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Transgenic rice expressing Bacillus thuringiensis (Bt) CrylAb protein is expected to be commercialized in China in the near future. The use of Bt rice for controlling insect pests sparks intensive debates regarding its biosafety. Folsomia candida is an euedaphic species and is often used as a "standard" test organism in assessing effects of environmental pollutants on soil organisms. In this study, growth, development, reproduction, and superoxide dismutase activity (SOD) of F. candida were investigated in the laboratory for populations reared on leaf tissue or leaf-soil mixtures of two CrylAb rice lines and a non-Bt rice isoline. Two independent tests were performed: 1) a 35-d test using petri dishes containing yeast diet (positive control) or fresh rice leaf tissue, and 2) a 28-d test in soil-litter microcosms containing yeast or a mixture of soil and rice leaf tissue. Biological parameters measured in both tests were number of progeny production, population growth rate, and SOD activity. For the petri dish test, data measured also included insect body length and number of exuviation. There were no significant differences between the populations reared on Bt and non-Bt rice leaf tissue in all measured parameters in both tests and for both Bt rice lines, suggesting no significant effects of the CrylAb protein in Bt rice on F. candida in the laboratory studies. Results of this study should add additional biosafety proofs for use of Bt rice to manage rice pests in China. [ABSTRACT FROM AUTHOR]

It was not unusual in soil and environmental studies that the distribution of data is severely skewed with several high peak values, which causes the difficulty for Kriging with data transformation to make a satisfied prediction. This paper tested an approach that integrates kriging and triangular irregular network interpolation to make predictions. A data set consisting of total Copper (Cu) concentrations of 147 soil samples, with a skewness of 4.64 and several high peak values, from a copper smelting contaminated site in Zhejiang Province, China. The original data were partitioned into two parts. One represented the holistic spatial variability, followed by lognormal distribution, and then was interpolated by lognormal ordinary kriging. The other assumed to show the local variability of the area that near to high peak values, and triangular irregular network interpolation was applied. These two predictions were integrated into one map. This map was assessed by comparing with rank-order ordinary kriging and normal score ordinary kriging using another data set consisting of 54 soil samples of Cu in the same region. According to the mean error and root mean square error, the approach integrating lognormal ordinary kriging and triangular irregular network interpolation could make improved predictions over rank-order ordinary kriging and normal score ordinary kriging for the severely skewed data with several high peak values. [ABSTRACT FROM AUTHOR]

Thirty typical soil profiles were sampled in Yangtze River Delta (YRD) region and analyzed for stable lead (Pb) isotopes and total concentrations of Pb and scandium (Sc). Pb isotopic compositions of A-horizon and C-horizon and Pb/Sc ratio were combined to estimate the amounts of endogenous and exogenous Pb accumulated in topsoil and identify possible sources. The results indicated that Pb exhibits a trend of accumulation in topsoil at regional scale. The isotopic composition of endogenous Pb is characterized by a narrow range of isotope ratios, varying with parent material, while that of exogenous Pb is characterized by a comparatively wide range of isotope ratios, varying with anthropogenic source. Coal combustion is probably the most important anthropogenic source of exogenous Pb in the soils of YRD region, as identified by isotopic ratio cross-plot combined with multi-elemental approaches. [ABSTRACT FROM AUTHOR]

total of 782 topsoil samples (0–20 cm) and 371 subsoil samples (20–40 cm) were collected from agricultural land in two rapidly industrialized areas with a large number of small rural industries in southeast China, Zhangjiagang City (ZJG) and Changshu City (CS), to measure soil chromium (Cr) concentrations. Kriging and cokriging were used to predict the spatial distribution of Cr in the topsoils and subsoils. Paired-samples t test and spatial distribution maps were used to compare the Cr concentrations in topsoils and subsoils. The mean Cr concentration in ZJG topsoils was significantly higher than that in ZJG subsoils and the mean Cr concentration in CS topsoils showed no significant difference from that in CS subsoils. The Cr concentrations in topsoils were higher than those in subsoils over most of the area of ZJG and part of CS, suggesting that Cr accumulation had occurred in these areas and extrinsic factors have an important role controlling the distribution of Cr in topsoils. Semivariogram/cross-semivariogram was used to evaluate soil Cr spatial variability. The Cr in ZJG topsoils, ZJG subsoils, and CS topsoils had moderate spatial dependence and the Cr in CS subsoils had strong spatial dependence. Cr in ZJG subsoils had longer effective range than Cr in ZJG topsoils, suggesting that the anthropogenic factors affecting Cr distribution in ZJG topsoils; and Cr in CS topsoils had longer effective range than Cr in CS subsoils, indicating that soil formation may be the major explanation for the decrease in the variation of Cr in topsoils. A significant correlation was found between the Cr in topsoils and Cr in subsoils, indicating that natural factors also play an important role as extrinsic factors that control the distribution of Cr in topsoils. [ABSTRACT FROM AUTHOR]

