Landscape ecological assessment and eco-tourism development in the South Dongting Lake Wetland, China

As an important resource and the living environment of mankind, wetland has become gradually a highlight, strongly concerned and intensively studied by scientists and sociologists. The governments in the world and the whole society have been paying more and more attention on it. The Dongting Lake of China is regarded as an internationally important wetland. For a rational development and protection of the wetland, an investigation and studied on its resources and its value to tourism in the South Dongting Lake was conducted, to create an assessment system of the ecological landscapes, and to evaluate qualitatively and quantitatively the value of wetland landscape to the eco-tourism. The results showed that the scenic value of the South Dongting Lake Wetland satisfied the criterion of AAAA grade of China national scenic attraction. The eco-tourism value of the landscape cultures in the South Dongting Lake Wetland was discussed with emphasis. It were formulated that a principle and frame of sustainable exploitation of the wetland landscapes and it was proposed as well that establishing a Wetland Park and developing eco-tourism in the South Dongting Lake. Wetland is a fragile ecosystem with low resistance to the impact of the exploitation. Thus, we must pay intensively attention to the influence of exploitation on the landscape, take the ecological risk in account to employ a right countermeasure and avoid the negative affection.

Ecological assessment of cities-procedure and a case study

This paper discusses the scientific background and content of the ecological assessment of cities, and takes Boda, a new town in Xinjiang province, China, as a case study.

THE LANDSCAPE ECOLOGICAL ASSESSMENTAND PLANNING IN THE CONTROL WATERSHED BY RESERVOIR OF ERLONG MOUNTAIN

Based on the theories of landscape ecology, landscape eco environment in the control watershed by reservoir of Erlong Mountain in Heilongjiang Province was analyzed and assessed by using GIS technique and statistical model of Principal Component Analysis and Spatial Cluster Analysis. It is found that 100.08km2(36%)of the total area is in the state of kilter,85.73km2(31%)of the total area is in the state of general,and 47.26km2(17%)and 15.48km2(16%)is in the relatively poor state and ideal state. According to landscape ecological structure,there are three landscape function areas being planned and designed. 1) Agricultural landscape function area: its developmental direction is tour agriculture and high benefit agriculture. 2) Eco environment protected function area:the direction of development and utilization of this region is to develop vigorously forest for soil and water conservation, and try to increase the rate of vegetation cover. 3) Forest landscape function area: rational cut and utilization of forest resources, space optimization disposal of category of forest, foster of forest and protection of wildwood will become the main development directions for this region. This study trys to provide scientific foundation for ecological restoration of the whole valley and its sustainable development.

Distribution, Mobility, and Health Risks Assessment of Trace Metals in River Sediments from Intense Agricultural Activity Areas in West Africa

The economy of West African countries is mainly based on agriculture. However, the trace metal(loid)s contamination status in rivers is relatively unknown in the region. In this work, 45 surface sediments collected from the Bandama, Comoé, and Bia Rivers in south and south eastern Côte d’Ivoire (West Africa), were analyzed for total metal concentrations and chemical speciation. The results showed that the river sediments were considerably contaminated by Cd and moderately contaminated by As, Cu, Pb, and Zn. Significant spatial variations were observed among the stations but not between the rivers. Metals Cd and Cu were likely to cause more ecological risks. The speciation analysis unravelled that the metal(loid)s partitioned mainly in the residual fraction, with the potential mobile fraction varying from 14% to 28%. The study calls for establishment of strict policies relative to the application of fertilizers and agrochemicals and mining activities to protect the environment and human health risks.

Comprehensive ecological risk assessment for heavy metal pollutions in three phases in rivers

Literature lacked in providing a comprehensive research on heavy metal detection in aquatic, biological and sedimentary states of rivers. The present study was imparted with all these three components of the river. Heavy metal toxicity or pollution index was used as a tool for ecological risk assessment by considering the single state studies conducted by many researchers. An intensive ecological risk assessment model was constructed and heavy metals were indicated as a serious threat to the environment. The model was applied to determining five toxic heavy metals in three states of the Songhua River. According to the ecological risk index, heavy metal pollution in three phases was categorized as aquatic〉biological〉sedimentary, while the overall descending order of heavy metal ecological risk index was as Cd〉Hg〉As〉Pb〉Cr. Cd and Hg were selected as the priority pollutants of Songhua River.

