scholarly journals Distribution Trends of Cadmium and Lead in Timberline Coniferous Forests in the Eastern Tibetan Plateau

2021 ◽  
Vol 11 (2) ◽  
pp. 753
Author(s):  
Longyu Jia ◽  
Ji Luo ◽  
Peihao Peng ◽  
Wei Li ◽  
Danli Yang ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Yunnan Province ◽  
Climatic Factors ◽  
Interpolation Method ◽  
Anthropogenic Activities ◽  
Principal Component ◽  
Eastern Tibetan Plateau ◽  
Gongga Mountain ◽  
The Mean ◽  
Cadmium And Lead

The concentrations of Pb and Cd in the needles and twigs of fir and spruce collected from 26 sites in the Eastern Tibetan Plateau were measured and analyzed in this study. The mean concentrations of Cd and Pb were 0.034 and 1.291 mg/kg, respectively, in the needles and 0.101 and 2.511 mg/kg, respectively, in the twigs. These concentrations increased significantly with needle and twig age and peaked at 5 years. The twigs were significantly enriched in Pb and Cd compared with the needles. The spatial distributions of Pb and Cd were determined using the inverse-distance-weighted spatial interpolation method on the basis of the mean concentration of the elements in the needles and twigs from each site. The highest concentrations of Pb and Cd in twigs and needles were found in Yunnan Province and Gongga Mountain. They showed a tendency to decline from Yunnan Province to the northern direction, as well as from Gongga Mountain to the western area. Principal component analysis showed that Pb and Cd originated from the anthropogenic activities in this area. The mining activities and climatic factors may be the main sources of Pb and Cd in this area. Combining the HYSPLIT (The Hybrid Single-Particle Lagrangian Integrated Trajectory) model and PCA, the results implied that exterior Pb and Cd sources from Southeast Asia and the eastern developed cities in China can infiltrate the ecosystem through long-range transportation and accumulate in timberline forests, with atmospheric deposition in the Eastern Tibetan Plateau. This plateau suffers from severe Pb pollution but slight Cd contamination.

Investigation of Soil Heavy Metal in Zhehai Town Huize County Yunnan Based on GIS- Approach and Geostatistics

2012 ◽  
Vol 610-613 ◽  
pp. 3067-3074
Author(s):  
Kun Shi ◽  
Dong Sheng Li ◽  
Bi Yun Zhao
Keyword(s):  
Heavy Metals ◽  
Risk Assessment ◽  
Heavy Metal ◽  
Principal Component Analysis ◽  
Correlation Matrix ◽  
Yunnan Province ◽  
Anthropogenic Activities ◽  
Principal Component ◽  
And Cluster Analysis ◽  
Soil Area

1144 sample points were collected using PXRF from an area of 99 square kilometers soil area Zhehai town Huizhe county of Yunnan province to acquire their concentrations and possible sources, and characterize their spatial variability for risk assessment. SPSS16.0 was used to deal the raw date and eliminate the outfits and perform Multivariate analysis (correlation matrix, principal component analysis, and cluster analysis). It discriminate distinct groups of heavy metals. From the Range of the semi-variorum models, it obtained elements spatial structure and the contamination resource caused mainly by natural resource or anthropogenic activities. The result of risk assessment attained the percentage of pollution accounts for whole investigate region, which provides the reference to deal with the soil pollution.

scholarly journals Physico-chemical trends in the sediments of Agbede Wetlands, Nigeria

2017 ◽  
Vol 64 (2) ◽  
pp. 111-126
Author(s):  
Abdul-Rahman Dirisu ◽  
John Ovie Olomukoro ◽  
Ifeanyi Maxwell Ezenwa
Keyword(s):  
Alkali Metals ◽  
Anthropogenic Activities ◽  
Sediment Quality ◽  
Principal Component ◽  
Mean Values ◽  
Physico Chemical ◽  
Lotic System ◽  
The Mean ◽  
And Cluster Analysis ◽  
Chemical Trends

AbstractThis study assessed the physico-chemical status of sediments in the Agbede Wetlands with the aim to create a reference archive for the Edo North catchment and to further identify the characteristics mostly influenced by the natural and anthropogenic activities going on at the watershed. Nutrients, zinc, nickel and lead were identified to be mostly of anthropogenic origin, while alkali metals and alkaline earth metals were from both anthropogenic and natural sources. The clustering of stations 1 and 4 indicates that the sediment quality in the lentic systems was not completely excluded from the lotic system, suggesting that principal component analysis (PCA) and cluster analysis (CA) techniques are invaluable tools for identifying factors influencing the sediment quality. The mean values of the particle size distribution were in the following order across the ecosystems: sand (61.86–80.53%) > silt (9.75–30.34%) > clay (7.83–13.89%). The contamination of the water bodies was primarily derived from agricultural run-offs and through geochemical weathering of the top soils. Therefore, our analysis indicates that the concentrations of cations, anions and nutrients in the sediments of the lotic and lentic ecosystems in Agbede Wetlands are not at an alarming level.

