Application of four watershed acidification models to Batchawana Watershed, Canada

Four watershed acidification models (TMWAM, ETD, ILWAS, and RAINS) are reviewed and a comparison of model performance is presented for a common watershed. The models have been used to simulate the dynamics of water quantity and quality at Batchawana Watershed, Canada, a sub-basin of the Turkey Lakes Watershed. The computed results are compared with observed data for a four-year period (Jan. 1981-Dec. 1984). The models exhibit a significant range in the ability to simulate the daily, monthly and seasonal changes present in the observed data. Monthly watershed outflows and lake chemistry predictions are compared to observed data. pH and ANC are the only two chemical parameters common to all four models. Coefficient of efficiency (E), linear (r) and rank (R) correlation coefficients, and regression slope (s) are used to compare the goodness of fit of the simulated with the observed data. The ILWAS, TMWAM and RAINS models performed very well in predicting the monthly flows, with values of r and R of approximately 0.98. The ETD model also showed strong correlations with linear (r) and rank (R) correlation coefficients of 0.896 and 0.892, respectively. The results of the analyses showed that TMWAM provided the best simulation of pH (E=0.264, r=0.648), which is slightly better than ETD (E=0.240, r=0.549), and much better than ILWAS (E=-2.965, r=0.293), and RAINS (E=-4.004, r=0.473). ETD was found to be superior in predicting ANC (E=0.608, r=0.781) as compared to TMWAM (E=0.340, r=0.598), ILWAS (E=0.275, r=0.442), and RAINS (E=-1.048, r=0.356). The TMWAM model adequately simulated SO4 over the four-year period (E=0.423, r=0.682) but the ETD (E=-0.904, r=0.274), ILWAS (E=-4.314, r=0.488), and RAINS (E=-6.479, r=0.126) models all performed poorer than the benchmark model (mean observed value).     

A comparison of polycyclic aromatic hydrocarbon and petroleum hydrocarbon uptake by mussels (Perna viridis) and semi-permeable membrane devices (SPMDs) in Hong Kong coastal waters

The ability of mussels (Perna viridis) and semi-permeable membrane devices (SPMDs) to accumulate polycyclic aromatic hydrocarbons (PAHs) and petroleum hydrocarbons (PHCs) from five sites in Hong Kong's coastal waters was compared. Mussels consistently had higher levels of contaminants, but their utility was limited at one highly polluted site due to mortality. Mussels and SPMDs ranked sites differently in terms of individual contaminant levels. Although SPMDs overcome many of the disadvantages of using living organisms to measure contaminants in marine waters, they cannot be used as "mimics" due to different PAH and PHC accumulation patterns.     

Risk to breeding success of waterbirds by contaminants in Hong Kong: evidence from trace elements in eggs

Concentrations of 17 trace elements (As, Se, Rb, Sr, Ag, Sb, Cs, Tl, Pb, V, Cr, Mn, Co, Cu, Zn, Cd, and Hg) were determined in eggs of little egrets (Egretta garzetta), black-crowned night herons (Nycticorax nycticorax) and bridled terns (Sterna anaethetus) from northwestern and northeastern coastal areas of Hong Kong. Results indicated significant differences among the three species. Eggs of little egrets and black-crowned night herons appeared to be good bioindicators for monitoring selected elements (As, Pb, Zn Cr, Cu, and V) due to consistent correlations between metal concentrations in eggs and those in coastal marine sediments. Based on limited toxicological information, the predicted no effect concentrations (PNECs) of Hg and Se in the bird eggs were estimated as 0.5 to 1.8 and 0.90 to 1.45 mug g(-1), dry wt., respectively. Hazard quotients (HQs) indicated that Hg and Se might pose some risk to certain waterbirds in Hong Kong.     

