River Systems In China Research Articles

Occurrence and a screening‐level risk assessment of human pharmaceuticals in the Pearl River system, South China

Ten nonsteroidal antiinflammatory drugs (NSAIDs), two blood lipid regulators (BLRs), and two antiepileptic drugs (AEDs) were analyzed in the Pearl River system in China (i.e., Liuxi, Zhujiang, and Shijing Rivers) and four sewage effluents during the dry and wet seasons, and the environmental risks they posed were assessed. Eight pharmaceuticals were detected in the rivers and effluents, including five NSAIDs (salicylic acid, ibuprofen, diclofenac, mefenamic acid, and naproxen), two BLRs (clofibric acid and gemfibrozil), and one AED (carbamazepine). The median concentrations for the eight pharmaceuticals ranged from 11.2 to 102 ng/L. Seasonal variations were not obvious for most pharmaceuticals in the three rivers, except for salicylic acid and clofibric acid in the Zhujiang River, and diclofenac in the Zhujiang and Shijing Rivers. However, spatially considerable variations in the concentrations were observed for the eight pharmaceuticals in all three rivers. For most of the pharmaceuticals, the effluents from the four wastewater treatment plants and Shijing River water were found to be the major discharge sources for the Zhujiang River, but with additional discharge sources from some small urban streams in the wet season. Diclofenac in the Shijing River was the only pharmaceutical that had a risk quotient (RQ) >1, indicating a high risk to aquatic organisms in the river. Although higher RQs were calculated for the mixture of the pharmaceuticals in each river, the risk rating remained the same for the three rivers with the RQ being >1 only in Shijing River.

Occurrence and risks of triclosan and triclocarban in the Pearl River system, South China: From source to the receiving environment

We investigated two commonly used antimicrobial agents triclosan (TCS) and triclocarban (TCC) in the Pearl River system in China (i.e., Liuxi, Zhujiang and Shijing Rivers) and four sewage effluents during dry and wet seasons. The median values for TCS and TCC were the highest in the surface water and sediments of the Shijing River, followed by the Zhujiang River and Liuxi River. Screening level risk assessment using the risk quotient (RQ) method showed that TCS and TCC in surface water posed median risks in the Zhujiang and Liuxi Rivers (RQs: 0.28–0.62 for TCS, and 0.15–0.80 for TCC) and high risks in the Shijing River (RQs: 5.15–9.55 for TCS, and 3.32–5.83 for TCC). Higher risks (RQs: 3.63–28.47 for TCS, and 3.13–24.54 for TCC) were found in the sediments than in surface water of the Pearl River system. The four sewage effluents and Shijing River as well as other urban streams in Guangzhou metropolitan area were identified as the sources of the two compounds in the main river Zhujiang River. The mass inventories of TCS and TCC in the Pearl River system indicate that the sediments are not only an important sink but also a potential source for the two compounds in surface water.

Effect of nutrient level on phytoplankton community structure in different water bodies

Increasing levels of pollution within water bodies can cause eutrophication and an associated rapid growth in and reproduction of phytoplankton. Although most frequently occurring in bodies of water such as lakes and dams, in recent years an increasing number of river systems in China have suffered serious algal blooms. The community structure of phytoplankton may differ, however, dependent on the hydrodynamic conditions and nutrient levels within the water body. The field investigation results obtained from a stagnant river in Suzhou City and Taihu Lake, China, showed that in water with higher concentrations of nitrogen and phosphorus, Chlorophyta became the predominant species and in water with lower concentrations of nitrogen and phosphorus, Cyanobacteria became the predominant species. Growth experiments with competitive species, Microcystis aeruginosa Kütz and Scenedesmus quadricauda (Turp.), were conducted at three different nutrient levels. The biomass of algae in pure and mixed cultures was measured under conditions of different N/P ratios at oligotrophic, eutrophic and hypertrophic nutrient levels. The results indicated that the most suitable state for the growth and reproduction of M. aeruginosa and S. quadricauda were eutrophic conditions in both pure and mixed cultures. Under competition, however, the lower medium nutrient levels favoured M. aeruginosa, while the higher medium nutrient levels better suited S. quadricauda. Under similar hydrodynamic conditions, the community structure of phytoplankton in the water body was determined by the dominant species in competition for nutrients.