Distribution Characteristic and Potential Ecological Risk Assessment of Heavy Metals in Latosol in the Western Area of Hainan Island

[Objective] The paper was to carry out ecological geochemical survey and ecological risk assessment on the heavy metals in latosol in western area of Hainan Island.[Method] The contents of six heavy metals including Cr,Cu,Zn,As,Cd and Pb in latosol in western area of Hainan Island were analyzed.Single-factor index method and Hakanson ecological risk index method were used to evaluate the integrated pollution effect of heavy metals in latosol.[Result] The average contents of Cr,Cu,Zn,As,Cd and Pb in latosol in western area of Hainan Island were 65.57,35.16,93.56,8.50,0.24 and 79.29 mg/kg,respectively.The major pollution factor of heavy metal was Pb.The sequence of influence factors of various heavy metals was PbCu = ZnCrAsCd.The potential ecological risk coefficient of various heavy metals was PbCdCuAsCrZn.The average value of potential ecological risk index（RI）was 45.14,belonging to low ecological risk range.[Conclusion] The heavy metal pollution in latosol in western area of Hainan Island belongs to slight pollution.

GIS-based Ecological Suitability Assessment for Land Use——A Case Study of an Economic Development Zone in Shenyang

Analysis indices of ecological suitability were selected through literature reviewing and expert consultation. Visualization of assessment course was achieved based on different land use functions with the help of ArcGIS9.0 and GIS layers with different properties were overlapped and computed with GIS grids. Hence, the areas were colored and reclassified（colors representing different ecological suitability degrees）. Finally, land use functions can be readjusted by the evaluation results,providing references for rational planning of economic development zones.

Distribution and Ecological Risk Assessment of HCHs and DDTs in Surface Seawater and Sediment of the Mariculture Area of Jincheng Bay,China

The distribution of hexachloroeyclohexanes （HCHs） and dichlorodiphenyltrichloroethanes （DDTs） in the surface sea- water and sediment of Jincheng Bay mariculture area were investigated in the present study. The concentration of total HCHs and DDTs ranged from 2.98 to 14.87ngL-l and were〈0.032ngL-1, respectively, in surface seawater, and ranged from 5.52 to 9.43 and from 4.11 to 6.72 ng g-l, respectively, in surface sediment. It was deduced from the composition profile of HCH isomers and DDT congeners that HCH residues derived from a mixture of technical-grade HCH and lindane whereas the DDT residues derived from technical-grade DDT and dicofol. Moreover, both HCH and DDT residues may mainly originate from historical inputs. The hazard quotient of α-HCH, β-HCH, γ-HCH and δ-HCH to marine species was 0.030, 0.157, 3.008 and 0.008, respectively. It was estimated that the overall probability of adverse biological effect from HCHs was less than 5%, indicating that its risk to seawater column spe- cies was low. The threshold effect concentration exceeding frequency of γ-HCH, p,p＇-DDD, p,p＇-DDE and p,p＇-DDT in sediment ranged from 8.3% to 100%, and the relative concentration of the HCH and DDT mixture exceeded their probable effect level in sediment. These findings indicated that the risk to marine benthos was high and potentially detrimental to the safety of aquatic prod- ucts, e.g., sea cucumber and benthic shellfish.

Spatial distribution,sources and ecological risk assessment of heavy metals in Shenjia River watershed of the Three Gorges Reservoir Area

