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Air pollutants have been investigated in many studies, but the variations of atmospheric pollutants and their relationship with rainwater chemistry are not well studied. In the present study, the criteria atmospheric pollutants in nine monitoring stations and rainwater chemistry were analyzed in karst Guiyang city, since the time when the Chinese Ambient Air Quality Standards (CAAQS, third revision) were published. Based on the three-year daily concentration dataset of SO2, NO2, CO, PM10 and PM2.5, although most of air pollutant concentrations were within the limit of CAAQS III-Grade II standard, the significant spatial variations and relatively heavy pollution were found in downtown Guiyang. Temporally, the average concentrations of almost all air pollutants (except for CO) decreased during three years at all stations. Ratios of PM2.5/PM10 in non- and episode days reflected the different contributions of fine and coarse particles on particulate matter in Guiyang, which was influenced by the potential meteorological factors and source variations. According to the individual air quality index (IAQI), the seasonal variations of air quality level were observed, that is, IAQI values of air pollutants were higher in winter (worst air quality) and lower in summer (best air quality) due to seasonal variations in emission sources. The unique IAQI variations were found during the Chinese Spring Festival. Air pollutant concentrations are also influenced by meteorological parameters, in particular, the rainfall amount. The air pollutants are well scoured by the rainfall process and can significantly affect rainwater chemistry, such as SO42−, NO3−, Mg2+, and Ca2+, which further alters the acidification/alkalization trend of rainwater. The equivalent ratios of rainwater SO42−/NO3− and Mg2+/Ca2+ indicated the significant contribution of fixed emission sources (e.g., coal combustion) and carbonate weathering-influenced particulate matter on rainwater chemistry. These findings provide scientific support for air pollution management and rainwater chemistry-related environmental issues.
Jie Zeng; Xin Ge; Qixin Wu; Shitong Zhang. Three-Year Variations in Criteria Atmospheric Pollutants and Their Relationship with Rainwater Chemistry in Karst Urban Region, Southwest China. Atmosphere 2021, 12, 1073 .
AMA StyleJie Zeng, Xin Ge, Qixin Wu, Shitong Zhang. Three-Year Variations in Criteria Atmospheric Pollutants and Their Relationship with Rainwater Chemistry in Karst Urban Region, Southwest China. Atmosphere. 2021; 12 (8):1073.
Chicago/Turabian StyleJie Zeng; Xin Ge; Qixin Wu; Shitong Zhang. 2021. "Three-Year Variations in Criteria Atmospheric Pollutants and Their Relationship with Rainwater Chemistry in Karst Urban Region, Southwest China." Atmosphere 12, no. 8: 1073.
Dissolved heavy metals (HMs), derived from natural and anthropogenic sources, are an important part of aquatic environment research and gain more international concern due to their acute toxicity. In this study, the geochemistry of dissolved HMs was analyzed in the upper Three Gorges Reservoir (TGR) of the Yangtze River (YZR) watershed to explore their distribution, status, and sources and further evaluate the water quality and HM-related risks. In total, 57 water samples were collected from the main channel and tributaries of the upper TGR. The concentrations of eight HMs, namely V, Ni, Cu, Zn, As, Mo, Cd, and Pb, were measured by ICP-MS. The mean concentrations (in μg/L) of eight HMs decreased in the order: As (1.46), V (1.44), Ni (1.40), Mo (0.94), Cu (0.86), Zn (0.63), Pb (0.03), and Cd (0.01). The concentrations of most HMs were 1.4~8.1 times higher than that in the source area of the YZR, indicating a potential anthropogenic intervention in the upper TGR. Spatially, the concentrations of V, Cu, As, and Pb along the main channel gradually decreased, while the others were relatively stable (except for Cd). The different degrees of variations in HM concentrations were also found in tributaries. According to the correlation analysis and principal component (PC) analysis, three PCs were identified and explained 75.1% of the total variances. combined with the concentrations of each metal, PC1 with high loadings of V, Ni, As, and Mo was considered as the main contribution of human inputs, PC2 (Cu and Pb) was primarily attributed to the contribution of mixed sources of human emissions and natural processes, and Zn and Cd in PC3 were controlled by natural sources. Water quality assessment suggested the good water quality (meeting the requirements for drinking purposes) with WQI values of 14.1 ± 3.4 and 11.6 ± 3.6 in the main channel and tributaries, respectively. Exposure risk assessment denoted that the health effects of selected HMs on the human body were limited (hazard index, HI < 1), but the potential risks of V and As with HI > 0.1 were non-negligible, especially for children. These findings provide scientific support for the environmental management of the upper TGR region and the metal cycle in aquatic systems.
Jie Zeng; Guilin Han; Mingming Hu; Yuchun Wang; Jinke Liu; Shitong Zhang; Di Wang. Geochemistry of Dissolved Heavy Metals in Upper Reaches of the Three Gorges Reservoir of Yangtze River Watershed during the Flood Season. Water 2021, 13, 2078 .
AMA StyleJie Zeng, Guilin Han, Mingming Hu, Yuchun Wang, Jinke Liu, Shitong Zhang, Di Wang. Geochemistry of Dissolved Heavy Metals in Upper Reaches of the Three Gorges Reservoir of Yangtze River Watershed during the Flood Season. Water. 2021; 13 (15):2078.
Chicago/Turabian StyleJie Zeng; Guilin Han; Mingming Hu; Yuchun Wang; Jinke Liu; Shitong Zhang; Di Wang. 2021. "Geochemistry of Dissolved Heavy Metals in Upper Reaches of the Three Gorges Reservoir of Yangtze River Watershed during the Flood Season." Water 13, no. 15: 2078.
