[Show abstract][Hide abstract] ABSTRACT: Mercury species samples for gaseous elemental mercury (GEM) with a temporal resolution of 5 min, 5 h and 20 min integrated measurements of reactive gaseous mercury (RGM), and 24-h sampling of particulate mercury (HgP) at urban Femman and total gaseous mercury (TGM) at rural Rörvik were conducted during the measurement campaign GÖTE-2005 in Göteborg, Sweden. Results showed that average concentrations for GEM, RGM, HgP and TGM were 1.96 ± 0.38 ng m−3, 2.53 ± 4.09 pg m−3, 12.50 ± 5.88 pg m−3 and 1.63 ± 0.19 ng m−3, respectively. A reverse diurnal distribution pattern between GEM and RGM was observed, and early morning GEM concentration was elevated compared to daytime values which was likely due to activation of fossil fuel combustion, electric utilities, etc., by the formation of a nighttime inversion layer, less activity of GEM and reduced mixing. The subsequent decline and afternoon minimum were likely related to increase vertical mixing, photochemical reaction, and coupling with the coal combustion. However, the photochemical conversion from GEM during daytime and nocturnal behavior of “sticky” gases under higher relative humidity may result in strong diurnal cycles for RGM. Sampling site was heavily affected by anthropogenic sources from two distinguished wind sectors. One was ESE-SSW sector which was likely impacted by long distance transport from south highly industrialized region; the other was likely tied with local sources from N–NE sector.
[Show abstract][Hide abstract] ABSTRACT: The assessment of the global mercury cycle involves estimations of the evasion of mercury form oceanic waters. In such estimations Henry's law constant is often used. In this study the Henry's law constant for elemental mercury has been re-determined in MQ water and artificial sea water. Moreover, for the first time it has been determined for 1.5M sodium chloride (NaCl) solution which is of relevance for modeling of atmospheric waters at coastal locations. For all solutions, experiments has been conducted at five different temperatures between 278 and 308K, using a novel technique, for mercury, based on direct measurements of the portioning of mercury between the aqueous and gaseous phase. Elemental mercury was extracted from the water column and the logarithm of the mass of extracted mercury was plotted against time. A dimensionless Henry's law constant, defined as: [see text] was obtained from the slope of the curve. Almost no difference was observed in the values comparing the Milli-Q water and artificial sea water, however for the 1.5M NaCl solution a salting-out effect was seen, i.e. the solubility of mercury in the water phase decreased. The decreased solubility will generate an increase in the value of Henry's law constant.
[Show abstract][Hide abstract] ABSTRACT: A novel continuous equilibrium system with high time resolution, i.e. every ten minutes, was developed to sample and determine dissolved gaseous mercury (DGM) in natural surface waters. The system is based on the opposite flow principle, can be connected to a ship's bow water system, and can be applied under most ambient conditions, such as high wind speeds and onboard a moving ship. For the DGM determination the system uses the measured equilibrium concentration of mercury established between the aqueous and gaseous phases, i.e. DGM = Hg(extr)/k(H'), where Hg(extr) is the measured mercury concentration in the outgoing gas phase and k(H') is the dimensionless Henry's Law constant at the desired temperature and salinity. The efficiency of the system was investigated via theoretical calculations and by comparing the continuous equilibrium system with discrete samples. The measurements obtained by the continuous equilibrium system agree within 13% at the 95% confidence level with the measurements of discrete samples obtained by the traditional technique. The theoretical calculations estimated that the continuous equilibrium system described here had an efficiency of 99% for determining the DGM concentration.