Surface soil/sediment samples were collected from the Water-Level Fluctuation Zone(WLFZ), cultivated land and forest land at 50 different grid points from Shenjia watershed, the Three Gorges Reservoir area in August 2013. The spatial distribution, sources and ecological risk assessment for Arsenic(As), Cadmium(Cd),Chromium(Cr), Copper(Cu), Nickel(Ni), Lead(Pb)and Zinc(Zn) were analyzed in this study. The results showed all tested metals had similar distribution patterns except Ni and Cr, with areas of high concentrations distributed in the southwest(WLFZ and watershed outlet) of the study area. Ni and Cr,which were highly positively correlated and present in high concentrations, were primarily distributed in the south and middle zones of the study area. Lower concentration areas of all metals were uniformly distributed west of the high-elevation zones and forest land. Factor analysis(FA) and factor analysismultiple linear regression(FA-MLR) showed that the major sources of Cd were fertilizer and traffic sources,which together accounted for 87% of Cd. As, Zn and Cu levels were primarily supplied by industrial and domestic sources, accounting for 76% of As, 75% of Cu and 67% of Zn. Surface soils/sediments of the study watershed contaminated by Cd represent a high ecological risk, whereas other metals represent low ecological risks. The potential ecological risk index(PERI) analysis indicated that it had a low(widerange) ecological risk and a moderate(small-range)ecological risk primarily distributed in the outlet of the study watershed. Fertilizers and traffic are the primary sources of Cd pollution, which should be more closely controlled for the purposes of water quality and ecological conservation.

Source apportionment and ecological risk assessment of PAHs in surface sediments from the Liaodong Bay,northern China

The sources and ecological risk from sixteen polycyclic aromatic hydrocarbons in surface sediment in the Liaodong Bay were investigated from 2014 to 2015.The total concentrations of PAHs ranged from 88.5 to 347.1 ng/g,and the high value occurred in the central region of the Liaodong Bay.Cluster analysis identified two site clusters representing the coastal region affected by land-based pollution and the central region of the Liaodong Bay.Principal component analysis-multiple linear regression and diagnostic ratios suggested that PAHs contaminants originated from a mixture of combustion and petroleum sources,and the major was combustion sources.Based on sediment quality guideline,naphthalene,acenaphthylene,acenaphthene,phenanthrene and dibenz[a,h]anthracene may occasionally cause adverse biological effects in some stations.The toxic equivalent concentrations of carcinogenic PAHs indicated low carcinogenic risk for the Liaodong Bay.The ecological risk and toxic pollution levels of PAHs were higher in the central region than in the coastal region along the Liaodong Bay.

Ecological impact assessment method of highways in Tibetan Plateau:A Case study of Gonghe-Yushu Expressway

In recent years,the ecological environment along highways in Tibetan Plateau has been severely affected due to the rapid construction of highways.In order to solve the problems of multiple indicators and inconsistent criteria in the ecological impact assessment of highways,and to scientifically screen assessment indicators,the paper proposes a multi-round indicator screening method,which combines literature analysis,expert rating,and statistical analysis.Based on this screening method,normalized difference vegetation index,land surface temperature,elevation,and normalized difference soil index are screened out.Combined with multiple linear regression,an ecological impact assessment model is established and applied to ecological impact assessment of Gonghe-Yushu Expressway.The results show that the expressway construction is the first driving force for the deterioration of the ecological environment along the roadside,and its interference range on the desert grassland ecosystem is greater than that on the agroforestry system.The ecological environment within 150 m on both sides of the expressway should be protected.

Content and Ecological Risk Assessment of Heavy Metals in Surface Sediment in Weishan Lake

[Objective] The aim was to analyze the content of heavy metals in surface sediment in Weishan Lake and further assess its ecological risk.[Method] Heavy metal pollution in surface sediment in Weishan Lake was studied,and the pollution indices and potential ecological risk indices of Cu,Zn,Pb,Cd and Cr were calculated to assess the potential ecological risk of heavy metal pollution.[Result] In surface sediment in Weishan Lake,the average contents of Cu,Zn,Pb,Cd,Cr and Ni were 64.78,185.05,78.76,0.17,37.76 and 46.84mg/kg respectively.Cr and Cd weren’t beyond standards in all stations,while Cu and Pb exceeded standards in all stations,with average super-standard multiple of 0.85 and 0.31,respectively,and Zn content wasn’t beyond standard in S2 station,with average super-standard multiple of 0.24.The average pollution indices of Cu,Zn,Pb,Cd and Cr were 1.85,1.23,1.31,0.34 and 0.47 respectively,with average comprehensive pollution index of 5.21,which showed that heavy metal pollution was light.In addition,heavy metal pollution in entryway portion and sea-route portion were more serious than that of breeding portion.Potential ecological risk assessment showed that the average potential ecological risk indices of Cu,Zn,Pb,Cd and Cr were 9.25,1.23,6.56,10.34 and 0.94 respectively,with average comprehensive potential ecological risk index of 28.33,and it revealed that potential ecological risk of heavy metals was slight.Besides,the potential ecological risk order of heavy metal pollution was sea-route portion>entryway portion>breeding portion.[Conclusion] The study could provide references for the regulation and improvement of ecological environment in Weishan Lake in the east route of south-to-north water transfer project.

