Biochemical indicators for the bioavailability of organic carbon in ground water

The bioavailability of total organic carbon (TOC) was examined in ground water from two hydrologically distinct aquifers using biochemical indicators widely employed in chemical oceanography. Concentrations of total hydrolyzable neutral sugars (THNS), total hydrolyzable amino acids (THAA), and carbon-normalized percentages of TOC present as THNS and THAA (referred to as "yields") were assessed as indicators of bioavailability. A shallow coastal plain aquifer in Kings Bay, Georgia, was characterized by relatively high concentrations (425 to 1492 μM; 5.1 to 17.9 mg/L) of TOC but relatively low THNS and THAA yields (∼0.2%–1.0%). These low yields are consistent with the highly biodegraded nature of TOC mobilized from relatively ancient (Pleistocene) sediments overlying the aquifer. In contrast, a shallow fractured rock aquifer in West Trenton, New Jersey, exhibited lower TOC concentrations (47 to 325 μM; 0.6 to 3.9 mg/L) but higher THNS and THAA yields (∼1% to 4%). These higher yields were consistent with the younger, and thus more bioavailable, TOC being mobilized from modern soils overlying the aquifer. Consistent with these apparent differences in TOC bioavailability, no significant correlation between TOC and dissolved inorganic carbon (DIC), a product of organic carbon mineralization, was observed at Kings Bay, whereas a strong correlation was observed at West Trenton. In contrast to TOC, THNS and THAA concentrations were observed to correlate with DIC at the Kings Bay site. These observations suggest that biochemical indicators such as THNS and THAA may provide information concerning the bioavailability of organic carbon present in ground water that is not available from TOC measurements alone.     

云南省威信县煤矿资源承载能力评价

【研究目的】矿产资源是经济社会发展的重要支撑,其承载能力大小是决定区域经济结构及发展模式的根本依据,开展区域矿产资源承载能力评价对促进地区矿产资源可持续开发利用具有十分重要的意义。【研究方法】以云南省威信县煤矿资源为研究对象,借助承载本底（资源可利用量占比,PRO）和承载状态（矿业开发指数,MDI）两个评价因子来构建评价指标体系。在此基础上对威信县煤矿资源的承载能力进行评价,并以威信县为评价试点对矿产资源评价体系及各分指标权重分配的合理性进行了相关探讨。【研究结果】威信县10个乡镇中,没有煤矿资源承载能力“大”的乡镇,承载能力“较大”的乡镇仅有2个,承载能力“中”的乡镇有2个,承载能力“小”的乡镇则达到了6个。【结论】在矿产资源承载能力评价体系中,正向指标与负向指标也应并重考虑,各占50%左右为宜。此外各分指标权重的分配也应与该地区当时在经济、社会、环境方面的政策紧密呼应。     

Polycyclic aromatic hydrocarbons in surface sediments of the East China Sea and their relationship with carbonaceous materials

This study measured concentrations of polycyclic aromatic hydrocarbons (PAHs) in surface sediments in the East China Sea (ECS) to investigate possible sources and fate of PAHs. Total concentration of PAHs in the sediments of the ECS ranged from 22 to 244 ng g(-1), with the highest levels in the coastal area and outer shelf. The observed PAH results showed elevated levels in both inner and outer shelf areas, a finding that is different from predictions by an ocean circulation model, suggesting that terrestrial sources are important for PAH contaminations in the ECS, while sediment resuspension, tidal changes and lateral transport may be important in affecting the distribution of PAHs in the outer shelf. The distribution of PAHs in the surface sediments of the ECS is similar to the distribution of carbonaceous materials (e.g., particulate organic carbon and black carbon), suggesting that carbonaceous materials may strongly affect the distribution of PAHs.     

北京平谷大华山镇土壤质量地球化学评价

北京市平谷区大华山镇位于北京市的东北部,距离北京市区70 km,素有”大桃之乡”之称,是北京市的大桃重要生产基地,更是全国大桃生产的第一区。1997年被北京市政府命名为“京郊大桃第一镇”,大桃现已成为大华山镇的主要经济作物。通过对该地区土壤进行系统地采样分析,统计分析地土壤中肥力元素,环境元素的地球化学元素含量分布特征,综合评估研究区土壤肥力和土壤环境地球化学等级,进一步评估土壤质量地球化学等级,以挖掘研究区土地资源利用潜力,提高土地利用价值,为名特优农产品种植、土壤配方施肥、土壤污染治理提供地球化学依据（赵其国等,1997;张庆利等,2003）。     

从PDAC 2012看地质理论研究与勘查方法技术年度进展

每年一度的加拿大探矿者与开发者年会(简称PDAC)在主要开展矿业招商活动的大前提下,对近年来全球地球科学理论以及矿产勘查开发技术方法的创新也都会有所关注。特别是,理论和技术的创新常常以新仪器设备研制使用的形式得到表现。本文尝试对2012年PDAC上反映出来的全球矿业界在地质理论、物探方法、化探方法、遥感技术以及钻探工艺设备等5个方面的创新做一粗浅的概述。本文并不是一个对全球地学界理论方法技术在过去一年来的系统完善的总结,仅是全豹之一斑,希冀本文对我国地质理论和技术方法创新有所裨益。     

断裂控制爆破─—工程爆破技术的新发展

介绍了断裂控制爆破技术的发展概况、基本方法、工程应用实例和效益。