In order to better constrain calcium cycling in natural soil and in soil used for agriculture, we present the δ44/40Ca values measured in rainwater, groundwater, plants, soil, and bedrock samples from a representative karst forest in SW China. The δ44/40Ca values are found to differ by ≈3.0‰ in the karst forest ecosystem. The Ca isotope compositions and Ca contents of groundwater, rainwater, and bedrock suggest that the Ca of groundwater primarily originates from rainwater and bedrock. The δ44/40Ca values of plants are lower than that of soils, indicating the preferential uptake of light Ca isotopes by plants. The distribution of δ44/40Ca values in the soil profiles (increasing with soil depth) suggests that the recycling of crop-litter abundant with lighter Ca isotope has potential effects on soil Ca isotope composition. The soil Mg/Ca content ratio probably reflects the preferential plant uptake of Ca over Mg and the difference in soil maturity. Light Ca isotopes are more abundant in mature soils than nutrient-depleted soils. The relative abundance in the light Ca isotope (40Ca) is in the following order: farmland > burnt grassland > forests > grassland > shrubland. Our results further indicate that biological fractionation in a soil–plant system is a vital factor for Ca–geochemical transformations in soil surface systems.
Guilin Han; Anton Eisenhauer; Jie Zeng; Man Liu. Calcium Biogeochemical Cycle in a Typical Karst Forest: Evidence from Calcium Isotope Compositions. Forests 2021, 12, 666 .
AMA StyleGuilin Han, Anton Eisenhauer, Jie Zeng, Man Liu. Calcium Biogeochemical Cycle in a Typical Karst Forest: Evidence from Calcium Isotope Compositions. Forests. 2021; 12 (6):666.
Chicago/Turabian StyleGuilin Han; Anton Eisenhauer; Jie Zeng; Man Liu. 2021. "Calcium Biogeochemical Cycle in a Typical Karst Forest: Evidence from Calcium Isotope Compositions." Forests 12, no. 6: 666.
Trace metal pollution is one of the most concerning issues in Yunnan province, where red soil is the dominant soil. To investigate the sources of trace metals and assess their pollution level and potential ecological and health risk, trace metal concentrations were measured in two red soil profiles (S1 and S2) from Yunnan province. Results show that Cr, As, and Zn are the most abundant trace metals in both soil profiles. However, As and Cr might be pollutants because their concentrations are higher than the local background values and the average concentrations in soils from other countries such as China, Japan, the UK, and the USA. Based on the correlation matrix and principal component analysis, As and Cr in red soils were affected by mining activities. Based on the single factor index and Nemero pollution index, the enrichment of As and Cr in Yunnan province can lead to light pollution in red soils. The RI values of trace metals exhibit a low ecological risk, of which the RI values of As and Cd in S1 are higher than those of Cr, Cu, Ni, Pb, and Zn in both profiles, implying a higher soil pollution level in south Yunnan. Furthermore, the HI results indicate that As can cause non‐carcinogenic risk on human health and should be paid more attention to. This study is aimed to help developing the ecological management of red soils and providing scientific evidence for preventing the hazardous contamination of trace metals in soils. This article is protected by copyright. All rights reserved
Bin Liang; Guilin Han; Jie Zeng; Rui Qu; Man Liu; Jinke Liu. Source and Risk Assessment of Trace Metals in Red Soils from Yunnan Province, Southwest China. CLEAN – Soil, Air, Water 2021, 2000288 .
AMA StyleBin Liang, Guilin Han, Jie Zeng, Rui Qu, Man Liu, Jinke Liu. Source and Risk Assessment of Trace Metals in Red Soils from Yunnan Province, Southwest China. CLEAN – Soil, Air, Water. 2021; ():2000288.
Chicago/Turabian StyleBin Liang; Guilin Han; Jie Zeng; Rui Qu; Man Liu; Jinke Liu. 2021. "Source and Risk Assessment of Trace Metals in Red Soils from Yunnan Province, Southwest China." CLEAN – Soil, Air, Water , no. : 2000288.
The rainwater chemistry and related air contaminants are used to investigate the rainwater ions sources, variations, and influence factors from 2012 to 2014 in Guiyang city (the typical karst urban area of Southwest China). According to temporal rainwater ion concentrations, the obvious variations were presented in the study period, such as Ca2+ (125∼6,652 μeq L−1) and SO4 2− (11∼4,127 μeq L−1). Consequently, Ca2+, Mg2+, SO4 2− and Cl− are considered as the leading ions. Three critical influencing factors of rainwater ions concentrations, including sources variations, rainfall amount and long-distance migration (rainfall amount > 100 mm) are identified. Based on the typical ionic ratios, source identification suggested that anthropogenic inputs mainly contributed to F−, NO3 − and SO4 2−, while the dusts (crustal sources) are the primary sources of Mg2+, Ca2+ and K+. Cl− Enrichment in long-distance transport is the main contributor of Cl−. According to the observation of high level of total wet acid deposition, the more detailed spatio-temporal monitoring of rainfall-related acid deposition (particularly sulfur deposition) is required to understand its potential environmental effects in the aquatic ecosystem of the earth surface.
Jie Zeng; Guilin Han. Rainwater chemistry observation in a karst city: variations, influence factors, sources and potential environmental effects. PeerJ 2021, 9, e11167 .
AMA StyleJie Zeng, Guilin Han. Rainwater chemistry observation in a karst city: variations, influence factors, sources and potential environmental effects. PeerJ. 2021; 9 ():e11167.
Chicago/Turabian StyleJie Zeng; Guilin Han. 2021. "Rainwater chemistry observation in a karst city: variations, influence factors, sources and potential environmental effects." PeerJ 9, no. : e11167.
Forty-eight suspended particulate matter (SPM) samples were collected from the Mun River, northeast Thailand and its junction with the Mekong River, to investigate the relationship between the distribution of rare earth elements (REE) in SPM and the soils in the watershed. The total REE contents (∑REE) in SPM in the Mun River ranged from 78.5 to 377.8 mg/kg with the average of 189.3 mg/kg, which was lower than ∑REE of 222.3 mg/kg at the Mekong River (one sample at junction). The Post Archean Australia Shale (PAAS)-normalized ratios of light REE (LREE), middle REE (MREE) and heavy REE (HREE) were averaged to 1.0, 1.3 and 1.0, which showed a clear enrichment in MREE. In short, along the Mun River, the REE contents in SPM were decreasing, and the PAAS-normalized patterns of REE showed gradually flat. The REE content in SPM and soils are highest in the upper catchment, indicating that soil/bedrock is the most important source of REE in SPM. Additionally, the positive Eu anomaly was enhanced by the higher Ca content in SPM (R = 0.45), which may be caused by more feldspars or carbonates with Ca and Eu substituting Ca. The results present the REE behaviors of SPM in the Mun River and relationship between REE in SPM and soil/bedrock, the findings may support the other studies in catchment weathering.