[Show abstract][Hide abstract] ABSTRACT: There is an urgent need to better constrain the global rates of mercury degassing from natural sources, including active volcanoes. Hitherto, estimates of volcanic fluxes have been limited by the poorly-determined speciation of Hg in volcanic emissions. Here, we present a systematic characterisation of mercury partitioning between gaseous (Hg(g)) and particulate (Hg(p)) forms in the volcanic plume of Mount Etna, the largest open-vent passively degassing volcano on Earth. We demonstrate that mercury transport is predominantly in the gas-phase, with a mean Hg(p)/Hg(g) ratio of ∼0.01 by mass. We also present the first simultaneous measurement of divalent gaseous mercury (HgII(g)) and total gaseous mercury (Hg(g)) in a volcanic plume, which suggests that Hg0(g) is the prevalent form of mercury in this context. These data are supported by the results of model simulations, carried out with HSC thermodynamic software. Based on a mean ‘bulk plume’ Hg/SO2 mass ratio of 8.7×10-6, and a contemporaneous volcanic SO2 flux of 0.8 Mt·yr-1, we estimate an Hg emission rate from Mt. Etna during passive degassing of 5.4 t·y-1 (range, 1.1-10 t·y-1). This corresponds to ~0.6% of global volcanic Hg emissions, and about 5% of Hg released from industrial activities in the Mediterranean area. published 7377-7388 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive 4.5. Degassamento naturale JCR Journal
[Show abstract][Hide abstract] ABSTRACT: An evaluation of mercury observations from North Sea coastal stations during 1995–2002 has been performed. The mercury data originate from EMEP/OSPAR stations in Ireland, Netherlands, Germany, Norway and Sweden where mercury in precipitation and Total Gaseous Mercury (TGM) have been measured. A decreasing trend in mercury wet deposition is observed. The decrease is sufficiently large to be significant considering measurement precision and appears to occur at all the studied sites. The reduction in deposition is 10–30% when comparing the two periods 1995–1998 and 1999–2002. The trend is likely to be due to emission controls in Europe. In contrast, no decreasing trend in TGM could be observed during the same time periods. A plausible explanation is that the TGM concentration measured in the OSPAR area to a larger extent than before is dominated by the hemispherical background concentration of TGM.
[Show abstract][Hide abstract] ABSTRACT: Mercury in air has been measured at five coastal Mediterranean sites, involving measurements in Spain, France, Italy, Slovenia and
Israel. Four two-weeks long measurements campaigns were performed at the five sites. The measurements were carried out during
autumn 2003 and winter, spring and summer 2004. Total gaseous mercury/elemental gaseous mercury, particulate mercury and divalent
gaseous mercury were measured in parallel at the five sites. The activities constituted a subtask of the EU funded MERCYMS
research project, which also included Mediterranean Sea cruises where both mercury in air and water were measured. The result
from an evaluation of all the coastal air data is presented. Mercury concentrations from the different sites are compared
with similar data obtained in northern Europe and elsewhere. The result shows that the background concentration of mercury
in Mediterranean coastal air is lower than earlier anticipated. Background concentrations of TGM, RGM and TPM corresponded
to 1.75–1.80ngm−3, 1–13 and 3–23pgm−3, respectively. The measurements also showed that the mercury concentration occasionally can be very high in some areas due
to local anthropogenic emissions. It is proposed that diurnal variation in RGM concentrations observed during situation with
nocturnal inversion merely is an effect of meteorology rather than due to local photochemistry.
[Show abstract][Hide abstract] ABSTRACT: Dissolved gaseous mercury (DGM) was measured continuously using two newly developed techniques and a manual technique. The continuous techniques were based on the equilibrium between the aqueous and gaseous phase (DGM = Hgextr / H', Hgextr is the measured mercury concentration in the gas phase, H' is the Henry's Law coefficient at the desired temperature). In order to calculate the annual mercury evasion from the Mediterranean Sea, diurnal and seasonal measurements of DGM, total gaseous mercury in air (TGM), water temperature and wind speed were performed. During August 2003, March–April 2004 and October–November 2004 measurements of these parameters were conducted on board the RV Urania. The continuous measurements of DGM showed a diurnal variation in concentration, at both coastal and off shore sites, with higher concentrations during daytime than nighttime. The concentration difference could be as large as 130 fM between day and night. The degree of saturation was calculated directly from the measurements, S = Hgextr / TGM and was found to vary between the different seasons. The highest average degree of saturation (850%) and the largest variation in saturation (600–1150%) was observed during the summer. The spring showed the lowest variation (260–360%) and the lowest average degree of saturation (320%). The autumn also showed a large variation in saturation (500–1070%) but a lower average (740%) compared to the summer cruise. This might be explained by the temperature difference between the different seasons, since that parameter varied the most. The flux from the sea surface was calculated using the gas exchange model developed by Nightingale et al. [Nightingale, P.D., Malin, G., Law, C.S., Watson, A.J., Liss, P.S., Liddicoat, M.I., Boutin, J., Upstill-Goddard, R. C., 2000. In situ evaluation of air–sea gas exchange parameterization using novel conservative and volatile tracers. Global Biogeochemical Cycles, 14(1):373–387]. The evasion varied between the different seasons with the highest evasion during the autumn, 24.6 pmol m− 2 h− 1. The summer value was estimated to 22.3 pmol m− 2 h− 1 and the spring to 7.6 pmol m− 2 h− 1. Using this data the yearly evasion from the Mediterranean Sea surface was estimated to 77 tons.
