In the present study, six sediment cores were collected from six river-dammed reservoirs to reveal the geochemical distribution of heavy metals(As, Cd, Pb, Sb,and Zn) in the Longjiang River, South China, which is high...In the present study, six sediment cores were collected from six river-dammed reservoirs to reveal the geochemical distribution of heavy metals(As, Cd, Pb, Sb,and Zn) in the Longjiang River, South China, which is highly impacted by nonferrous metal mining and smelting activities. The sediments were geochemically characterized, combining geochemical analysis, sequential extractions, and210 Pb chronology. The results indicated that the river sediments were severely polluted by heavy metals in the order of Cd [ Zn & Pb & Sb [ As. These heavy metals generally exhibited relatively low enrichment in the upstream sediments because of the limited anthropogenic impact, but their abundances drastically increased in the midstream sediments due to local smelting activities. In downstream sediments, the heavy metal concentrations(except for Cd) decreased, owing to the effect of dam interception and detrital inputs. Cadmium levels tended to increase in downstream sediments, which were attributed to the intensive discharge of Cd during the pollution event in 2012. The sedimentary records were traced back to1985, and a significant decrease of heavy metal enrichments could be found after the year 2000, suggesting the enhancement of environmental management in this period.The statistical results indicated that local metal smelting and mining activities were the main anthropogenic contributors for the enrichment of heavy metals in the dammed-river sediments. High enrichment factor and nonresidual fractions of heavy metals in local sediments may pose a direct threat to aquatic organisms. Cd presents significant danger because of its extreme enrichment and high labile fractions.展开更多
Estimating recovery times from pollution incident is an important issue of targeted biomonitoring programs.In the present study,the impact and recovery of macroinvertebrate communities from a cadmium wastewater discha...Estimating recovery times from pollution incident is an important issue of targeted biomonitoring programs.In the present study,the impact and recovery of macroinvertebrate communities from a cadmium wastewater discharge in the Longjiang River,Guangxi,China,in early January 2012 were studied based on 83 samples collected in fi ve surveys within 20 months after the incident.The pollution aff ected seriously the local aquatic biota,and consequently,the invertebrate abundance and species richness were reduced considerably.Twelve months later,the taxonomic number of macroinvertebrates began to increase.However,sensitive taxa remained rare.Twenty months later,the taxon richness and abundance of macroinvertebrates increased signifi cantly compared to those in the previous four time points.To explore the possible time-scale over which pre-disturbance conditions might occur,we chose four diff erent typical metrics of taxa richness(total taxa number,cumulative taxa number,taxa number per samples,and the Shannon-Wiener diversity index)and extrapolated modeled recovery trajectories.Target values for the four metrics were set at average values for sites from the nearby Lijiang River,which were used as a reference.Assuming a continued linear trajectory,the recovery times were estimated to be 52,39,39,and 31 months,respectively,which was roughly 3-5 years.This is consistent with results from recovery times from other studies of acute pollution cases,but contrasted strongly to the much longer recovery times associated with chronic pollution from groundwater contamination and mine-tailing runoff.展开更多
We report a new genus and species of Paleonisciformes-Cretolepis dongbeiensis gen. et sp. nov.,from the Early Cretaceous Longjiang Formation in Qiqihar City, Heilongjiang Province. The new materials can be distinguish...We report a new genus and species of Paleonisciformes-Cretolepis dongbeiensis gen. et sp. nov.,from the Early Cretaceous Longjiang Formation in Qiqihar City, Heilongjiang Province. The new materials can be distinguished from other Paleonisciformes genera by possessing the following characteristics: a sclerotic ring composed of more than five small bones; three pieces of suborbitals; one dermohyomandibular;a jaw hanging apparently inclined anteriorly; long and tall horizontal branch of the preopercular, a short vertical branch, with the angle formed by the two branches slightly higher than 90°; a triangular dorsal fin in the middle point between the pelvic and anal fins. The discovery of Mesozoic Paleonisciformes in northeastern China adds to the biodiversity and geographic distribution of Paleonisciformes.展开更多
