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G3 (II) Sources and emissions

Thursday, 28 July, 2011

RG3-O1 — 15:00-15:15
GASEOUS MERCURY AIR-SURFACE EXCHANGE MEASUREMENTS FROM NATURAL SOURCES IN AUSTRALIAN LANDSCAPES
Authors: EDWARDS, Grant1, SALLI, Lyndall K1, NELSON, Peter F2
(1) Macquarie University, grant.edwards@mq.edu.au; (2) .

There are essentially no data on the emission and deposition of atmospheric mercury from natural sources over Australian environs. Moreover, there is an overall lack of data on natural sources and sinks for atmospheric mercury in the Southern Hemisphere. A not well constrained, estimate, based on data from non-Australian environments and modelling, suggest natural emissions to be 93% of the total mercury emission from the Australian Continent. Furthermore, with only 7% anthropogenic emissions, Australia presents a unique opportunity to study the natural emission/deposition/re-emission/biogeochemical cycling of mercury. A measurement program has been initiated to collect Australian specific data to better constrain the natural sources inventory. Micrometeorological and dynamic flux chamber based Total Gaseous Mercury (TGM) air-surface exchange, ambient Reactive Gaseous Mercury (RGM), and in all compartments, (i.e., soil, vegetation, aquatic, atmosphere), an extensive suite of environmental correlates (e.g., substrate properties, temperature, humidity, solar radiation, energy balance components, precipitation, other trace gases), are being measured over various Australian landscapes. This paper presents some of the first total gaseous mercury flux measurements from natural geogenic sources in Australia. Comparisons are made to gaseous mercury emissions from natural sources in Canadian landscapes.

RG3-O2 — 15:15-15:30
ATMOSPHERIC MERCURY EMISSION FROM CHINESE COPPER SMELTERS IN 2007
Authors: WANG, Shuxiao1, WU, Qingru1, ZHANG, Lei1, MENG, Yang1, STREETS, David2, CHIN, Conrad3
(1) Department of Environmental Science and Engineering, Tsinghua University, Beijing 100084, China, shxwang@tsinghua.edu.cn; (2) Decision and Information Sciences Division, Argonne National Laboratory, Argonne, IL 60439, USA; (3) Office of Air Quality Planning and Standards, U.S. Environmental Protection Agency, USA.

Mercury pollution is one of the most important global environmental issues. China is the largest anthropogenic mercury emitter in the world, where coal combustion and nonferrous metals smelting process are regarded as the most significant emission sources. However, previous mercury emission estimates for nonferrous metals smelters suffer from high uncertainty.

We sampled and analyzed 110 copper concentrate samples from 36 concentrate mills and copper smelters in China. The mercury concentrations of copper concentrates in China had large variations, ranging from 0.04 gxt-1 to 127.24 gxt-1. Our analysis indicated that the mean Hg concentration in Cu concentrates was 1.5 gxt-1 and the median Hg concentration was 4 gxt-1.

Based on the mercury contents of copper concentrates, mercury removal efficiencies of air pollution control devices, Chinese smelter copper production and copper concentrate consumption, the mercury emissions from Chinese copper concentrate smelting were estimated. According to our study, emission factor in primary copper ores smelters is 4.65 gxt-1, while in secondary copper smelters is only 0.041 gxt-1. About 10.96 t of mercury has been emitted to the atmosphere from Chinese copper smelters in 2007, including 10.91 t from copper ores smelters and 0.05 t from secondary copper smelters. For primary copper smelters, 78.54% of mercury emissions were from Inner Mongolia, Yunnan, Jiangxi, Hubei, Anhui and Gansu provinces.