Kunhua Yang; Guilin Han; Jie Zeng; Wenxiang Zhou. Distribution, fractionation and sources of rare earth elements in suspended particulate matter in a tropical agricultural catchment, northeast Thailand. PeerJ 2021, 9, e10853 .
AMA StyleKunhua Yang, Guilin Han, Jie Zeng, Wenxiang Zhou. Distribution, fractionation and sources of rare earth elements in suspended particulate matter in a tropical agricultural catchment, northeast Thailand. PeerJ. 2021; 9 ():e10853.
Chicago/Turabian StyleKunhua Yang; Guilin Han; Jie Zeng; Wenxiang Zhou. 2021. "Distribution, fractionation and sources of rare earth elements in suspended particulate matter in a tropical agricultural catchment, northeast Thailand." PeerJ 9, no. : e10853.
Rivers transport terrestrial matter into the ocean, constituting a fundamental channel between inland and oceanic ecosystem and affect global climate change. To reveal chemical weathering processes and environmental health risks during flood periods, water samples were collected in the upper reaches of Three Gorges Reservoir (TGR) in 2020. HCO3 − and Ca2+ were the most abundant anions and cations of the river water, respectively. The range of HCO3 − concentration was between 1.81 and 3.02 mmol/L, while the mean content of Ca2+ was 1.03 mmol/L. The results of the Piper diagram and element ratios revealed that the river solutes were mainly contributed by carbonate weathering and gypsum-rich evaporite dissolution. A mass balance model indicated that the contribution order of sources to cations in the main channel (Yibin-Luzhou) was evaporites > carbonates > atmospheric input > silicates. The order in the Chongqing—Three Gorges Dam was carbonates > atmospheric input > evaporites > silicates. These results showed a lithologic control on hydrochemical characteristics. Most sampling sites were suitable for agricultural irrigation according to the water quality assessment. However, indexes sodium adsorption ratio (SAR) and soluble sodium percentage (Na%) were higher than 1.0 in Yibin-Luzhou and 30% in Yibin–Chongqing, respectively, suggesting a potential sodium hazard. In addition, except Tuojiang River and Shennong River, the risk of sodium hazard in tributaries was relatively low. High Na+ concentration in irrigation water can damage soil structure and function and ultimately affect agricultural production. Water quality in the upstream of a Piper diagram should attract enough attention.
Di Wang; Guilin Han; Mingming Hu; Yuchun Wang; Jinke Liu; Jie Zeng; Xiaoqiang Li. Major Elements in the Upstream of Three Gorges Reservoir: An Investigation of Chemical Weathering and Water Quality during Flood Events. Water 2021, 13, 454 .
AMA StyleDi Wang, Guilin Han, Mingming Hu, Yuchun Wang, Jinke Liu, Jie Zeng, Xiaoqiang Li. Major Elements in the Upstream of Three Gorges Reservoir: An Investigation of Chemical Weathering and Water Quality during Flood Events. Water. 2021; 13 (4):454.
Chicago/Turabian StyleDi Wang; Guilin Han; Mingming Hu; Yuchun Wang; Jinke Liu; Jie Zeng; Xiaoqiang Li. 2021. "Major Elements in the Upstream of Three Gorges Reservoir: An Investigation of Chemical Weathering and Water Quality during Flood Events." Water 13, no. 4: 454.
Temporal rainwater chemistry was used to reveal air pollution in the Maolan National Karst Forest Park (MNKFP), which is representative of the typical karst forest region of southwest China (SW China). The rainwater ions’ sources, variations, trends, and potential environmental effects were investigated from 2007 to 2010 and from 2013 to 2014. Based on the analysis of the temporal ionic concentrations of rainwater in the MNKFP, significant variations of ions were observed, including in NH4+ (9.7~266.6 μeq L−1) and SO42− (14.5~1396.4 μeq L−1), which were mainly controlled by variations in the source and rainfall amount; a decreased trend of rainwater pH was also observed. Accordingly, NH4+, Ca2+, SO42−, and Cl− were regarded as the most dominant ions. Typical ionic ratios and positive matrix factorization (PMF) model-based source apportionment suggested that anthropogenic inputs (coal combustion, industrial, traffic, and agricultural emissions) contributed 51% of F−, 93% of NO3−, 62% of SO42−, and 87% of NH4+, while the natural sources (crustal dust and sea salt) were the main sources of Cl− (74%), Na+ (82%), K+ (79%), Mg2+ (94%), and Ca2+ (93%). In combination with the reducing neutralization trend of temporal rainwater observed in the MNKFP and the potential effect of rainwater ion deposition on karst forests, more detailed monitoring of the rainfall-related deposition process is required for a better understanding of its potential environmental effects on the Earth’s surface.
Jie Zeng; Guilin Han. Rainwater Chemistry Reveals Air Pollution in a Karst Forest: Temporal Variations, Source Apportionment, and Implications for the Forest. Atmosphere 2020, 11, 1315 .
AMA StyleJie Zeng, Guilin Han. Rainwater Chemistry Reveals Air Pollution in a Karst Forest: Temporal Variations, Source Apportionment, and Implications for the Forest. Atmosphere. 2020; 11 (12):1315.
Chicago/Turabian StyleJie Zeng; Guilin Han. 2020. "Rainwater Chemistry Reveals Air Pollution in a Karst Forest: Temporal Variations, Source Apportionment, and Implications for the Forest." Atmosphere 11, no. 12: 1315.