[Show abstract][Hide abstract] ABSTRACT: As part of the European Mercury Emissions from Chlor Alkali Plants (EMECAP) project, we tested the hypothesis that contamination of ambient air with mercury around chlor alkali plants using mercury cells would increase the internal dose of mercury in people living close to the plants. Mercury in urine (U-Hg) was determined in 225 individuals living near a Swedish or an Italian chlor alkali plant, and in 256 age- and sex-matched individuals from two reference areas. Other factors possibly affecting mercury exposure were examined. Emissions and concentrations of total gaseous mercury (TGM) around the plants were measured and modeled. No increase in U-Hg could be demonstrated in the populations living close to the plants. This was the case also when the comparison was restricted to subjects with no dental amalgam and low fish consumption. The emissions of mercury to air doubled the background level, but contributed only about 2 ng/m(3) to long-term averages in the residential areas. The median U-Hg levels in subjects with dental amalgam were 1.2 microg/g creatinine (micro/gC) in Italy and 0.6 microg/gC in Sweden. In individuals without dental amalgam, the medians were 0.9 microg/gC and 0.2 microg/gC, respectively. The number of amalgam fillings, as well as chewing, fish consumption, and female sex were associated with higher U-Hg. The difference between the countries is probably due to higher fish consumption in Italy, demethylated methyl mercury (MeHg) being partly excreted in urine. Post hoc power calculations showed that if the background mercury exposure is low it may be possible to demonstrate an increase in U-Hg of as little as about 10 ng/m(3) as a contribution to ambient mercury from a point source.
Science of The Total Environment 10/2006; 368(1):326-34. DOI:10.1016/j.scitotenv.2005.08.048 · 4.10 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Mercury in air near a mercury cell chlor-alkali plant in Sweden has been measured within the EU-project EMECAP. Based on the measurements and modelling the annual distributions of GEM and RGM have been calculated for the local area around the plant. The average concentration of GEM in residential areas near the plant was found to be 1–3.5ngm−3 higher in comparison to the background concentration in this part of Sweden. The emission of RGM (0.55kgyear–1) results in elevated RGM concentrations close to the plant. The greatest impact on the local area is due to wet deposition of RGM. However, only a small fraction (0.4%) of all mercury being emitted was found to be deposited in the local area. No impact on urinary mercury could be demonstrated in the population living close to the plant.
[Show abstract][Hide abstract] ABSTRACT: The concentration of total atmospheric gaseous mercury (TGM) and total particulate mercury (TPM) have been measured during one summer campaign (19–29 August 2003) and one winter campaign (26 January–3 February 2004) at a rural site in Poland. Mercury deposition was also measured using bulk samplers. The measurement campaigns were performed in a typical agricultural area of Southern Poland where 85% of the houses use low capacity domestic heating units (DHUs) fuelled with hard coal during the cold season. An average TGM value of 1.63±0.35ngm-3 was obtained in the summer campaign, whereas a 2.5 times higher TGM concentration was found during winter. The mean TPM concentration during summer was 0.11±0.05ngm-3 while 10 times higher values were obtained during the winter campaign. The mercury deposition was also found to be much higher during winter in comparison to summer. The summer TGM values are at the same level as the annual average TGM at background locations in most West European countries including Scandinavia. The higher TGM values in winter are most likely due to the use of DHUs in the local area. However, both summer and winter TPM concentrations and mercury deposition fluxes are much higher than in most neighbouring West European countries. This probably reflects the regional use of coal combustion for electric energy production and in low-capacity DHUs.
