Mercury Translocation Research Articles

Converting flooded rice to dry farming can alleviate MeHg accumulation in grains

The study explored the impact of water management on rice cultivation in mercury-contaminated paddy soil. The objective was to analyze the characteristics of mercury translocation by converting flooded soils to dry farming (non-flooded) to alleviate mercury accumulation in rice grains. The experiment was conducted over three consecutive rice-growing seasons, employing two distinct water management models: a continuously flooded rice cultivation mode and a flooded rice planting mode in the first season, followed by a non-flooded rice farming mode in the second and third seasons. The results showed that the change from flooded to non-flooded rice cultivation patterns presented extremely excellent environmental potential for inhibiting the uptake of both methylmercury and total mercury in rice. When transitioning from flooded cultivation to dry farming, the concentration of methylmercury and total mercury in the grains of non-flooded rice decreased by 87.15 % and 9.57 %, respectively, compared to that in the grains of flooded rice. In the third season, the methylmercury and total mercury in the grains of non-flooded rice decreased further by 95.03 % and 69.45 %, respectively. This study verified that the conversion of rice cultivation from flooded to non-flooded is an efficient strategy for suppressing the accumulation of methylmercury in rice grains, and it might offer a promising solution for managing soil mercury risks and ensuring the safety of rice for human consumption.

Bioaccumulation and translocation of Hg and Cr by tobacco in Sichuan Province, China: understanding the influence of soil pH.

The present study investigated the bioaccumulation and translocation of mercury (Hg) and chromium (Cr) in Yunyan 87 flue-cured tobacco (Nicotiana tabacum) and assessed the influence of soil pH on the metal uptake by plant organs at the field scale. The study was conducted in 4 different regions selected from Sichuan Province, China: Guangyuan, Luzhou, Panzhihua, and Yibin. The results revealed that Hg highly contaminated Yibin soils at 0.29 mg kg-1 and by Cr at 147 mg kg-1, which is above the permissible limit. The levels of Hg in tobacco plant organs were predominantly in the order of leaves > root > stem. The overall trend for Cr contents in tobacco organs was in the order of root > leaves > stem. The results of an index of bioaccumulation (IBA) and translocation factor (TF) showed that the values observed in Panzhihua and Guangyuan tobacco leaves were generally higher, despite the low levels of soil contamination. The linear mixed model (LMM) demonstrated that the log of Hg IBA in tobacco organs was likely to decrease with soil pH increase, whereas the log of Cr IBA only decreased in the root but gradually increased in the aerial parts with soil pH increase. The total random variation in the log of metals' IBA due to regions indicated that for Hg, 33.42% of the variation was explained by regional differences, while for Cr, only 13% was accounted. The results suggested that Yibin and Luzhou need to correct the soil acidity if they are set to reduce Hg contamination in tobacco-growing soils. Guangyuan and Panzhihua need efforts to keep the soil pH on track to avoid high contamination levels, and effective measures of soil nutrients supply are required to produce high tobacco leaf quality free from heavy metal content. The findings of this study may be used to ascertain regional differences in heavy metals, particularly Hg and Cr uptake by tobacco plant organs, and to prevent the cultivation areas contamination through soil pH monitoring.

Salicylic acid restricts mercury translocation by activating strong antioxidant defense mechanisms in sweet pepper (Capsicum annum L.)

Mercury (Hg) availability in soil and its absorption in plants is seriously concerned for plant production and human health. Salicylic acid (SA) is one of the major plant hormones involved in plant growth and development under biotic and abiotic stress conditions. So, the experiment was designed to assess the effect of SA on sweet pepper (Capsicum annum L.) seedlings grown under different Hg toxicity concentrations. Spraying of 100 μM SA at three different Hg levels, i.e., 0 μM, 50 μM, 100 μM, and 150 μM. The maximum decrease in photosynthetic machinery, plant growth attributes (shoot length, root length, no. of leaves, fresh and dry biomass (shoot and root)), and more accumulation of Hg in leaves, roots, and fruits of sweet pepper. Additionally, SA significantly reduced the reduction in photosynthetic attributes and plant growth, and increased antioxidant enzymes (SOD, POD, and CAT) under Hg toxicity. H2O2 was found to be lower in plants treated with SA under Hg toxicity than in non-treated plants. The SA application also restricts the accumulation of Hg in sweet pepper roots, leaves, and fruits. Hg translocation in leaves and fruits was also reduced under SA. These findings provide a novel perspective on Hg accumulation in sweet pepper. They open a door to identify SA signaling pathways to clarify the mechanisms of SA inhibiting Hg accumulation in leaves and fruits.

