Clinical value of the expression levels of tumor protein D52 and miR-133a on prognosis assessment of pancreatic cancer surgery.

Objective: To investigate the clinical value of the expression levels of tumor protein D52 (TPD52) and miR-133a on the prognosis assessment of pancreatic cancer surgery. Methods: This was a retrospective study. Ninety-seven patients who underwent radical surgery for pancreatic cancer in Cangzhou Central Hospital from January 2018 to January 2022 were selected and divided into four groups: TPD52 high expression group, TPD52 low expression group, miR-133a high expression group and miR-133a low expression group. The relationship between the expression levels of TPD52 and miR-133a and the clinicopathological features of patients with pancreatic cancer was analyzed. The COX regression model was used to analyze the risk factors affecting the prognosis of patients with pancreatic cancer. Results: The high expression rate of TPD52 and the low expression rate of miR-133a in pancreatic cancer tissues were higher than those in normal paracancerous tissues(P<0.05). Based on the comparison of prognosis and survival, the median survival time of patients with high expression of TPD52 and low expression of miR-133a was lower than that of patients with low expression of TPD52 and high expression of miR-133a, with a statistically significant difference(P<0.05). Moreover, multivariate Cox regression analysis showed that low differentiation of pancreatic cancer, III-IV stage of TNM, high expression of TPD52, as well as low expression of miR-133a were independent risk factors for postoperative survival of patients with pancreatic cancer(P<0.05). Conclusion: TPD52 is expressed at a high level whereas miR-133a at a low level in pancreatic cancer tissues, both of which together with low differentiation of pancreatic cancer and III-IV stage of TNM constitute independent risk factors affecting the surgical prognosis of patients with pancreatic cancer.

Adsorption and desorption of Hg(II) by four aged microplastics and its effects on gaseous elemental mercury production in seawater.

Microplastics (MPs) weather after entering the environment gradually, and the interaction with metal ions in the aqueous environment has received extensive attention. However, there are few studies on Hg(Ⅱ), especially the effect of MPs on the release of Hg0(DEM) in water after entering the aqueous environment. In this study, four types of MPs (PP, PE, PET, PVC) were selected to study the adsorption and desorption behavior of Hg(Ⅱ) after photoaging and to explore the influence of MPs on the release of DEM in seawater under different lighting conditions. The results showed that the specific surface area, negative charges, and oxygen-containing functional group of MPs increased after aging. The adsorption capacity of aged MPs for Hg(Ⅱ) was significantly improved, which was consistent with the pseudo-first-order and pseudo-second-order model, indicating that the adsorption process was a chemical and physical adsorption. The fitting results of the in-particle diffusion model indicated that the adsorption was controlled by multiple steps. Hg(Ⅱ) was easier to desorb in the simulated gastric fluid environment. Because the aged MPs had the stronger binding force to Hg(Ⅱ), their desorption rate is lower than new MPs. Under visible light and UVA irradiation, MPs inhibited the release of Hg0. Under UVA, the mass of DEM produced in seawater with aged PE and PVC was higher than that of new PE and PVC. The aged PE and PVC could produce more ·O2-, which was conducive to the reduction of mercury. However, in UVB irradiation, the addition of MPs promoted the release of DEM, and ·O2- also played an important contribution in affecting the photochemical reaction of mercury. Therefore, the presence of aged MPs will significantly affect the water-air exchange of Hg in water. Compared with new MPs, aged MPs improved the contribution of free radicals in Hg transformation by releasing reactive oxygen species. This study extends the understanding of the effects of MPs on the geochemical cycle of Hg(Ⅱ) in seawater, better assesses the potential combined ecological risks of MPs and Hg(Ⅱ), and provides certain guidance for the pollution prevention and control of MPs.

Speciation and source changes of atmospheric arsenic in Qingdao from 2016 to 2020 - Response to control policies in China.

