山西省出生缺陷高发区土壤元素分布特征

目的 了解出生缺陷高发区土壤中元素分布特征,为出生缺陷的干预和治疗提供理论依据.方法 于2005年1-5月,选择山西省吕梁山区出生缺陷高发的中阳县和交口县作为出生缺陷高发区,以人口相对集中的河道两侧为采样点,共涉及8个乡镇,79个行政村;选择晋中盆地出生缺陷低发的祁县作为出生缺陷对照区,采样点均匀分布,共涉及6个乡镇,27个行政村.采集距耕地表层10～20cm深的土壤,共采集样品131件.采用ICP-电感耦合等离子发射光谱法,对土壤样品中的16种元素进行测定.结果 高发区土壤中元素总量明显高于低发区.与祁县相比,交口县土壤中元素含量偏高的有As、Mo、Pb、Ni、V,含量偏低的元素有Se,差异均有统计学意义(P＜0.05);中阳县土壤中含量偏高的元素为Sn、Se、Mo、Zn、Sr、Pb、Ni、Fe、V、Ca、Cu、Al,偏低的元素为Mg和Na,差异均有统计学意义(P＜0.05).土壤中元素含量(μg/g)与出生缺陷发病率的(1/万)逐步回归分析显示,交口县土壤中Mo、Al、As、Ni、Pb、Zn元素对病情影响有统计学意义(均P＜0.01),其标准的逐步回归判别方程为:y=-1.321 1.106 Mo-0.509 Al 0.117 As 0.663 Ni-0.429 Pb-0.262 Zn(R2a=0.891);中阳县土壤中Pb、Mg、Ca、Al、Zn元素对病情影响有统计学意义(均P＜0.05),其标准回归方程为:y=-1.757 0.441 Pb-0.264Mg 0.309 Ca-0.186Al 0.162Zn (R2a2=0.839).结论 交口县和中阳县土壤中Pb、Mo、Al等含量异常可能是两县出生缺陷高发的原因之一.     

土壤环境基因组技术及其在新药发现中的应用

土壤是微生物最重要的生境，土壤微生物具有极大的多样性。然而传统培养技术只能得到约1％的微生物纯培养，其余都是未被纯培养微生物。利用土壤环境基因组技术，可以把未被纯培养微生物的基因克隆到载体中并在宿主中进行表达，获得比已培养微生物丰富的代谢产物多样性，这为我们发现新颖结构先导化合物以及新药开辟了新的道路。本文介绍应用环境基因组技术构建土壤DNA文库的思路和方法。     

Vertical profile of Cs in soil

In this paper, a vertical distribution of ¹³⁷Cs in undisturbed soil was investigated experimentally and theoretically. Soil samples were taken from the surroundings of the city of Kragujevac in central Serbia during spring-summer of 2001. The sampling locations were chosen in such a way that the influence of soil characteristics on depth distribution of ¹³⁷Cs in soil could be investigated. Activity of ¹³⁷Cs in soil samples was measured using a HpGe detector and multi-channel analyzer. Based on vertical distribution of ¹³⁷Cs in soil which was measured for each of 10 locations, the diffusion coefficient of ¹³⁷Cs in soil was determined. In the next half-century, ¹³⁷Cs will remain as the source of the exposure. Fifteen years after the Chernobyl accident, and more than 30 years after nuclear probes, the largest activity of ¹³⁷Cs is still within 10 cm of the upper layer of the soil. This result confirms that the penetration of ¹³⁷Cs in soil is a very slow process. Experimental results were compared with two different Green functions and no major differences were found between them. While both functions fit experimental data well in the upper layer of soil, the fitting is not so good in deeper layers. Although the curves obtained by these two functions are very close to each other, there are some differences in the values of parameters acquired by them.     