Mussel-based monitoring of trace metal and organic contaminants along the east coast of China using Perna viridis and Mytilus edulis

Green lipped mussels, Perna viridis, and blue mussels, Mytilus edulis, were collected from seven locations along the east coast of China in September and October 2001. The mussel tissues were analyzed for metals (Ag, As, Cd, Cr, Ni, Pb, Se, Zn, Cu, Fe and Hg), and trace organic contaminants including organochlorine compounds (OCs), polycyclic aromatic hydrocarbons (PAHs; based on 24 individual PAHs), polychlorinated biphenyls (PCBs) and petroleum hydrocarbons (PHCs). Maximum concentrations of Ag, As, Cd, Cr, Ni, Pb, Se, Zn, Cu, Fe and Hg in the mussel tissues were 0.14, 26.76, 5.31, 15.72, 4.78, 2.93, 7.40, 231.0, 54.17, 1002 and 317.3 microg/g dry weight respectively. Levels of DDTs, PAHs, PCBs and PHCs in the mussel samples were 14-640, 456-3495, 1-13 ng/g and 621-2863 microg/g dry weight, respectively. Results of this study indicated that contaminant levels were, in general, higher or at least comparable to those reported in other local or regional studies. Mussel samples collected in Chongming Dao in Shanghai and Jiao Zhou Wan in Qingdao had significantly higher levels of metal and trace organic contaminants among the seven sampling stations. Examination of the contaminant profiles suggests that PHCs originated from petrogenic sources, while both petrogenic and pyrolytic sources were important for PAHs. The generally high levels of metals and organochlorine compounds are probably the result of increasingly intense industrial activities along the east coast of China. An assessment of potential risks to human health due to consumption of the mussels was undertaken for the metals, PCBs, DDTs and chlordanes, and the results indicated that all metals, except Ni, could pose a health risk to heavy seafood consumers, while Hg appears to be of concern even for low level consumers.     

Petroleum hydrocarbons and polycyclic aromatic hydrocarbons in the surficial sediments of Xiamen Harbour and Yuan Dan Lake, China

Surficial sediments were sampled from nine stations in Xiamen Harbour and two stations in Yuan Dan Lake during April 2002. Sediment samples were extracted by organic solvents, separated by silica gel column chromatography and analyzed by gas chromatography-mass selective detector (GC-MSD). Selected ion monitoring was at M/Z=57 for petroleum hydrocarbons (PHCs) and individual M/Zs for each of the 15 typical polycyclic aromatic hydrocarbons (PAHs) and nine alkylated PAHs. The results showed that concentrations of PHCs and total PAHs in the sediments of Yuan Dan Lake were 1397 microg g(-1) (dry weight, dw) and 1377 ng g(-1) (dw), respectively. The ranges for PHCs and total PAHs in the sediments from Xiamen Harbour were 133-943 microg g(-1) (dw) and 98-309 ng g(-1) (dw), respectively. Shipping activities, industrial wastewater discharges, fuel oil spillage from ships and vehicles were the main sources of PHCs and PAHs in the Harbour. In addition, the widespread use of coal for industrial processes and domestic consumption accounted for the second largest source of PAHs in the sediments, while atmospheric transport and deposition of PAHs are also important.     

A preliminary risk assessment of trace elements accumulated in fish to the Indo-Pacific Humpback dolphin (Sousa chinensis) in the northwestern waters of Hong Kong

In order to assess the potential risks associated with consumption of contaminated prey items to the Indo-Pacific Humpback dolphin (Sousa chinensis), fish species (Collichthys lucida, Pseudosciaena crocea, Johnius sp., Thryssa sp., Mugil sp. and Trichiurus sp.) representing the main food items of the dolphin were collected from the northwestern waters of Hong Kong, including the Sha Chau and Lung Kwu Chau Marine Park, which form the main habitat of the dolphin in Hong Kong. Within these waters, there are several potential sources of pollution including significant inputs from the Pearl River catchment, several major sewage outfalls and a series of mud pits that receive contaminated dredged sediments. Concentrations of thirteen trace elements (Ag, As, Cd, Co, Cr, Cs, Cu, Hg, Mn, Ni, Se, V, and Zn) in the fish tissue were analyzed by inductively coupled plasma mass spectrometer (ICP-MS). An assessment of the risks of adverse effects on the dolphin due to consumption of tainted fish was undertaken using two toxic reference benchmarks, namely the reference dose (RfD) and toxicity reference value (TRV). The risk quotient (RQ) calculated for each element showed that the risks from consumption of fish were generally low and within safe limits. The risks associated with arsenic, cadmium and mercury were, however, elevated. The highest calculated RQ was associated with total arsenic; however, the majority of arsenic in marine organisms tends to be in the non-toxic organic form, and the actual risk to the dolphin due to this metalloid is likely to be lower.     