Heavy metals are of public concern in aquatic ecosystems due to their growing release from industries and mining activities. This study investigated the sources, temporal-spatial distributions and water quality of dissolved heavy metals (Mn, Co, Al, Ni, Ba, V, Sb, Fe, Sr) in the Lake Aha watershed, an area under the influence of sewage and acid mining drainage. These heavy metals displayed significant spatial and temporal variabilities. The water quality index results (WQI values ranged from 3.21 to 15.64) and health risk assessment (all hazard indexes are below 1) indicated that dissolved heavy metals in this study pose a low risk for human health. Correlation analysis and principal component analysis indicated that Fe and Sr mainly presented a natural geological feature in the study area, and Mn, Co, Al and Ni were influenced by the acid coal mine drainage, whereas Ba, V and Sb were under the impact of local industrial or medical activities. This study provides new insights into the risk assessment of heavy metals in small watersheds.
Shilin Gao; Zhuhong Wang; Qixin Wu; Jie Zeng. Multivariate statistical evaluation of dissolved heavy metals and a water quality assessment in the Lake Aha watershed, Southwest China. PeerJ 2020, 8, e9660 .
AMA StyleShilin Gao, Zhuhong Wang, Qixin Wu, Jie Zeng. Multivariate statistical evaluation of dissolved heavy metals and a water quality assessment in the Lake Aha watershed, Southwest China. PeerJ. 2020; 8 ():e9660.
Chicago/Turabian StyleShilin Gao; Zhuhong Wang; Qixin Wu; Jie Zeng. 2020. "Multivariate statistical evaluation of dissolved heavy metals and a water quality assessment in the Lake Aha watershed, Southwest China." PeerJ 8, no. : e9660.
The profile distributions of soil organic carbon (SOC), soil organic nitrogen (SON), soil pH and soil texture were rarely investigated in the Lancangjiang River Basin. This study aims to present the vertical distributions of these soil properties and provide some insights about how they interact with each other in the two typical soil profiles. A total of 56 soil samples were collected from two soil profiles (LCJ S-1, LCJ S-2) in the Lancangjiang River Basin to analyze the profile distributions of SOC and SON and to determine the effects of soil pH and soil texture. Generally, the contents of SOC and SON decreased with increasing soil depth and SOC contents were higher than SON contents (average SOC vs. SON content: 3.87 g kg−1 vs. 1.92 g kg−1 in LCJ S-1 and 5.19 g kg−1 vs. 0.96 g kg−1 in LCJ S-2). Soil pH ranged from 4.50 to 5.74 in the two soil profiles and generally increased with increasing soil depth. According to the percentages of clay, silt, and sand, most soil samples can be categorized as silty loam. Soil pH values were negatively correlated with C/N ratios (r = −0.66, p < 0.01) and SOC contents (r = −0.52, p < 0.01). Clay contents were positively correlated with C/N ratios (r = 0.43, p < 0.05) and SOC contents (r = 0.42, p < 0.01). The results indicate that soil pH and clay are essential factors influencing the SOC spatial distributions in the two soil profiles.
Wenxiang Zhou; Guilin Han; Man Liu; Jie Zeng; Bin Liang; Jinke Liu; Rui Qu. Determining the Distribution and Interaction of Soil Organic Carbon, Nitrogen, pH and Texture in Soil Profiles: A Case Study in the Lancangjiang River Basin, Southwest China. Forests 2020, 11, 532 .
AMA StyleWenxiang Zhou, Guilin Han, Man Liu, Jie Zeng, Bin Liang, Jinke Liu, Rui Qu. Determining the Distribution and Interaction of Soil Organic Carbon, Nitrogen, pH and Texture in Soil Profiles: A Case Study in the Lancangjiang River Basin, Southwest China. Forests. 2020; 11 (5):532.
Chicago/Turabian StyleWenxiang Zhou; Guilin Han; Man Liu; Jie Zeng; Bin Liang; Jinke Liu; Rui Qu. 2020. "Determining the Distribution and Interaction of Soil Organic Carbon, Nitrogen, pH and Texture in Soil Profiles: A Case Study in the Lancangjiang River Basin, Southwest China." Forests 11, no. 5: 532.
Nitrogen (N) deposition plays a key role in ecosystem function as one of the major N sources for natural vegetation, particularly in karst agricultural areas with thin soil cover, which drive the karst N fate via rainwater. To understand the seasonal and spatial variation in nitrogen deposition and to identify the major sources of nitrate in wet deposition in a karst agricultural area (Houzhai Catchment) in southwestern China, two sites with different land use were selected to assess wet and dry deposition for one year. Houzhai village (HZV) is an area highly influenced by agriculture, whereas Muzhu reservoir (MZR) is a more pristine environment with less anthropogenic influence. Nitrogenous species and dual nitrate isotopes were analyzed. The results showed that agriculture-derived NH4+ was the major contributor of annual total wet N deposition (>55 %). The contribution of NH4+ to wet N deposition was 1.63 times higher than that of NO3− and dissolved organic nitrogen (DON). The annual nitrogen deposition in this study was approximately twice as much as the average wet N deposition over China, while lower dry N deposition relative to other Chinese monitoring sites was observed. The δ15N-NO3− showed a seasonal trend of negative summer values and positive winter values, which were primarily controlled by the variations in NOx emission sources. Seasonal variation in δ18O-NO3− was mainly controlled by NOx oxidation pathways and showed a similar trend to δ15N-NO3−. The contributions from four endmembers (coal combustion, vehicle exhaust, biomass burning, and soil emission) were calculated using a stable isotope mixing model. Contributions show a clear seasonal variation (except vehicle exhaust), with the four sources accounting for 20.0 %, 25.6 %, 22.9 % and 31.5 % respectively (annual mean probability estimate, AMPE) at HZV, and 19.0 %, 27.8 %, 23.2 % and 30.0 % (AMPE) at MZR. Isotopic evidence determined agricultural soil emission is a major contributor to rainwater during the summer growing season, which can significantly impact the agricultural ecosystems.
