[Contamination of Organophosphorus Pesticides Residue in Fresh Vegetables and Related Health Risk Assessment in Changchun, China].

This study aims to investigate the concentrations of organophosphorus pesticides (OPs) in fresh vegetables. A total of Z14 samples from seven types of vegetables were collected from the suburb in Changchun City. The OPs were analyzed by gas chromatography coupled with flame photometric detector (GC-FPD).

[Effects of elevated atmospheric CO2 concentration and nitrogen addition on the growth of Calamagrostis angustifolia in Sanjiang Plain freshwater marsh].

By using open top chamber, an experiment with two levels of atmospheric CO2 concentration (350 and 700 micromol x mol(-1)) and three levels of nitrogen supply (0, 5, and 15 g N x m(-2)) was conducted to investigate the effects of elevated atmospheric CO2 and nitrogen supply on the growth of Calamagrostis angustifolia in the freshwater marsh of Sanjiang Plain. Under elevated atmospheric CO2 concentration, the phenophase of C. angustifolia advanced.

[Spatial distribution and environmental risk of As and Pb from street dust in non-ferrous metals smelting areas].

ArcGIS analysis was applied to study the content level and the spatial distribution characteristics of As and Pb in street dust of Huludao city. Geoaccumulation Indexes and Potential Ecological Risk Index technique were applied to assess the ecological risk of As and Ph. The average contents of As and Pb were 33.

[Effects of simulated soil warming on the growth and physiological characters of Deyeuxia angustifolia].

By using improved heating cables, a field experiment was conducted to study the effects of 1 degrees C-30 degrees C soil warming on the growth and physiological characters of Deyeuxia angustifolia. Soil warming obviously promoted the growth of D. angustifolia.

[Seasonal changes of potassium, calcium and magnesium contents and accumulation in Calamagrostis angustifolia in Sanjiang Plain].

From May to October 2004, the seasonal changes of K, Ca, and Mg contents and accumulation in Calamagrostis angustifolia, the dominant species in the typical meadow and marsh meadow communities of Sanjiang Plain, were studied. There was a greater difference in the seasonal changes of K, Ca, and Mg contents in different parts of typical meadow C. angustifolia (TMC) and marsh meadow C.

[Spatial variation of heavy metals contamination in the soil and vegetables of Huludao City].

Hg, Pb, Cd, Zn, and Cu concentrations in the soil, vegetables and crop of Huludao city were investigated. The Hg, Pb, Cd, Zn, and Cu concentrations in soils of the smelting areas are 1.422, 443.

[Nitrogen accumulation and allocation in Calamagrostis angusifolia in different plant communities of Sanjiang Plain].

From May to October in 2004, the characteristics of nitrogen (N) accumulation and allocation in Calamagrostis angustifolia, the dominant species in the typical meadow and marsh meadow communities of Sanjiang Plain, were studied. The results showed that the total nitrogen (TN) content in the aboveground organs and litters of typical meadow C. angustifolia (TMC) and marsh meadow C.

[Dynamic coupling of ecological supporting capability and socioeconomic development of west Jilin Province].

The coupling relations between ecological supporting capability [F(x)] and socioeconomic situation [F(y)] of west Jilin Province from 1986 to 2004 were analyzed by harmonious development model and scissor difference method. The results showed that in study period, the F(x) of west Jilin Province had a trend of decreasing first and slightly increasing then, while F(y) had an overall exponential increase. Influenced by natural and anthropogenic factors, both F(x) and F(y) had obvious vulnerability.

[Effects of simulated nitrogen deposition on biomass of wetland plant and soil active carbon pool].

A simulation study was made on the responses of biomass of Deyeuxia angustifolia and soil active carbon pool in Sanjiang Plain of Northeast China to simulated nitrogen deposition. Two water conditions (W1: non-flooded, W2: flooded) and four N treatments (equivalent to 0, 1, 3, 5 g N x m(-2) x a(-1) nitrogen deposition rate) were installed. The results showed that under effects of nitrogen deposition, the total biomass, above-ground biomass, and root biomass of D.

[Dynamics of initial decomposition of Calamagrostis angustifolia litter in Sanjiang Plain of China].

A 28-day leaching-decomposition experiment was conducted to study the effects of microbial activity and leaching on the initial decomposition of Calamagrostis angustifolia litters taken from the boggy meadow and meadow in Sanjiang Plain of China. The results showed that the mass loss of the litters at their initial decomposition stage accounted for 59% and 22% of yearly mass loss, respectively, and the remaining dry mass decreased significantly after 28-day decomposition. By the end of the experiment, the N content in the litters decreased by 32.