Arsenic (As) is a toxic pollutant in the atmosphere. The atmospheric As concentration is high over the East Asian continent. At present, there is less research on the long-term trend of atmospheric arsenic pollution, which is not conducive to understanding its behavior. Total suspended particulate matter (TSP) samples were collected in Qingdao in autumn and winter from 2016 to 2020 to analyze total arsenic (TAs), As(V) and As(III). The interannual variation patterns, influencing factors and health risks of arsenic concentrations in aerosols were discussed. The results showed that As(V) is the dominant species of arsenic in aerosols. The average concentration of TAs gradually decreased and the proportion of As(III) increased during autumn and winter from 2016 to 2020. The levels of TAs, As(V) and As(III) in aerosols increased during the heating period and on polluted days. Negative correlation between TAs/TSP and TSP indicated that higher concentrations of TSP in the atmosphere would reduce the content of TAs in particulate matter. The increase of secondary aerosol particles played a dilution effect. Mobile source emissions, biomass and coal combustion were main sources of atmospheric arsenic. The distribution range of large potential sources of atmospheric arsenic decreased from 2016 to 2020, and concentrated, mainly in parts of Shandong province and its offshore areas. Local sources contributed the most to atmospheric arsenic pollution in Qingdao in autumn and winter. TAs, As(V) and As(III) posed a low non-carcinogenic risk and a negligible carcinogenic risk to adults and children. This study reveals the influence of strict air pollution control policies on the speciation and source of arsenic in aerosols.

Identification of the prognostic, diagnostic, and biological significance of the miR-148a-3p/cathepsin A axis in hepatocellular carcinoma.

A comprehensive analysis of the prognostic, diagnostic, and biological significance of miR-148a-3p and cathepsin A (CTSA) in hepatocellular carcinoma (HCC) was performed using bioinformatics algorithms with The Cancer Genome Atlas (TCGA) data. miR-148a-3p and CTSA gene expression in HCC tissues and nontumor specimens was analyzed using TCGA database with R software. CTSA staining analysis was validated using the Human Protein Atlas database. Prognostic, diagnostic, gene set enrichment, Gene Ontology, Kyoto Encyclopedia of Genes and Genomes, and immune infiltration analyses were implemented using the TCGA database with R software. Based on TCGA data and our cohort populations, CTSA expression was significantly elevated in HCC tissues compared with nontumor specimens. A significant negative correlation between miR-148a-3p and CTSA was observed in the TCGA data and our cohort population. Mechanistically, CTSA was a direct gene target of miR-148a-3p. Both CTSA and miR-148a-3p could serve as prognostic and diagnostic indicators in HCC. miR-148a-3p expression was significantly and negatively correlated with the StromalScore, ImmuneScore, and ESTIMATEScore in patients with liver cancer. miR-148a-3p mimic-mediated apoptosis and the inhibition of HCC cell growth and migration were counteracted by CTSA overexpression. The miR-148a-3p/CTSA axis was implicated in immune cell infiltration and carcinogenesis of HCC. miR-148a-3p and CTSA might be prospective molecular targets to enhance the potency of immunotherapy in HCC.

Magnetic Resonance Imaging and Serum AFP-L3 and GP-73 in the Diagnosis of Primary Liver Cancer.

Objective: To investigate the combined application value of magnetic resonance imaging (MRI) combined with serum alpha-fetoprotein (AFP)-L3 and Golgi protein (GP)-73 in the diagnosis of primary liver cancer. Methods: The data of 200 patients with suspected liver cancer admitted to our hospital from February 2020 to February 2021 were retrospectively analyzed, and they were randomly divided into an experimental group and a control group, with 100 cases in each group. The experimental group received a combined detection of MRI with serum AFP-L3 and GP-73, and the control group adopted traditional diagnostic methods (spiral computed tomography and serum AFP). The diagnostic yields of the two groups were compared. Surgical resection was performed after the diagnosis of primary liver cancer, and the correlation between the efficacy and combined detection of MRI with serum AFP-L3 and GP-73 levels was analyzed. Results: The two groups presented comparable general information (P >0.05). The surgical results showed 160 cases of primary liver cancer, including 75 cases in the experimental group and 85 cases in the control group, and 40 cases of benign liver lesions. The diagnostic accuracy of the experimental group (73/75, 95%) was significantly higher than that of the control group (76/85, 86%) (P < 0.05). The serum levels of AFP-L3, GP-73, and AFP in patients with primary liver cancer were remarkably decreased after surgery (P < 0.001). The preoperative and postoperative AFP-L3, GP-73, and AFP levels of patients with primary liver cancer were significantly higher than those of patients with benign liver lesions. The AUC (95% CI) for the combined detection of MRI and serum AFP-L3 and GP-73 levels in patients with surgically confirmed primary liver cancer was 0.747 (0.619-0.874). Conclusion: MRI combined with serum AFP-L3 and GP-73 presents favorable diagnostic efficiency in the diagnosis of primary liver cancer, which is worthy of clinical application.

