In this paper, the contents and various forms of Cd, Cu, Zn and Pb in the sediments of the Xiangjiang River have been investigated. The presentation of this paper focuses on the various forms and characteristics of th...In this paper, the contents and various forms of Cd, Cu, Zn and Pb in the sediments of the Xiangjiang River have been investigated. The presentation of this paper focuses on the various forms and characteristics of the heavy metals in the column sediments at Xiawan Port of Zhuzhou, which has been severely polluted by a metallurgical plant.The forms of the heavy metals discussed in this paper are: The concentration of the exchangeable forms of Cd, Cu, Zn and Pb, in the forms of carbonates and Fe/ Mn oxide in water, the combination of Cu with organic matter and form, and the proportion of the residue form at each section have been studied.展开更多
The general form of the north-branch of the Changjiang River mouth has changed much as a result of the change of the main stream lines of the Nantong reach of the Changjiang River and the influence of human activities...The general form of the north-branch of the Changjiang River mouth has changed much as a result of the change of the main stream lines of the Nantong reach of the Changjiang River and the influence of human activities since 1915. By the 1930s, the main stream lines of the Nantong reach of the Changjiang River has shifted to the Tongzhou Bar west channel. The north-branch at the Changjiang River mouth has become atrophic because of Tongzhou Bar east channel's deposition. After 1958, Toughal Bar and Jiangxin Bar were exploited. And in 1970, the north channel of Jiangxin Bar was blocked up. All these things make the water of the north-branch more difficult to pass through. It leads to the decline of the total discharge percentage of the north-branch. And it causes the rising tide to go back to the south-branch. However, since 1978, with the development of Tongzhou Bar east channel and its left bank being scoured, the water amount of the north-branch has been increasing. And the water,load and salt of going back to the south-branch has been becoming less.展开更多
Several argillaceous platforms lie along the Yellow River（YR） of the eastern Guide Basin, northeastern Tibetan Plateau, and their compositions, formation processes, and geomorphic evolution remain debated. Using fie...Several argillaceous platforms lie along the Yellow River（YR） of the eastern Guide Basin, northeastern Tibetan Plateau, and their compositions, formation processes, and geomorphic evolution remain debated. Using field survey data, sample testing, and high-resolution remote sensing images, the evolution of the Erlian mudflow fans are analyzed. The data show significant differences between fans on either side of the YR. On the right bank, fans are dilute debris flows consisting of sand and gravel. On the left bank, fans are viscosity mudflows consisting of red clay. The composition and formation processes of the left bank platforms indicate a rainfall-induced pluvial landscape. Fan evolution can be divided into two stages： early-stage fans pre-date 16 ka B.P., and formed during the last deglaciation; late-stage fans post-date 8 ka B.P.. Both stages were induced by climate change. The data indicate that during the Last Glacial Maximum, the northeastern Tibetan Plateau experienced a cold and humid climate characterized by high rainfall. From 16–8 ka, the YR cut through the Erlian early mudflow fan, resulting in extensive erosion. Since 8 ka, the river channel has migrated south by at least 1.25 km, and late stage mudflow fan formation has occurred.展开更多
The distribution of different nitrogen forms and their spatial and temporal variations in different pollution types of tributaries or reaches were investigated. Based on the catchments characteristics the tributaries ...The distribution of different nitrogen forms and their spatial and temporal variations in different pollution types of tributaries or reaches were investigated. Based on the catchments characteristics the tributaries or reaches can be classified into 4 types, including headwater in mountainous areas （type Ⅰ）, agricultural non-point source （NPS） pollution in rural areas （type Ⅱ）, municipal and industrial pollution in urban areas （type Ⅲ）, and combined pollution in main stream （type IV）. Water samples were collected monthly from July 2003 to June 2006 in the Cao-E River Basin in Zhejiang, eastern China. The concentrations of NO3^--N, NH4^＋ -N, and total nitrogen （TN） were measured. The mean concentrations of NO3^- -N were decreased in the sequence type IV 〉 type Ⅱ〉 type Ⅲ 〉 type Ⅰ, whereas, NH4^＋-N, total organic nitrogen （TON）, and TN were in the sequence： type Ⅲ〉 type Ⅳ 〉 type Ⅱ〉 type Ⅰ. In headwater and rural reaches, CNO^-2-N was much higher than Crea^＋ 4-N. In urban reaches, TON and NH4^＋ -N were the main forms, accounting for 54.7% and 32.1% of TN, respectively. In the whole river system, Crea^＋ 4--N decreased with increasing distance from cities, and CNo^-3 -N increased with the increasing area of farmland in the catchments. With increased river flow, CNO^-3 N increased and Crea4^＋-N decreased in all types of reaches, while the variations of CTON and CTN were different. For TN, the concentration may be decreased with the increase of river flow, but the export load always increased.展开更多