GRASS CARP (<I>CTENOPHARYNGODON IDELLUS</I>) GENETIC STRUCTURE ANALYSIS AMONG NATIVE POPULATIONS IN CHINA AND INTRODUCED POPULATIONS IN USA, EUROPE AND JAPAN BASED ON MITOCHONDRIAL SEQUENCE

Grass carp (Ctenopharyngodon idellus) is one of the most important freshwater species in aquaculture. Meanwhile,the grass carp is originally distributes in China,and then it has been introduced into more than 100 countries for aquatic weed control and aquaculture since 1960s. In the past five decades,the grass carps have been adapted to the local environment and developed local groups. However,the genetic variation among the grass carps in native and introduced regions,as well the genetic phylogeny,is not clear. Meanwhile,there is no available literature to clarify which river systems in China are the most likely origins of colonized populations in introduced regions. In this study,partial sequences of the mitochondrial D-Loop (764bp),COII+tRNA (719bp) were analyzed from native (the Yangtze,Amur and Pearl Rivers in China) and introduced (the Danube River in Hungary,the Mississippi River in USA and the Tonegawa River in Japan) populations of the grass carp. The data of the two mtDNA fragments showed no competitive with the ILD (Incongruence Length Difference) test (p=0.42),and they could combine together as one data. The results indicated that there were the total of 32 haplotypes in all specimens,and 5 haplotypes were shared,all other haplotypes were singletons. In the 5 shared haplotypes,one was found in all populations,one in Amur River and Pearl River,two in China and Hungary,and the last one was found only in China. The genetic variation in the native populations was higher than that in the colonized populations. In the native populations,the genetic diversity ordered as the Pearl Rivers (π=0.0042) Yangtze River (π=0.0028) Amur River (π=0.0013). In the introduced populations,the genetic diversity ordered as the Danube River (π=0.0019) Mississippi River (π=0.0010) Tonegawa River (π=0.0001). The analysis of AMOVA using Arlequin 3.01 indicated that the variation mostly existed within populations (77.27%),but it was very low contribution from the sampling regions (0.38%). The pairwise FST values demonstrated that there was a significant differentiation in most pairwise populations. The Tajima's D values were significant negative in the populations of the Amur River and Mississippi River (was marginable significance in Tonegawa River),which demonstrating the recent population expansion in their histories,and were positive in the other populations. Base on the software TCS 1.21,the haplotype network showed that the Yangtze River population would be the most original and then expanded to other rivers. Based on the base composition,transition/transversion values from the software MEGA4,the gene flow among populations using the software Migrate-2.4.3 showed that the Danube River population and the Tonegawa River population might have two origins from China,namely the Yangtze and Amur River,the Mississippi River population might have three origins,the Yangtze,Amur and Pearl Rivers. The gene flow gave a sign that all grass carp populations would be derived from the Yangtze River,which is agreement with the results of the haplotype network.

Phosphorus content and fractionation of phosphate in the surface sediments of the Daliao river system in China

The Daliao river system in China has been seriously affected by long-term intensive industrial, urban and agricultural activities. The objectives of this study were to determine the total phosphorus (TP) content and forms of phosphate in the sediments and investigate geochemical relationships between P forms and sediment mineral phases. Twenty-seven samples of surface sediments were collected and analyzed for P and major elements. Chemical forms of phosphate in the sediments were measured by sequential selective extraction method. Results indicate that TP in the sediments of the Daliao river system averaged 703 mg kg−1, in the range from 206 to 1,342 mg kg−1. The sediments in the tributaries and near cities contained high TP, due to discharge of municipal and industrial effluents. The distribution of phosphate in the various mineral phases followed the order: Ca-P > RES-P > RS-P > Fe-P > Al-P > S/L-P for the Hun river and Taizi river, and Ca-P > Fe-P > RES-P > RS-P > Al-P > S/L-P for the Daliao river. Fe and Ca contents in the sediments were positively correlated to Fe associated P (Fe-P and RS-P) and Ca-P, respectively. In addition, sediment organic matter, Fe and Ca contents were positively correlated to TP in the sediments. However, Al content was not correlated to Al-P or TP in the sediments. Generally, the sediments contaminated by effluents and in tidal zone contained more bioavailable P. Possible release of P from these sediments to overlying water might pose potential risk on estuarine eutrophication.

