Analyzing the Variation of Building Density Using High Spatial Resolution Satellite Images: the Example of Shanghai City.

Building density is an important issue in urban planning and land management. In the article, building coverage ratio (BCR) and floor area ratio (FAR) values extracted from high resolution satellite images were used to indicate buildings' stretching on the surface and growth along the third dimension within areas of interest in Shanghai City, P.R. China. The results show that the variation of FAR is higher than that of BCR in the inner circle, and that the newer commercial centers have higher FAR and lower BCR values, while the traditional commercial areas have higher FAR and BCR ratios. By comparing different residential areas, it was found that the historical "Shikumen" areas and the old residential areas built before 1980s have higher BCR and lower FAR, while the new residential areas have higher FAR and lower BCR, except for the villa areas. These results suggest that both older building areas and villa areas use land resources in an inefficient way, and therefore better planning and management of urban land are needed for those fast economic growing regions.

[Effects of nitrogen fertilization and root separation on the plant growth and grain yield of maize and its rhizosphere microorganisms].

A field experiment with root separation was conducted to study the effects of root interaction in maize-soybean intercropping system on the plant growth and grain yield of maize and its rhizosphere microorganisms under different nitrogen fertilization levels (0.1, 0.3, 0.5, and 0.7 g x kg(-1)). Root interaction and nitrogen fertilization had positive effects on the plant height, leaf length and width, and leaf chlorophyll content of maize. Less difference was observed in the root dry mass of maize at maturing stage between the treatments root separation and no root separation. However, as compared with root separation, no root separation under the nitrogen fertilization levels 0.1, 0.3, 0.5, and 0.7 g x kg(-1) increased the biomass per maize plant by 8.8%, 6.3%, 3.6%, and 0.7%, and the economic yield per maize plant by 17.7%, 10.0%, 8.2%, and 0.9%, respectively. No root separation increased the quantity of rhizosphere fungi and azotobacteria significantly, as compared with root separation. With increasing nitrogen fertilization level, the quantity of rhizosphere bacteria, fungi, and actinomycetes presented an increasing trend, while that of rhizosphere azotobacteria decreased after an initial increase. The root-shoot ratio of maize at maturing stage was significantly negatively correlated with the quantity of rhizosphere bacteria, fungi, and actinomycetes, but less correlated with the quantity of rhizosphere azotobacteria. It was suggested that the root interaction in maize-soybean intercropping system could improve the plant growth of maize and increase the maize yield and rhizosphere microbial quantity, but the effect would be decreased with increasing nitrogen fertilization level.

Fraction distribution and bioavailability of soil heavy metals in the Yangtze River Delta--a case study of Kunshan City in Jiangsu Province, China.

Mobility and bioavailability of soil heavy metals strongly depend on their fractions. Secondary-phase fraction (SPF) of heavy metal, including acid-soluble, reducible and oxidizable fractions, is considered as direct and potential hazardous fraction to organisms. The ratio of SPF to the total concentration of heavy metal represents its bioavailability. In this study, 126 topsoil samples were collected in Kunshan, Jiangsu, China. Fraction concentrations of heavy metals, and their bioavailability and spatial distributions were determined, and relationships between their fractions and types of industry zones were analyzed. Results showed that Cd and Pb had the greatest SPFs among all metals (78.61% and 62.60%, respectively). Great SPFs of Cd and Pb were observed in the dyeing and paper-making industry zone, while great SPFs of Cr, Cu, Zn, Ni were in the smelting and plating industry zone. For most metals, fraction distributions were controlled by soil organic matter and clay contents. Spatial principal component analysis showed SPFs of heavy metals can be explained by two principle components (PCs). PC1 represented SPFs of Cd, Cr, Cu, Pb and Zn, while PC2 represented SPFs of Ni and Co. The spatial distributions of SPFs were influenced by geochemical character, industrial sewage irrigation and soil physico-chemical properties.

[Evaluation of soil heavy metals accumulation in the fast economy development region].