Black flies, vectors of Onchocercavolvulus, are known to colonize fast flowing sections of rivers.A study on aspects of ecology of immature forms of black flies was conducted at River Mada. Larvae and Pupae of the Gen...Black flies, vectors of Onchocercavolvulus, are known to colonize fast flowing sections of rivers.A study on aspects of ecology of immature forms of black flies was conducted at River Mada. Larvae and Pupae of the Genus: Simulium were prospected on natural substrates found at various water currents along the course of the river over a 12-month period. Larvae of six speciesand pupae of three species were identified colonizing different substrates in the river. A total of 443 larvae and 142 pupae were collected, and thepeak month of collection was April. 405 (91.4%) larvae were identified as S.damnosum sl while 38 (8.6%) comprised S. adersi, S.hargreavesi, S.cervicornotum, S. bovisand S.vorax. 110 (77.5%) of the pupae collected were S.damnosumsl while 32 (22.5%) were S.adersi, and S.hargreavesi. The larvae unlike pupae appeared to be non discriminatory in substrate colonization and current preference. Paucity of the population of immature forms is observed and attributed primarily to scarcity of suitable substrates and other factors also discussed herein.展开更多
The five chemical bound forms of Fe, Al and Mn in sediments in the main channel of the Zhujiang River.and its estuary, namely, exchangeable, carbonic, oxidative, organic and residual (in crystal) forms, were determine...The five chemical bound forms of Fe, Al and Mn in sediments in the main channel of the Zhujiang River.and its estuary, namely, exchangeable, carbonic, oxidative, organic and residual (in crystal) forms, were determined. The method of sequential extraction was used for separating the five bound forms.The main chemical form of the three elements in the sediments of the Zhujiang River and its estuarine zone is the residual one. The exchangeable form exists only in a small fraction.Correlationships between the concentration of a certain form of heavy metals and Eh. pH and salinity were discussed. The principles of geochemistry are used to explain the mechanism of heavy metal transport in the river.It was also found that the distribution rule of the chemical forms of Fe, Al and Mn in sediments in the lower reaches of the Zhujiang River was similar to the one in the lower reaches of the Yamaska River.展开更多
An improved sequential extraction method was used to extract and determine 7 forms of phosphorus exchangeable or loosely sorbed P (Ads P), aluminum bound P (Al P), iron bound P (Fe P), occluded P (Occ P), authigenic a...An improved sequential extraction method was used to extract and determine 7 forms of phosphorus exchangeable or loosely sorbed P (Ads P), aluminum bound P (Al P), iron bound P (Fe P), occluded P (Occ P), authigenic apatite plus biogenic apatite plus CaCO 3- associated P (CFAP P), detrital apatite P (FAP P), and organic bound P (Org P) in suspended matter and surface sediments of the Huanghe River (Yellow River), its estuary and nearby shelf. The concentrations of dissolved inorganic and organic P in river water were also determined. A dissolved P flux of 1.6 billion grams per year, solubilized P flux of 281 billion grams per year, and buried P flux of 588 billion grams per year from the Huanghe River to the Bohai Sea were calculated using the concentrations of P determined in the water column, suspended matter and sediments. Due to the high suspended load and low discharge of the Huanghe River, the direct contribution of dissolved P carried in solution by it to the Bohai Sea is minor compared to the solubilized P released from the suspended matter and sediments. More than two thirds of the total P transported by the Huanghe River is deposited and buried in marine sediments. Decomposition of riverine organic matter which releases organic bound P is an essential source of dissolved/solubilized P in the sea.展开更多
文摘In this paper, the contents and various forms of Cd, Cu, Zn and Pb in the sediments of the Xiangjiang River have been investigated. The presentation of this paper focuses on the various forms and characteristics of the heavy metals in the column sediments at Xiawan Port of Zhuzhou, which has been severely polluted by a metallurgical plant.The forms of the heavy metals discussed in this paper are: The concentration of the exchangeable forms of Cd, Cu, Zn and Pb, in the forms of carbonates and Fe/ Mn oxide in water, the combination of Cu with organic matter and form, and the proportion of the residue form at each section have been studied.
