Transformation of ammonium nitrogen and response characteristics of nitrifying functional genes in tannery sludge contaminated soil          下载免费PDF全文

Kong Xiang-ke  Zhang Zi-xuan  Wang Ping  Wang Yan-yan  Zhang Zhao-ji  Han Zhan-tao  Ma Li-sha 《地下水科学与工程》2022,10(3):223-232

High concentrations of ammonium nitrogen released from tannery sludge during storage in open air may cause nitrogen pollution to soil and groundwater. To study the transformation mechanism of NH₄⁺-N by nitrifying functional bacteria in tannery sludge contaminated soils, a series of contaminated soil culture experiments were conducted in this study. The contents of ammonium nitrogen (as NH₄⁺-N), nitrite nitrogen (as NO₂^?-N) and nitrate nitrogen (as NO₃^?-N) were analyzed during the culture period under different conditions of pollution load, soil particle and redox environment. Sigmodial equation was used to interpret the change of NO₃^?-N with time in contaminated soils. The abundance variations of nitrifying functional genes (amoA and nxrA) were also detected using the real-time quantitative fluorescence PCR method. The results show that the nitrification of NH₄⁺-N was aggravated in the contaminated silt soil and fine sand under the condition of lower pollution load, finer particle size and more oxidizing environment. The sigmodial equation well fitted the dynamic accumulation curve of the NO₃^?-N content in the tannery sludge contaminated soils. The Cr(III) content increased with increasing pollution load, which inhibited the reproduction and activity of nitrifying bacteria in the soils, especially in coarse-grained soil. The accumulation of NO₂^?-N contents became more obvious with the increase of pollution load in the fine sand, and only 41.5% of the NH₄⁺-N was transformed to NO₃^?-N. The redox environment was the main factor affecting nitrification process in the soil. Compared to the aerobic soil environment, the transformation of NH₄⁺-N was significantly inhibited under anaerobic incubation condition, and the NO₃^?-N contents decreased by 37.2%, 61.9% and 91.9% under low, medium and high pollution loads, respectively. Nitrification was stronger in the silt soil since its copy number of amoA and nxrA genes was two times larger than that of fine sand. Moreover, the copy numbers of amoA and nxrA genes in the silt soil under the aerobic environment were 2.7 times and 2.2 times larger than those in the anaerobic environment. The abundance changes of the amoA and nxrA functional genes have a positive correlation with the nitrification intensity in the tannery sludge-contaminated soil.  相似文献   

Testing a new combined (U,Th)–He and U/Th dating approach on Plio-Pleistocene calcite speleothems     

《Quaternary Geochronology》2022

The geochronology of cave deposits in the Cradle of Humankind UNESCO World Heritage Site in South Africa provides a timeframe essential for the interpretation of its fossils. The uranium-lead (U–Pb) and uranium-thorium disequilibrium (U/Th) dating of speleothems, mostly flowstones that underlie and blanket the fossil-bearing sediments, have been effective in this sense, but U–Pb is limited by the requirement of ∼1 ppm U concentrations and low common Pb contents, and U/Th has a c. 500 ka limit of applicability. Here we report age results for calcite-aragonite speleothems obtained using a new combined uranium-thorium-helium ((U,Th)–He) and U/Th dating routine. We reproduced within analytical uncertainty, the published U–Pb or U/Th ages for (a) flowstone in three drill core samples in the range 2000–3000 ka, (b) a flowstone hand sample taken at surface with an age of 1800 ka, and (c) five underground flowstone samples in the range 100–800 ka. Calcite retentivity for He under cave conditions is thus demonstrated. In the few cases where helium loss was observed in speleothems, only some of the subsamples were affected, and to varying degrees, suggesting loss by lattice damage not related to diagenetic processes, rather than volume diffusion. In the 100 to 800 ka range, the combined U/Th disequilibrium and (U,Th)–He method also yielded reliable values for initial (²³⁰Th/²³⁸U) and (²³⁴U/²³⁸U) activity ratios. Importantly, most subsamples had high initial (²³⁰Th/²³⁸U) values, ranging from 1.0 to 19.7, although having low Th/U ratios. This is probably due to incorporation of Fe–Mn oxides-hydroxides dust, on which ²³⁰Th was previously adsorbed. Such samples are mostly not dateable by U/Th without the additional input from the He analysis. If not detected and corrected for, such high initial (²³⁰Th/²³⁸U) values can lead to inaccurate U/Th and U–Pb ages. Our study shows that the incorporation of He analysis in U/Th dating has broad potential application, with four methods for calculating the ages, in carbonates from different environments where U-Pb or U/Th dating would not work.  相似文献   