Jie Zeng; Fu-Jun Yue; Si-Liang Li; Zhong-Jun Wang; Cai-Qing Qin; Qi-Xin Wu; Sheng Xu. Agriculture driven nitrogen wet deposition in a karst catchment in southwest China. Agriculture, Ecosystems & Environment 2020, 294, 106883 .
AMA StyleJie Zeng, Fu-Jun Yue, Si-Liang Li, Zhong-Jun Wang, Cai-Qing Qin, Qi-Xin Wu, Sheng Xu. Agriculture driven nitrogen wet deposition in a karst catchment in southwest China. Agriculture, Ecosystems & Environment. 2020; 294 ():106883.
Chicago/Turabian StyleJie Zeng; Fu-Jun Yue; Si-Liang Li; Zhong-Jun Wang; Cai-Qing Qin; Qi-Xin Wu; Sheng Xu. 2020. "Agriculture driven nitrogen wet deposition in a karst catchment in southwest China." Agriculture, Ecosystems & Environment 294, no. : 106883.
Dissolved heavy metals are not only the essential micronutrients, but also the toxic elements for human bodies. To investigate the heavy metal sources and assess the water quality of the Lancangjiang River, dissolved Cr, Ni, Cu, Zn, Mo, and Pb were detected in this study. The results show that dissolved Ni and Mo, Cr and Pb, and Cu and Zn were similarly distributed within the drainage basin. The correlation analysis exhibited that dissolved Ni and Mo had correlation with water parameter, and dissolved Cu was weakly correlated with Ni, indicating that they might be affected by natural processes. The principal component analysis explained 68.342% of the total variance for three principal components, of which dissolved Ni, Mo, and Cu were controlled by natural inputs; dissolved Cu and Cr were affected by anthropogenic activities; and dissolved Zn was influenced by agricultural activities in the downstream. The water quality showed that the water in upstream was worse than in midstream and downstream, and the whole drainage basin had water of excellent quality. Water within the drainage basin poses no risks to human bodies via daily diets and dermal routes. Dissolved Zn, Cu, and Mo occupied the major proportion of heavy metals transporting into the Mekong River. The agricultural inputs of dissolved Zn might pose potential risks to the Mekong River.
Bin Liang; Guilin Han; Jie Zeng; Rui Qu; Man Liu; Jinke Liu; Liu. Spatial Variation and Source of Dissolved Heavy Metals in the Lancangjiang River, Southwest China. International Journal of Environmental Research and Public Health 2020, 17, 732 .
AMA StyleBin Liang, Guilin Han, Jie Zeng, Rui Qu, Man Liu, Jinke Liu, Liu. Spatial Variation and Source of Dissolved Heavy Metals in the Lancangjiang River, Southwest China. International Journal of Environmental Research and Public Health. 2020; 17 (3):732.
Chicago/Turabian StyleBin Liang; Guilin Han; Jie Zeng; Rui Qu; Man Liu; Jinke Liu; Liu. 2020. "Spatial Variation and Source of Dissolved Heavy Metals in the Lancangjiang River, Southwest China." International Journal of Environmental Research and Public Health 17, no. 3: 732.
High discharge associated with rainfall events causes rapid transport of nutrients to drainage systems in karst terrain. The objective of this study was to understand nitrate dynamics and transport mechanisms during rainfall events in a typical mixed land-use karst catchment in Southwest China. High frequency (hourly) water sampling, discharge and hydrochemistry sensor data at a 15-minute interval were collected from a karst agricultural surface river over four rainfall events, spanning 40 days at the commencement of the wet season. The results showed that high [NH4+–N] (up to 3.12 mg L−1) and [PO43−– P] (up to 1037 μg L−1) were observed in the first rainfall event of the wet season, after a long preceding dry period. Increased [NO3−–N] also occurred during the high discharge associated with early event flows, but the highest [NO3−–N] concentrations (up to 14.9 mg L−1) were observed later in the season during the highest discharge events. All minima for dual nitrate isotopes were found during high discharge conditions and increased through the event time series. This indicates that nitrogen accumulated in the catchment prior to the commencement of the wet season and was flushed by the early rainfall events into the drainage system. Analysis of [NO3−–N], δ15N and δ18O-NO3− values indicate that denitrification, not assimilation, resulted in the high nitrate isotope values before and after rainfall events. According to source apportionment, chemical fertilizer, soil organic nitrogen, and manure and sewage, which varied with discharge, were the main sources of nitrate during rainfall events. The high proportion of nitrate from soil organic nitrogen suggested that soil loss from peak clusters and lowland farmland during heavy rainfall events should be paid more attention in karst area.
Zhong-Jun Wang; Si-Liang Li; Fu-Jun Yue; Cai-Qing Qin; Sarah Buckerfield; Jie Zeng. Rainfall driven nitrate transport in agricultural karst surface river system: Insight from high resolution hydrochemistry and nitrate isotopes. Agriculture, Ecosystems & Environment 2019, 291, 106787 .
AMA StyleZhong-Jun Wang, Si-Liang Li, Fu-Jun Yue, Cai-Qing Qin, Sarah Buckerfield, Jie Zeng. Rainfall driven nitrate transport in agricultural karst surface river system: Insight from high resolution hydrochemistry and nitrate isotopes. Agriculture, Ecosystems & Environment. 2019; 291 ():106787.
Chicago/Turabian StyleZhong-Jun Wang; Si-Liang Li; Fu-Jun Yue; Cai-Qing Qin; Sarah Buckerfield; Jie Zeng. 2019. "Rainfall driven nitrate transport in agricultural karst surface river system: Insight from high resolution hydrochemistry and nitrate isotopes." Agriculture, Ecosystems & Environment 291, no. : 106787.