Accurately measuring soil organic matter content (SOM) in paddy fields is important because SOM is one of the key soil properties controlling nutrient budgets in agricultural production systems. Estimation of this soil property at an acceptable level of accuracy is important; especially in the case when SOM exhibits strong spatial dependence and its measurement is a time- and labor-consuming procedure. This study was conducted to evaluate and compare spatial estimation by kriging and cokriging with remotely sensed data to predict SOM using limited available data for a 367-km² study area in Haining City, Zhejiang Province, China. Measured SOM ranged from 5.7 to 40.4 g kg-1, with a mean of 19.5 g kg-1. Correlation analysis between the SOM content of 131 soil samples and the corresponding digital number (DN) of six bands (Band 1-5 and Band 7) of Landsat Enhanced Thematic Mapper (ETM) imagery showed that correlation between SOM and DN of Band 1 was the highest (r = -0.5 87). We used the DN of Band 1 as auxiliary data for the SOM prediction, and used descriptive statistics and the kriging standard deviation (STD) to compare the reliabilities of the predictions. We also used cross-validation to validate the SOM prediction. Results indicate that cokriging with remotely sensed data was superior to kriging in the case of limited available data and the moderately strong linear relationship between remotely sensed data and SOM content. Remotely sensed data such as Landsat ETM imagery have the potential as useful auxiliary variables for improving the precision and reliability of SOM prediction. [ABSTRACT FROM AUTHOR]

The article discusses research that applied a regression model to predict the average cadmium content in rice grains for paddy fields located in China's Zhejiang province. Soils in the Fuyang valley have been contaminated by heavy metals. Cadmium has a tendency to bioaccumulate in rice grains, posing a potential human health risk. A multiple linear model for assessing cadmium content is the most effective predictor, as it examines the sensitivity of calcium chloride-extracted cadmium for changes in oxidation-reduction potential.

Atmospheric NOx concentrations (including NO2 and NO) on the roadside environments of urban trunk, belt highway and suburban road as well as a reference in a forest area were measured. NOx concentrations on roadside environments tended to be higher than that on the reference. With the exception of suburban road, NOx concentrations over both of the urban trunk and belt highway exceeded the limited value of National Air Environmental Quality Standards. Gradient measurement of NOx on the downwind side of the belt highway shows that it declined to background level over 100 m from the road edge. [ABSTRACT FROM AUTHOR]

Organochlorine pesticides were used extensively in the Yangtze River Delta, China. However, knowledge about their residual levels and environmental fates in soils of this area is limited. This paper presents the residue isomers and spatial pattern of dichlorodiphenyltrichloroethane (DDT) in soils across 17 main cities in the Yangtze River Delta. Forty-three soil surface (0-15 cm) samples were collected during a field campaign conducted in October 2003 in the Delta. Six DDT isomers (1-[2-chlorophenyl]- 1-[4-chlorophenyl]-2,2-dichloroethane [o,p'-DDD], 1-[2-chlorophenyl]-1-[4-chlorophenyl]-2,2-dichloroethylene [o,p-'DDE], 1,1,1- trichloro-2-[p-chlorophenyl]-2-[o-chlorophenyl]ethane [o,p'-DDT], p,p'-dichlorodiphenyldichloroethane [p,p'-DDD], p,p'-dichlorodiphenyldichloroethylene [p,p'-DDE], p,p'-dichlorodiphenyltrichloroethane [p,p'-DDT]) were detected using gas chromatography. The results show that p,p'-DDE was the dominant isomer in the soil samples. The levels of DDT are generally low in soils of this area and are comparable to DDT levels in other cities in China and in soils from developed countries such as the United States and Germany. The isomer ratios of o,p'-DDT to p,p'-DDT and DDT to (DDD + DDE) were employed to identify the source of DDT. The computed ratios implied that the source of DDT might be related to the application of dicofol, an acaricide manufactured from technical DDTs and mainly used on cotton fields to treat mites. [ABSTRACT FROM AUTHOR]