Probabilistic ecological risk assessment of cadmium in the Bohai Sea using native saltwater species

Predicted no-effect concentration （PNEC） is often used in ecological risk assessment to determine low-risk concentrations for chemicals. In the present study, the chronic data from native saltwater species were used to calculated PNEC values using four methods： log-normal distribution （ETX 2.0）, log-triangle distribution （US EPA＇s water quality criteria procedure）, burr III distribution （BurrliOZ） and traditional assessment fac-tor （AF）. The PNECs that were calculated using four methods ranged from 0.08 μg/L to 1.8 μg/L. Three of the SSD-derived PNECs range from 0.94 to 1.8 μg/L, about a factor of two apart. To demonstrate the use of SSD-based PNEC values and comprehensively estimate the regional ecological risk for cadmium in surface water of the Bohai Sea, in the Liaodong Bay, Bohai Bay, and Laizhou Bay, China, the dissolved cadmium con-centrations were measured and obtained 753 valid data covering 190 stations from July 2006 to November 2007. Based on three ecological risk assessment approaches, namely hazard quotient （HQ）, probabilistic risk quotient and joint probability curve （JPC）, the potential ecological risk of cadmium in surface water of the Liaodong Bay, Bohai Bay, and Laizahou Bay were estimated. Overall, the ecological risk of cadmium to aquatic ecosystem in the whole Bohai Sea was at acceptable ecological risk level, the order of ecological risk was Liaodong Bay〉Bohai Bay〉Laizhou Bay. However, more concerns should be paid to aquatic ecological risk in the Liaodong Bay which is the home of many steel, metallurgy and petrochemical industrial in China.

Ecological risk assessment of the Gannan Plateau,northeastern Tibetan Plateau

Desertification, soil salinization and grassland degradation are the major environmental hazards faced by the Gannan Plateau, northeastern Tibetan Plateau. Ecological risk assessment plays an important role in formulating environmental management strategies yet little attention to this region. In this study, we established an ecological risk assessment index system based on 30 evaluation indices in the categories of hydrometeorology, ecological environment, ground surface disturbance, and society and economy for the Gannan Plateau. An entropy method was used to calculate an index weight,and subsequently the matter-element method was used together with extension theory to establish a matter-element extension model of ecological risk. We assessed the ecological risk in this region by calculating the degree of association between index layer, system layer and target layer, and the cumulative ecological risk index. The degrees of ecological risk for the counties of the region were determined by using Arc GIS which would represent a spatial heterogeneity of the risk grade in production. Our results showed that the areas of high ecological risk were in Zhouqu County and Zhuoni County, and others were of low risk(Hezuo City, Diebu County, Xiahe County and Lintan County) or intermediate risk(Maqu County). The results of the assessment were in accord with the actual observed situation. Thus, our ecological risk assessment index system is appropriate for this region and suggests that high risk counties need a priori ecological protection. Such research could provide a technological support which would potentially prevent or reduce disasters by establishing an ecological barrier to promote the sustainable development of Gannan Plateau.