常用锂同位素地质标准物质的多接收器电感耦合等离子体质谱分析研究   总被引：3，自引：3，他引：0  

赵悦  侯可军  田世洪  杨丹  苏嫒娜 《岩矿测试》2015,34(1):28-39

锂同位素研究是非传统稳定同位素地球化学研究的前沿,已广泛应用于从地表到地幔的岩石圈及流体等固体地球科学的研究领域。准确测定锂同位素比值是应用该同位素体系的前提。本文报道了国际上7种常用地质标准物质(BHVO-2、JB-2、BCR-2、AGV-2、NKT-1、L-SVEC、IRMM-016)的锂同位素组成数据。分析中采用硝酸-氢氟酸混合酸消解岩石标准样品,通过3根阳离子交换树脂(AG50W-X8,200~400目)填充的聚丙烯交换柱和石英交换柱对锂进行分离富集,利用Neptune型多接收器电感耦合等离子体质谱(MC-ICPMS)测定锂同位素比值,使用标准-样品交叉法(SSB)校正仪器的质量分馏。实验得到这7种常用地质标准物质的锂同位素组成与测试精度(2SD)分别为:δ7LiBHVO-2—L-SVEC=4.7‰±1.0‰(n=53),δ7LiJB-2—L-SVEC=4.9‰±1.0‰(n=20),δ7LiBCR-2—L-SVEC=4.4‰±0.8‰(n=8),δ7LiAGV-2—L-SVEC=6.1‰±0.4‰(n=14),δ7LiNKT-1—L-SVEC=9.8‰±0.2‰(n=3),δ7LiL-SVEC—L-SVEC=-0.3‰±0.3‰(n=10),δ7LiIRMM-016—L-SVEC=0.0‰±0.5‰(n=10),这些数据在误差范围内与国际上已发表的数据一致。Li同位素分析精度可以达到大约0.5‰,长期的分析精度即外部重现性≤±1.0‰,达到了国际同类实验室水平。7种常用地质标准物质的锂同位素组成数据的发表为锂同位素研究提供了统一的标准,使地质样品的锂同位素数据的质量监控成为可能。在基质效应的研究中,使用不同量的IRMM-016配制的标准溶液过柱,深入探讨了样品量对锂同位素测定值的影响,结果表明,在现有测试精度下,只要分析样品的锂含量达到100μg/L,且不超过树脂的承载量,样品的锂同位素组成在误差范围内与真值吻合,样品量的大小不影响锂同位素测定结果的准确性。  相似文献   