[Show abstract][Hide abstract] ABSTRACT: Fluxes of mercury from a waste repository and from an agricultural field amended with sewage sludge were measured. The measurements
were performed by utilising a Relaxed Eddy Accumulation (REA) system synchronously coupled to automated mercury cold vapour
atomic fluorescence analysers (CVAFA). The waste repository was severely contaminated and fluxes of between 0.16μg m−2 h−1 and 29μg m−2 h−1 could be measured. Fluxes at the slightly contaminated agricultural field measured between 8 ng m−2 h−1 and 1.9μg m−2 h−1. The results showed that the REA-CVAFA system could be used for measurements above both severely-and slightly contaminated
soils. The measurements at the chlor-alkali plant showed that temperature was the most important parameter controlling the
release of mercury at this site. At the agricultural field, the measurements indicated that both solar radiation and temperature
may have influenced the emissions. Most of the mercury added to the field was lost to the atmosphere during the summer season.
Water Air and Soil Pollution 09/2005; 167(1):331-352. DOI:10.1007/s11270-005-0012-8 · 1.55 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: This work summarizes field studies that have been carried out to investigate the chemistry and environmental behavior of atmospheric mercury on different spatial and temporal scales in North-western and Central Europe. The spatial scales cover local and regional dimensions. Temporal scales include short-term variations of atmospheric mercury concentrations within less than one hour, variations that typically occur within time steps of a few hours to several days and long-term observations that cover almost three decades. The knowledge of the worldwide trend of atmospheric mercury concentrations during the last few decades is valuable for at least two reasons. The trend may reveal the impact of the control measures (OECD, 1994; US EPA, 1997) on the global cycle of atmospheric mercury. The response of mercury concentrations to the control measures may also provide information about the poorly defined ratio of anthropogenic to natural emissions (Schroeder and Munthe, 1998; Ebinghaus et al, 1999a). Slemr et al. (2003) have attempted to reconstruct the worldwide trend of total gaseous mercury (TGM) concentrations from long term measurements of known documented quality (Ebinghaus et al., 1999b) on 6 sites in the northern hemisphere (NH), 2 sites in the southern hemisphere (SH), and 8 ship cruises over the Atlantic Ocean made intermittently since 1977.(figure presented) The data presented in Figure 1 shows a generally good agreement between ship TGM measurements over the northern Atlantic Ocean and land-based measurements at Mace Head (Ireland), Lista, and Ny Ålesund (both Norway). The measurements at Mace Head also agree excellently with those made at Alert (Canada). TGM median values at the summit of the Wank mountain in southern Germany tend to be higher, most likely due to emissions in western and central Europe. Measurements at Rorvik in Sweden tend to provide the lowest values in the NH but are still in reasonable agreement with measurements at Alert and Lista (see also discussion in Munthe et al., 2003). All data, when taken together, suggest that the TGM concentrations in the NH had been increasing since the first measurements in 1977 to a maximum in the 1980s (most likely in the 2nd half (Slemr et al., 2003), then decreased to a minimum in 1996 and have remained constant since that time at a level of about 1.7 ng m-3. Slemr et al. (2003) claim that the observed temporal profile is primarily the result of the temporal change of mercury emissions. The temporal trend is qualitatively consistent with changes in global anthropogenic emissions (e.g. Pacyna and Pacyna, 2002; Pirrone et al, 1996) emphasising that the analysis of emission changes may help to explain observed long-term trends. However, these estimates do not reflect the measured decrease from 1990 to 1996 (Slemr et al., 2003).
[Show abstract][Hide abstract] ABSTRACT: Mercury in different environmental compartments has been measured at Ny-Ålesund (78°54? N, 11°53? E) during an intensive campaign, 17 April to 14 May 2002. Time-resolved speciated determination of mercury in the atmosphere and snow was conducted at the Norwegian research station at the Zeppelin mountain, 474 m above the sea level, and at the Italian research facility Dirigibile Italia, 12 m above the sea level. Total Gaseous Mercury (TGM) was present in the range <0.1 to 2.2 ng m<sup>?3</sup> during the campaign. Three mercury depletion events, identified as periods with decreased TGM concentrations, were observed. At the lower altitude, TGM concentrations following such events were found to exhibit both higher magnitude and larger variability in comparison to results from the Zeppelin station. Oxidised mercury species in air and fall-out with snow as well as mercury attached to particles were also measured and their concentrations were found to be anti-correlated with TGM in air. The strongest modulation was observed for total mercury concentration (Hg-tot) in snow (range 1.5?76.5 ng L<sup>?1</sup>). Solid evidence for photo-stimulated emissions of Hg<sup>0</sup>(g) from the snow pack in conjunction to depletion events were obtained from gradient measurements as well as from flux chamber measurements. Steep diurnal concentration variations of Hg<sup>0</sup>(aq) in surface seawater were also found to concur with changing solar radiation. The concentration of Hg<sup>0</sup>(aq) in seawater was found to be in the range 12.2?70.4 pg L<sup>?1</sup>, which corresponds to supersaturation. Hence, the seawater surface constituted a source emitting elemental mercury. The concentrations of the transient mercury forms RGM (Reactive Gaseous Mercury) and PM (Particulate Mercury) respectively and BrO column densities detected using a zenith and off-axis sky viewing DOAS instrument were very low except for a few individual samples during the major depletion event. An evaluation of trajectories for selected events and comparisons with BrO vertical column densities obtained by the GOME (Global Ozone Monitoring Experiment) instrument aboard the earth remote sensing satellite ESR-2 indicates that the air masses exhibiting low Hg<sup>0</sup> concentrations originated from areas with high BrO densities. It was concluded that the observed depletion events at Ny-Ålesund were a results of transport from areas with high photochemical activity around the polar region.