Trophic distribution of mercury from an abandoned cinnabar mine within the Záskalská reservoir ecosystem (Czech Republic).

The distribution of mercury species was studied in all aquatic ecosystem components (i.e., water, sediment, emergent aquatic plants, invertebrates and omnivorous and piscivorous fish) of the Záskalská water reservoir (Central Bohemia, Czech Republic) which is in the vicinity of an abandoned cinnabar mine. The results indicate that the transport of mercury from the cinnabar mine is the major source of mercury in the Záskalská reservoir. The legal maximum limit (0.07μg/L) for total mercury concentration in water samples was exceeded only during rainy periods. The total mercury concentration in the surface sediments was in the range from 0.22 to 9.19mg/kg in dry matter (up to 0.2% CH3Hg+) and was sample site-specific. The dominant form of mercury in sediments was mercury sulphide (22.9-79.2%). The emergent macrophytes accumulated mercury primarily by the roots from sediments, and no significant translocation of mercury to leaves was observed. The legal maximum limit for mercury content in fish muscle (0.5mg/kg in the fresh matter) was exceeded up to 4.48 times for piscivorous fish. Hazard index values indicate a health risk concern for children and for people consuming more than 100g of fish muscle per day. Our results emphasise the need to implement legal restrictions on the consumption of piscivorous fish caught in ecosystems downstream of abandoned cinnabar mines.

Comparison of co-located ice-core and tree-ring mercury records indicates potential radial translocation of mercury in whitebark pine

Tree-ring records are a potential archive for reconstructing long-term historical trends in atmospheric mercury (Hg) concentrations. Although Hg preserved in tree rings has been shown to be derived largely from the atmosphere, quantitative relationships linking atmospheric concentrations to those in tree rings are limited. In addition, few tree-ring-based Hg records have been evaluated against co-located proxies of atmospheric Hg deposition or direct atmospheric measurements. Here we develop long-term Hg records extending from 1800 to 2018 CE using cores collected from two stands of whitebark pine located near the Upper Fremont Glacier in the Wind River Range, Wyoming, where a long-term record of atmospheric Hg deposition previously was developed from an ice core. The tree ring record showed that Hg concentrations increased beginning in 1800 CE to a broad peak centered at ~1960 CE, before decreasing to present, generally paralleling the ice-core record of Hg deposition. The exact timing and magnitude of the Hg increases in the trees, however, is offset earlier relative to the ice-core record. These discrepancies potentially arise from biotic processes that impact Hg uptake and preservation in whitebark pine, and results from an advection-diffusion model indicate that the temporal differences are consistent with radial movement of Hg within the trees. The forms of atmospheric Hg and seasonality may also impact the Hg record preserved by each archive, but are less likely to affect long-term trends. Further work is needed to assess radial Hg translocation in more controlled studies with larger sample sizes.

Effect of lactic acid bacteria on mercury toxicokinetics

The capacity of two LAB strains to inhibit inorganic [Hg(II)] and organic (methyl-Hg; MeHg) mercury translocation through monolayers of co-cultures of NCM460 and HT29-MTX colonic cells was evaluated. Lactobacillus casei BL23 and Lactobacillus acidophilus ATCC4356 reduced the permeability of Hg(II) and MeHg from aqueous solutions through NCM460/HT29-MTX monolayers (20–94% reduction). However, assays using the bioaccessible (soluble) Hg fraction obtained by in vitro gastrointestinal digestion of Hg-contaminated swordfish only showed a reduction (42%) with the BL23 strain. In vivo experiments carried out in mice receiving an acute dose of Hg(II) or MeHg (0.5 mg/kg body weight/day) with or without lactobacilli resulted in significant decreases of the bioavailability of MeHg with both strains and increased excretion of Hg in feces after treatment with the lactobacilli. However, Hg(II) bioavailability or excretion was not affected. Hg accumulation in liver and kidney remained similar in LAB-treated or non-treated animals. This is the first study of the impact of LAB on Hg(II) and MeHg toxicokinetics and shows that some LAB strains have potential to diminish MeHg bioavailability. Furthermore, it has established the basis for new studies on the protective effect of LAB under conditions resembling subchronic and chronic Hg exposures.