[Objectives] The purpose of this research was to investigate the water quality of the Longjiang River in Guangxi. Concentrations of heavy metals( As,Cd,Zn,Pb and Cu) in the surface water of Longjiang River were analyz...[Objectives] The purpose of this research was to investigate the water quality of the Longjiang River in Guangxi. Concentrations of heavy metals( As,Cd,Zn,Pb and Cu) in the surface water of Longjiang River were analyzed to figure out the distribution characteristics of heavy metal pollutants in this area. [Methods]The Nemerow comprehensive index method and the health risk assessment model were adopted to evaluate the grade of Longjiang River water quality and the health risk level imposed by heavy metals in the water. [Results] The concentrations of heavy metals in each sampling point conformed to Grade-II water quality standard. The water samples collected on 13 sampling points of the Longjiang River were clean and not polluted by heavy metals. The health risk values of heavy metals As and Zn were greater than Cd,Pb and Cu in the Longjiang River,but still lower than the maximum acceptable risk level 5. 0 × 10^(-5)a^(-1). [Conclusions]Water quality condition reflected by the comprehensive pollution index and the health risk value of heavy metal was consistent in the Longjiang River,showing as that the value in middle and lower reaches was slightly higher than in the upper reaches. As is the major pollutant of water environment health risk in the Longjiang River,and it should be regarded as the key object of water environment risk management in Longjiang River.展开更多
Wetland is a unique habitat with great biodiversity and important ecological functions between land and water on the earth. With the irrational utilization of wetland resources, the ecological destruction and pollutio...Wetland is a unique habitat with great biodiversity and important ecological functions between land and water on the earth. With the irrational utilization of wetland resources, the ecological destruction and pollution of wetland are becoming more and more serious. To evaluate the pollution of heavy metals in the sediments of Longjiang Wetland in Binzhou City, chromium(Cr), copper(Cu), zinc(Zn), cadmium(Cd) and lead(Pb) were measured by inductively coupled plasma mass spectrometry. Concentrations of Cr, Cu, Zn, Cd and Pb in the sediments were 5.3–13.6, 5.6–15.0, 16.6–33.0, 0.1–0.4 and 7.9–24.9 mg/kg dry weight, respectively. The concentrations of heavy metals in Longjiang Wetland was lower than soil background values of Shandong Province and in lower level compared with those reported in sediments/soils of wetlands in some other locations. Based on geo-accumulation index(Igeo), Cr, Cu, Zn and Pb showed low levels of contamination at all stations, while Cd was observed at a moderate pollution degree. Potential ecological risk factor(E_r^i) and risk index(RI) values showed low ecological risk of heavy metals in sediments of the wetland.展开更多
基金funded the National Natural Science Foundation of China (41473124, 41673138)
文摘In the present study, six sediment cores were collected from six river-dammed reservoirs to reveal the geochemical distribution of heavy metals(As, Cd, Pb, Sb,and Zn) in the Longjiang River, South China, which is highly impacted by nonferrous metal mining and smelting activities. The sediments were geochemically characterized, combining geochemical analysis, sequential extractions, and210 Pb chronology. The results indicated that the river sediments were severely polluted by heavy metals in the order of Cd [ Zn & Pb & Sb [ As. These heavy metals generally exhibited relatively low enrichment in the upstream sediments because of the limited anthropogenic impact, but their abundances drastically increased in the midstream sediments due to local smelting activities. In downstream sediments, the heavy metal concentrations(except for Cd) decreased, owing to the effect of dam interception and detrital inputs. Cadmium levels tended to increase in downstream sediments, which were attributed to the intensive discharge of Cd during the pollution event in 2012. The sedimentary records were traced back to1985, and a significant decrease of heavy metal enrichments could be found after the year 2000, suggesting the enhancement of environmental management in this period.The statistical results indicated that local metal smelting and mining activities were the main anthropogenic contributors for the enrichment of heavy metals in the dammed-river sediments. High enrichment factor and nonresidual fractions of heavy metals in local sediments may pose a direct threat to aquatic organisms. Cd presents significant danger because of its extreme enrichment and high labile fractions.