应用FTIR-XRD-XRF分析测试技术研究新型仿制绿松石的矿物学特征   总被引：4，自引：3，他引：1  

严俊  刘晓波  王巨安  方飚  刘培钧  杨彬彬 《岩矿测试》2015,34(5):544-549

近年来绿松石及其仿制品的鉴定工作较多局限于应用傅里叶变换红外光谱对仿制品进行简单的筛选,前人报道的仿制绿松石的矿物组成主要为单一的矿物相(如异极矿、三水铝石、磷铝石、羟硅硼钙石、菱镁矿等)。本文应用傅里叶变换红外光谱(FTIR)、X射线粉晶衍射(XRD)与X射线荧光光谱(XRF)对当前珠宝市场上几种新型仿制绿松石进行了初步分类,并对不同类别的仿制绿松石的具体矿物组成、物相及晶型特征作了对比研究。结果表明,这些新型仿制绿松石可分为三大类:一类主要由硅酸盐(斜硅钙石)与碳酸盐(方解石)两种矿物组成;另一类为白云石与方解石两种碳酸盐矿物的混合相;第三类以硅酸盐类为主要矿物,并含有钡长石、辉石与石英。显然,新型仿制绿松石的矿物组成明显相异于传统仿制品,可见仿制绿松石的矿物组成日趋多样性、复杂化,该现状必然对新型仿制样品的物相鉴定提出了更高的要求。  相似文献   

酸溶-电感耦合等离子发射光谱法测定密西西比型铅锌矿床矿石中的铅   总被引：1，自引：1，他引：0  

卢彦  冯勇  李刚  刘卫 《岩矿测试》2015,34(4):442-447

密西西比型(MVT)铅锌矿床的主要矿物有方铅石、闪锌矿,常伴生有重晶石、萤石等矿物,使得MVT型矿石在酸处理过程中易生成不溶于水和酸的硫酸铅钡复盐,故而检测矿样中铅的含量偏低。本文建立了采用盐酸-硝酸-氢氟酸体系酸溶分解MVT型矿石,电感耦合等离子体发射光谱法(ICP-OES)测定铅含量的分析方法。实验比较了盐酸-硝酸-氢氟酸、盐酸-硝酸-氢氟酸-高氯酸、盐酸-硝酸-硫酸三种酸溶体系的溶样效果,并通过X射线衍射论证了方法的可行性。结果表明,盐酸-硝酸-氢氟酸体系克服了复盐硫酸铅钡和硫酸铅沉淀的生成,适量的氢氟酸促进了Pb SO4的溶解,X射线衍射表征也表明此种酸溶体系的沉淀中不含有Pb SO4,可更彻底地分解MVT型矿石。本方法精密度(RSD)为0.3%~0.6%,实际样品的加标回收率为96.0%~99.2%,铅的最佳检测范围为0.01%~20.0%。  相似文献   

应用电感耦合等离子体质谱/光谱法研究上扬子区新华磷块岩稀土元素特征及沉积学意义   总被引：2，自引：2，他引：0  

段凯波  王登红  何汉江  郑国栋  熊先孝  袁建国  贺宝宝  屈云燕 《岩矿测试》2015,34(2):261-267

新华磷矿床是我国重要的富集稀土元素的沉积型含稀土磷块岩矿床,本文利用电感耦合等离子体质谱/光谱法(ICP-MS/AES),辅以岩矿鉴定等分析技术,结合沉积学理论研究了新华磷块岩稀土元素地球化学特征及相关问题。结果表明,新华磷块岩稀土总量(∑REEs)较高,集中值介于800×10-6~1200×10-6,其组成属轻稀土+钇型,稀土元素主要以类质同象形式存在于胶磷矿中;新华磷块岩和昆阳磷块岩具相似的REEs配分曲线和明显铈负异常,δCe介于0.28~0.36,表明上扬子区南缘成磷环境为氧化条件,且为稳定的滨浅海被动大陆边缘沉积环境;但新华磷块岩与其上覆黑色岩系REEs配分曲线迥异,后者表现出不明显的铈、铕异常,说明黑色岩系主要形成于深海-半深海静水还原环境,从梅树村期早期至晚期经历了海平面升高的过程,地层层序整体显示向上变深的沉积相变,磷块岩和黑色岩系之间的接触面可能为三级层序甚至更小层序级别的界面。这些沉积学的认识揭示了上扬子区下寒武统层序地层学意义和海相沉积环境特征,对华南早寒武世生命大爆发和层序地层学深入研究提供了证据。  相似文献   