Two-year chemical and stable Ca isotopic compositions (δ44/40Ca) of rainwater were detected in a typical karst virgin forest site (Maolan National Nature Reserved Park, Southwest China, MNNRP). The results show that the pH values and the ionic concentrations of rainwater samples vary considerably, and about half of them are defined as acidic rain (pH < 5.0). NH4+ is the predominant cation in rainwater with a volume weighted mean (VWM) value of 110 μmol L−1 (1.3−377 μmol L−1), and the second is Ca2+ with VWM value of 11.7 μmol L−1 (0.9–67.7 μmol L−1). SO42- and NO3- are the principal anions with VWM values of 51.8 μmol L−1 (9.8−203 μmol L−1) and 24.7 μmol L−1 (2.7−151 μmol L−1), respectively. Source identification shows that the NO3- and SO42- of rainwater are controlled by anthropogenic sources, and the agricultural activities and natural processes are the main sources of NH4+, while the part of Ca2+, K+ and Mg2+ originate from crustal inputs. The higher concentration of alkaline ions is a significant contributor to reduce rainwater acidification. Based on the reported data of previous literature, the stable Ca isotopes (δ44/40Ca) are applied to decipher the different sources. The three sources include as the carbonate weathering (low δ44/40Ca ∼ 0.6‰, low NH4+/Ca2+ and NO3-/Ca2+ ratios), the silicate weathering which refers to the dissolvable soil dirt minerals from both local and the surrounding place (high δ44/40Ca ∼ 0.9‰, low NH4+/Ca2+ and NO3-/Ca2+ ratios), and the anthropogenic source (mainly from fertilizers, moderate δ44/40Ca ∼ 0.8‰, high NH4+/Ca2+ and NO3-/Ca2+ ratios). This study highlights the broader applicability of the chemical and Ca isotopic method in tracing the sources (particularly agricultural sources) of rainwater solute and atmospheric mixing/trapping processes, and can also provide additional insight regarding the elemental biogeochemical cycle in karst areas.
Jie Zeng; Guilin Han; Qixin Wu; Yang Tang. Effects of agricultural alkaline substances on reducing the rainwater acidification: Insight from chemical compositions and calcium isotopes in a karst forests area. Agriculture, Ecosystems & Environment 2019, 290, 106782 .
AMA StyleJie Zeng, Guilin Han, Qixin Wu, Yang Tang. Effects of agricultural alkaline substances on reducing the rainwater acidification: Insight from chemical compositions and calcium isotopes in a karst forests area. Agriculture, Ecosystems & Environment. 2019; 290 ():106782.
Chicago/Turabian StyleJie Zeng; Guilin Han; Qixin Wu; Yang Tang. 2019. "Effects of agricultural alkaline substances on reducing the rainwater acidification: Insight from chemical compositions and calcium isotopes in a karst forests area." Agriculture, Ecosystems & Environment 290, no. : 106782.
Climate changes and other human activities have substantially altered the hydrological cycle with respect to elevation. In this study, longitudinal patterns in the stable isotopic composition (δ2H and δ18O) of Lancang River water, originating from the Qinghai–Tibetan Plateau, are presented, and several controlling factors in the wet season are hypothesized. Lancang River water δ2H (−145.2‰ to −60.7‰) and δ18O (−18.51‰ to −8.49‰) were low but close to those of the Global Meteoric Water Line. In the upper reaches of the river, δ2H decreased longitudinally, potentially due to groundwater inputs and melting ground ice in the headwater zone and to an increasing proportion of glacier meltwater with decreasing elevation. In the middle reaches of the river, δ2H values increased slowly moving downstream, likely due to shifts in precipitation inputs, as evidenced by the isotopic composition of tributaries to the main stream. In the lower reaches of the river, the isotopic composition was relatively invariant, potentially related to the presence of large artificial reservoirs that increase the water resident time. The results reveal different hydrological patterns along an alpine river in central Asia associated with both natural and anthropogenic processes. Understanding the degree and type of human interference with the water cycle in this region could improve water management and water security.
Kunhua Yang; Guilin Han; Jie Zeng; Bin Liang; Rui Qu; Jinke Liu; Man Liu; Liu. Spatial Variation and Controlling Factors of H and O Isotopes in Lancang River Water, Southwest China. International Journal of Environmental Research and Public Health 2019, 16, 4932 .
AMA StyleKunhua Yang, Guilin Han, Jie Zeng, Bin Liang, Rui Qu, Jinke Liu, Man Liu, Liu. Spatial Variation and Controlling Factors of H and O Isotopes in Lancang River Water, Southwest China. International Journal of Environmental Research and Public Health. 2019; 16 (24):4932.
Chicago/Turabian StyleKunhua Yang; Guilin Han; Jie Zeng; Bin Liang; Rui Qu; Jinke Liu; Man Liu; Liu. 2019. "Spatial Variation and Controlling Factors of H and O Isotopes in Lancang River Water, Southwest China." International Journal of Environmental Research and Public Health 16, no. 24: 4932.
To examine the chemical composition, potential sources of solutes, and water quality of Lancangjiang River, the concentrations of major ions (Ca2+, Mg2+, Na+, K+, HCO3−, SO42−, Cl− and NO3−) in 45 river water samples collected in July and August 2019 were determined. Ca2+ and HCO3− are the predominant ions in river water. The extremely low K+ and NO3− concentrations and the sparse population suggest that the anthropogenic inputs are limited. The Pearson correlation coefficients and the elemental ratios Ca2+/Na+ versus Mg2+/Na+, Ca2+/Na versus HCO3−/Na+, [Ca2+ + Mg2+]/[HCO3−] versus [SO42−]/[HCO3−] reveal the mixing processes of different sources; the chemical composition of the river water is controlled by the mixture of carbonate weathering, evaporite weathering and silicate weathering inputs. To quantify the contributions of atmospheric input and rock dissolution, the forward method is employed in this study, which is based on the mass balance equation. The calculation results suggest the carbonate weathering inputs and gypsum dissolution make up the majority of the riverine cations, while silicate weathering and halite dissolution constitutes a relatively small proportion, the contributions of the atmospheric input are limited. The fast dissolution rate of evaporite and carbonate minerals and their lithologic distributions should be the key factor. To evaluate the water quality for drinking and irrigation purposes, the drinking water quality guidelines and the calculated parameters were employed, including sodium adsorption ratio (SAR), soluble sodium percentage (Na%,) and residual sodium carbonate (RSC). The assessments indicate that the river waters in the middle-lower reaches are generally suitable for irrigation and drinking purpose, and will not lead to health and soil problems, such as soil compaction and salinization. While in the upper reaches, the dissolution of carbonate and gypsum minerals transport abundant ions into river water and the river waters are not appropriate to use directly. This result highlights that the water quality status can also be affected by natural weathering processes in the area without anthropogenic inputs, where the long-time monitoring of water quality is also necessary.
