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On the basis of investigations on the composition and contents of heavy metals in the domestic refuse in the Three-Gorges region of the Yangtze River, in combination with the experimental results, this paper deals with the distribution rule of heavy metals in the various compartments of an incineration system: leachate pool, fly ash and residue. It is concluded that in the leachate pool heavy metals should not be neglectable since about 30% of Pb and 10% of Cr are leached here; in the incineration system, above 74% of Cr, As and Pb exists in residue; above 96% of Hg exists in fly ash and the contents of Cd in fly ash are close to those of residue. It is also concluded that the physical conditions of incineration have a significant influence on the distribution of heavy metals in the incineration system. [ABSTRACT FROM AUTHOR]

The Lower Yangtze region is one of the important marine sedimentation areas of oil and gas distribution in southern China, for its favorable source rocks, reservoirs and covers. However, the intense tectonic movements and complex hydrocarbon generation process made it highly impossible to form large-sized oil and gas reservoirs. So it was divided to different hydrocarbon-bearing preservation units in oil-gas exploration. Recent study shows that the Permian and Lower Triassic source rocks in the Lower Yangtze region are complicated in lithology. The hydrocarbon generation potential of limestone there is low while argillaceous source rocks are overall of high abundance with excellent organic types, now in the process of hydrocarbon generation, so differences in high maturity influence the evaluation of organic matter abundance and type. Biomarker characteristics indicate a reductive environment. n-alkanes are marked by a single peak, with no odd-even predominance. The composition and distribution of the carbon numbers of n-alkanes, and the high abundance of long-chain tricyclic terpanes are indicative of marine sedimentation. The high contents of pregnane, homopregnane, rearranged hopane suggest that the source rocks are of high maturity. There is a good linear correlation between methylphenanthrene index and vitrinite reflectance. The correlation of oil-source rocks indicated that the oil of Well HT-3 may come from the Permian Longtan Formation in the Huangqiao area, the oil of Wells Rong-2 and Juping-1 came from the Lower Triassic Qinglong Formation in the Jurong area. The exploration here is promising in those different source rocks which all have great potential in hydrocarbon generating, and oil and gas were produced in the late stage of hydrocarbon generation. [ABSTRACT FROM AUTHOR]

We conducted ship-board incubation experiments to investigate changes in nutrient uptake of phytoplankton under different phosphate concentrations and irradiances in the Changjiang River Estuary and its adjacent waters in China. Under 100% natural irradiance the uptake rates of phosphate, silicate, and nitrate were accelerated at high phosphate levels (1.84 μM), while under low irradiance (about 50% natural irradiance) their uptake rates were restrained at the high but stimulated greatly at the intermediate phosphate concentrations (1.26 μM), as the growth of phytoplankton, changes in nitrite and ammonium uptake didn’t follow an obvious pattern. Our results also showed that there were linear relationships between nitrate, silicate and phosphate uptake at different phosphate concentrations under low and high irradiances, and the growth period of phytoplankton was prolonged both at the high phosphate concentrations under high irradiance and at the intermediate concentrations under low irradiance, suggesting that the limitation of phytoplankton growth mainly reflected changes in its growth period, and because no such environment (low irradiance and low phosphate concentrations) actually existed in a high turbidity zone, phytoplankton blooms hardly occurred there. In the absence of irradiance, denitrification occurred readily and phytoplankton was kept decreasing, which resulted in phosphate regeneration. [ABSTRACT FROM AUTHOR]

In an annual cycle from March 2005 to February 2006, benthic nutrient fluxes were measured monthly in the Dongtan intertidal flat within the Changjiang (Yangtze River) Estuary. Except for NH4 +, there always showed high fluxes from overlying water into sediment for other four nutrients. Sediments in the high and middle marshes, covered with halophyte and consisting of macrofauna, demonstrated more capabilities of assimilating nutrients from overlying water than the low marsh. Sampling seasons and nutrient concentrations in the overlying water could both exert significant effects on these fluxes. Additionally, according to the model provided by previous study, denitrification rates, that utilizing NO3 − transported from overlying water (DW) in Dongtan sediments, were estimated to be from −16 to 193 μmol·h−1·m−2 with an average value of 63 μmol·h−1·m−2 ( n=18). These estimated values are still underestimates of the in-situ rates owing to the lack of consideration of DN, i.e., denitrification supported by the local NO3 − production via nitrification. [ABSTRACT FROM AUTHOR]