Mercury accumulation plant Cyrtomium macrophyllum and its potential for phytoremediation of mercury polluted sites

Cyrtomium macrophyllum naturally grown in 225.73 mg kg−1 of soil mercury in mining area was found to be a potential mercury accumulator plant with the translocation factor of 2.62 and the high mercury concentration of 36.44 mg kg−1 accumulated in its aerial parts. Pot experiments indicated that Cyrtomium macrophyllum could even grow in 500 mg kg−1 of soil mercury with observed inhibition on growth but no obvious toxic effects, and showed excellent mercury accumulation and translocation abilities with both translocation and bioconcentration factors greater than 1 when exposed to 200 mg kg−1 and lower soil mercury, indicating that it could be considered as a great mercury accumulating species. Furthermore, the leaf tissue of Cyrtomium macrophyllum showed high resistance to mercury stress because of both the increased superoxide dismutase activity and the accumulation of glutathione and proline induced by mercury stress, which favorited mercury translocation from the roots to the aerial parts, revealing the possible reason for Cyrtomium macrophyllum to tolerate high concentration of soil mercury. In sum, due to its excellent mercury accumulation and translocation abilities as well as its high resistance to mercury stress, the use of Cyrtomium macrophyllum should be a promising approach to remediating mercury polluted soils.

Translocation of mercury from substrate to fruit bodies of Panellus stipticus, Psilocybe cubensis, Schizophyllum commune and Stropharia rugosoannulata on oat flakes

The cultivation and fructification of 15 saprotrophic and wood-rotting fungal strains were tested on three various semi-natural medium. The formation of fruit bodies was observed for Panellus stipticus, Psilocybe cubensis, Schizophyllum commune and Stropharia rugosoannulata in the frame of 1–2 months. Mercury translocation from the substrate to the fruit bodies was then followed in oat flakes medium. Translocation was followed for treatments of 0, 1.25, 2.5, 5, 10 and 20ppm Hg in the substrate. All four fungi formed fruit bodies in almost all replicates. The fruit body yield varied from 0.5 to 15.3g dry weight. The highest bioconcentration factor (BCF) of 2.99 was found for P. cubensis at 1.25ppm Hg. The BCF decreased with increasing Hg concentration in the substrate: 2.49, 0, 2.38, 1.71 and 1.82 for P. stipticus; 3.00, 2.78, 2.48, 1.81 and 2.15 for P. cubensis; 2.47, 1.81, 1.78, 1.07 and 0.96 for S. commune; and 1.96, 1.84, 1.21, 1.71 and 0.96 for S. rugosoannulata. The Hg contents in the fruit bodies reflected the Hg contents in the substrate; the highest contents in the fruit bodies were found in P. cubensis (43.08±7.36ppm Hg) and P. stipticus (36.42±3.39ppm).

TRANSLOKASI MERKURI (HG) PADA DAUN TANAMAN BAYAM DURI (AMARANTHUS SPINOSUS L) DARI TANAH TERCEMAR

Research about mercury translocation (Hg) into the leaf of Amaranthus Spinosus L from polluted soil has been carried out. The research aim was to know influences of remediation time on the abilty of mercury absorptions , knowing the concentration of mercury distribution in the leaf of A. spinosus L and abilty of A . spinosus L as hyperacumulator plant to the mercury. Remediation times used 14 days, 21 days and 42 days. The consentration of Mercury on the growth medium were 25 ppm, 50 ppm, 75 ppm, and 100 ppm. The result showed that the time of maximum absorptions were at remediation times of 14 days by mercury acumulation of 70.6901 mg/kg DM (Dry Measure). This value indicated that A . spinosus L. is hyperacumulator to the mercury and it have a potential as phytoremediator on the area that contaminated by mercury.

