Wang Jin-da

SPATIAL-TEMPORAL VARIATION OF HEAVY METAL ELEMENTS CONTENT IN COVERING SOIL OF RECLAMATION AREA IN FUSHUN COAL MINE

Grid method is employed for sampling covering soil at the test field, which is reclamation area filled by coal mining wastes for cropland in the Fushun coal mine, Liaoning Province, the Northeast China. The soil samples are taken at different locations, including three kinds of covering soil, three different depths of soil layers and four different covering ages of covering soil. The spatial-temporal variation of heavy metal element content in reclamation soil is studied. The results indicate that the content of heavy metal elements is decreasing year after year; the determinant reason why the content of heavy metal elements at 60cm depth layer is higher than that at 30cm depth layer and surface is fertilizer and manure application; the metal elements mainly come from external environment; there is no metal pollution coming from mother material (coal mining wastes) in plough layer of covering soil.

Biogeochemical cycle of Sulfer in the Calamagrostis angustifolia wetland ecosystem in the Sanjiang Plain, China

Abstract To better understand the Sulfur (S) cycle in the wetland ecosystem, the S cycle and its compartmental distribution within an atmosphere-plant-soil system were studied using a compartment model in the Calamagrostis angustifolia wetland in the Sanjiang Plain, Northeast China. The results showed that the soil was the main S storage and flux hinge in which 97.78% S was accumulated. In the plant subsystem, the root was the main S storage, and it remained at 79.60% of the total S contents, which in the Calamagrostis angustifolia wetland ecosystem showed that the parts above the ground took up 0.75 g S/m2, the S re-transferring biomass to the root was 0.24 g S/m2, and to the litter was 0.51 g S/m2; the root took up 3.76 g S/m2 and the S transferring biomass to the soil took up 3.07 g S/m2; the litter S biomass was 0.75 g S/(m2·a) and the S transferring biomass to the soil was more than 0.52 g S/(m2·a). The emission amount of H2S from the Calamagrostis angustifolia wetland ecosystem to the atmosphere was 1.42 mg S/m2, whereas carbonyl sulfide (COS) was absorbed by the Calamagrostis angustifolia wetland from the atmosphere and the absorption amount was 1.83 mg S/m2. The S input biomass from the rain to the ecosystem was 4.85mg S/m2 during the growing season. The difference between input and output amounts was 5.26 mg S/m2, which indicated that S was accumulated in the ecosystem and would lead to wetland acidification in the future.

Ecotoxicity of Cadmium to Maize and Soybean Seedling in Black Soil

Ecotoxicity and bioavailability of cadmium (Cd) to the maize (Zea mays L.) and the soybean (Glycine max (L.) Merr.) were investigated by acute toxicity experiment in the laboratory with black soil. Ecotoxicity and bioavailability of Cd were quantified by calculating the median effective concentration (EC50) and bioaccumulation factor (BAF). The measurement endpoints used were seed germination and seedling growth (shoot and root). The results showed that concentrations of Cd in the soil had adverse effect on the growth of roots and shoots. Seed germination was not the sensitive indicator for the ecotoxicity of Cd in the soil, while the growth of roots was the most sensitive measurement endpoint. Absorbability and transport of Cd in plants depended on the test crop species and Cd concentrations in the soil. The maize retains more Cd in its roots, while the soybean transports more Cd to the shoots from roots.

Biomass structure and nitrogen, phosphorus nutrient of Calamagrostis angustifolia populations in different communities of Sanjiang Plain, Northeast China

Calamagrostis angustifolia is the dominant species in the typical meadow and marsh meadow communities of Sanjiang Plain. The study on its biomass, the nitrogen (N) and phosphorus (P) contents in its different organs showed that the biomass of different C. angustifolia organs in the two types of wetland communities was distinctly different, which could be described by polynomial. The biomass of aboveground part and each organ presented single peak changing, with the maximum value of the latter occurred 15 days after. The F/C values were all less than 1, which were bigger in typical meadow than those in marsh meadow. The total N and P contents in different organs of aboveground part all descended monotonically in growth season, with the order of leaf>vagina>stem. The change of total N content in roots of the two types of C. angustifolia was consistent, while that of total P was quite different. The content of total N, ammonium nitrogen (NH4+-N) and nitrate nitrogen (NO3−-N), especially of NH4+-N and NO3−-N, varied widely in different organs, with NH4+-N/NO3−-N>1. Root was the important storage of N and P, but the storage of N and P in stem, leaf and vagina fluctuated greatly. The N/P ratios of the two types of C. angustifolia were all less than 14, which implied that N might be the limiting nutrient of C. angustifolia, and the limitation degree was higher in typical meadow than that in marsh meadow.