in the 1980s. These findings represent the first publicly available quantitative results estimating the 210Po emissions from large oil shale-fired PPs.

The presence and partitioning behavior of flame retardants in waste, leachate, and air particles from Norwegian waste-handling facilities.

Flame retardants in commercial products eventually make their way into the waste stream. Herein the presence of flame retardants in Norwegian landfills, incineration facilities and recycling sorting/defragmenting facilities is investigated. These facilities handled waste electrical and electronic equipment (WEEE), vehicles, digestate, glass, combustibles, bottom ash and fly ash. The flame retardants considered included polybrominated diphenyl ethers (∑BDE-10) as well as dechlorane plus, polybrominated biphenyls, hexabromobenzene, pentabromotoluene and pentabromoethylbenzene (collectively referred to as ∑FR-7). Plastic, WEEE and vehicles contained the largest amount of flame retardants (∑BDE-10: 45,000-210,000µg/kg; ∑FR-7: 300-13,000µg/kg). It was hypothesized leachate and air concentrations from facilities that sort/defragment WEEE and vehicles would be the highest. This was supported for total air phase concentrations (∑BDE-10: 9000-195,000pg/m3 WEEE/vehicle facilities, 80-900pg/m3 in incineration/sorting and landfill sites), but not for water leachate concentrations (e.g., ∑BDE-10: 15-3500ng/L in WEEE/Vehicle facilities and 1-250ng/L in landfill sites). Landfill leachate exhibited similar concentrations as WEEE/vehicle sorting and defragmenting facility leachate. To better account for concentrations in leachates at the different facilities, waste-water partitioning coefficients, Kwaste were measured (for the first time to our knowledge for flame retardants). WEEE and plastic waste had elevated Kwaste compared to other wastes, likely because flame retardants are directly added to these materials. The results of this study have implications for the development of strategies to reduce exposure and environmental emissions of flame retardants in waste and recycled products through improved waste management practices.

Active biomonitoring of palladium, platinum, and rhodium emissions from road traffic using transplanted moss.

The use of transplanted moss (Pleurozium schreberi) in active biomonitoring of traffic-related emissions of Pd, Pt, and Rh was studied. Moss mats were transplanted to three locations along highway E75 (in Oulu, Finland) at three different distances from the highway. Five samples were collected from a background site after the same exposure period. Mass fractions of Pd, Pt, and Rh as well as mass fractions of 18 other elements were determined in these samples. The results indicated that P. schreberi is well suited for active biomonitoring of Pd, Pt, and Rh. Mass fractions above the background values were observed in the samples exposed to traffic-related emissions. When the results were compared with those of the other elements, high correlations of Pd, Pt, and Rh with commonly traffic-related elements (e.g., Cu, Ni, Sb, Zn, etc.) were found. It was also found that the amounts of Pd, Pt, and Rh in moss samples decreased when the distance to the highway increased. This trend gives evidence for the suitability of P. schreberi for active biomonitoring of Pd, Pt, and Rh. Furthermore, it can be concluded that the mass fractions determined in this study provide valuable evidence about the current state of Pd, Pt, and Rh emissions in Oulu, Finland.

Tracing changes in atmospheric sources of lead contamination using lead isotopic compositions in Australian red wine.

Air quality data detailing changes to atmospheric composition from Australia's leaded petrol consumption is spatially and temporally limited. In order to address this data gap, wine was investigated as a potential proxy for atmospheric lead conditions. Wine spanning sixty years was collected from two wine regions proximal to the South Australian capital city, Adelaide, and analysed for lead concentration and lead and strontium isotopic composition for source apportionment. Maximum wine lead concentrations (328 µg/L) occur prior to the lead-in-air monitoring in South Australia in the later 1970s. Wine lead concentrations mirror available lead-in-air measurements and show a declining trend reflecting parallel reductions in leaded petrol emissions. Lead from petrol dominated the lead in wine ((206)Pb/(207)Pb: 1.086; (208)Pb/(207)Pb: 2.360) until the introduction of unleaded petrol, which resulted in a shift in the wine lead isotopic composition closer to vineyard soil ((206)Pb/(207)Pb: 1.137; (208)Pb/(207)Pb: 2.421). Current mining activities or vinification processes appear to have no impact with recent wine samples containing less than 4 µg/L of lead. This study demonstrates wine can be used to chronicle changes in environmental lead emissions and is an effective proxy for atmospherically sourced depositions of lead in the absence of air quality data.