Metal interactions in mice under environmental stress

A metallomic analytical approach based on the use of size exclusion chromatography coupled to ICP-MS has been used to obtain metal profiles related to overexpression or inhibition of metal-binding biomolecules, which is connected to exposure experiment of laboratory mice Mus musculus to toxic metals, such as Cd, Hg and As. Exposure to Cd induces the formation of Cd-metallothionein in liver that reveals the protective role of this organ; however, exposure to Hg reduces the intensity of the peak associated to Cu-superoxide dismutase (Cu-SOD) while Hg-SOD peak increases, which suggests the competence of Cu and Hg for the active sites of SOD in liver that causes mercury translocation to kidney, in which the concentration of Hg as Hg-metallothionein increases drastically to be excreted by urine. It has been also observed the protective effect of selenium on mercury toxicity in blood plasma, which produces decreasing of the intensity of Se-protein in plasma with Hg exposure and correlative increases of Hg-albumin that transport mercury to kidney for excretion. Finally, arsenic exposure provokes the accumulation of small metabolites of this element, such as dimethylarsenic and monomethylarsenic for excretion. The application of the metallomic approach to liver extracts from free-living mouse Mus spretus shows the overexpression of Cu, Zn and Cd-peaks at 7kDa (related to metal-metallothionein) in environmental contaminated sites, as well as the increase of peaks related to Cu- and Zn-SOD and Zn-albumin. However, in kidney, can be checked the presence of high concentration of arsenic small metabolites in contaminated areas, similarly to results found in exposure experiments. In addition, the application of a metabolomic approach based on direct infusion mass spectrometry to organ extracts (liver, kidney and serum) from mice (M. musculus) exposed to arsenic reveals important metabolic changes related to antioxidative activity, membrane cell damage, energy metabolism and arsenic elimination. Similar results were obtained from free-living mouse (M. spretus) from areas contaminated with arsenic. The integration of metallomics and metabolomics results provides a more comprehensive evaluation about the biological response in exposure experiments to toxic metals as well as in environmental assessment of contamination.

Concentration, distribution, and translocation of mercury and methylmercury in mine-waste, sediment, soil, water, and fish collected near the Abbadia San Salvatore mercury mine, Monte Amiata district, Italy

The distribution and translocation of mercury (Hg) was studied in the Paglia River ecosystem, located downstream from the inactive Abbadia San Salvatore mine (ASSM). The ASSM is part of the Monte Amiata Hg district, Southern Tuscany, Italy, which was one of the world’s largest Hg districts. Concentrations of Hg and methyl-Hg were determined in mine-waste calcine (retorted ore), sediment, water, soil, and freshwater fish collected from the ASSM and the downstream Paglia River. Concentrations of Hg in calcine samples ranged from 25 to 1500μg/g, all of which exceeded the industrial soil contamination level for Hg of 5μg/g used in Italy. Stream and lake sediment samples collected downstream from the ASSM ranged in Hg concentration from 0.26 to 15μg/g, of which more than 50% exceeded the probable effect concentration for Hg of 1.06μg/g, the concentration above which harmful effects are likely to be observed in sediment-dwelling organisms. Stream and lake sediment methyl-Hg concentrations showed a significant correlation with TOC indicating considerable methylation and potential bioavailability of Hg. Stream water contained Hg as high as 1400ng/L, but only one water sample exceeded the 1000ng/L drinking water Hg standard used in Italy. Concentrations of Hg were elevated in freshwater fish muscle samples and ranged from 0.16 to 1.2μg/g (wet weight), averaged 0.84μg/g, and 96% of these exceeded the 0.3μg/g (methyl-Hg, wet weight) USEPA fish muscle standard recommended to protect human health. Analysis of fish muscle for methyl-Hg confirmed that >90% of the Hg in these fish is methyl-Hg. Such highly elevated Hg concentrations in fish indicated active methylation, significant bioavailability, and uptake of Hg by fish in the Paglia River ecosystem. Methyl-Hg is highly toxic and the high Hg concentrations in these fish represent a potential pathway of Hg to the human food chain.

Metallothionein expression in chloroplasts enhances mercury accumulation and phytoremediation capability

Genetic engineering to enhance mercury phytoremediation has been accomplished by expression of the merAB genes that protects the cell by converting Hg[II] into Hg[0] which volatilizes from the cell. A drawback of this approach is that toxic Hg is released back into the environment. A better phytoremediation strategy would be to accumulate mercury inside plants for subsequent retrieval. We report here the development of a transplastomic approach to express the mouse metallothionein gene (mt1) and accumulate mercury in high concentrations within plant cells. Real-time PCR analysis showed that up to 1284 copies of the mt1 gene were found per cell when compared with 1326 copies of the 16S rrn gene, thereby attaining homoplasmy. Past studies in chloroplast transformation used qualitative Southern blots to evaluate indirectly transgene copy number, whereas we used real-time PCR for the first time to establish homoplasmy and estimate transgene copy number and transcript levels. The mt1 transcript levels were very high with 183,000 copies per ng of RNA or 41% the abundance of the 16S rrn transcripts. The transplastomic lines were resistant up to 20 μm mercury and maintained high chlorophyll content and biomass. Although the transgenic plants accumulated high concentrations of mercury in all tissues, leaves accumulated up to 106 ng, indicating active phytoremediation and translocation of mercury. Such accumulation of mercury in plant tissues facilitates proper disposal or recycling. This study reports, for the first time, the use of metallothioneins in plants for mercury phytoremediation. Chloroplast genetic engineering approach is useful to express metal-scavenging proteins for phytoremediation.