Variation of mercury fractionation and speciation in municipal sewage treatment plant: effects of mercury on the atmosphere.

The speciation of mercury in various processing units of sewage treatment in autumn and winter were studied to understand the conversion and fate of mercury. The results show that the average concentrations of total mercury (THg) in the influent were 130.5 ± 69.8 ng/L and 231.3 ± 107.2 ng/L in autumn and winter, respectively, and the particulate mercury was the main speciation (accounting for 59.3% and 86.9%, respectively). The proportion of dissolved mercury increased after treatment, and the total removal efficiencies of THg were 78.9% and 90.8%, respectively. The release of mercury into the atmosphere during wastewater treatment was studied for the first time. The dissolved gaseous mercury levels in the influent in autumn and winter were 0.60 ± 0.40 ng/L and 0.34 ± 0.21 ng/L, respectively. The average gaseous element mercury concentration in aerobic tank air was 6.34 ± 0.49 ng/m3. The estimated mercury from aeration was 6.4 kg per year in China. The dissolved gaseous mercury will be released to the air if the sewage treatment plant is open-air. Closed sewage treatment and collection of waste gas treatment can reduce the influence of released mercury. Mercury releases into the atmosphere in the process of sewage treatment are one of the fates of mercury in sewage. Closed sewage treatment and collection of waste gas treatment are necessary to reduce the influence of released mercury. The reactive mercury levels in the influents of autumn and winter were 1.28 ± 0.49 ng/L and 1.96 ± 0.43 ng/L, and these levels account for a small proportion of THg, only 1.7% and 0.8%. Hg2+ were released by the degradation of organic matter in the secondary biological treatment. The THg levels in dehydrated sludge were higher than those in biochemical sludge but lower than the maximum limit of THg in agricultural sludge.

Behaviour and distribution of arsenic in seawater and suspended particulate matter in the adjacent area of the Changjiang Estuary during summer and autumn.

Water and suspended particulate matter (SPM) were collected from the Changjiang Estuary and its adjacent areas during summer (July) and autumn (October) to study the distributions and partitioning of arsenic. The dissolved arsenic (DAs) and particulate arsenic (PAs) concentration distributions were strongly affected by inputs from riverine discharge and water masses in the East China Sea, generally exhibiting a decreasing trend from inshore to offshore. The DAs concentration was higher in the surface water due to the influence of seawater stratification in summer, but it was not obvious in autumn. DAs and PAs concentrations in the estuary were significantly higher in autumn than in summer. Seasonal variations in arsenic were due to seasonal differences in riverine input (mainly the Changjiang River) and the intrusion of water masses. PAs showed a positive correlation with both SPM and turbidity. The highest PAs concentration was observed in the northern Changjiang Estuary affected by the YSCC, with higher turbidity during autumn. The higher concentration of PAs in autumn was affected by the high SPM input and resuspension of sediment. The water-particulate distribution coefficient of As in summer showed an increasing tendency with salinity, which might be caused by the decrease in the diameter of suspended particles in the open sea.

[Distribution Characteristics and Seasonal Variations of Arsenic in Atmospheric Aerosols over the Yellow Sea and Bohai Sea].