Evaluation of soil heavy metals accumulation was studied in Kunshan City, a typical region of the fast economy development region in China. 126 soil samples were collected and analyzed, and evaluation indexes of soil heavy metal accumulation, which including total concentration of soil heavy metal index (THMI), soil available heavy metal index (AHMI) and fractionation of soil heavy metal index (FHMI), were established, and the heavy metal accumulation conditions of soil in this region were also discussed. Results showed as follows: the spatial variability of THMI was relative lower, with a mean value of 42.57%, whereas strong variability was found in AHMI and FHMI (especially active fraction of soil heavy metals), with the average value of 82.75% and 77.83%, respectively. Judging by each index reference standard of C Horizon, THMI was low-grade with a mean value of 1.01, while the AHMI and FHMI reached to medium accumulation and serious accumulation, with the average values of 2.46 and 4.32, respectively. The synthetic accumulation index of soil heavy metals (SHMI) was 2.56, reaching to medium grade level and with strong variability. 21.54% land area was in low-grade accumulation and 54.70% land area was in medium grade accumulation, while 23.76% land area was in serious accumulation under SHMI evaluation system. All the accumulation evaluation indexes in livestock breeding zone were the lowest, while the indexes in the smelting and plating zone were the highest, but the indexes difference between two zones were unobvious. There were markedly differences in soil types, which the accumulation indexes in Wushan soil were significantly higher than those in Huangni soil and Qingni soil.

[Characterizing the plant uptake factor of As, Cd and Pb for rice and wheat cereal].

The statistical characteristics of plant uptake factor (PUF) of As, Cd and Pb for rice/wheat cereal were analyzed and summarized based on collected data in China. The data were selected and distinguished between field investigation and glasshouse experiment in which metal salts were added to clean soils as grown media. Results showed that the PUF median and range of As, Cd and Pb for rice cereal were 0.026 (0.004-0.090), 0.150 (0.014-1.470), 0.005 (0.001-0.031) and 0.010 (0.003-0.033), 0.360 (0.056-1.700), 0.002 (0.001-0.019) for field investigation and salt added experiment respectively. The PUF median and range of As, Cd and Pb for wheat cereal were 0.010 (0.001-0.110), 0.190 (0.030-2.110), 0.017 (0.001-0.075) and 0.010 (0.003-0.028), 0.150 (0.055-0.730), 0.001 (0.001-0.014) for field investigation and salt added experiment respectively. Significant PUF distribution differences were found between field investigation and salt added experiment. PUF provided not exactly predictive ability of metal uptake by crops since the PUF values were influenced by a variety of factors including the soil contamination levels, basic soils characteristics, the cultivation of the crops and other environmental conditions. However, the ln (PUF) followed Gaussian distribution (R2 = 0.38-0.94) which is useful for general risk assessment and soil benchmark derivation of contaminated croplands. Use of these statistical models is restricted to the range of data they have been derived, as extrapolation outside this range is often unreliable. Soil properties and surrounding environment of the crops should also be in accordance with the conditions PUF derived.

[Development of lead benchmarks for soil based on human blood lead level in China].

Lead benchmarks for soil are mainly established based on blood lead concentration of children. This is because lead plays a dramatically negative role in children's cognitive development and intellectual performance and thus soil lead has been concerned as main lead exposure source for children. Based on the extensively collection of domestic available data, lead levels in air, drinking water are 0.12-1.0 microg x m(-3) and 2-10 microg x L(-1); ingestion of lead from food by children of 0-6 years old is 10-25 microg x d(-1); geometric mean of women blood lead 1concentration of child bearing age is 4.79 microg x dL(-1), with 1.48 GSD. Lead benchmarks for soil were calculated with the Integration Exposure Uptake Biokinetic Model (IEUBK) and the Adult Lead Model (ALM). The results showed the lead criteria values for residual land and commercial/industrial land was 282 mg x kg(-1) and 627 mg x kg(-1) respectively, which was slightly lower compared with U.S.A. and U.K. Parameters sensitivity analysis indicated that lead exposure scenario of children in China was significantly different from children in developed countries and children lead exposure level in China was obviously higher. Urgent work is required for the relationship studies between lead exposure scenario and blood lead level of children and establishment of risk assessment guideline of lead contaminated soil based on human blood lead level.