土壤中砷含量与非砷职业暴露人群肺癌发病关系研究

[目的]探讨土壤中砷含量与非砷职业暴露人群肺癌发病率的关系。[方法]测定污染区与对照区土壤中砷含量,收集其非砷职业暴露人群与砷职业暴露人群肺组织中砷含量及其肺癌发病率,并进行统计学分析。[结果]污染区土壤砷含量是对照区的14.3-19.7倍。[结论]土壤中砷含量与非砷职业暴露人群肺癌发病呈显著及非常显著的正相关(r=0.9281-0.963,P<0.05-0.01)。     

利用石墨炉原子吸收分光光度法测定土壤中铬的含量

目的：建立土壤中铬含量的石墨炉原子吸收分光光度测定法.方法：试样经酸消解后,注入原子吸收分光光度计石墨炉中,电热原子化后吸收357.9 nm共振线,在一定浓度范围其吸收值与铬含量成正比,与标准系列比较定量.结果：线性范围为0～20ng/mL,回收率为98％～102％,检出限为0.26ng/mL,相对标准偏差RSD为4.6％.结论：该试验方法具有操作简单,技术条件便于掌握,消解彻底,结果重复性好等优点,可用作土壤中铬含量的测定.     

天麻生长地土壤生态因子与天麻素含量相关性的研究

目的:考察天麻生长地生态因子对天麻素含量的影响,探讨土壤生态因子与天麻品质的关系;方法:选择天麻采收期采集不同产地的野生和栽培天麻及其生长地土壤样本,检测土壤中微生物数量、有机质含量、金属元素含量、土壤酸碱度及天麻素含量,分析这些生态因子与天麻素含量的关系。结果:在采集样本中,野生和栽培天麻生长地土壤中细菌总数及细菌/真菌比值与天麻素含量总体趋势都呈负相关(P<0.05或P<0.01或P<0.001),真菌总数与天麻素含量总体趋势都呈正相关(P<0.05或P<0.01或P<0.001);土壤有机质含量与天麻素含量分别在野生或栽培样本群内呈正相关(P<0.05或P<0.01或P<0.001);土壤pH值与天麻素含量之间的相关性散点图大致以pH6.0为峰值,呈典型的抛物线型趋势分布;土壤中Cu元素和Zn元素分别在个别样本群中与天麻素含量呈相关系数达到0.4以上,但tr值检验没有显著性。结论:天麻生长地土壤细菌/真菌构成状况、有机质含量和pH值很可能是影响天麻品质的重要生态因子。     

田菁以磷增氮的研究

对环境施磷增加田菁[Sesbania cannabina(Retz.)pers.]结瘤固氮的作用是有限度的,受环境供磷水平的制约。 在广州石牌地区花岗岩发育赤红壤中,田菁以磷增氮的土壤有效磷临界水平(ppm P)为25.6(0.1 N HCL法)。 在无氮培养液中,秋植和春植田菁以磷增氮的供磷临界水平(毫摩尔P)分别为0.78和0.48,植株体内含磷量的临界水平(P％)分别为0.213和0.157。该临界供磷水平与含磷量有受季节性影响的倾向。介质的高磷水平还会引起田菁固氮量的下降。 在低磷的介质中,增磷对田菁根瘤的形成,发育和固氮酶活性有明显的促进作用。在磷供应达到一定水平后,继续增磷的促进作用不显著。未发现高磷供应对田菁的根瘤数有不良影响,但对其根瘤干重、特别是固氮酶活性有抑制作用。     

2015年云南省人体土源性线虫感染调查

目的 了解云南省人体土源性线虫病流行现状,为制定全省土源性线虫病防治对策提供科学依据.方法 2015年,采用分层整群随机抽样方法抽取云南省10个县(市)共20个调查点.以各调查点1岁及以上本地常住人口为调查对象,收集调查对象粪便,采用改良加藤厚涂片法检查土源性线虫虫卵并计数,并用试管滤纸培养法鉴别钩虫虫种,3～6岁儿童...     

Porosity distribution by computed tomography and its importance to characterize soil clod samples

Gamma-ray computed tomography (CT) was employed to study the soil quality of clod samples used to investigate porosity (ϕ). Samples with volumes varying from 50 to 100 cm³ were collected from the soil surface. 2D CT images were obtained with millimetric resolution. Porosity distribution analyses were carried out to infer the soil clod structure. Results obtained provided a new insight on the variability of internal clod structure due to the large amount of data analyzed, information that is not provided by traditional methods used in physics applied to soil.