Marine aerosol samples of total suspended particulates (TSP) were collected in winter (2017) and spring and summer (2018) over the Yellow Sea and Bohai Sea. These samples were analyzed for total arsenic (As), As(Ⅴ) and As(Ⅲ), and water soluble ions to investigate the distribution and seasonal variation of As in atmospheric aerosols, as well as the dry deposition flux. Results showed that As concentrations in winter, spring, and summer were 6.6, 5.5, and 4.4 ng·m-3, respectively. The highest As concentrations occurred in the winter. Obvious differences in the spatial distribution of As were observed in different seasons. The highest concentrations of As were observed over the Bohai Sea in winter and the northern Yellow Sea in spring, with an average of 8.8 and 11.3 ng·m-3, respectively. As concentrations exhibited a relatively uniform spatial pattern in summer over the Yellow Sea and Bohai Sea, which may have been affected by the different sources of As. As(Ⅴ) was the main species of As, while As(Ⅴ)/As(Ⅲ) ratios were 0.41 in winter and 0.21 in summer, respectively. Average As/TSP ratios in the winter, spring, and autumn were 95.4, 83.9, and 81.4 µg·g-1, respectively. Obviously higher As/TSP ratios, indicating higher intensity, occurred in winter. Air masses carry pollutants released over the Bohai Rim Region by the winter monsoon, resulting in higher As concentrations in winter. In summer, As concentrations are also higher, because air masses bring pollutants to the southeast coastal economic zone via the northeast monsoon. In spring, most air masses arriving in this region originate from Siberia and the southeast ocean with high rate, resulting in lower As concentrations. The significant correlation between K+/TSP and As/TSP (r=0.78, P<0.05) in winter indicates that As is affected by the combustion of land biomass. No significant correlation in summer reveals the difference in As sources between winter and summer. The dry deposition flux of As over the Yellow Sea and Bohai Sea was 1.15 µg·(m2·d)-1 in winter, 0.77 µg·(m2·d)-1 in spring, and 0.97 µg·(m2·d)-1 in summer, with an annual mean value of 0.95 µg·(m2·d)-1.

Long noncoding RNA TSLNC8 enhances pancreatic cancer aggressiveness by regulating CTNNB1 expression via association with HuR.

Pancreatic cancer (PC) is one of the most lethal malignancies worldwide. Tumor suppressor long noncoding RNA on chromosome 8p12 (TSLNC8) is a newly identified long noncoding RNA (lncRNA) and play an important role in human cancers. However, the function and molecular mechanism of TSLNC8 in PC progression remain to be elucidated. Our results showed a significant increase of TSLNC8 expression in PC tissues and cell lines. Upregulation of TSLNC8 expression in PC tissues was closely correlated with TNM stage, distant and lymph node metastasis, and poor prognosis of PC patients. Functional experiments demonstrated that TSLNC8 promoted PC cells proliferation and invasion in vitro, and enhanced PC growth and metastasis in vivo. Mechanistically, TSLNC8 associated with HuR, promoted the binding of HuR with CTNNB1 mRNA and increased the stability of CTNNB1 mRNA, thus activating WNT/ß-catenin signaling pathway. Taken together, our present study revealed that oncogenic lncRNA TSLNC8 positively regulate PC growth and metastasis via HuR-mediated mRNA stability of CTNNB1, extending the understanding of PC pathogenesis regulated by lncRNAs.

FXYD6 overexpression in HBV-related hepatocellular carcinoma with cirrhosis.

OBJECTIVE: The aim of this study was to investigate the expression of FXYD domain-containing ion transport regulator 6 (FXYD6) mRNA and protein in hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC) tissues with cirrhosis, the corresponding paracancerous tissues and the normal liver tissues, and to explore the clinical significance of FXYD6 expression in HBV-related HCC with cirrhosis. METHODS: The FXYD6 mRNA and protein were examined by semi-quantitative reverse transcription polymerase chain reaction and immunohistochemistry, respectively. RESULTS: The FXYD6 mRNA in HBV-related HCC tissues was significantly higher than that in the cirrhosis tissues or that in the normal liver tissues. The positive expression rate of FXYD6 protein was statistically higher in HBV-related HCC tissues than that in HBV-related cirrhosis or that in normal liver tissues. There was no significant correlation between the expression of FXYD6 protein and gender, age, histological differentiation, tumor diameter, tumor number, integrity of tumor capsule or not and alpha fetoprotein (AFP) concentration in serum, but the protein expression was associated with microvascular invasion, pathological stage, and early recurrence after operation within 1 year. CONCLUSION: FXYD6 might be involved in hepatocyte carcinogenesis and tumor progression in HBV-related HCC with cirrhosis and indicated a poor prognosis.

