Mercury fluxes from air/surface interfaces in paddy field and dry land

Zhu, Jinshan; Wang, Dingyong; Liu, Xiao; Zhang, Yutong

doi:10.1016/j.apgeochem.2010.11.025

Cited by 36 publications

(26 citation statements)

References 31 publications

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“…They had a significant positive correlation (r=0.73, n=264, P<0.01 at CS and r=0.78, n=395, P<0.01 at CJ, respectively; see Table 3 and Figure 3). This was in agreement with previous studies [15,[20][21][22][23]. The regression analysis showed that mercury emission had a power relation with solar radiation (R 2 =0.91 for CJ and (Figure 4).…”

Section: Effects Of Environmental Factors On Hg Fluxessupporting

confidence: 81%

Mercury release flux and its influencing factors at the air-water interface in paddy field in Chongqing, China

Zhu

Wang

2012

Chin. Sci. Bull.

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The exchange of mercury (Hg) across the air-water interface is an important part of Hg biogeochemical cycle. Mercury fluxes across the air-water interface in paddy fields were measured by a Dynamic Flux Chamber (DFC) coupled with a Lumex ® multifunctional mercury analyzer RA-915 + at two sites (Chengjiang (CJ) and Caoshang (CS)) in Beibei, Chongqing, China in 2008. The results showed that mercury emission followed a power-law relationship with solar radiation and air temperature, and it increased exponentially with water temperature at both sites. Mercury emission was mainly influenced by the solubility of gaseous elemental Hg, photo-thermal effect, electron activity (Eh) and air Hg concentrations. Solar radiation made the greatest direct contribution to mercury emission during the daytime (0.80), with an 83.60% contribution, whereas at nighttime the water temperature (0.72) contributed to 71.65% of emissions. The temperature gradient between water and air might also influenced mercury emission across the air/water interface at nighttime. These findings suggest that paddy fields could act as a significant source of atmospheric mercury, and it can contribute significantly to the atmospheric mercury in a local region.

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Section: Effects Of Environmental Factors On Hg Fluxessupporting

confidence: 81%

Mercury release flux and its influencing factors at the air-water interface in paddy field in Chongqing, China

Zhu

Wang

2012

Chin. Sci. Bull.

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“…For example, the seasonal data from Choi and Holsen (2009a) showed a higher evasion from forest floor soil in the Adirondack Mountains (New York, USA) in the summer (1.46 ng m −2 h −1 ) shifted to insignificant exchange in the winter (0.19 ng m −2 h −1 ). Similar trends were also found in agricultural soils, freshwater and mine surfaces (Fu et al, 2010a;Eckley et al, 2011b;Zhu et al, 2011). However, an opposite low flux in spring and summer was observed in a pristine background deciduous forest floor (Hartman et al, 2009;Kuiken et al, 2008a), which, likely due to drier conditions and lower irradiation, resulted from intense leaf cover.…”

Section: Spatial Distribution and Temporal Variationsupporting

confidence: 57%

“…Construction materials such as fluorinated ethylene propylene (FEP) films and quartz have been recommended for DFCs due to its high actinic light transmittance and low blank Carpi et al, 2007;Lin et al, 2012). Reported DFCs volumes and flushing flow rates range from 1 to 32 L and 1.5 to 20 L min −1 , resulting in a turnover time (TOT) ranging from 0.1 to 14 min (Eckley et al, 2010;Zhu et al, 2011). Using DFCs, the Hg 0 flux is calculated as follows:…”

Section: Dynamic Flux Chambersmentioning

confidence: 99%

Global observations and modeling of atmosphere–surface exchange of elemental mercury: a critical review

et al. 2016

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Abstract. Reliable quantification of air-surface fluxes of elemental Hg vapor (Hg 0 ) is crucial for understanding mercury (Hg) global biogeochemical cycles. There have been extensive measurements and modeling efforts devoted to estimating the exchange fluxes between the atmosphere and various surfaces (e.g., soil, canopies, water, snow, etc.) in the past three decades. However, large uncertainties remain due to the complexity of Hg 0 bidirectional exchange, limitations of flux quantification techniques and challenges in model parameterization. In this study, we provide a critical review on the state of science in the atmosphere-surface exchange of Hg 0 . Specifically, the advancement of flux quantification techniques, mechanisms in driving the air-surface Hg exchange and modeling efforts are presented. Due to the semi-volatile nature of Hg 0 and redox transformation of Hg in environmental media, Hg deposition and evasion are influenced by multiple environmental variables including seasonality, vegetative coverage and its life cycle, temperature, light, moisture, atmospheric turbulence and the presence of reactants (e.g., O 3 , radicals, etc.). However, the effects of these processes on flux have not been fundamentally and quantitatively determined, which limits the accuracy of flux modeling.We compile an up-to-date global observational flux database and discuss the implication of flux data on the global Hg budget. Mean Hg 0 fluxes obtained by micrometeorological measurements do not appear to be significantly greater than the fluxes measured by dynamic flux chamber methods over unpolluted surfaces (p = 0.16, one-tailed, Mann-Whitney U test). The spatiotemporal coverage of existing Hg 0 flux measurements is highly heterogeneous with large data gaps existing in multiple continents (Africa, South Asia, Middle East, South America and Australia). The magnitude of the evasion flux is strongly enhanced by human activities, particularly at contaminated sites. Hg 0 flux observations in East Asia are comparatively larger in magnitude than the rest of the world, suggesting substantial re-emission of previously deposited mercury from anthropogenic sources. The Hg 0 exchange over pristine surfaces (e.g., background soil and water) and vegetation needs better constraints for global analyses of the atmospheric Hg budget. The existing knowledge gap and the associated research needs for future measurements and modeling efforts for the air-surface exchange of Hg 0 are discussed.