Distribution and fate of anthropogenic nitrogen in the Calamagrostis angustifolia wetland ecosystem of Sanjiang Plain, Northeast China.

Wetlands are important for the protection of water quality of rivers and lakes, especially those adjacent to agricultural landscapes, by intercepting and removing nutrients in runoff. In this study, the 15N tracer technique was applied to study the distribution and fate of anthropogenic nitrogen (15N-fertilizer) in Calamagrostis angustifolia Kom wetland plant-soil microcosms to identify the main ecological effects of it. 15NH415NO3 solution (14.

[Effects of urbanization on supply and demand of regional ecological footprint].

Based on the time series of ecological footprint (EF) in Jilin Province from 1994 to 2003, the relationship models of EF, ecological budget, and EF intensity with urbanization level were established. The results showed that in Jilin Province, there existed significant correlations of EF, ecological budget, and EF intensity with urbanization level. Along with the development of urbanization, the EF in the Province increased from 1.

[Phosphorus fractions under different land uses in Sanjiang plain].

Five land-uses type (soybean-filed, rice-field, abandoned cultivation, artificial forest, natural wetland) were obtained before planting and soil P fractions were determined by a modified Hedley fraction method. The result showed that the content of total P (TP) in natural wetland was higher than other soil. While the proportion of total inorganic P (TPi) in TP of farm land soil was higher than that of wetland.

[Soil nitrogen net mineralization and nitrification in typical Calamagrostis angustifolia wetlands in Sanjiang Plain].

From June 2004 to July 2005, the dynamics of soil inorganic N pool and N net mineralization/nitrification rates in typical meadow Calamagrostis angustifolia wetland (TMCW) and marsh meadow C. angustifolia wetland (MMCW) in Sanjiang Plain were studied by top-closed PVC tube in situ incubation method, with the affecting factors and annual N net mineralization/nitrification investigated. The results showed that the soil inorganic N in the two wetlands had evident dynamic characteristics.

Nitrogen cycling of atmosphere-plant-soil system in the typical Calamagrostis angustifolia wetland in the Sanjiang Plain, northeast China.

The nitrogen (N) distribution and cycling of atmosphere-plant-soil system in the typical meadow Calamagrostis angustifolia wetland (TMCW) and marsh meadow Calamagrostis angustifolia wetland (MMCW) in the Sanjiang plain were studied by a compartment model. The results showed that the N wet deposition amount was 0.757 gN/(m2 x a), and total inorganic N (TIN) was the main body (0.

[Nitrification-denitrification and N2O emission of typical Calamagrostis angustifolia wetland soils in Sanjiang plain].

With intact soil core and by using acetylene inhibition method, this paper measured the N2O emission and denitrification rates of typical Calamagrostis angustifolia wetland soils in Sanjiang Plain, analyzed their relationships with environmental factors, and estimated the total amounts of N2O emission and denitrification loss. The results showed that meadow marsh soil and humus marsh soil had a similar change range of N2O emission rate (0.020-0.

[Dynamics of H2S and COS emission fluxes from Calamagrostis different calamagrostis angustifolia wetlands in Sanjiang Plain].

Using the static chamber and chromatogram method, H2S and COS emission fluxes from the mash meadow Calamagrostis angustifolia in Sanjiang Plain were measured during growth season(5-9 month), the results showed that the seasonal and diurnal variations of H2S and COS emission fluxes were obvious, the mean H2S and COS emission fluxes from the mash meadow Calamagrostis angustifolia were 0.34 microg x (m2 x h)(-1) and - 0.29 microg x (m2 x h)(-1) respectively, the Calamagrostis angustifolia wetlands were the sources for H2S and the sinks for COS during the growth time.

Element cycling in the dominant plant community in the Alpine tundra zone of Changbai Mountains, China.

Element cycling in the dominant plant communities including Rh. aureum, Rh. redowskianum and Vaccinium uliginosum in the Alpine tundra zone of Changbai Mountains in northeast China was studied.

The long-term nutrient accumulation with respect to anthropogenic impacts in the sediments from two freshwater marshes (Xianghai Wetlands, Northeast China).

Sediment cores, representing a range of watershed characteristics and anthropogenic impacts, were collected from two freshwater marshes at the Xianghai wetlands (Ramsar site no. 548) in order to trace the historical variation of nutrient accumulation. Cores were (210)Pb- and (137)Cs-dated, and these data were used to calculate sedimentation rates and sediment accumulation rates.