Increased expression of insulin-like growth factor-1 receptor predicts poor prognosis in patients with hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is a lethal disease worldwide. In this study, we sought to explore the expression of insulin-like growth factor-1 receptor (IGF-1R) and its prognostic value in HCC.The expressions of IGF-1R mRNA and protein were estimated using quantitative real-time polymerase chain reaction and immunohistochemistry assays, respectively. The association between IGF-1R expression and clinicopathologic characteristic of patients with HCC was analyzed through Chi-squared test. Kaplan-Meier analysis and multivariate Cox analysis were performed to analyze prognostic value of IGF-1R in HCC.The IGF-1R was significantly upregulated in HCC tissues at both mRNA and protein levels compared with adjacent normal ones (P < .01). Its expression was associated with tumor node metastasis stage (P = .037) and lymph node metastasis (P = .027) of patients with HCC. Patients with HCC with high expression of IGF-1R had worse overall survival than those with low expression. IGF-1R might be a potential prognostic biomarker for HCC (hazard ratio [HR] = 1.912, 95% confidence interval [CI]: 1.023-3.572, P = .042).The IGF-1R expression level is upregulated in HCC tissues and may act as a prognostic biomarker for the disease.

Pollution characteristics and source difference of gaseous elemental mercury between haze and non-haze days in winter.

The distribution characteristics and sources of gaseous elemental mercury (GEM) on haze and non-haze days are still not clear. During the winter heating period in 2017, the GEM concentrations in Qingdao were studied for their differences, sources, and pollution characteristics on haze and non-haze days. The GEM concentration on haze days (2.81 ±â€¯2.23 ng/m3) was higher than that on non-haze days (1.90 ±â€¯1.21 ng/m3) and the difference was significant (p < 0.01) during the period of artificial heating. The average concentration of GEM was 2.27 ng/m3 in the heating period, but lower than that before heating (3.30 ng/m3). However, the mercury to carbon monoxide ratio (GEM/CO) on haze days was lower than that on non-haze days. The ratio of GEM/CO in this study was lower than that in other studies reported from China. There was a positive correlation between the GEM/CO ratio and the air temperature (p < 0.01), suggesting that the mercury released from the Earth's surface was important. The environmental policies of China also contributed to decrease of the GEM/CO ratio. Similar diurnal patterns appeared on both haze and non-haze days, with one GEM peak at 14:00-15:00. This pattern was different from the bimodal pattern of other atmospheric pollutants in the morning and evening rush hours and was controlled by GEM from the Earth's surface (mostly re-emission of legacy Hg) whether on haze or non-haze days. Principal component analysis showed that the contribution of GEM directly from anthropogenic sources was relatively small. The main influencing factor on haze days was air temperature. GEM concentrations showed large spatial differences in air masses from different places. The GEM concentration in air masses from southern and the western Shandong Province was higher than from the north on haze days.

Histone deacetylase inhibitor quisinostat activates caspase signaling and upregulates p53 acetylation to inhibit the proliferation of HepG2 cells.

Histone deacetylase inhibitor (HDACi) has been a major target of anticancer agents. Quisinostat (JNJ­26481585), a novel second­generation HDACi, has previously demonstrated antiproliferative activity against non­small cell lung cancer; however, the function of quisinostat in hepatocellular carcinoma (HCC) remains to be elucidated. In the present study, it was revealed that quisinostat suppressed the cell viability of HepG2 cells in vitro and in vivo. Increased cell apoptosis was observed in quisinostat­treated HepG2 cells. The underlying mechanism revealed that quisinostat treatment activates the cleavage of caspase proteins. Furthermore, quisinostat upregulated p53 acetylation at K381/K382 sites by impairing the interaction between histone deacetylase 6 and p53, which resulted in the activation of p53, and triggered cell cycle arrest at the G1 phase. Collectively, the results of the present study demonstrated the antiproliferative effect of quisinostat on HepG2 cells; these results suggest that histone deacetylase may be a promising therapeutic target of HCC.

Highly expressed UNC119 promotes hepatocellular carcinoma cell proliferation through Wnt/ß-catenin signaling and predicts a poor prognosis.

