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Purpose: Soils develop via a complex interaction of time, environment, climate, and human activity. As a proxy for paleoclimate reconstruction, soils have received less attention than other geological systems, and the limited attention was concentrated in loess sequences. Fluvisols form a subrecent natural archive that documents mid-term pedogenic processes and environmental change in floodplains. We investigated the pedological characteristics and pedogenesis of fluvisols in the Beijing region and presented a Late Holocene paleoenvironmental reconstruction based on it. Methods: We applied the radiocarbon dating method to investigate soil formation in the floodplain of the North Canal in Beijing's southeast suburbs. Soil morphology, soil texture, and environmental physical–chemical indicators (calcium carbonate, organic matter, total phosphorus, and total potassium) were selected for comprehensive analysis. Results and discussion: Thorough integrated interpretation of soil development processes in the fluvisols sequence revealed regional paleoenvironmental and climatic developments. The paleoclimate of Beijing underwent a transition from warm and humid to temperate and dry, as well as multiple cold fluctuations. Multiple humic burial horizons in the fluvisol sequence were overlain by a mineral soil horizon with weak soil formation, indicating that fluvic geology processes interrupted the process of the fluvisol formation, corresponding to cold-dry fluctuations in a warm-humid paleoclimatic context in Beijing floodplain. There is a correlation between paleoclimatic environmental conditions and soil texture, organic matter, calcium carbonate, and other physical and chemical properties in the soil chronology. Conclusions: As an emerging paleoenvironmental proxy, the geological process and soil-forming process of fluvisols inferred from soil properties can reconstruct the variation of paleoclimatic-environmental conditions. Fluvisol sequence build-up and illuviated accumulation of mineral material in the soil complex were more pronounced in warm and humid climatic conditions. Millennia of farming practices dominate the development of the uppermost fluvisols. Environmental reconstruction based on fluvisol soil properties is complementary to reconstruction drawing on other prevalent paleoclimate proxies. Fluvisol characterisation allows to disentangle gradual paleoenvironmental developments, including changes of climate, vegetation, and topography. [ABSTRACT FROM AUTHOR]

To understand the level of radon exhalation rate from soil surface and its variation, a continuous measurement system was developed and applied for a field measurement in Beijing from April 2012 to February 2013. For seasonal variation, It was indicated by measurement results that radon exhalation rate was higher in spring (52.9 mBq m s in average) and lower in winter (17.0 mBq m s in average). The precipitation had a strong influence on the radon exhalation rate, usually radon exhalation rate increased quickly after rain. Daily variation of radon exhalation rate was also observed in spring, usually higher at noon and lower at midnight. [ABSTRACT FROM AUTHOR]

Highlights: [•] Presence of polybrominated compounds in bivalves from Beijing markets was studied. [•] Levels of PBDEs in this study were higher than those in Baltic blue mussels. [•] Levels of OH- and MeO-PBDEs in this study were lower than in Baltic blue mussels. [•] Polybrominated compounds showed significant seasonal variations in blue mussels. [•] Acidic components displayed different seasonal variations from neutral components. [Copyright &y& Elsevier]