The control of soil pollution in China has become an issue, and in this study, a compound contaminated site was selected and focus on the site and its nearby environment, organochlorine pesticides (OCPs) were investigated in both soil (top and deep soil) and air samples. The main pollutants in top soils at site are dichlorodiphenyltrichloroethane (DDTs, 0.05–104 mg/kg d.w., avg: 14.5 mg/kg d.w.) and hexachlorobenzene (HCB, 0.02–4.85 mg/kg d.w., avg: 0.72 mg/kg d.w.) which is in accordance with its production history. As for the deep soils, ΣOCPs at site were found concentrated at workshops especially the technical pesticide workshop (5.29–22.1 mg/kg d.w., avg: 9.15 mg/kg d.w.) and the history DDTs’ workshop (4.00–64.8 mg/kg d.w., avg: 20.4 mg/kg d.w). Around site, OCPs were mainly concentrated at layers of −20 cm and the −40 cm and decreased with distance being far away, at 5000 m, the ΣOCPs was comparable with normal agriculture soil (22.1−91.4 ng/g d.w., avg: 55.4 ng/g d.w.). ΣOCPs in the air samples ranged 64.6–823 ng/m3 (avg: 459 ng/m3) at site and 9.93–176 ng/m3 (avg: 50.8 ng/m3) around site which are all dominated with DDTs and HCHs. Soil–air exchange fugacity was calculated to judge the transportation of the OCPs and the results showed soils at the site and its nearby areas (within 5000 m) are releasing most of the OCPs into air, and accordingly through evaluation, inhalation was found to be the major source for human health risk, which is a great threat to the workers at site and the nearby residents.
Water resources provide the foundation for human development and environmental sustainability. Water shortage occurs more or less in some regions, which usually causes sluggish economic activities, degraded ecology, and even conflicts and disputes over water use sectors. Game theory can better reflect the behaviors of involved stakeholders and has been increasingly employed in water resources management. This paper presents a framework for the allocation of river basin water in a cooperative way. The proposed framework applies the TOPSIS model combined with the entropy weight to determine stakeholders’ initial water share, reallocating water and net benefit by using four solution concepts for crisp and fuzzy games. Finally, the Fallback bargaining model was employed to achieve unanimous agreement over the four solution concepts. The framework was demonstrated with an application to the Dongjiang River Basin, South China. The results showed that, overall, the whole basin gained more total benefits when the players participated in fuzzy coalitions rather than in crisp coalitions, and \(\left\{ {NHS_{Fuzzy} \,and\, SV_{Crisp} } \right\}\) could better distribute the total benefit of the whole basin to each player. This study tested the effectiveness of this framework for the water allocation decision-making in the context of water management in river basins. The results provide technical support for water right trade among the stakeholders at basin scale and have the potential to relieve water use conflicts of the entire basin. 相似文献
In recent years, fish invasion has become one of the main reasons for the decline of nativefish stocks. Pseudorasbora parva is considered one of the major invasive species worldwide. The present study investigated the fish resources of the Chabalang Wetland(Lhasa, Tibet) during dif ferent seasons in2009 and 2013. Four hundred and twelve individuals were subsampled to estimate age, growth, and feeding habit of P. parva. Furthermore, food relationships between P. parva and the native Schizothoracinae fish were also examined. The results revealed a significant shift in species composition and community structure characterized by the disappearance of native fish and outbreak of non-native fish. The percentage of nonnative P. parva in the fish collections significantly increased from 33.64% in 2009 to 64.08% in 2013.The standard length(SL) ranged from 22.00 to 78.71 mm, and their age was 1–5 a. The von Bertalanf fy function was used to model the observed length-at-age data as Lt =112.19(1– e~(-0.1495(t +0.8012))) for females and as Lt =123.12(1– e~(-0.1500(t +0.7132))) for males. The results indicated that P. parva in Tibet has lower growth and mortality rates compared with that from the native ranges. Ninety-seven prey taxa belonging to 9 prey categories were identified in the gut of 38 P. parva. P. parva can be considered a generalized and opportunistic predator, competing with the native fish, especially Schizothorax o'connori, Schizopygopsis younghusbandi younghusbandi, and Ptychobarbus dipogon, for Bacillariophyta and Chironomid larvae.This is an important reason for the decline in native fish population. 相似文献
Sound understanding of hydrological alterations and the underlying causes means too much for the water resource management
in the Pearl River Delta. Incision of river channels plays the key role in the hydrological alterations. As for the causes
behind the river channel incision, sand dredging within the river network of the Pearl River Delta is usually assumed to play
the overwhelming role in changes of geometric shapes of the river channels. Based on thorough analysis of well-collected data
of channel geometry, streamflow, sediment load and water level, this study exposes new findings, investigating possible underlying
causes behind the changes of the geometric shapes of the river channels at the Sanshui and Makou station. The results of this
study indicate: (1) different changing properties of the geometric shapes are identified at the Sanshui and Makou stations.
Larger magnitude of changes can be found in the river channel geometry of the cross section at the Sanshui station when compared
to that at the Makou station. Lower water level due to fast riverbed downcutting at the Sanshui station than that at the Makou
station is the major reason why the reallocation of streamflow occurred and hence the hydrological alterations over the Pearl
River Delta; (2) depletion of sediment load as a result of construction of water reservoirs in the middle and upper Pearl
River basin, sand dredging mainly in the Pearl River Delta and heavy floods all contribute much to the incision or deposition
of the riverbed. Regulations of erosion and siltation process of the river channel often alleviate the incision of the river
channels after a relatively long time span, and which makes it even harder to differentiate the factors causing the river
channel incision; (3) the intensifying urbanization in the lower Pearl River basin greatly alters the underlying surface properties,
which has the potential to shorten the recession of the flood event and may cause serious scouring processes and this role
of flash floods in the incision of the river channels can not be ignored. This study is of great scientific and practical
merits in improving human understanding of regulations of river channels and associated consequences with respect to hydrological
alterations and water resource management, particularly in the economically booming region of China. 相似文献
The skull of Anshunsaurus huangnihensis Cheng, 2007, especially the skull roof, is described in detail in this paper. Compared to other genera and species of Askeptosauroidea, Anshunsaurus huangnihensis has some important transitional characters from Askeptosaurus italicus to Anshunsaurus huangguoshuensis: the rostral length related to the skull length between Askeptosaurus italicus and Anshunsaurus huangguoshuensis; the postfrontal existing but distinctly reduced; the posterolateral process relatedly short and overlapping the parietal. The phylogenetic analysis weakly supports the evolutional progress from Anshunsaurus huangnihensis to Anshunsaurus huangguoshuensis. The skeletal ratios indicated that the node among the Askeptosauridae ingroup. The evolutional direction of Askeptosauridae should be from Askeptosaurus italicus to Anshunsaurus huangguoshuensis. The skeletal ratios indicated that the evolutional progress is Askeptosaurus italicus – Anshunsaurus huangnihensis – Anshunsaurus huangguoshuensis. In biogeography provinces, the Askeptosauroidea taxa from south China have a close relationship with those from western Tethys; however, Xinpusaurus from the Late Triassic is more related to those from the eastern Pacific. 相似文献