Coastal land reclamation (CLR), particularly port reclamation, is a common approach to alleviating land shortages. However, the spatial extent, percentages, and processes of these newly reclaimed ...ports are largely unknown. The Bohai Sea is the most concentrated area of port reclamation worldwide. Thus, this study addresses the changes in the different coastline types and port reclamation process in the area. The reclamation area of the 13 ports in the Bohai Sea in 2002-2018 was 2,300 km2, which decreased the area of the sea by 3%. The natural coastline length in Tianjin decreased by 47.5 km, whereas the artificial coastline length increased by 46.6 km. Based on the port boundary, however, only 26.3% of the reclaimed areas have been used for port construction, which concentrates in the Tianjin and Tangshan ports. The ratio of built-up area within the ports is only 32.5%, and approximately 48.3% of the reclaimed areas have no construction projects. The port land reclamation in the Bohai Sea has been undergoing periods of acceleration, peak, deceleration, and stagnation since 2002. Hence, future port reclamation should not be totally prohibited, and fine management should be conducted based on the optimization of the reclaimed port area. The innovation of this research is its analysis of the port internal land use pattern, the percentage of built-up area in the ports, and the sustainability of port reclamation policies. The findings have vital implications for scientifically regulating the spatial pattern and exploring the utility of port reclamation.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Nine units in new-born intertidal zone of the Yellow River estuary, China were examined for concentrations of heavy metals (Pb, Cr, Cu, Zn and Ni) in sediments and plants. Heavy metal levels in ...surface sediments were in the order of Zn>Pb≈Cr>Cu≈Ni and generally increased in a seaward direction except for Z6 (Tamarix chinensis-Suaeda salsa zone) and Z7 (S. salsa-T. chinensis zone) units. Significant differences in metal concentrations of the 9 units were observed in the profiles (p<0.01). Heavy metal levels in the shoots or roots of different plants decreased in the order of Zn>Cu>Pb>Ni>Cr and differed among plants or tissues. The roots at Z2 (Calamagrostis pseudophragmites zone), Z3 (Imperata cylindrical zone) and Z4 (Phramites australis zone) units accumulated greater metals than shoots TFs (translocation factors)<1, while the shoots at Z1 (Sparganium minimum-Potentilla supina zone), Z7 and Z8 (S. salsa zone) units accumulated greater metals than roots (TFs>1), implying that intertidal plants showed different pathways in metal accumulation and internal transportation. Except for Pb, the concentrations of Cr, Cu, Zn and Ni in sediments were lower than the criteria of Class I recommended by the Environmental Quality Standard for Soils of China. Although heavy metal levels in intertidal zone were generally the lowest (Cr, Cu, Zn and Ni) or relatively moderate (Pb) compared with other estuaries or bays in Asia and Europe, high eco-toxic risk of Pb and Ni exposure still could be observed at Z4, Z6 and Z9 (mudflat zone) units. S. salsa was more suitable for the potential biomonitor or phytoremediation of all five heavy metals if intertidal sediments was seriously contaminated with increasing of pollutants loading in the Yellow River estuary.
•Significant differences in heavy metal concentrations of the 9 units occurred in the profiles.•Heavy metal concentrations in sediments were related to pollutant inputs, grain-size and SOM.•Intertidal plants showed different pathways in metal accumulation and internal transportation.•Intertidal zone (Z4, Z6 and Z9 units) showed high eco-toxic risk of Pb and Ni exposure.•Suaeda salsa was more suitable for the potential biomonitor or phytoremediation of heavy metals.