UNC119, also known as Retinal Protein 4 (HRG4) is significantly up-regulated in hepatocellular carcinoma (HCC) tissues. However, the clinical significance of UNC119 and its biological roles and associated mechanisms in HCC tumorigenesis remain unknown. In current study, quantitative real-time PCR, western bolt and immunohistochemical analyses were applied to evaluate the expression of UNC119 in HCC tissues and cell lines. The roles of UNC119 in cell proliferation, cell growth and cell cycle were analyzed by both loss- and gain-function assays in vitro and in vivo. Luciferase reporter assays and western blot were employed to investigate the mechanisms. We found that compared with normal liver, UNC119 is highly expressed in HCC tissues both in published GSE datasets and in our fresh or TMA tissues. We further found that highly expressed UNC119 is not only closely correlated with liver cirrhosis, tumor size and TNM stage but also predicts a poor prognosis of patients. Cellular function assays reveal that UNC119 promotes cell proliferation. In addition, it might through enhancing the activity of Wnt/ß-catenin signaling to promote the progression of cell cycle and ultimate promotes cell proliferation and growth. Taken together, we found that UNC119 is commonly highly expressed HCC tissues and the expression pattern makes a difference in the prognosis of patients. Furthermore, it promotes cell proliferation and growth through Wnt/ß-catenin signaling.

A temporary stent graft as a new shunt for juxtahepatic vena cava injury.

BACKGROUND: Juxtahepatic vena cava (JHC) injury is difficult to handle because of JHC injury's specific position and liver obstruction. The traditional shunt method initially appeared to be useful but ultimately failed. Simple and effective methods are needed to solve it. METHODS: Firstly, the clinical data, including the computed tomography images, of 120 patients were collected. In addition, a JHC digital model was constructed based on computed tomography images. According to the digital model data, a circulation loop simulating the blood flow in the JHC was established. Secondly, we analyzed the hemodynamics of a JHC shunt with pig blood. Finally, the new shunt was designed based on the data obtained. The shunt consists of a covered stent and transfer device and was tested. RESULTS: The JHC has a three-dimensional cylindrical structure. The mean (SD) length of the retrohepatic vena cava is 78.21 (9.83) mm, which shows correlations with the patient's age and weight (r = -0.343 and 0.271, respectively, p < 0.05). An equation is obtained as follows: retrohepatic vena cava (millimeter) = 71.23 - 0.293 × age (year) + 0.32 × weight (kilogram). The shunt diameters must be 10 mm and 12 mm to maintain the blood pressure difference Point a and Point b at approximately 3.75 mm Hg (5 cm H2O), when the flow rate is 3,000 mL/min and 5,000 mL/min, respectively. The stent graft showed effective hemostasis in tests. However, it failed when the inferior vena cava was pulled harder. CONCLUSION: A temporary stent graft as a new shunt for JHC injury has not been previously reported. It is a combination of both a traditional operation and a simple endovascular technique, which showed effective hemostasis in tests.

[Research on the mercury species in Jiaozhou Bay in spring].

In April 2010, seawater samples collected every twenty minutes in the Jiaozhou Bay were separated and determined in-situ and indoor to study mercury speciation and its daily variation and to further understand the end-result and effect of mercury on offshore environment. Results showed that dissolved element mercury (DEM) concentration of seawater ranged from 38.2 pg x L(-1) to 156 pg x L(-1), with an average value of 97.5 pg x L(-1). The highest and the lowest value appeared at around 13:00 and 17:30 respectively under the influence of tide and light intensity. DEM concentration gradually declined with depth. DEM of surface sea primarily derived from photoreduction of bivalent mercury. Dissolved mercury (DHg) concentrations ranged from 7.32 ng x L(-1) to 49.1 ng x L(-1) (average value was 13.9 ng x L(-1)), from 4.39 ng x L(-1) to 19.3 ng x L(-1) (average value was 7.94 ng x L(-1)) for dissolved reactive mercury (RHg). The maximum peaks of DHg and RHg all appeared around 13:00, due to dirty seawater carried by tidal movement in the lowest tide. The variation trend with depth of RHg and DHg concentrations was similar at different time. Under the influence of the light and water temperature, the ratio of RHg to DHg was higher in the surface water. RHg accounted for 62% of DHg, so the mercury had relatively high activity and biological availability, and contributed to the form of DEM. The methylmercury concentration was low, with an average value of 0.30 ng x L(-1), and some samples were lower than the detection limit.