文摘The general form of the north-branch of the Changjiang River mouth has changed much as a result of the change of the main stream lines of the Nantong reach of the Changjiang River and the influence of human activities since 1915. By the 1930s, the main stream lines of the Nantong reach of the Changjiang River has shifted to the Tongzhou Bar west channel. The north-branch at the Changjiang River mouth has become atrophic because of Tongzhou Bar east channel's deposition. After 1958, Toughal Bar and Jiangxin Bar were exploited. And in 1970, the north channel of Jiangxin Bar was blocked up. All these things make the water of the north-branch more difficult to pass through. It leads to the decline of the total discharge percentage of the north-branch. And it causes the rising tide to go back to the south-branch. However, since 1978, with the development of Tongzhou Bar east channel and its left bank being scoured, the water amount of the north-branch has been increasing. And the water,load and salt of going back to the south-branch has been becoming less.
基金financially supported by the National Nature Science Foundation of China under Grant No.41372333,41172158China Geological Survey(grant No.1212011220123)
文摘Several argillaceous platforms lie along the Yellow River（YR） of the eastern Guide Basin, northeastern Tibetan Plateau, and their compositions, formation processes, and geomorphic evolution remain debated. Using field survey data, sample testing, and high-resolution remote sensing images, the evolution of the Erlian mudflow fans are analyzed. The data show significant differences between fans on either side of the YR. On the right bank, fans are dilute debris flows consisting of sand and gravel. On the left bank, fans are viscosity mudflows consisting of red clay. The composition and formation processes of the left bank platforms indicate a rainfall-induced pluvial landscape. Fan evolution can be divided into two stages： early-stage fans pre-date 16 ka B.P., and formed during the last deglaciation; late-stage fans post-date 8 ka B.P.. Both stages were induced by climate change. The data indicate that during the Last Glacial Maximum, the northeastern Tibetan Plateau experienced a cold and humid climate characterized by high rainfall. From 16–8 ka, the YR cut through the Erlian early mudflow fan, resulting in extensive erosion. Since 8 ka, the river channel has migrated south by at least 1.25 km, and late stage mudflow fan formation has occurred.