[Show abstract][Hide abstract] ABSTRACT: The inventories of global anthropogenic emissions of mercury for years
from 1979/1980 to 1995 suggest a substantial reduction in the 1980s and
almost constant emissions afterwards. In contrast to emission
inventories, measurements of atmospheric mercury suggest a concentration
increase in the 1980s and a decrease in the 1990s. Here we present a
first attempt to reconstruct the worldwide trend of atmospheric mercury
concentrations from direct measurements since the late 1970s. In
combination, long term measurements at 6 sites in the northern, 2 sites
in the southern hemispheres, during 8 ship cruises over the Atlantic
Ocean (1977-2000) provide a consistent picture, suggesting that
atmospheric mercury concentrations increased in the late 1970s to a peak
in the 1980s, then decreased to a minimum at about 1996, and have been
nearly constant since. The observed trend is not consistent with the
published inventories of anthropogenic emissions and the assumed ratios
of anthropogenic/natural emissions, and suggests the need to improve the
mercury emission inventories and to re-evaluate the contribution of
Geophysical Research Letters 05/2003; 30(10). DOI:10.1029/2003GL016954 · 4.20 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Total particulate mercury (TPM) in air has been measured during five 2-week campaigns at five measurement sites in Northern Europe. The measurements covered four seasons and the result constitutes a unique TPM data set from this region. Evidence for transport of TPM on a regional scale is reported as well as the historical trend of TPM in south of Sweden. All TPM measurements were made using a new mini particulate sampler. The device consists of a quartz fibre filter contained in a quarts glass filter holder and is a modified version of the MiniSamplr. This approach proves to be reliable and more cost efficient in comparison to alternative methods. Tests made to evaluate the performance of the sampler in terms of precision and comparability with sampling on Teflon membrane filters are also reported.
Science of The Total Environment 04/2003; 304(1-3):53-9. DOI:10.1016/S0048-9697(02)00556-9 · 4.10 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: A procedure for sampling gaseous methylmercury (MeHg) in ambient air using a refluxing mist chamber (MC) has been developed. The MC consists of a glass bulb with an air inlet tube at the bottom. Via a capillary mounted adjacent to the inlet tube, the solution inside the MC is pulled from the bottom of the bulb to form a mist inside the chamber. Two different aqueous sampling solutions were tested and evaluated, a dilute HCl (0.003 M) solution and a solution containing the chelating agent ammonium salt of pyrrolidine-1-dithiocarboxylic acid. The airflow rate through the sampler was 10-15 l min(-1). The sampling time was 6 h when using dilute HCl as an extraction solution, and 3 h when using the solution containing the chelating solution. Determination of atmospheric MeHg collected in the aerated water sample was accomplished using GC/CVAFS after aqueous phase ethylation, and pre-collection onto carbotrap column. To test the reproducibility and accuracy of the method, parallel sampling, and standard additions tests were carried out. Other quality control tests, i.e. procedure blanks and duplicated analysis have also been performed. The detection limit, based on three times the standard deviation of total blank (including sampling, distillation, and analysis) is 2 pg, which corresponds to a procedural detection limit of approximately 1 pgm(-3) in ambient air when sampling for 3 h. Measurements performed on the roof of the IVL building yielded concentrations from 3 to 22 pgm(-3) corresponding to 0.3-1% of the total gaseous mercury in ambient air.