A compound system involving three matrices (water, sediment, and paddy soil) was conceived to determine the potential sources of metal(loid)s (Ti, Fe, Co, Ni, Cu, Zn, As, Cd, Pb, and U) and ...synthetically evaluate their pollution levels in the Le’an River basin. The result indicated that the established background values (BVs) of paddy soil and sediment in the compound system were obviously higher than those of the upper continental crust (UCC) and soils from Jiangxi Province, a difference which was especially marked for sediment. The concentrations of Cu, Zn, As, Cd in the system had high coefficients of variation (CVs), and metal(loid)s in sediment showed higher levels than those in paddy soil, except for Pb. Cd and Cu in the system had the highest Ef levels, which probably pose a high risk to organisms and the health of local residents. There were significantly linear relationships between the site rank index (SRI) for water and that for sediment or paddy soil, revealing that matrices in the system interacted with each other. Principal component analysis (PCA) and absolute principal component scores and multiple linear regression model (APCS-MLR) results demonstrated that Cu, Zn, As, Cu, Pb, and U enrichments in the system were mainly affected by mining activities and were predominately deposited in sediment. Point pollution sources rather than non-point pollution sources such as mining activities, contributed most of the anthropogenic metal(loid)s to sediment. Both SRI and Hierarchical cluster analysis (HCA) results visually showed that S5, S8, S9, S10, S11, and S12 severe pollution grouped together and scattered through areas with extensive mining activities, while other sites with moderate pollution were spread along the main stream of the Le’an River.
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•The compound system involving water, sediment and paddy soil was established.•There were latent interactions of metal(loid) among matrices in the compound system.•Cd and Cu enrichment in the compound system likely posed high risk to the organism and human health.•Sediment was the main sink of anthropogenic metal(loid)s mainly contributed by point pollution sources.•Sampling sites in the area with violent mining activities suffered severe pollution.
Main finding: Establishing the compound system is an effective way to evaluate the pollution level in a specific basin. Efs indicate the migration of anthropogenic pollutants in the system.
The article examines the detailed spatial and temporal distributions of coastal reclamation in the northwest coast of Bohai Bay experiencing rapid coastal reclamation in China from 1974 to 2010 in ...annual intervals. Moreover, soil elements properties and spatial distribution in reclaimed area and inform the future coastal ecosystems management was also analyzed. The results shows that 910.7 km2 of coastal wetlands have been reclaimed and conversed to industrial land during the past 36 years. It covers intertidal beach, shallow sea and island with a percentage of 76.0%, 23.5% and 0.5%, respectively. The average concentration of Mn is 686.91mg/kg and the order of concentration of heavy metal are Cr>Zn>As>Ni>Cu>Pb>Cd>Hg. We used the "space for time substitution" method to test the soil properties changes after reclamation. The potential ecological risk of heavy metal is in low level and the risk of Cd and As is relatively higher. The ecosystem-based coastal protection and management are urgent to support sustainable coastal ecosystems in Bohai bay in the future.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Land use change is one of the main drivers of biodiversity loss. In the last 20 years, China＇s land use pattern has undergone profound changes. This study constructs an Eco- system Comprehensive ...Anthropogenic Disturbance Index （ECADI） to assess disturbance impacts of land use change between 1990 and 2010 on biodiversity conservation priority areas at national and regional scales. Four levels of biodiversity conservation areas were categorized： generally important areas, moderately important areas, important areas, and very important areas. The results indicated a higher ECADI value in 2010 in Central and Eastern China than in Western China, and the values of the moderately important, important and very important regions were lower than the average value of the whole country at all levels. Notably, in recent 20 years, the change extent of ECADI values in Central and Eastern China were much greater compared with that in Western China, and ECADI values in the moderately important, important and very important biodiversity conservation areas all showed increasing trends, with the increasing extent lower than that of whole China at all levels. Due to human activities such as urbanization in Eastern China and cropland reclama- tion in Northeast China and Xinjiang, ECADI values showed a medium increase trend （the change rate was about 1%-5% in 10 years）, which indicated the need for more conservation efforts in those regions. However, ECADI values in the Loess Plateau presented a low decline trend （the change rate was about-1% to -0.1% in 10 years） after 2000 because of the ob- vious effectiveness of Green for Grain Project. Furthermore, the variation was negligible in the Tibetan Plateau.
