Based on 11004 satellite images from CBERS CCD and Landsat TM/ETM, changes in the spatial characteristics of all lakes in China were determined following pre-established interpretation rules. This dataset was supported by 6843 digital raster images (1:100000 and 1:50000), a countrywide digital vector dataset (1:250000), and historical literature. Comparative data were corrected for seasonal variations using precipitation data. There are presently 2693 natural lakes in China with an area greater than 1.0 km 2 , excluding reservoirs. These lakes are distributed in 28 provinces, autonomous regions and municipalities and have a total area of 81414.6 km 2 , accounting for ~0.9% of China's total land area. In the past 30 years, the number of newly formed and newly discovered lakes with an area greater than 1.0 km 2 is 60 and 131, respectively. Conversely, 243 lakes have disappeared in this time period.
Chlorinated paraffins (CPs) are a class of compounds that are currently produced and used in large amounts in commercial products worldwide. In this study, food, indoor air, indoor dust, and drinking water samples were collected to evaluate the external exposure levels of CPs and possible pathway for the general population in Beijing, China. Short chain CPs (SCCPs) and medium chain CPs (MCCPs) in 199 samples were analyzed using a gas chromatography tandem time-of-flight high-resolution mass spectrometry (GC-TOF-HR-MS) method. High levels of CPs were observed in the indoor environment from residential houses, offices, and student dormitories. The geometric mean concentrations (GM) of ∑SCCPs and ∑MCCPs in indoor dust were 92 μg g and 82 μg g, respectively, while in indoor air, the concentrations were 80 ng m and 3.4 ng m, respectively. The GM of ∑SCCPs and ∑MCCPs in the diet were 83 ng g dry weight (dw) and 56 ng g dw, respectively. The most important external exposure routes to CPs to the general populations in Beijing were food intake and indoor dust ingestion. Indoor dust and indoor air posed higher risks for toddlers and infants than for adults.
Variation in the rubidium to strontium (Rb/Sr) ratio of the loess-palaeosol sequences has been proposed to reflect the degree of pedogenesis and weathering in the northwestern region of China. To characterize the Rb/Sr ratio of the dissolved loads of a single catchment, we analysed a 12·08 m sediment core from Daihai Lake in Inner Mongolia, north China.
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