Paternity and performance of golden-winged warblers (<Emphasis Type="Italic">Vermivora chrysoptera</Emphasis>) and golden-winged X blue-winged warbler (<Emphasis Type="Italic">V. pinus</Emphasis>) hybrids at the leading edge of a hybrid zone

We examined two components of reproduction in a population of golden-winged warblers in the initial stages of hybridization with blue-winged warblers. First, we used genetic analyses of mate choice to determine whether copulations outside the social pairbond (extra-pair copulations; EPCs) occur in these species and their hybrids. Second, we compared several aspects of reproduction (pairing success, clutch size, hatching success, fledging success, and loss of paternity) in nests raised by phenotypic golden-winged warblers to those raised by hybrid individuals. Together, these data provide us with the first quantitative analysis of reproduction within this hybrid system. Our data suggest several reasons why the level of hybridization between these species is likely being underestimated. First, many birds in our population showed only subtle phenotypic signs of introgression indicating that hybrid status can only be determined by close examination. Second, high rates of extra-pair paternity indicate that we cannot base our estimates of hybridization on pairbond data alone. More than 30% of nestlings were the result of EPCs, occurring in 55% of all nests. Third, there was no difference in the number of hybrid or “pure” golden-winged warbler males chosen as social mates, relative to their abundance. Indeed, based on several components of nesting success, it appears as though hybrids are having as great realized reproductive success as are phenotypic golden-winged warblers in our population. Accordingly, we argue that hybrid reproductive success and extra-pair fertilizations are likely playing a major role in the ongoing hybridization between blue-winged and golden-winged warblers. Studies such as this one are important to our understanding of the process and implications of hybridization, and findings may be applicable to other hybrid zones.     

珊瑚可持续采集吗?

引言 随着人们对世界珊瑚礁健康关注程度的日益提高[1],国际珊瑚贸易已被确定为是一件利益悠关的事[2,3].珊瑚和"活岩石"(即:由带有附着生物的死珊瑚构成的岩石或碎石)的商业性贸易被认为有可能造成珊瑚礁局部遭到破坏,包括侵蚀增加和重要生境的丧失[4,5].     

Overview of surface ozone variability in East Asia-North Pacific region during IGAC/APARE(1994—1996)

IntroductionDuringthelastdecade ,theEastAsiancontinentalrimregionhasbeencharacterizedbyhighanthropogenicemissionsduetotherapidindustrialization .Airpollutioninthisregionhascreatedmuchattentiontothescientistsovertheworld(Kato,1992 ;Akimoto ,1994a ;Aardenne…     

How does the social context fuel the proactive fire? A multilevel review and theoretical synthesis

The role of social context (e.g., leadership, team climate, and organizational support) in shaping employee proactive behavior has received considerable attention and has been investigated across multiple forms of proactive behavior. However, the research has not been well integrated. In this review, we adopt a multilevel approach to synthesize what is known about how social context factors influence employees' proactive behavior, as well as what mechanisms underpin these effects. Our analyses show that leader‐, team‐, and organization‐related social context factors mainly influence employee proactivity through shaping “reason to,” “can do,” and “energized to” states (i.e., proactive motivational states) via individual‐, team‐, and cross‐level processes. That has been most frequently investigated is the effect of the discretionary social context, particularly leadership, on proactive behavior. We also review the interaction effects between social context factors and other factors on employee proactive behavior and found inconsistent support for the motivational‐fit perspective that stimuli with the same directions enhance each other's effect. We offer a research agenda to advance theoretical insights on this important topic.