Craspedacusta sowerbii, Lankester 1880 – population dispersal analysis using COI and ITS sequences

Craspedacusta sowerbii (Hydrozoa, Limnomedusae, Olindiidae) is a freshwater jellyfish, which was discovered in England in 1880. Although thought to originate in South America, it became obvious that the species is native to the Yangtze River system in China. It has spread from China into lakes all over the world. Many different species, variations and sub-species have been described based on morphological characters. Specimens discovered in North America were described as separate species, as morphological differences appeared to be significant compared to European specimens. Even within Europe, differences were assumed to be obvious. Up to this point, three valid species are published; others are considered by various scientists to be true species as well, but mostly are recognized as variations. To obtain further insight into population dynamics of C. sowerbii as well as molecular information on the species itself, sequences of internal transcribed spacers (ITS) and cytochrome oxidase subunit I (COI) have been used to analyze specimens collected in Germany and Austria. These sequences have been compared to sequences published of different Chinese Craspedacusta species and variations. In addition, morphological descriptions were compared. For the COI sequences, we found uniformity throughout the complete set of samples. However, no comparisons could be made, as no data had been published on COI of Chinese specimens. ITS1, 5.8S and ITS2, including partial 18S and 28S, sequences, were almost uniform within the German populations, showing only minor base pair exchanges. However, comparisons to Chinese organisms indicated, that the investigated sequences of C. sowerbii from Germany and Austria are similar, although not identical in morphology, to Craspedacusta sowerbii var. kiatingi from China. Overall our data support the assumption that there are three valid species, with the possibility of C. ziguiensis being a fourth one, and several, morphological quite different sub-species or variations of the freshwater jellyfish C. sowerbii.

The Glacier Inventory of China

AbstractFollowing recommendations from the International Commission on Snow and Ice for a world glacier inventory, an inventory of glaciers in China was carried out by Chinese glaciologists from 1978 to 2002. Each glacier was measured from aerial photographs and topographical maps and 34 parameters recorded. These parameters were then analyzed statistically for the various river systems in China. Twelve volumes of the Glacier Inventory of China (GIC) have been published, consisting of 22 parts in 21 books. The data were subsequently abridged into a Concise GIC, published in Chinese (2005) and in English (2008), to make the glacier inventory more accessible and better adapted for assessing glacier response to climate change. After the GIC was completed, new aerial photographs became available and remote-sensing techniques became more common. To investigate glacier changes since completion of the first GIC, a second Glacier Inventory of China was initiated in 2007. This 5 year project, supported by the Ministry of Science and Technology, will be undertaken mainly using remote-sensing techniques.

Range-wide Yangtze freshwater dolphin expedition: The last chance to see Baiji?

Background, Aim and Scope There are two species of fresh water cetaceans surviving in the Yangtze River system in China: Baiji (Lipotes vexillifer) and Yangtze finless porpoise (Neophocaena phocaenoides asiaeorientalis). As a result of the expansion of human activities on the river, their distribution ranges appear to be decreasing and in the case of the Baiji, are even being restricted to several sections. The Baiji is the world’s most critically endangered cetacean species with a population estimated at only a few tens of individuals. The Yangtze finless porpoise is the world’s only freshwater-adapted population of the species, and it has been estimated that only around 1,000 individuals remain in the river system. In order to prevent the extinction of Baiji and a sharp decline in the abundance of the porpoise, in situ conservation (i.e. in the river) and two ex situ conservation (i.e. in semi-natural reserves and in captivity) strategies were proposed and have been implemented since the early 1990s. In view of both the severely endangered status of the animals and the severely degraded conditions of their habitats, the feasibility and actual status of these two strategies are raised for discussion.