RG3-O3 — 15:30-15:45
ONSITE MEASUREMENTS OF MERCURY EMISSIONS FROM ZINC, LEAD AND COPPER SMELTERS IN CHINA
Authors: ZHANG, Lei1, WANG, Shuxiao1, MENG, Yang1, WU, Qingru1, HAO, Jiming1
(1) School of Environment, Tsinghua University, Beijing 100084, China, zhanglei03@mails.tsinghua.edu.cn;

Non-ferrous metal smelting takes up a large proportion of the anthropogenic mercury emission inventory in China. Zinc, lead and copper smelting are three leading sources. Onsite measurements of mercury emissions were conducted for one out of each type of smelters. The mercury emission factors for the tested zinc, lead and copper smelters were 0.57 g Hg/t Zn produced, 1.00 g Hg/t Pb produced, and 0.23 g Hg/t Cu produced, respectively. Only 0.6%, 3.2% and 0.3% of the mercury in the concentrates of zinc, lead and copper respectively were emitted to the atmosphere. The highest-temperature processes of each smelting procedure (e.g. roasting furnace for zinc smelting, oxygen enriched bottom blowing furnace for lead smelting and flash smelting furnace for copper smelting) tend not to be the largest contributor to atmospheric mercury emission, owing to the acid producing processes in each smelter. Over 99% of the mercury in flue gas can be captured in the acid plants of all three smelters. In the flue gas out from the acid plants, 78%–85% was oxidized mercury which can be easily scavenged. Therefore, acid plants in non-ferrous metal smelters have significant co-benefit on mercury removal.

RG3-O4 — 15:45-16:00
MERCURY FLUXES RELEASE ON WATER/AIR INTERFACE FROM THE WATER-LEVEL-FLUCTUATING ZONE OF THREE GORGES RESERVOIR AREA, CHINA
Authors: ZHU, Jinshan1, MA, Ming1, SHEN, Yuanyuan1, SUN, Rongguo1, WANG, Dingyong1
(1) 1. Key Laboratory of the Three Gorges Reservoir Region’s Eco-Environment (Ministry of Education), College of Resources and Environment, Southwest University, Chongqing 400715, China, jszhu@163.com

Determination of only total mercury in sediments does not give an accurate estimate of the likely environmental impacts. Speciation study of mercury in sediment provides information on the potential availability of mercury to biota under various environmental conditions. The toxicity of mercury depends especially on its chemical forms rather than its total content. According to regulation model (water levels were projected to fluctuate in a cycle opposite from natural conditions, with lower levels during the summer and higher levels in the winter) for Three Gorges Reservoir, the characteristic of speciation of mercury in sediment of water-level-fluctuating zone of Three Gorge Reservoir Area was investigated. Samples of flooding sediments, semi-flooding sediments, drying sediments, original soil and overlying water were collected from five sites during the flood season (summer) and mercury speciation (operationally defined) and some physicochemical parameters were analyzed. The results indicated that mercury mainly existed in residual fraction for flooding sediments, alkali-soluble fraction and residual fraction for semi-flooding sediments and original soil, Fe-Mn oxides and residual fraction for drying sediments. In flood season, with the increasing waterlogging duration caused the increase of TOC and pH and decrease of ORP. Mercury has the tendency to release to water body. The amount of migration of bioavailable fractions of mercury in five sites were 0.002mg/kg, 0.005 mg/kg, 0.010 mg/kg, 0.027 mg/kg and 0.003 mg/kg respectively. Correspondingly, the migration rates of mercury were 5.5%, 16.90%, 33.50%, 47.90%, and 7.20%, respectively. The total mercury and methyl mercury in overlying water were 29.88±18.78ng/L and 0.19±0.11ng/L. The regulation model for Three Gorges Reservoir increased the ecological risk of mercury. Still, even though the concentrations of Hg in the study areas were low, a long-term water quality monitoring in Three Gorges Reservoir was necessary.

RG3-O5 — 16:00-16:15
TBA
RG3-O6 — 16:15-16:30
MERCURY IN STACK GAS-CONTINUOUS MONITORING VS. SORBENT TRAPS.
Author: SIPERSTEIN, Joseph1
(1) Ohio Lumex Co, Inc, mail@ohiolumex.com

A compilation of field results obtained at Coal Fired Power plants, Metal Recycling and other anthropogenic sources in the USA.