Ecological Risk Assessment of World Heritage Sites Using RS and GIS:A Case Study of Huangshan Mountain, China

Ecological risk assessment(ERA) is an indispensable method for systematic monitoring of World Heritage Sites(WHSs) exposed to various anthropogenic factors and natural disasters. Remote sensing(RS) and geographical information systems(GIS) can eliminate many limitations in traditional ERA methods. In this study, changes in ecological risk at Huangshan Mountain, the first mixed WHS in China, over the period of 1984–2019 were explored using remote sensing images and products by considering both natural disasters and human disturbance. Results show that of the four land cover types in Huangshan Mountain, namely water, forest, building and farmland, the main land cover type is forest. During the 35 yr, lands categorised at low or relatively low ecological risk levels are dominant in Huangshan Mountain, with the lowest and highest ERIs(ecological risk index) in 1990 and 2010, respectively. The areas at the five ecological risk levels have declined as follows: relatively low > low > medium > relatively high > high. Changes in ecological risks are closely related to changes in land cover and natural disasters. Even though major natural disasters may affect the ecological risk level in the whole region, changes in land cover caused by human activities will shift the ecological risk level in some areas. Our attempts can be modified and applied to other sites, and offer policy implications for protection and preservation of WHSs.

Spatial Distribution and Ecological Risk Assessment of Heavy Metals in Surface Sediment of Songhua River,Northeast China

The Songhua River,one of the seven major rivers in China,locates in Northeast China with 1897 km long.This study aims to investigate the concentrations,distribution,source apportionment and ecological risk assessment of heavy metals including copper(Cu),zinc(Zn),cadmium(Cd),lead(Pb),nickel(Ni)and chromium(Cr)in main stream and tributaries of the Songhua River in Jilin Province,Northeast China.Surface sediment samples(0–15 cm)were collected from 39 sampling sites in the Songhua River in July 2012.Concentrations of Cu,Zn,Cd,Pb,Ni and Cr were analyzed.The mean concentrations of heavy metals were(24.0±9.2)mg/kg,(59.3±18.0)mg/kg,(4.0±2.1)mg/kg,(39.0±27.9)mg/kg,(18.5±8.6)mg/kg and(56.1±17.6)mg/kg for Cu,Zn,Cd,Pb,Cr and Ni,respectively.The average contents of Cu,Cd,Pb,Cr and Ni were higher than their background values.Higher concentrations of heavy metals were found in the lower reaches with industrial enterprises and cities along the Songhua River.Zn,Pb and Ni might come from industrial sewage and mineral processing,while Cu and Cd were derived from electroplating wastewater and agricultural non-point source sewage.Cr originated from lithogenic sources.The concentrations of Cu,Zn and Cr were below the effect range low(ERL)at all sites,while Cd,Pb and Ni concentrations were detected ranging from ERL to the effect range median(ERM)at more than 15%of samples.Concentrations of Ni exceeded ERM in more than 50%of samples.The mean toxic units of heavy metals in the Songhua River decreased following the order:Cd(6.7)>Pb(2.2)>Ni(1.6)>Cu(0.7)>Cr(0.5)=Zn(0.5).Potential ecological risk index was found to be higher in middle and lower reaches of the Songhua River,where Cd could impose an extremely high ecological risk.

An ecological risk assessment for heavy metals of the lead-zinc ore tailings

The structure of Pb,Zn,Cu and Cd in lead zinc ore tailing soils in Yongzhou,Hunan is analyzed by the optimized BCR sequential extraction procedure.The content and proportion of heavy metals of the mine are measured.Meanwhile,the ecological risks are evaluated with the Lars Hakanson＇s potential ecological risk exponential method.The analysis shows that the content of heavy metals is very high,reaching the level of serious pollution.The order of metal pollution degrees are Cd〉Pb〉Cu〉Zn.On the other hand,it is very possible that the heavy metals may combine together as compounds or cling to the crystal form of clay.Since the form of soluble acid and free metals are very little,it is not an easy job for metal elating or restoration of plants.Yet it is possible to take out those heavy metals adopting the chemical extraction technology.DTPA and EDTA,indicated by a research,both have iterative value and strong conformity effect.So they are effective elutriants to restore the polluted soil.A chemical extraction method is put forward in this paper.