Bioaccumulation and physiological effects of mercury in Pteris vittata and Nephrolepis exaltata

Anatomical, histochemical and biochemical approaches were used to study mercury uptake and phytotoxicity as well as anti-oxidative responses in two species of ferns [Chinese brake fern (Pteris vittata) and Boston fern (Nephrolepis exaltata)], grown in a hydroponic system. The roots of both cultivars accumulated large amounts of mercury, but exhibited limited mercury translocation to shoots. Mercury exposure led to more pronounced phytotoxicity accompanied by stronger oxidative stress in the shoots of P. vittata than in N. exaltata. N. exaltata established a more effective anti-oxidative system against mercury-induced oxidative stress than did P. vittata. The activity of anti-oxidative enzymes (superoxide dismutase, catalase and glutathione reductase) increased. The reduced ascorbate (ASA) and oxidized ascorbate (DHA) are regulated. Mercury exposure led to an increase in the concentration of glutathione (GSH) in both fern species. The present study suggests that N. exaltata is more tolerant to mercury exposure than P. vittata, which has been also reported to be more tolerant to arsenic exposure. N. exaltata may thus have potential for phytostabilization of soils or phytofiltration of waste water contaminated with mercury.

MERCURY CYCLING IN LITTER AND SOIL IN DIFFERENT FOREST TYPES IN THE ADIRONDACK REGION, NEW YORK, USA

The fate of mercury in decomposing leaf litter and soil is key to understanding the biogeochemistry of mercury in forested ecosystems. We quantified mercury dynamics in decomposing leaf litter and measured fluxes and pools of mercury in litterfall, throughfall, and soil in two forest types of the Adirondack region, New York, USA. The mean content of total mercury in leaf litter increased to 134% of its original mass during two years of decomposition. The accumulation pattern was seasonal, with significant increases in mercury mass during the growing season (+4.9% per month). Litterfall dominated mercury fluxes into the soil in the deciduous forest, whereas throughfall dominated fluxes into the coniferous forest. The increase in mercury mass in decomposing deciduous litter during the growing season was greater than could be accounted for by throughfall inputs during the growing season (P < 0.05), suggesting translocation of mercury from the soil to the decomposing deciduous litter. This internal recycling mechanism concentrates mercury in the organic horizons and retards transport through the soil, thereby increasing the residence time of mercury in the forest floor. A mass balance assessment suggests that the ultimate fate of mercury in the landscape depends upon forest type and associated differences in the delivery and incorporation of mercury into the soil. Our results show that incorporation of mercury into decaying leaf litter increases its residence time in the landscape and may further delay the recovery of surface waters, fish, and associated biota following control of mercury emissions to the atmosphere.

The impact of sewage irrigation on the uptake of mercury in corn plants ( Zea mays) from suburban Beijing

The impact of sewage irrigation on the uptake and translocation of mercury (Hg) in corn plants ( Zea mays) was investigated. Corn plants were harvested the same day from two nearby fields in suburban Beijing, one irrigated historically with sewage effluent, and one irrigated solely with groundwater. Hg content was analyzed in the soil, roots and stems, while percent moisture and soil organic content were analyzed in the soil samples. The concentration of Hg in the soil and roots, and the soil organic content were not significantly different between the two fields, despite the historic practice of sewage irrigation. Hg content in roots was positively correlated with soil Hg concentration ( r = 0.95, n = 6). The transfer coefficients between roots and stems were significantly higher in the control site (control: 2.06, sewage-irrigated: 0.44, p < 0.05), indicating that the barrier effect of the roots was not consistent between the two fields.

Physiological Responses of Transgenic merA-TOBACCO (Nicotiana tabacum) to Foliar and Root Mercury Exposure