2011-2013年乌鲁木齐城-郊冬季积雪深度与密度空间分布特征     

李小兰  姜逢清  王少平  王蕾  穆叶赛尔·吐地  张兆永  张登清 《冰川冻土》2015,37(5):1168-1177

利用2011-2013年冬季4次地面实测乌鲁木齐城-郊积雪深度与密度数据,应用普通克里格空间插值方法,分析了乌鲁木齐城-郊冬季积雪深度与密度从2011年12月下旬-2012年2月下旬及2012年1月中旬和2013年同期的时空分布特征.结果表明:乌鲁木齐城-郊冬季积雪深度与密度存在显著地区域分布差异及变化特征.整个冬季位于城东北部的米东石化工业园区积雪均较深,尤其12月和2月,在主城区内部又存在不同下垫面下积雪较多的区域.从12月下旬-次年2月下旬,积雪逐渐累积,且积雪深度比密度具有更大的空间变化幅度.除12月下旬大部分主城区雪密度比郊区大之外,1月中旬、2月下旬主城区雪密度均比城东和城东北方向低.2013年1月中旬积雪与2012年同期相比,平均积雪量明显偏厚,约31 cm,但雪密度变化范围不大且深度与密度的空间分布均发生明显改变.本文结果对于了解乌鲁木齐城区积雪的区域差异,为主城区道路积雪清运、保障道路通畅优化方案及春季融雪洪水防御预案的制定提供基础数据支撑,也可以弥补当前气象站点少且空间分布不匀的不足.此外,本文对卫星遥感数据反演的积雪参数精度验证也具有实际参考价值.  相似文献   

智能地质调查体系与架构   总被引：1，自引：0，他引：1       下载免费PDF全文

李超岭  李丰丹  李健强刘园园刘 畅  吕霞 《中国地质》2015,(4):828-838

中国地质调查局用了近10年时间,在基础地质调查和矿产调查领域基本完成了地质调查全流程数字化过程。在"云"计算与大数据技术等新一代信息技术的兴起大环境下,未来5至10年,地质调查主流程信息化的方向和目标是什么呢?本文基于新一代信息智能技术和智能设备在地质调查数据采集、数据分析处理、数据交换传输、三维建模、信息泛在服务、业务管理全面深度融合的基础上,结合智能空间与普适计算概念给出了智能地质调查定义,提出了基于云计算和Hadoop生态体系为基础的天地空一体化的智能地质调查体系、架构和应用模式,并对其关键技术进行了讨论。  相似文献   

AMT勘查贵州铁(稀土)多金属矿效果分析     

张西君  杨胜发  张海  李家斌 《物探化探计算技术》2015,(1)

贵州铁(稀土)多金属矿资源储量丰厚,但是因其赋存条件的特殊性,勘查具有一定的挑战性,在此开展铁(稀土)多金属矿的物探方法试验研究,对今后勘查工作具有重要的指导意义。这里简要介绍了AMT(音频大地电磁法)工作方法以及贵州威宁秋木构工区的地质和地球物理特征,重点讨论了AMT在秋木构工区铁(稀土)多金属矿勘查中的应用效果,通过对电阻率断面图的综合推断解释,划分出了二叠系宣威组与峨嵋山玄武岩组地层界面,圈出了含矿有利部位。经钻孔验证,取得了良好的找矿效果。  相似文献   

四平山门—放牛沟一带成矿系列及成矿区带划分     

初凯  于锡伟  李祥 《吉林地质》2015,(2)

山门—放牛沟一带分布有众多的贵金属、多金属矿床(点),是吉林省重要的成矿区带之一,本文根据前人的工作成果,总结了该区的成矿地质背景和成矿系列,并在全国Ⅲ级成矿区带划分的基础上进行了Ⅳ级成矿亚带的划分,对各成矿亚带的特征进行了总结。  相似文献