Investigating the mechanisms that influence the concentration of heavy metals (Cu, Cr, Ni, Zn, Pb, and Cd) and possible sources of these elements is vital in developing lake management strategies and ...conserving lake ecosystems. This is the first systematic research focusing on the content, distribution, and origin of heavy metals in Poyang Lake area, the largest freshwater lake in China. Samples were collected, and the concentration of trace elements was measured. The distribution, sources, and potential ecological risk, which has undergone rapid economic development and intensive anthropogenic activity, was evaluated. Multivariate statistical analyses were carried out to determine the relationship between these trace elements and to identify the possible pollution sources. Assessment methods were carried out by applying the geoaccumulation index (
I
geo
) along with potential ecological risk indices (PERI) and USEPA guidelines. The results show that: (1) in comparison to Chinese Soil Standard I, the study area was polluted with Cd and Cr, which had an average concentration that was higher than the Class I criteria. However, the results showed that the heavy metal concentration of Cd was lower than that in other areas. (2) The correlation analysis indicates that Pb and Cd may potentially have the same pollution source. (3) The geoaccumulation (Igeo) and potential ecological risk index (PERI) of these metals were evaluated. The average pollution degree of Igeo decreased in the following order: Cd > Cr > Ni > Cu > Zn > Pb > As, which is similar to that observed from the EF values. PERI varied between 48.64 and 453.45 for all metals, and the general average was calculated as 113.71. Both Igeo and ER indicate that the study area was polluted by Cd. The results of FA show that 87.90 % of the variance could be explained by three factors and an independent variable. The research results obtained from this study can provide the scientific impetus to create policies for the economic development and environmental protection in Poyang Lake and other areas of the world.
Samples were collected at 71 sites in the Yellow River Delta Natural Reserve in December 2010 to represent soil conditions before and after the Yellow River (YR) diversion. The As, Cd, Cu, Pb, Zn, ...and Ni concentrations were measured to determine metal contamination levels. Results suggest that Cd concentrations were significantly higher after the YR diversion than before. The As, Cd, Cr, Cu, Ni, Pb, and Zn soil contamination indices did not exceed contamination levels, although the heavy metal content increased after the YR diversion. The mean concentrations of these heavy metals were lower than the Class I criteria. Correlation analysis shows significant correlations between As and Cr, Cu, Ni, Pb, and Zn concentrations both before and after the YR diversion. However, no significant correlations were observed between heavy metal concentration and pH before the diversion, and no heavy metal concentration was correlated with salinity. The principal component analysis indicates that these trace elements, including As, were closely correlated with each other and therefore likely originated from shared pollution sources before the diversion. These results are useful for assessing the heavy metal contamination and proposing feasible suggestions to improve soil quality.
Natural and anthropogenic factors in coastal wetland changes are widely discussed in wetland studies. Previous literatures have demonstrated that many factors may cause wetland change and argued that ...the global climate change and nutrient enrichment may become the most important ones in the next 50 years. Through field investigation, with the help of remote sensing technology and geographic information system, this research discusses the wetland change in Tianjin under the great pressure of rapid economic development, population growth, and sea-level rising. These findings include: (1) the wetland area expanded from 466.50
km
2 to 658.38
km
2 between 1987 and 1998, but it shrank to 550.5
km
2 by the year of 2006. (2) The results show that the groundwater has not been contaminated while the surface water has been polluted. (3) The questionnaire survey shows that the social environment in some specific ways impedes the protection of natural reserve. In order to achieve the harmony between human and nature, feasible countermeasures on how to keep ecological balance should be immediately taken. Consequently, natural conservation and sustainable economic development will be realized.
Research on changes of land use in natural reserves is a critical issue and discussion of land use policies relevant to them is needed for their preservation in face of pressures of local ...socio-economic development. This study examined Tianjin Palaeocoast and Wetland National Natural Reserve (TJPW) and reviewed its development processes, status of adjustments and evolutionary mechanisms. Land use/cover change (LUCC), driving forces, adjustment schemes, and land use policy changes were also investigated. Land use changes were studied by supervised classification of Landsat TM remote sensing images of 1988, 1998, and 2008, respectively. Local economic development is the main driving force of LUCC. As such, it is critical to lay out a scientific, integrated development plan for adjustment that pays more attention to changes in natural reserve land properties and establishes ecological protection networks. In addition, the ecological integrity of natural reserves needs to be preserved and sustained instead of randomly modifying their boundaries to meet the demand of key infrastructure projects. Therefore, the results described in the study provides a detailed reference model that can lead to adopt boundary adjustment strategy to balance coastal wetland protection and a sustainable development of resource’s management.
► The protection effects of TJPW are vague. ► Boundary adjustment is needed for rationalizing the functional zones. ► Nature reserve should hold land rights and do ecological compensation. ► The protection effects of TJPW are vague. ► Boundary adjustment is needed for rationalizing the functional zones. ► Nature reserve should hold land rights and do ecological compensation.
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