Science of The Total Environment 04/2003; 304(1-3):107-13. DOI:10.1016/S0048-9697(02)00560-0 · 4.10 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Atmospheric mercury species/fractions were measured near a chlor-alkali plant in Sweden during August 28 to September 4, 2001. The concentration of total gaseous mercury in the plume from the plant was measured using TEKRAN and GARDIS instruments. Gaseous elemental mercury was measured using a light detection and ranging (LIDAR) technique. From vertical LIDAR sweeps through the plume from the chlor-alkali plant mercury emission rates could be calculated. The concentrations of reactive gaseous mercury (RGM) in the plume and also inside the cell house were measured using annular KCl coated denuders. The RGM emission constitutes 0.5-1.0% of the total mercury emitted from the plant. The mercury concentration adsorbed on particles was measured as well as the mercury flux from soil. The data presented also include an intercomparison showing an excellent agreement between TEKRAN/GARDIS and LIDAR gaseous mercury measurements.
Science of The Total Environment 04/2003; 304(1-3):29-41. DOI:10.1016/S0048-9697(02)00554-5 · 4.10 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Dissolved gaseous mercury (DGM) was measured in coastal Atlantic seawater and in the Mediterranean Sea. The Atlantic measurements were performed during September 1999 at the Mace Head Atmospheric Research Station, situated on the Irish west coast. The measurements in the Mediterranean Sea were made along a 6000 km cruise path from 14 July to 9 August 2000 in the framework of the Med-Oceanor project. Total gaseous mercury (TGM) concentrations in air were continuously measured with a 5 min time resolution using an automated mercury analyser (Tekran 2537A) during both expeditions. Paired TGM and DGM samples from all campaigns showed that the surface water was supersaturated with elemental mercury. The mercury evasion was estimated using a gas exchange model (J. Geophys. Res. 97 (1992) 7373), which uses salinity, wind speed and water temperature as independent parameters. The predicted average mercury evasion from the coastal Atlantic water was 2.7 ng m−2 h−1 implying that the concentration of TGM in the Atlantic air is enhanced by mercury evasion from the sea.Measurements in different regions of the Mediterranean Sea showed spatial variations in DGM concentrations. The highest DGM concentration (∼90 pg l−1) was observed at a location in the Strait of Sicily (37°16N 11°52E). The mercury evasion in the eastern sector of the Mediterranean Sea (area: 32–36°N, 17–28°E) was generally higher (7.9 ng m−2 h−1) than that observed in the Tyrrhenian Sea (4.2 ng m−2 h−1) or in the western sector (2.5 ng m−2 h−1) (areas: 38–42°N, 8–13°E and 38–41°N, 7–8°E, respectively). Estimations of mercury evasion were also made at Mediterranean coastal sites using a dynamic chamber technique.In addition, a newly developed method making continuous in situ DGM measurements possible was tested.
[Show abstract][Hide abstract] ABSTRACT: The mercury species over Europe (MOE) project was aimed at identifying sources, occurrence and atmospheric behaviour of atmospheric Hg species. Within MOE, emission measurements, ambient air measurements, process and regional-scale modelling and laboratory measurements were conducted. In this work, a summary of some of the main results is given. From the emission measurements, information on stack gas concentrations and emission factors for five coal fired power plants and three waste incinerators are presented. Results from field measurements of mercury species in ambient air at five locations in Northern Europe are presented. Examples from regional-scale atmospheric modelling are also given. The results emphasise the importance of information on Hg species for instance in emission inventories and measurement data from background sites. Furthermore, the importance of considering the role of the global cycling of mercury in future control strategies is emphasised.
[Show abstract][Hide abstract] ABSTRACT: A comparison of manual procedures for measurements of dissolved gaseous mercury (DGM) in seawater was accomplished. The experiments were performed on board the Italian research vessel Urania during July 2000 as a subtask in the CNR "Med-Oceanor Project 2000". Water samples for DGM were collected by Go-Flo bottles and subsequently analysed for DGM on board the ship. Determinations of DGM were made in parallel by two groups using different analytical routines. The two sets of data obtained compare favourably. Based on the fieldwork and an additional laboratory study, analytical procedures are discussed and an optimised method to determine DGM is presented. In addition, a method for automated in situ measurements of DGM positioned in the water body was tested. This method has the potential to simplify studies of DGM dynamics, that is variation in concentration as a function of water temperature and solar radiation etc.