The testing performed by US EPA standardized methodology per method 30B and PS 12A.

The testing results traceable to the US National Institute of Standards and Technology.

Oxidized and elemental mercury levels captured and compared simultaneously.

Real Time data from Continuous Monitors and semi continuous sorbent trap data obtained on the same sources and compared.

RG3-O7 — 16:30-16:45
MODELING EXPOSURE TO MERCURY VAPOR FROM POLYURETHANE FLOORS IN SCHOOL GYMNASIUMS
Authors: HERBRANDSON, Carl1, SWAIN, Edward2, BUSH, Christina R.3
(1)Minnesota Department of Health, carl.herbrandson@state.mn.us; (2) Minnesota Pollution Control Agency; (3) Michigan Department of Community Health.

Even with most known mercury and mercury-containing products removed from schools, in some schools there is potential for significant exposures from unexpected sources. For example, some polyurethane floors installed in school gymnasiums since the late 1960s contained up to 0.1% mercury as a catalyst. The total amount of mercury in a large gym floor at the time of installation may have exceeded 20 kg. Monitoring data show that mercury-retention times are long, and that mercury vapor concentrations in gymnasiums floored more than 15 years ago can still exceed health-based criteria. Mercury vapor emissions from mercury-containing floors increase with higher temperature. As a result, emissions from floors are likely highest during seasons when ground temperature is warm and active ventilation is at a minimum. In Minnesota, this is likely in the late summer and early fall. Mercury vapor concentrations can be reduced below levels of concern by active ventilation to outside. Exposure models and mitigation strategies will be presented.

RG3-O8 — 16:45-17:00
METHYLATION POTENTIAL OF MERCURY DERIVED FROM A COAL ASH SPILL: FINDS FROM THE TVA KINGSTON DISASTER
Authors: DEONARINE, Amrika1, HSU-KIM, Heileen1, RUHL, Laura1, VENGOSH, Avner1, BARTOV, Gideon2, JOHNSON, Tom2
(1) Duke University, amrika.deonarine@duke.edu; (2) University of Illinois at Urbana-Champaign;

Coal combustion products (CCPs) represent the largest industrial waste stream in the U.S. Coal ash, in particular, contains elevated levels of toxic elements such as mercury (Hg), yet much of this waste is typically stored in unlined holding ponds and landfills that are not monitored for their discharge to adjacent waters. Moreover, these holding ponds are susceptible to failures. In this study we investigated the impacts stemming from the largest coal ash spill in U.S. history that occurred on December 23, 2008 at the TVA Kingston Fossil Plant in Harriman, TN. The disaster was caused by a failure of a holding pond that resulted in the release of 4.1 million m3 of coal ash into the adjacent Emory River. Here, we report our findings from an 18-month survey after the disaster that documented elevated levels of methylmercury (MeHg) in the river sediments near the spill site. Moreover, we used isotopes of Hg to differentiate between mercury originating from the coal ash and mercury originating from historical contamination sources to this ecosystem. We also observed other water and sediment parameters (e.g., organic carbon, sulfide, sulfate) that indicated conditions favorable for mercury methylation by anaerobic bacteria. Overall, our results suggested that the coal ash was stimulating biomethylation of Hg in the river sediments (either by providing Hg or other substrates for sediment bacteria). This study highlights the need to consider the bioavailability of the mercury to methylating bacteria and the potential for MeHg production when evaluating the hazards of CCPs with respect to mercury.

RG3-O9 — 17:00-17:15
MERCURY RELEASE FROM SOILS AMENDED WITH FLUE GAS DESULFURIZATION SOLIDS
Authors: BRIGGS, Christian W.1, GUSTIN, Mae S.1
(1)University of Nevada, Reno, briggsc9@gmail.com