scholarly journals Cryoconite on a glacier on the north-eastern Tibetan plateau: light-absorbing impurities, albedo and enhanced melting

2019 ◽  
Vol 65 (252) ◽  
pp. 633-644 ◽  
Author(s):  
YANG LI ◽  
SHICHANG KANG ◽  
FANGPING YAN ◽  
JIZU CHEN ◽  
KUN WANG ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Mass Balance ◽  
Glacier Mass Balance ◽  
Eastern Tibetan Plateau ◽  
The North ◽  
Ice Surface ◽  
Northern Tibetan Plateau ◽  
North Eastern ◽  
The Mean

ABSTRACTCryoconite is a dark-coloured granular sediment that contains biological and mineralogical components, and it plays a pivotal role in geochemistry, carbon cycling and glacier mass balance. In this work, we collected cryoconite samples from Laohugou Glacier No. 12 (LHG) on the north-eastern Tibetan Plateau during the summer of 2015 and measured the spectral albedo. To explore the impacts of this sediment on surface ablation, the ice melting differences between the cryoconite-free (removed) ice and the intact layers were compared. The results showed that the mean concentrations of black carbon (BC), organic carbon (OC) and total iron (Fe) in the LHG cryoconite were 1.28, 11.18 and 39.94 mg g−1, respectively. BC was found to play a stronger role in solar light adsorption than OC and free Fe. In addition, ice covered by cryoconite exhibited the lowest mean reflectance (i.e., <0.1). Compared with the cryoconite-free ice surface, cryoconite effectively absorbed solar energy and enhanced glacial melting at a rate of 2.27–3.28 cm d−1, and free Fe, BC and OC were estimated to contribute 1.01, 0.99 and 0.76 cm d−1, respectively. This study provides important insights for understanding the role of cryoconite in the glacier mass balance of the northern Tibetan Plateau.

scholarly journals Variation of Net Primary Production and Its Correlation with Climate Change and Anthropogenic Activities over the Tibetan Plateau

2018 ◽  
Vol 10 (9) ◽  
pp. 1352 ◽  
Author(s):  
Zhaohui Luo ◽  
Wenchen Wu ◽  
Xijun Yu ◽  
Qingmei Song ◽  
Jian Yang ◽  
...  
Keyword(s):  
Climate Change ◽  
Tibetan Plateau ◽  
Climatic Factors ◽  
Anthropogenic Activities ◽  
Mean Value ◽  
Mean Annual Temperature ◽  
The Tibetan Plateau ◽  
Casa Model ◽  
Negative Effect ◽  
Cumulative Precipitation

Grasslands in the Tibetan Plateau are claimed to be sensitive and vulnerable to climate change and anthropogenic activities. Quantifying the impacts of climate change and anthropogenic activities on grassland growth is an essential step for developing sustainable grassland ecosystem management strategies under the background of climate change and increasing anthropogenic activities occurring in the plateau. Net primary productivity (NPP) is one of the key components in the carbon cycle of terrestrial ecosystems, and can serve an important role in the assessment of vegetation growth. In this study, a modified Carnegie–Ames–Stanford Approach (CASA) model, which considers remote sensing information for the estimation of the water stress coefficient and time-lag effects of climatic factors on NPP simulation, was applied to simulate NPP in the Tibetan Plateau from 2001 to 2015. Then, the spatiotemporal variations of NPP and its correlation with climatic factors and anthropogenic activities were analyzed. The results showed that the mean values of NPP were 0.18 kg∙C∙m−2∙a−1 and 0.16 kg∙C∙m−2∙a−1 for the original CASA model and modified CASA model, respectively. The modified CASA model performed well in estimating NPP compared with field-observed data, with root mean square error (RMSE) and mean absolute error (MAE) of 0.13 kg∙C∙m−2∙a−1 and 0.10 kg∙C∙m−2∙a−1, respectively. Relative RMSE and MAE decreased by 45.8% and 44.4%, respectively, compared to the original CASA model. The variation of NPP showed gradients decreasing from southeast to northwest spatially, and displayed an overall decreasing trend for the study area temporally, with a mean value of −0.02 × 10−2 kg∙C∙m−2∙a−1 due to climate change and increasing anthropogenic activities (i.e., land use and land cover change). Generally, 54% and 89% of the total pixels displayed a negative relationship between NPP and mean annual temperature, as well as annual cumulative precipitation, respectively, with average values of –0.0003 (kg∙C∙m−2 a−1)/°C and −0.254 (g∙C∙m−2∙a−1)/mm for mean annual temperature and annual cumulative precipitation, respectively. Additionally, about 68% of the total pixels displayed a positive relationship between annual cumulative solar radiation and NPP, with a mean value of 0.038 (g∙C∙m−2·a−1)/(MJ m−2). Anthropogenic activities had a negative effect on NPP variation, and it was larger than that of climate change, implying that human intervention plays a critical role in mitigating the degenerating ecosystem. In terms of human intervention, ecological destruction has a significantly negative effect on the NPP trend, and the absolute value was larger than that of ecological restoration, which has a significantly positive effect on NPP the trend. Our results indicate that ecological destruction should be paid more attention, and ecological restoration should be conducted to mitigate the overall decreasing trend of NPP in the plateau.