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“…GEM fluxes from different landscapes in cold seasons (from November to April) were relatively limited. Several studies found that GEM Fu et al (2007Fu et al ( , 2008Fu et al ( , 2010bFu et al ( , 2012cFu et al ( , 2013, Zhu et al (2011Zhu et al ( , 2013, Ma et al (2013), and Liu et al (2014) fluxes from dry farmland, forest soil, and lake waters were about 2.5-40 times (mean = 6.5, n = 18) lower than those in warm seasons Ma et al, 2013;Fu et al, 2010b;Fu et al, 2013). Given the different landscapes and seasonal patterns of GEM fluxes in mainland China, we estimate the annual natural GEM emissions to be 528 t in China.…”

Section: Estimates Of Gem Emissionsmentioning

confidence: 99%

Correlation slopes of GEM / CO, GEM / CO<sub>2</sub>, and GEM / CH<sub>4</sub> and estimated mercury emissions in China, South Asia, the Indochinese Peninsula, and Central Asia derived from observations in northwestern and southwestern China

Zhang

Lin

et al. 2015

Atmos. Chem. Phys.

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Abstract. Correlation analyses between atmospheric mercury (Hg) and other trace gases are useful for identification of sources and constraining regional Hg emissions. Emissions of Hg in Asia contribute significantly to the global budget of atmospheric Hg. However, due to the lack of reliable data on the source strength, large uncertainties remain in the emission inventories of Hg in Asia. In the present study, we calculated the correlation slopes of GEM / CO, GEM / CO 2 , and GEM / CH 4 for mainland China, South Asia, the Indochinese Peninsula, and Central Asia using the ground-based observations at three remote sites in northwestern and southwestern China, and applied these values to estimate GEM emissions in the four source regions. The geometric mean GEM / CO correlation slopes for mainland China, South Asia, the Indochinese Peninsula, and Central Asia were 7.3 ± 4.3, 7.8 ± 6.4, 7.8 ± 5.0, and 13.4 ± 9.5 pg m −3 ppb −1 , respectively, and values in the same source regions were 33.3 ± 30.4, 27.4 ± 31.0, 23.5 ± 15.3, and 20.5 ± 10.0 pg m −3 ppb −1 for the GEM / CH 4 correlation slopes, respectively. The geometric means of GEM / CO 2 correlation slopes for mainland China, South Asia, and Central Asia were 240 ± 119, 278 ± 164, 315 ± 289 pg m −3 ppm −1 , respectively. These values were the first reported correlation slopes of GEM / CO, GEM / CO 2 , and GEM / CH 4 in four important source regions of Asia, not including the GEM / CO ratios in mainland China. The correlation slopes of GEM / CO, GEM / CO 2 , and GEM / CH 4 in Asia were relatively higher than those observed in Europe, North America, and South Africa, which may highlight GEM emissions from nonferrous smelting, large-scale and artisanal mercury and gold production, natural sources, and historically deposited mercury (re-emission) in Asia. Using the observed GEM / CO and GEM / CO 2 slopes, and the recently reported emission inventories of CO and CO 2 , the annual GEM emissions in mainland China, South Asia, the Indochinese Peninsula, and Central Asia were estimated to be in the ranges of 1071-1187, 340-470, 125, and 54-90 t, respectively. The estimated quantity of GEM emissions from the GEM / CH 4 correlation slopes is significantly larger, which may be due to the larger uncertainties in CH 4 emissions in Asia as well as insufficient observations of GEM / CH 4 correlation slopes, therefore leading to an overestimate of GEM emissions. Our estimates of GEM emissions in the four Asian regions were significantly higher (3-4 times) than the anthropogenic GEM emissions reported in recent studies. This discrepancy could come from a combination of reasons including underestimates of anthropogenic and natural GEM emissions; large uncertainties related to CO, CO 2 , and CH 4 emission inventories; and inherent limitations of the correlation slope method.

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Mercury fluxes from air/surface interfaces in paddy field and dry land

Cited by 36 publications

References 31 publications

Mercury release flux and its influencing factors at the air-water interface in paddy field in Chongqing, China

Mercury release flux and its influencing factors at the air-water interface in paddy field in Chongqing, China

Global observations and modeling of atmosphere–surface exchange of elemental mercury: a critical review

Correlation slopes of GEM / CO, GEM / CO<sub>2</sub>, and GEM / CH<sub>4</sub> and estimated mercury emissions in China, South Asia, the Indochinese Peninsula, and Central Asia derived from observations in northwestern and southwestern China

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Mercury fluxes from air/surface interfaces in paddy field and dry land

Cited by 36 publications

References 31 publications

Mercury release flux and its influencing factors at the air-water interface in paddy field in Chongqing, China

Mercury release flux and its influencing factors at the air-water interface in paddy field in Chongqing, China

Global observations and modeling of atmosphere–surface exchange of elemental mercury: a critical review

Correlation slopes of GEM / CO, GEM / CO&lt;sub&gt;2&lt;/sub&gt;, and GEM / CH&lt;sub&gt;4&lt;/sub&gt; and estimated mercury emissions in China, South Asia, the Indochinese Peninsula, and Central Asia derived from observations in northwestern and southwestern China

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Correlation slopes of GEM / CO, GEM / CO<sub>2</sub>, and GEM / CH<sub>4</sub> and estimated mercury emissions in China, South Asia, the Indochinese Peninsula, and Central Asia derived from observations in northwestern and southwestern China