[Distribution and stock of mercury in typical wetland plant in the Sanjiang Plain].

Total mercury concentration of typical wetland plant was analyzed. There were great difference in mercury content among different plants, and the order was moss > alga > carex > herb > shrub. There was a trend of increasing total Hg concentrations from vascular plants to bryophytes, and from dry to wet site. The wetland soil was the source of mercury in the air close to the ground, so it influenced the content of mercury in the plant. In different components of plants, mercury contents were in the order of dead stand > root > leaf > stem. Mercury concentration increased in initial stage and decreased in the end of the growing season. According to the mercury content and biomass, the mercury stock of plant were calculated, and it was 24.9 micrograms.m-2 in the above ground of plant in Calamagrostis angustifolia wetland and 35.8 micrograms.m-2 in Carex lasiocarpa wetland.

Distribution and speciation of mercury in the peat bog of Xiaoxing'an Mountain, northeastern China.

Most reports on mercury (Hg) in boreal ecosystems are from the Nordic countries and North America. Comparatively little information is available on Hg in wetlands in China. We present here a study on Hg in the Tangwang River forested catchment of the Xiaoxing'an Mountain in the northeast of China. The average total Hg (THg) in peat profile ranged from 65.8 to 186.6 ng g(-1) dry wt with the highest at the depth of 5-10 cm. THg in the peat surface was higher than the background in Heilongjiang province, the Florida Everglades, and Birkeness in Sweden. MethylHg (MeHg) concentration ranged from 0.16 to 1.86 ng g(-1) dry wt, with the highest amount at 10-15 cm depth. MeHg content was 0.2-1.2% of THg. THg and MeHg all decreased with the depth. THg in upland layer of soil (0-20 cm) was comparable to the peat surface, but in deeper layers THg concentration in peat was much higher than that in the forested mineral soil. THg in the peat bog increased, but MeHg decreased after it was drained. THg content in plant was different; THg contents in moss (119 ng g(-1) dry wt, n=12) were much higher than in the herbage, the arbor, and the shrubs. The peat bog has mainly been contaminated by Hg deposition from the atmosphere.

[Mercury in the peat bog ecosystem in Xiaoxing'an mountain in China].

The mercury content in Tangwang River forested catchment of Xiaoxingan Mountain in Northeast of China was studied. The average total mercury (THg) in peat profile ranged from 65.8 ng/g to 186.6 ng/g with the highest in the depth of 5-10 m. THg in the peat surface was higher than the background in Heilongjiang province, and higher than the Florida Evergrade in America and Birkeness in Sweden. MeHg ranged from 0.16 ng/g to 1.86 ng/g with the highest in the depth of 10-15 cm. MeHg was 0.2-1.2% of THg. They all decreased with the depth. There was no strong significant correlation between the THg and MeHg (p = 0.05, r = 0.28). THg in upland mor layer of soil (0-20 cm) was comparable to the peat surface (0-20 cm), but in deeper layer THg in peat was much higher than the forested mineral soil. THg in the peat bog increased, but MeHg decreased after it was drained 30 years ago. THg in plant was different, THg in the moss (119 ng/g, n = 12) was much larger than the herbage, the arbor and the shrub. The peat bog was contaminated by mercury coming from the atmosphere to some degree.

Mercury exchange at the air-water-soil interface: an overview of methods.

An attempt is made to assess the present knowledge about the methods of determining mercury (Hg) exchange at the air-water-soil interface during the past 20 years. Methods determining processes of wet and dry removal/deposition of atmospheric Hg to aquatic and terrestrial ecosystems, as well as methods determining Hg emission fluxes to the atmosphere from natural surfaces (soil and water) are discussed. On the basis of the impressive advances that have been made in the areas relating to Hg exchange among air-soil-water interfaces, we analyzed existing problems and shortcomings in our current knowledge. In addition, some important fields worth further research are discussed and proposed.