Plants expressing a modified bacterial mercury reductase, merA, are highly resistant to Hg(II) toxicity as a result of the enzymatically catalyzed electrochemical reduction of Hg(II) to the much less toxic and volatile Hg(0). merA expression may allow plants to manifest a suite of responses to mercury exposure, making them more capable than wild-type plants of interacting with and removing mercury from contaminated soil or water. We have engineered merA-expressing Nicotiana tabacum (tobacco) as a model plant for examining these responses. Mercury resistance was demonstrated by germinating and growing merA tobacco seeds on semi-solid medium spiked with a HgCl2 concentration acutely toxic to wild-type plants. On similar growth medium, merA plant roots penetrated a highly concentrated, localized Hg(II) zone of HgS (cinnibar) more readily than wild-type roots. In hydroponic medium spiked with HgCl2, merA plants maintained higher evapotranspiration activity than wild-type plants. The ability of merA Hg(II)-reductive activity to counter typical plant-catalyzed Hg(0) oxidation to Hg(II) was demonstrated by a lower net foliar absorption of atmospheric Hg(0) than wild-type plants. Mercury translocation through merA plants was examined through reciprocally grafted merA and wild-type tobacco grown on HgCl2-spiked hydroponic medium. Elevated mercury concentrations in wild-type shoots grafted to merA roots suggest the vertical movement of mercury within merA tissues or plants may be facilitated by dynamic balance between native Hg(0) oxidation and MerA-catalyzed Hg(II) reduction. These experiments demonstrate that merA-engineered tobacco plants display an array of tissue-level and whole-plant attributes which should allow for more efficient mercury extraction and processing compared to the wild-type.

Mercury translocation in and evaporation from soil. III. quantification of evaporation of mercury from podzolized soil profiles treated with Hg Cl

Abstract Mercury evaporation from undisturbed iron‐humus podzol lysimeters was measured over 3 months after treatment with HgCl2 spiked with radioactive 203Hg. The relative evaporation rate from HgCl2 treated soils followed the sum of two exponential functions. Because evaporation asymptotically approaches zero with time, the integral of the fit curve represents the evaporative loss in percent of atmospheric deposition. For the soil investigated, about 5% of atmospheric Hg deposition was reemitted into the atmosphere. It is hypothesized that mercury evaporation can decrease the leaching of mercury in and from soil significantly; this effect is probably increasing with decreasing rain acidity or soil acidity. Mercury deposited as soluble salt remains susceptible to reemission to air for 300 d after incorporation into the soil matrix. Indications are found that Hg evaporation from soils in geological background areas predominantly derives from recent atmospheric Hg deposition and not from geological sources.

Effect of selenite and selenate on plant uptake and translocation of mercury by tomato (Lycopersicum esculentum)

Pot culture experiments containing sand and soil, at two levels of mercury (2 and 5 μg mL-1) added through irrigation with increasing supplementation of selenium (selenite and selenate) led to a decrease in the uptake of mercury by tomato (Lycopersicum esculentum) plant. Both the forms of selenium (selenite and selenate) were found to be equally effective in reducing the mercury accumulation by plants. The observed reduction pattern of mercury accumulation in plant tissues has been discussed on the basis of the formation of insoluble HgSe complex in soil-root environment.

Mercury translocation in and evaporation from soil. I. soil lysimeter experiments with203Hg‐radiolabeled compounds

Abstract Due to a considerable increase of anthropogenic mercury emissions, the mercury load of many soils has risen significantly, for instance in northern Europe. Understanding the fate of mercury in soils is a prerequisite for assessing the effects of ecotoxicological concern. This paper presents a method for obtaining qualitative and quantitative information about mercury translocation in and evaporation from soil. Soil lysimeters were treated with 203Hg‐labeled HgCl2 and CH3HgCl and irrigated with artificial rain. It was demonstrated that the leaching of Hg can be detected by measuring the relative y‐activity throughout the soil profile by means of Na(TI)I detectors. Furthermore, the set‐up was designed to allow detection of Hg volatilization from soil by using traps of iodized charcoal, followed by a potassium peroxodisulfate solution and measuring the γ‐activity. The amount of radioactive Hg in soil leachate was measured by a Na(Tl)I well‐type detector after upconcentration. The determination of mo...

Mercury translocation in and evaporation from soil. II. Evaporation of mercury from podzolized soil profiles treated with HgCl2and CH3HgCl

Abstract Mercury evaporation from soil columns of an iron humus podzol treated with various amounts of HgCl2 and CH3HgCl was measured over 3500 h. The effects of rain acidity, rain duration, and rain intensity were investigated. Hg evaporation from CH3HgCl‐treated soil columns seems to be a biologically determined process. Hg evaporation from HgO2‐treated soil probably is mainly an abiotic process, following a pseudo first‐order reaction with rapidly decreasing evaporation rate due to a decreasing amount of available Hg. The added Hg compounds were transformed to highly volatile Hg0 and/or (CH3)2Hg. The Hg evaporation rate decreased with increasing rain acidity, which may cause accumulation of Hg in the soil. No effects of rain duration and rain intensity were found.