基金supported by the National Natural Science Foundation of China (No. 40571070)the National Basic Research Program (973) of China (No.2002CB410807)the Project of Science and Technology of Zhejiang Province (No. 2004C33067)
文摘The distribution of different nitrogen forms and their spatial and temporal variations in different pollution types of tributaries or reaches were investigated. Based on the catchments characteristics the tributaries or reaches can be classified into 4 types, including headwater in mountainous areas （type Ⅰ）, agricultural non-point source （NPS） pollution in rural areas （type Ⅱ）, municipal and industrial pollution in urban areas （type Ⅲ）, and combined pollution in main stream （type IV）. Water samples were collected monthly from July 2003 to June 2006 in the Cao-E River Basin in Zhejiang, eastern China. The concentrations of NO3^--N, NH4^＋ -N, and total nitrogen （TN） were measured. The mean concentrations of NO3^- -N were decreased in the sequence type IV 〉 type Ⅱ〉 type Ⅲ 〉 type Ⅰ, whereas, NH4^＋-N, total organic nitrogen （TON）, and TN were in the sequence： type Ⅲ〉 type Ⅳ 〉 type Ⅱ〉 type Ⅰ. In headwater and rural reaches, CNO^-2-N was much higher than Crea^＋ 4-N. In urban reaches, TON and NH4^＋ -N were the main forms, accounting for 54.7% and 32.1% of TN, respectively. In the whole river system, Crea^＋ 4--N decreased with increasing distance from cities, and CNo^-3 -N increased with the increasing area of farmland in the catchments. With increased river flow, CNO^-3 N increased and Crea4^＋-N decreased in all types of reaches, while the variations of CTON and CTN were different. For TN, the concentration may be decreased with the increase of river flow, but the export load always increased.
文摘Black flies, vectors of Onchocercavolvulus, are known to colonize fast flowing sections of rivers.A study on aspects of ecology of immature forms of black flies was conducted at River Mada. Larvae and Pupae of the Genus: Simulium were prospected on natural substrates found at various water currents along the course of the river over a 12-month period. Larvae of six speciesand pupae of three species were identified colonizing different substrates in the river. A total of 443 larvae and 142 pupae were collected, and thepeak month of collection was April. 405 (91.4%) larvae were identified as S.damnosum sl while 38 (8.6%) comprised S. adersi, S.hargreavesi, S.cervicornotum, S. bovisand S.vorax. 110 (77.5%) of the pupae collected were S.damnosumsl while 32 (22.5%) were S.adersi, and S.hargreavesi. The larvae unlike pupae appeared to be non discriminatory in substrate colonization and current preference. Paucity of the population of immature forms is observed and attributed primarily to scarcity of suitable substrates and other factors also discussed herein.
文摘The five chemical bound forms of Fe, Al and Mn in sediments in the main channel of the Zhujiang River.and its estuary, namely, exchangeable, carbonic, oxidative, organic and residual (in crystal) forms, were determined. The method of sequential extraction was used for separating the five bound forms.The main chemical form of the three elements in the sediments of the Zhujiang River and its estuarine zone is the residual one. The exchangeable form exists only in a small fraction.Correlationships between the concentration of a certain form of heavy metals and Eh. pH and salinity were discussed. The principles of geochemistry are used to explain the mechanism of heavy metal transport in the river.It was also found that the distribution rule of the chemical forms of Fe, Al and Mn in sediments in the lower reaches of the Zhujiang River was similar to the one in the lower reaches of the Yamaska River.
文摘An improved sequential extraction method was used to extract and determine 7 forms of phosphorus exchangeable or loosely sorbed P (Ads P), aluminum bound P (Al P), iron bound P (Fe P), occluded P (Occ P), authigenic apatite plus biogenic apatite plus CaCO 3- associated P (CFAP P), detrital apatite P (FAP P), and organic bound P (Org P) in suspended matter and surface sediments of the Huanghe River (Yellow River), its estuary and nearby shelf. The concentrations of dissolved inorganic and organic P in river water were also determined. A dissolved P flux of 1.6 billion grams per year, solubilized P flux of 281 billion grams per year, and buried P flux of 588 billion grams per year from the Huanghe River to the Bohai Sea were calculated using the concentrations of P determined in the water column, suspended matter and sediments. Due to the high suspended load and low discharge of the Huanghe River, the direct contribution of dissolved P carried in solution by it to the Bohai Sea is minor compared to the solubilized P released from the suspended matter and sediments. More than two thirds of the total P transported by the Huanghe River is deposited and buried in marine sediments. Decomposition of riverine organic matter which releases organic bound P is an essential source of dissolved/solubilized P in the sea.