Flue Gas Desulfurization derived gypsum (FGD) can be applied for beneficial use as an agricultural soil amendment however concern has been raised regarding the release of mercury (Hg) from these materials to the environment. Recent work showed that a component of Hg present in the pure FGD material could be lost to the atmosphere. This study investigated Hg release to the air and water, from planted and bare soils from Indiana, Alabama, and Ohio amended with FGD in a laboratory setting. FGD was homogenized into each soil at rates of 4.5, 45, and 170t/ha and added at 4.9t/ha as a thin layer to represent a tilled and no-till agricultural setting, respectively. Data was also collected from unamended soils and those with applications of commercial gypsum. Twenty four hour Hg flux was measured from each material on a seasonal time step over one year. Water that had leached through select materials was collected seasonally and analyzed for total dissolved and methyl mercury. Hg accumulation in perennial rye grass (Lolium perenne) grown in a subset of soil treatments and was quantified.

Total Hg concentrations in the amended soils were similar to background soils and did not change significantly over the course of a year (46±9 to 47±2 µg kg-1, 24±4 to 27±6 µg kg-1, and 56±9 to 56±12 µg kg-1 for Indiana, Alabama, and Ohio, respectively; p=0.212, n=17). Hg concentrations of leach solutions from the FGD amended soils were not different from those reported for US surface waters. Emissions from amended soils were higher initially relative to unamended soils however became similar over time. Rye grass Hg concentrations were not related to amendment rate and were similar to values reported for foliage grown in uncontaminated settings.

RG3-O10 — 17:15-17:30
MERCURY CONCENTRATIONS AND SPECIATION IN MINING AND URBAN IMPACTED RIVERS AND DRAINAGE SYSTEMS TRIBUTARY TO SAN FRANCISCO BAY, CALIFORNIA
Authors: MCKEE, Lester J1, BONNEMA, Autumn2, CARTER, Annie3, DAVID, Nicole1, GILBREATH, Alicia1, GREENFIELD, Ben1, HEIM, Wesley2, HUNT, Jennifer1, STEPHENSON, Mark2, STILWATER, Tiffany3, YEE, Don1
(1) San Francisco Estuary Institute, lester@sfei.org; (2) Moss Landing Marine Laboratories; (3) Brooks Rand Laboratories;

Mercury speciation has a direct bearing on the effectiveness of source and treatment control options in mining and urban impacted systems adjacent to contaminated water bodies. However, little research has been reported describing mercury speciation in runoff from mercury mines and urban areas under flood flow conditions when the majority of transport occurs. To address this issue, stormwater was sampled in 25 drainage systems near San Francisco Bay to support improved management of this mercury impacted water body.

Results to-date indicate that total mercury concentration varies systematically with suspended sediment concentration, between watersheds of contrasting land use, and with proximity to sources. In rivers and creeks impacted by legacy mining, total mercury concentration varies from below detection to near 20,000 ng/L. In tributaries influenced by urban land uses exclusively, total mercury is less variable and ranges from below detection to near 1500 ng/L. Particle bound mercury dominates total mercury during all flow conditions in all systems but is proportionally greater during flood flow and varies distinctly with watershed size. Generally, methyl mercury accounts for <5% of total mercury and concentrations are greater during flood flow, correlate with suspended sediment concentration, and forms a greater proportion of total mercury during low flow. Acid labile mercury was measured and results to-date show this form of mercury makes up between 0.3 and 77% of total mercury in a 100% urban land use drainage with greatest proportions during spring base flow conditions. In contrast, in a large mixed land use watershed, acid labile mercury averages <10% of total mercury.

Findings from these studies are being used by local water resource agencies to develop management approaches to reduce loads of anthropogenic mercury and biological impacts in receiving waters. Treatment measures being considered include conventional source control such as enhanced mercury recycling, focused street sweeping, and soil removal or capping. Treatment control measures being considered include routing storm water to wastewater treatment during first flush and base flow conditions, and the use of low impact development/redevelopment in built out areas. Contaminated watersheds adjacent to more sensitive higher productivity sub-regions of the Bay are being identified and prioritized for management. It is hypothesized that prioritization in this manner will lead to faster rates of improvement in mercury contaminated sediments and mercury impacts to key bird species, sport fish, and humans.

Thursday, 28 July, 2011