An assessment of exposure to mercury in Changchun city has been undertaken. We estimated Hg exposure to members of the general population based on currently available information and our research. We also studied the Hg concentrations in scalp hair of adults. Adults have an estimated intake of all Hg species via all routes of 6.780 μg day−1 (excluding dental amalgam), which equates to an absorbed dose of 1.718 μg day−1. Fish consumption was the most important exposure route (12% of intake, 43% of absorbed dose). Furthermore, air, cereals and vegetables were important exposure routes, and these exposure were estimated for absorbed dosed at 0.296, 0.209 and 0.318 μg day−1, respectively. The mean Hg concentration in hair was 0.448 μg g−1 (range 0.092–10.463 μg g−1). Hg concentration in the hair of males was 0.422 μg g−1 (0.105–2.665 μg g−1), and was 0.474 μg g−1(0.092–10.463 μg g−1) in the hair of females. Neither place of residence nor age had any significant effect on hair Hg concentrations. [ABSTRACT FROM AUTHOR]

Polychlorinated biphenyls (PCBs) were determined in surface soil samples from Zhejiang Province, east China. Concentrations of total PCBs ranged widely from 7.50 to 263 ng kg−1 with a mean value of 45.4 ng kg−1 (dry matter basis). In general, concentrations in soil samples from the southern part of the test area and especially from some sites near hills tended to be higher than those from other sites. The prevailing winds may have been the main factor influencing the spatial distribution of PCBs in soils. Other factors may have included the distribution of residential areas and land use variables. In this paper we also discuss the relationships between OCPs and PCBs in soils and relationships between these and land use variables as revealed by correlation analysis. [ABSTRACT FROM AUTHOR]

A survey was conducted on the accumulation and spatial distribution of PAHs in surface soils under different land use patterns in a valley in the Yangtze Delta region with an area of 10 km2 containing 15 small copper- and zinc-smelting furnaces. Sixty-five topsoil (0–20 cm) samples were collected and 16 PAHs were determined. The average amount of all the 16 PAHs ranged from 0 to 530 μg kg−1 (oven dry basis), with a mean concentration of 33.2 μg kg−1. Benzo[a]pyrene and indeno[1, 2, 3, -cd]pyrene were the two main PAHs present at high concentrations, while pyrene and fluorene had very low concentrations. PAH concentrations were higher in uncultivated than in cultivated soils, and areas of woods and shrubbery had the␣lowest soil PAH contents. The average PAH-homologue concentrations ranked as follows: 5-rings >> 3-rings, 4-rings > 6-rings >2-rings. Much higher concentrations of PAHs were found in the southern part of the sampling area, perhaps due to deposition of airborne particles by the southeasterly winds in winter and spring. We conclude that the small smelting furnaces were the dominant source of PAHs that accumulated in the soils and the southeasterly winds led to the spatial distribution of PAHs in the topsoils. Land vegetation cover and soil utilization patterns also affected the accumulation and distribution of soil PAHs. [ABSTRACT FROM AUTHOR]

A comparison of structure and pattern of the soil seed bank was made between active and stabilized sand dunes in northeastern Inner Mongolia, China. The objective of this paper was to determine the significance of seed bank in vegetation restoration of sand dunes. The results showed that (1) average seed density decreased from stabilized sand dune to interdune lowland of stabilized sand dune, to interdune lowland of active sand dune, and to active sand dune; (2) horizontally, along the transect from interdune lowland to ecotone and to sand dune top, a ‘V’ shaped pattern was presented in the active dune system, and a reverse ‘V’ shaped pattern in the stabilized sand dune system; (3) vertically, the proportion (accounting for the total seeds) of seeds found in 0–20 mm soil profile decreased from stabilized sand dune to interdune lowland of stabilized sand dune, to interdune lowland of active sand dune, and to active sand dune. The same order was also found in 20–50 mm and 50–100 mm soil profiles; (4) the Sokal and Sneath similarity indices in the species-composition between soil seed bank and above-ground vegetation were ranked as: the stabilized sand dune (24%) > the interdune lowland of active sand dune (21%) > the interdune lowland of stabilized sand dune (18%) > the active sand dune (5%); and (5) vegetation restoration of active sand dunes depends on the dispersal of seeds from nearby plant communities on the interdune lowlands. Much effort must be made to preserve the lowlands, as lowlands are the most important seed reservoir in the active sand dune field. [ABSTRACT FROM AUTHOR]