scholarly journals Modern Pollen Assemblages in Typical Agro-Pastoral Ecotone in the Eastern Tibetan Plateau and Its Implications for Anthropogenic Activities

2021 ◽  
Vol 9 ◽  
Author(s):  
Ronglei Duan ◽  
Haicheng Wei ◽  
Guangliang Hou ◽  
Jingyi Gao ◽  
Yongsheng Du ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Anthropogenic Activities ◽  
Principal Component ◽  
Environment Interaction ◽  
Human Environment ◽  
Surface Pollen ◽  
Modern Pollen ◽  
Pollen Types ◽  
Poaceae Pollen ◽  
The Impact

Long-term evolution of human-environment interaction in the Qinghai-Tibetan Plateau (QTP) has been discussed intensively in recent years. The identification of human-related pollen types may help explore the coupled process of climate change, ecological response and anthropogenic activities on the QTP. The aim of this study is to evaluate the impact of anthropogenic activities on surface pollen assemblages and identify pollen indicators associated with grazing and cultivation in typical agro-pastoral ecotone of the eastern QTP. Totally 84 surface samples were analyzed from five vegetational communities in the eastern QTP, which are identifiable based on surface pollen assemblages. Principal component analysis of 29 pollen types and two supplementary variables of human influences were used to assess the impact of anthropogenic activities on surface pollen assemblages in eastern QTP. Severe grazing led to increase of Rosaceae, Ranunculaceae, Fabaceae, Taraxacum-Type, Aster-type and Saussurea-Type in pollen assemblages. Highland agricultural cultivation can be identified by the content and morphological characteristic of Brassicaceae and Cerealia Poaceae pollen. The aerial dispersed distances of Brassicaceae and Cerealia Poaceae pollen are very short, and domesticated herbivores are important factors, which disperse the Cerealia Poaceae pollen into pastures in agro-pastoral ecotone of the QTP. Modern pollen indicators of cultivation and grazing activity will provide precise references for fossil pollen study of prehistoric human activities in the QTP.

The cadmium and lead of soil in timberline coniferous forests, Eastern Tibetan Plateau

2014 ◽  
Vol 73 (1) ◽  
pp. 303-310 ◽  
Author(s):  
Ronggui Tang ◽  
Ji Luo ◽  
Jia She ◽  
Youchao Chen ◽  
Dandan Yang ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Coniferous Forests ◽  
Eastern Tibetan Plateau ◽  
Cadmium And Lead

scholarly journals Assessment of Heavy Metals in the Sediments of Chalan Beel Wetland Area in Bangladesh

Processes ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 410
Author(s):  
Mohammad Abdus Salam ◽  
Mohammad Ashraful Alam ◽  
Sulav Indra Paul ◽  
Fatama Islam ◽  
Dinesh Chandra Shaha ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Anthropogenic Activities ◽  
Risk Index ◽  
Contamination Factor ◽  
Principal Component ◽  
Potential Ecological Risk ◽  
Northwestern Part ◽  
Accumulation Index ◽  
Significant Enrichment ◽  
The Mean

This study aimed to determine the levels and possible sources of heavy metals (HMs) in the sediments of Chalan beel (a large lake-like aquatic ecosystem) area located in the northwestern part of Bangladesh. The mean concentrations (mg kg−1) of two HMs, Cd (6.22) and Pb (51.39) exceeded the world normal averages (WNA), whereas the mean concentrations (mg kg−1) of Ni (60.46), Zn (10.75), Mn (8.64) and Cu (4.71) were below the WNA. The sediments showed significant enrichment with Cd, Pb and Ni in the studied area. The geo-accumulation index values of Cd (3.72) and Pb (0.76) were significantly higher in the sediments. The contamination factor and potential ecological risk index values of Cd and Pb revealed that Chalan beel was extremely and moderately contaminated by these heavy metals, respectively. Analysis of dye complexes used in handlooms around the Chalan beel areas revealed that mean concentrations of Cd and Pb exceeded the WNA. Furthermore, analyses of principal component, cluster and correlation matrix indicated that the presence of the higher levels of Cd and Pb in the sediments might be linked to various anthropogenic activities like discharged dyes into the beel water from the nearby handloom dyeing factories.

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