基金Supported by the Environmental Protection Department of China(No.PM-ZX019-201207-018)the National Natural Science Foundation of China(No.31100407)。
文摘Estimating recovery times from pollution incident is an important issue of targeted biomonitoring programs.In the present study,the impact and recovery of macroinvertebrate communities from a cadmium wastewater discharge in the Longjiang River,Guangxi,China,in early January 2012 were studied based on 83 samples collected in fi ve surveys within 20 months after the incident.The pollution aff ected seriously the local aquatic biota,and consequently,the invertebrate abundance and species richness were reduced considerably.Twelve months later,the taxonomic number of macroinvertebrates began to increase.However,sensitive taxa remained rare.Twenty months later,the taxon richness and abundance of macroinvertebrates increased signifi cantly compared to those in the previous four time points.To explore the possible time-scale over which pre-disturbance conditions might occur,we chose four diff erent typical metrics of taxa richness(total taxa number,cumulative taxa number,taxa number per samples,and the Shannon-Wiener diversity index)and extrapolated modeled recovery trajectories.Target values for the four metrics were set at average values for sites from the nearby Lijiang River,which were used as a reference.Assuming a continued linear trajectory,the recovery times were estimated to be 52,39,39,and 31 months,respectively,which was roughly 3-5 years.This is consistent with results from recovery times from other studies of acute pollution cases,but contrasted strongly to the much longer recovery times associated with chronic pollution from groundwater contamination and mine-tailing runoff.
基金financially supported by the China Geological Survey (Grants No. DD20160207, DD20160126)
文摘We report a new genus and species of Paleonisciformes-Cretolepis dongbeiensis gen. et sp. nov.,from the Early Cretaceous Longjiang Formation in Qiqihar City, Heilongjiang Province. The new materials can be distinguished from other Paleonisciformes genera by possessing the following characteristics: a sclerotic ring composed of more than five small bones; three pieces of suborbitals; one dermohyomandibular;a jaw hanging apparently inclined anteriorly; long and tall horizontal branch of the preopercular, a short vertical branch, with the angle formed by the two branches slightly higher than 90°; a triangular dorsal fin in the middle point between the pelvic and anal fins. The discovery of Mesozoic Paleonisciformes in northeastern China adds to the biodiversity and geographic distribution of Paleonisciformes.
基金Supported by Key Project of Guangxi Natural Science Foundation(2013GXNSFEA053001)
文摘[Objectives] The purpose of this research was to investigate the water quality of the Longjiang River in Guangxi. Concentrations of heavy metals( As,Cd,Zn,Pb and Cu) in the surface water of Longjiang River were analyzed to figure out the distribution characteristics of heavy metal pollutants in this area. [Methods]The Nemerow comprehensive index method and the health risk assessment model were adopted to evaluate the grade of Longjiang River water quality and the health risk level imposed by heavy metals in the water. [Results] The concentrations of heavy metals in each sampling point conformed to Grade-II water quality standard. The water samples collected on 13 sampling points of the Longjiang River were clean and not polluted by heavy metals. The health risk values of heavy metals As and Zn were greater than Cd,Pb and Cu in the Longjiang River,but still lower than the maximum acceptable risk level 5. 0 × 10^(-5)a^(-1). [Conclusions]Water quality condition reflected by the comprehensive pollution index and the health risk value of heavy metal was consistent in the Longjiang River,showing as that the value in middle and lower reaches was slightly higher than in the upper reaches. As is the major pollutant of water environment health risk in the Longjiang River,and it should be regarded as the key object of water environment risk management in Longjiang River.
基金Sponsored by the Natural Science Foundation of Shandong Province(ZR2018PD002)
文摘Wetland is a unique habitat with great biodiversity and important ecological functions between land and water on the earth. With the irrational utilization of wetland resources, the ecological destruction and pollution of wetland are becoming more and more serious. To evaluate the pollution of heavy metals in the sediments of Longjiang Wetland in Binzhou City, chromium(Cr), copper(Cu), zinc(Zn), cadmium(Cd) and lead(Pb) were measured by inductively coupled plasma mass spectrometry. Concentrations of Cr, Cu, Zn, Cd and Pb in the sediments were 5.3–13.6, 5.6–15.0, 16.6–33.0, 0.1–0.4 and 7.9–24.9 mg/kg dry weight, respectively. The concentrations of heavy metals in Longjiang Wetland was lower than soil background values of Shandong Province and in lower level compared with those reported in sediments/soils of wetlands in some other locations. Based on geo-accumulation index(Igeo), Cr, Cu, Zn and Pb showed low levels of contamination at all stations, while Cd was observed at a moderate pollution degree. Potential ecological risk factor(E_r^i) and risk index(RI) values showed low ecological risk of heavy metals in sediments of the wetland.