Jinke Liu; Guilin Han; Man Liu; Jie Zeng; Bin Liang; Rui Qu. Distribution, Sources and Water Quality Evaluation of the Riverine Solutes: A Case Study in the Lancangjiang River Basin, Tibetan Plateau. International Journal of Environmental Research and Public Health 2019, 16, 4670 .
AMA StyleJinke Liu, Guilin Han, Man Liu, Jie Zeng, Bin Liang, Rui Qu. Distribution, Sources and Water Quality Evaluation of the Riverine Solutes: A Case Study in the Lancangjiang River Basin, Tibetan Plateau. International Journal of Environmental Research and Public Health. 2019; 16 (23):4670.
Chicago/Turabian StyleJinke Liu; Guilin Han; Man Liu; Jie Zeng; Bin Liang; Rui Qu. 2019. "Distribution, Sources and Water Quality Evaluation of the Riverine Solutes: A Case Study in the Lancangjiang River Basin, Tibetan Plateau." International Journal of Environmental Research and Public Health 16, no. 23: 4670.
Atmospheric wet deposition is a vital part of biogeochemical cycles in earth surface environment systems, which is not only controlled by local sources and long-range transported continental substances from natural and anthropogenic sources, but also potentially influenced by the topographical features (e.g. peak clusters and depressions in karst areas). To investigate the depression trapping effect of vertical distribution of rainwater chemical composition and evaluate the effect of trapping by depression on wet deposition flux, rainwater samples from two sites (HR, a hilltop shrubbery area, and LR, inside a depression paddy field area) of a karst agricultural depression in Southwest China, were collected during the rainy season. From these, the major ionic concentrations were measured. The results indicated a variance in pH from 4.8 to 6.4 with a volume-weighted mean (VWM) value of 5.7 at the HR, and, a range of 5.4–6.9 with a VWM of 6.0 at the LR. The VWM concentrations of ions were decreased in the order of SO42- > NH4+ > Ca2+ > NO3- > Mg2+ > K+ > Na+ > Cl− > F− at both sites, and were dominated by SO42-, NH4+, Ca2+, and NO3-, accounting for >87% of the total ions at the two sites. The result of fractional acidity (FA) and neutralization factors (NF) revealed that the relatively high pH values were the result of neutralization of the alkaline substances (NH4+ and Ca2+) rather than the scarcity of acidic materials. Source analysis of major ions showed that anions were predominantly controlled by anthropogenic emission, while cations originated from both terrestrial sources and anthropogenic activity. The vertical distribution of dominant ions (NH4+, NO3-, Ca2+, Mg2+, and SO42-) were ascribed to the relatively weak air convection movement within the depression area (specific atmospheric circulations) and the differences in human interference at two sites (LR, cultivated land; HR, luxuriant vegetation). This is further supported by the more negative rainwater δ15N–NO3- values (−8.5 to −6.0‰), in LR than that in HR (−6.2 to −3.4‰). The depression trapping effect could significantly affect the estimation of wet deposition fluxes (up to 80.6% for Ca2+ and 68.7% for NH4+), which requires consideration in future studies, e.g. N wet deposition.
Jie Zeng; Fu-Jun Yue; Zhong-Jun Wang; Qixin Wu; Cai-Qing Qin; Si-Liang Li. Quantifying depression trapping effect on rainwater chemical composition during the rainy season in karst agricultural area, southwestern China. Atmospheric Environment 2019, 218, 116998 .
AMA StyleJie Zeng, Fu-Jun Yue, Zhong-Jun Wang, Qixin Wu, Cai-Qing Qin, Si-Liang Li. Quantifying depression trapping effect on rainwater chemical composition during the rainy season in karst agricultural area, southwestern China. Atmospheric Environment. 2019; 218 ():116998.
Chicago/Turabian StyleJie Zeng; Fu-Jun Yue; Zhong-Jun Wang; Qixin Wu; Cai-Qing Qin; Si-Liang Li. 2019. "Quantifying depression trapping effect on rainwater chemical composition during the rainy season in karst agricultural area, southwestern China." Atmospheric Environment 218, no. : 116998.
Agricultural land in karst systems can pollute water courses, with polluted waters travelling quickly to and through the sub-surface. Understanding how rapidly nitrate moves within the highly-transmissive karst critical zone (from soils to aquifers) is limited by low resolution data. To understand nitrate behavior and its controls, we deployed sensor technology at five sites to generate autonomously high-resolution time series of discharge and NO3−–N, which is the major nitrogenous component, in a farmed karst catchment in Southwestern China. The [NO3−–N] time series exhibited rapid response to rainfall-induced increases in discharge and a large magnitude in [NO3−–N], from 0.72 to 16.3 mg/L across five sites. However, the magnitude of NO3−–N response at each site was varied during rainfall events (wet season) and dry season. The highest mean [NO3−–N] and normalized annual fluvial export occurred in a headwater catchment with a developed karst aquifer system. Seasonal variation in NO3−–N export occurred in response to source availability, most notable in catchments with valley agriculture: in the wet season up to 94% of nitrate was exported from the headwater catchments within two months, but at the larger catchment scale, over the 6 month wet season, only 61% of total export occurred. At the larger catchment scale, [NO3−–N] were lower due to buffering by the karstic aquifer network. From the time series we observe little decrease in [NO3−–N] as discharge decreases in the dry season, indicating the karst aquifers are chronically-polluted with nitrate through slow flow pathways.