Assessment of ecological importance of the Qinghai-Tibet Plateau based on ecosystem service flows

Assessments of ecological importance based on static indexes that do not consider service flows frequently underestimate the importance of the Qinghai-Tibet Plateau as a "source".On the basis of natural environmental characteristics,this study selected six type of ecosystem services for evaluation,including water retention,soil retention,carbon sequestration,biodiversity conservation,sandstorm prevention,and tourism.According to the attributes of each ecosystem service flow,we calculated the flow length and traffic accessibility indexes,using Arc GIS hydrological module and kernel functions separately,to comprehensively analyse the ecological importance levels of the Qinghai-Tibet Plateau.Results showed that after considering the service flows,the ecologically important zone shifted to the core area of the Three River Source Region,such as Zadoi County located in the Tanggula Mountains.The area of extreme importance is mainly distributed in the Yarlung Zangbo River basin,Tanggula Mountains,Hengduan Mountains,and Qilian Mountains,which accounts for 31.7% of the Qinghai-Tibet Plateau,providing approximately 60% of the ecosystem services and having extremely high protection efficiency and protection value.By introducing ecosystem service flow indexes,this study confirmed the ecological importance of core source areas such as the Tanggula Mountains,weakened the space bias caused by not considering the spatial transfer of ecosystem services,and provided technical support for optimizing ecological protection strategies and coordinating regional development.

Ecological risk assessment of heavy metals in surface seawater and sediment near the outlet of a zinc factory in Huludao City, Liaoning Province, China

At present, the methods widely applied to assess ecological risk of heavy metals are essentially single-point estimates in which exposure and toxicity data cannot be fully used and probabilities of adverse biological effects cannot be achieved. In this study, based on investigation of concentrations of six heavy metals(As, Hg, Pb, Cd, Cu, and Zn) in the surface seawater and sediment near the outlet of a zinc factory, located in Huludao City, Liaoning Province, China, a tiered approach consisting of several probabilistic options was used to refi ne ecological risk assessment for the individuals. A mixture of various heavy metals was detected in the surface seawater, and potential ecological risk index(PERI) was adopted to assess the potential ecological risk of heavy metals in the surface sediment. The results from all levels of aquatic ecological risk assessment in the tiered framework, ranging from comparison of single effects and exposure values to the use of distribution-based Hazard Quotient obtained through Monte Carlo simulation, are consistent with each other. Briefl y, aquatic Zn and Cu posed a clear ecological risk, while Cd, Pb, Hg, and As in the water column posed potential risk. As expected, combined ecological risk of heavy metal mixture in the surface seawater was proved signifi cantly higher than the risk caused by any individual heavy metal, calculated using the concept of total equivalent concentration. According to PERI, the severity of pollution by the six heavy metals in the surface sediment decreased in the following sequence: Cd>Hg>As>Pb>Cu>Zn, and the total heavy metals in the sediment posed a very high risk to the marine environment. This study provides a useful mathematical framework for ecological risk assessment of heavy metals.

Distribution and risk assessment of heavy metals in surface sediments of coastal mudflats on Leizhou Peninsula,China

Mudflats play a vital role in maintaining the dynamic balance between sea and land.To understand the characteristics,sources,and pollution risks of six heavy metals(As,Cd,Cr,Cu,Hg,and Pb)in the coastal mudflats on the Leizhou Peninsula,257 surface sediment samples were studied using mathematical statistics,correlation analysis,and factor analysis.The results show that the overall concentrations of these heavy metals are low although there are several high abnormal points in the local areas.The strong correlation between these heavy metals indicates that the sources of some of the metals are similar,yet their elemental combinations in different cities(counties)varied.According to the calculated enrichment factor(EF),anthropogenic activity-induced heavy metals were determined in order of decreasing influence:As,Cd,Pb,Cr,Cu,and Hg.The low EF values of Hg indicate that it does not present as a contaminant in the study area,while low values of Cr and Cu from the Lianjiang City suggest that these two metals were also attributed to natural sources.The presence of As,Cd,Cr,Cu,and Pb from the remaining cities(counties)should be influenced by anthropogenic activities.The overall potential ecological risk index indicates that the ecological risks posed by the six analyzed heavy metals to the Leizhou Peninsula mudflats,in order of decreasing risk,are Cd,As,Hg,Pb,Cu,and Cr.It is noteworthy that only Cd in Lianjiang City demonstrated substantial ecological risk.Other examined heavy metals in other cities of the study area showed slight ecological risk.