[Arsenic contents in soil, water, and crops in an e-waste disposal area].

In order to study whether disposing electronic wastes and secondary metal smelting could cause an arsenic pollution in the environment or not, Luqiao town, Taizhou City, Zhejiang Province was selected as a study area. The main purpose of this paper was to characterize arsenic contents in the local environment, including waters, sediments, soils and rice, and to assess the potential risk to humans. Additionally, the arsenic spatial distribution property and arsenic uptake-translocation rule in soil-rice system were also studied. The results showed that the average arsenic levels in the surface water and the groundwater were 8.26 microg/L and 18.52 microg/L, respectively, which did not exceed the limiting value of Chinese Environment Standards class III . Whereas,some groundwater exceeded the recommended standard by the WHO for drinking water (10 microg/L). The arsenic (on average 7.11 mg/kg) in paddy soils and arsenic (on average 6.17 mg/kg) in the vegetable garden soils were lower than the value recommended by the National Standard (level I). The average arsenic contents in brown rice and husks were 165.1 microg/kg and 144.2 microg/kg, which was also lower than the Chinese Foods Quality Standard. The arsenic contents between the corresponding soils-rice and husks-brown rice showed significantly positive correlations. By comparison, the arsenic contents of soils and husks collected around electroplating were relatively higher than most of other pollutant sources, indicating the electroplating may lead accumulation of arsenic in the paddy soil-rice system.

[Characteristics of six elements contents in human hairs in the vicinity of metal smelting factories].

To assess the impact of secondary smelting activities to the local resident's well beings, the contents of six elements-Cu, Zn, Pb, Cd, As, Se-in human scalp hairs of residents in suburb Fuyang, Zhejiang Province, were determined by atomic absorption spectrometer (AAS) and by atomic fluorescence spectrometer (AFS-930), respectively. The results showed that hair elemental contents were markedly higher than those in unpolluted area. The highest hair contents of Cu, Zn, Pb and Cd reached 312, 513, 700 and 7.41 microg x g(-1), respectively, As and Se 10.08 and 0.85 microg x g(-1), respectively. Additionally, a significant relationship between Cu, Zn, Pb, Cd and As in human hair was observed, which indicated at a certain degree that the elemental pollution was caused by similar source-small blast furnace smelting. Moreover, it showed that the Cu, Zn, Pb, Cd, and As contents in hair of human who were above 40 years old was twice more than those whose age below 40. There was no apparent difference in average content of Cu, Zn, Cd, Se between male and female, except that Pb and As of male hair was higher than female, however, by statistic analysis showing no significant age and gender dependence.

[Coregionalization, spatial-correlation and spatial-factor analysis of soil available heavy metals in a typical region of the Yangtze River Delta].

The method of factorial kriging based on the theory of coregionalization is developed by the combination of multi-statistics, geostatistics and GIS. Soil available heavy metals of 126 topsoil samples in Kunshan city, a typical region of Yangtze River Delta, were analyzed, and the spatial distribution pattern was investigated by the method of factorial kriging. Based on the analysis of multi-scale spatial structure characteristics of available heavy metals, we discussed the pollution source and cause of this spatial distribution by means of spatial scale-correlation analysis and spatial principal component analysis. Our results show that all the available heavy metals distribute normally or lognormally with great variability, and the contamination of available Cd is the biggest. The available heavy metals are categorized into three spatial scales, i.e. nugget, short-range (15 km) and long-range (40 km), respectively, and a linear model of coregionalization comprising these three spatial scales is fitted to the experimental auto-and cross-variograms of the soil available heavy metals. Significant relationship is found between Cd and Zn in the three scales. The spatial correlation of available heavy metals in short-range and long-rang are stronger than it in nugget, while the long-rang has more obvious negative correlation than the other two spatial scales. The results of spatial principal component analysis show the pollution sources are different in the three spatial scales. The kriging interpolation method was applied to work out the distribution maps of first and second principal component of available heavy metal, which indicate that available heavy metal concentrations in the soils are closely related to their industry activity, sewage irrigation and soil characteristics.