Fu-Jun Yue; Susan Waldron; Si-Liang Li; Zhong-Jun Wang; Jie Zeng; Sen Xu; Zhi-Cai Zhang; David Oliver. Land use interacts with changes in catchment hydrology to generate chronic nitrate pollution in karst waters and strong seasonality in excess nitrate export. Science of The Total Environment 2019, 696, 134062 .
AMA StyleFu-Jun Yue, Susan Waldron, Si-Liang Li, Zhong-Jun Wang, Jie Zeng, Sen Xu, Zhi-Cai Zhang, David Oliver. Land use interacts with changes in catchment hydrology to generate chronic nitrate pollution in karst waters and strong seasonality in excess nitrate export. Science of The Total Environment. 2019; 696 ():134062.
Chicago/Turabian StyleFu-Jun Yue; Susan Waldron; Si-Liang Li; Zhong-Jun Wang; Jie Zeng; Sen Xu; Zhi-Cai Zhang; David Oliver. 2019. "Land use interacts with changes in catchment hydrology to generate chronic nitrate pollution in karst waters and strong seasonality in excess nitrate export." Science of The Total Environment 696, no. : 134062.
To investigate the abundance, water/particle interaction behavior, sources, and potential risk of heavy metals in suspended particulate matter (SPM), a total of 22 SPM samples were collected from the Zhujiang River, Southwest China, in July 2014 (wet season). Nine heavy metal(loid)s (V, Cr, Mn, Ni, Cu, Zn, As, Cd and Pb) in SPM were detected. The results show that the selected heavy metal(loid)s in SPM appear in the following order: Mn (982.4 mg kg−1) > Zn (186.8 mg kg−1) > V (143.6 mg kg−1) > Cr (129.1 mg kg−1) > As (116.8 mg kg−1) > Cu (44.1 mg kg−1) > Ni (39.9 mg kg−1) > Pb (38.1 mg kg−1) > Cd (3.8 mg kg−1). Furthermore, both the enrichment factor (EF) and geo-accumulation index (Igeo) indicate that SPM is extremely enriched in metal(loid)s of Cd and As, while SPM is slightly enriched, or not enriched, in other heavy metals. According to the toxic risk index (TRI) and hazard index (HI), arsenic accounts for the majority of the SPM toxicity (TRI = 8, 48.3 ± 10.4%) and causes the primary health risk (HI > 1), and the potential risks of V and Cr are also not negligible. By applying a correlation matrix and principal component analysis (PCA), three principal components (PC) were identified and accounted for 79.19% of the total variance. PC 1 (V, Cr, Mn, Ni, Cu, and Pb) is controlled by natural origins. PC 2 (As and Cd) is mainly contributed by anthropogenic origins in the basin. PC 3 (Zn) can be attributed to mixed sources of natural and anthropogenic origins. Moreover, all the partition coefficients (lgKd) exceeded 2.9 (arithmetical mean value order: Mn > Pb > Cd > V ≈ Cu > Cr ≈ Ni), indicating the powerful adsorptive ability of SPM for these heavy metal(loid)s during water/particle interaction.
Jie Zeng; Guilin Han; Qixin Wu; Yang Tang. Heavy Metals in Suspended Particulate Matter of the Zhujiang River, Southwest China: Contents, Sources, and Health Risks. International Journal of Environmental Research and Public Health 2019, 16, 1843 .
AMA StyleJie Zeng, Guilin Han, Qixin Wu, Yang Tang. Heavy Metals in Suspended Particulate Matter of the Zhujiang River, Southwest China: Contents, Sources, and Health Risks. International Journal of Environmental Research and Public Health. 2019; 16 (10):1843.
Chicago/Turabian StyleJie Zeng; Guilin Han; Qixin Wu; Yang Tang. 2019. "Heavy Metals in Suspended Particulate Matter of the Zhujiang River, Southwest China: Contents, Sources, and Health Risks." International Journal of Environmental Research and Public Health 16, no. 10: 1843.
The dissolved molybdenum (Mo) contents and Mo isotope in water samples from the upper Xijiang River (XJR), draining the carbonate terrain, southwest China, are reported to investigate the seasonal and spatial variations, sources, ion budget, and isotopic fractionation of dissolved Mo. The results show that the Mo concentrations (5.3–18.9 nmol/L) exhibit an extensive variation along the mainstream without significant spatial pattern, but the Mo concentrations are slightly higher in the dry season than in the wet season caused by the dilution effect. There is a slight spatial tendency for δ98/95Mo to become higher along the mainstream (0.51–1.78%), while the seasonal variations in δ98/95Mo values of NPR (Nanpanjiang River) reach and BPR (Beipanjiang River) reach can be identified higher in the dry season but lower in the wet season. Based on the hydro-geochemical analysis, the sources of dissolved Mo are identified as the carbonates and sulfide/sulfate minerals weathering with a seasonal contribution. Moreover, our results suggest there is no significant Mo isotopic fractionation during weathering and riverine transportation. The calculation of Mo budget demonstrates that the dissolved δ98/95Mo of river draining the carbonate terrain is underestimated, which could significantly influence the redox history of oceans by Mo isotope model.
Jie Zeng; Guilin Han; Jian-Ming Zhu. Seasonal and Spatial Variation of Mo Isotope Compositions in Headwater Stream of Xijiang River Draining the Carbonate Terrain, Southwest China. Water 2019, 11, 1076 .
AMA StyleJie Zeng, Guilin Han, Jian-Ming Zhu. Seasonal and Spatial Variation of Mo Isotope Compositions in Headwater Stream of Xijiang River Draining the Carbonate Terrain, Southwest China. Water. 2019; 11 (5):1076.
Chicago/Turabian StyleJie Zeng; Guilin Han; Jian-Ming Zhu. 2019. "Seasonal and Spatial Variation of Mo Isotope Compositions in Headwater Stream of Xijiang River Draining the Carbonate Terrain, Southwest China." Water 11, no. 5: 1076.