原子吸收法间接测定水中可溶性PO4^3—的研究

研究并建立了测定水中PO4^3-的方法,用草酸钙将PO4^3-转化为磷酸钙,加醋酸溶解磷酸钙,离心沉降未反应的试剂,用AAS法测定清液中的Ca^2 ,即可间接测定PO4^3-的含量。     

ICP-AES法测定磷矿浆烟气脱硫剂固液相中硫含量的研究

SO₂是大气主要污染物,与雾霾的形成有直接关系,烟气脱硫是保护环境、减少雾霾的有效措施。磷矿浆法烟气脱硫是一种以磷矿浆为吸收剂的新型脱硫方法。采用电感耦合等离子体原子发射光谱(ICP-AES)法测定磷矿浆烟气脱硫剂固液相(磷矿粉、磷矿浆脱硫液和脱硫渣)中硫含量。在选定了较灵敏的硫分析线后,探讨了ICP光谱仪工作条件对分析结果的影响,同时研究了样品预处理方法以及共存元素对硫测定结果的影响。分别用三种不同的方式对磷矿粉、磷矿浆脱硫液和脱硫渣样品进行前处理,确保样品溶解完全。选用181.973 nm光谱线为分析线,避免共存元素的光谱干扰。选择仪器的入射功率为1 300 W,观测高度为12 mm,雾化气流量为0.65 L·min-1,泵进样量为1.5 mL·min-1。在光谱仪最佳分析条件下,利用该方法测定磷矿粉、磷矿浆脱硫液及脱硫渣中硫的含量,其检出限为0.000 38%,加标回收率在89.5%～104.5%之间,相对标准偏差(RSD)≤2.30%,同时与硫酸钡重量法进行对比实验,结果基本吻合,相对偏差≤3.88%,该方法简便快捷,精密度和准确度较高,适用于磷矿浆脱除烟气SO₂的科研及生产中。     

原子吸收法测定磷矿和肥料中的钙和镁

肥料及肥料原料中含有的钙和镁是植物主要的营养成份,在植物体内碳水化合物的代谢过程中起着重要的作用。本文用原子吸收方法对磷矿及各种肥料中钙和镁的测定。并探讨了磷矿及肥料中共存元素对测定钙、镁的干扰及消除。     

萃取-磷钼蓝比色法测定镍铬丝中磷

在0．7—1．0mol/L的硝酸介质中^[3]，采用萃取-磷钼蓝比色法测定镍铬丝中的磷，络合物的最大吸收峰位于680nm，测定范围为0．001％-0．05％，相对标准偏差为＜3．8％。     

快速测定硅铁中铝和磷

试样以硝酸、氢氟酸溶解,用高氯酸冒烟驱除氟。铝的测定：于氢氧化钠溶液中将铁、锰、钛等元素与铝分离,加入过量EDTA与铝络合,以PAN为指示剂,用硫酸铜滴定计算铝含量;磷的测定：于硝酸介质中,用硫代硫酸钠还原砷,用抗坏血酸乙醇溶液还原成铋磷钼蓝,用分光光度计测量吸光度,计算磷含量。本方法采取一次溶样同时完成铝和磷的测定,方法快速、准确、可靠,适用于出口铁的日常检验。     

ICP-AES法测定磷酸盐中的钙和磷

一般磷酸盐中的磷是用重量法测定,钙是用分离磷酸根后用ＥＤＴＡ滴定法测定。分析过程冗长,不利于生产质控。用ＩＣＰ－ＡＥＳ法测定,钙选用３１７．９３３ｎｍ分析线在多道测定（ＪＹ３２）,磷选用２１３．６１８ｎｍ分析线用扫描测定（ＪＹ３８）。用本方法所得结果与用ＥＤＴＡ测定钙,用重量法测定磷结果一致,方法快速、准确。     

工业硅中钛、磷的测定

在pH1的盐酸介质中，Ti（Ⅳ）与变色酸形成桔红色配合物，Fe（Ⅲ）干扰用坏血酸还原消除；在0.42mol/L硫酸介质中，PO4^3-与钼酸铵形成磷钼杂多酸，用抗坏血酸还原为钼蓝，为此对工业硅中钛、磷进行光度法测定，结果令人满意。     

ICP—AES法测定磷矿中稀土元素及钪

本文研究了磷矿样品的分析方法,选择了同时测定微量稀土及铣的合适条件。此法测定磷矿中十五种稀土元素及钪取得了较满意的结果。     

铬渣中铬,镍,锌,锰和铁的X射线荧光法测定

本文首次研究了用X射线荧光光谱法测定铬渣中Cr、Zn、Ni、Mn和Fe元素的模拟标样,样品直接压片不经化学处理。用稀释样品校正试样的基体效应。用人工模拟标样所建立的元素浓度与X射线强度间的线性函数关系令人满意,所试元素的线性相关系数均在0.99以上,测定结果与化学法基本一致。Cr的检测下限为0.036%;Fe为0.039%;Ni为35.33μg/g;Mn为498.18μg/g;Zn为55.61μg/g。各元素的相对标准偏差均低于2.48%。并首次用非线性方法研究了铬渣样品稀释比中Cr、Ni、Zn、Mn、Fe与X射线强度的线性关系。     

测定树木中总氮和总磷的新方法

本文采用过硫酸盐氧化树样中的总氮为硝态氮、总磷为磷酸盐,用分光光度法测定总氮量和总磷量,测得结果表明,本法所得精密度和准确度是比较好的,本方法能批量处理样品;省时、省电、省试剂、环境污染少。本法适用于树木中总氮总磷的测量。     

Radioactivity levels in some wild edible mushroom species in Turkey

Eleven different wild-growing edible mushroom species collected from various regions of Turkey were analysed for their content of 137Cs, 40K, 226Ra and 232Th using a high-resolution gamma-ray spectrometry. Specific activities of 226Ra and 232Th were generally below detection limits. The specific activities of 137Cs and 40K ranged from 2.4+/-0.3 to 109.0+/-7.3 Bq kg-1 with a mean of 28.4+/-27.2 Bq kg-1 (dry matter) and 715.5+/-50.1 to 1779.0+/-163.7 Bq kg-1 with a mean of 1150.8+/-315.2 Bq kg-1 (dry matter), respectively. The mean annual effective dose of 137Cs and 40K through mushrooms were estimated to be (7.0+/-6.0)x10(-3) microSv and 0.13+/-0.03 microSv, respectively. The overall intake of 137Cs is quite low and no significant contamination was found in collected mushroom species. The highest contents of 137Cs and 40K among the analysed mushrooms were in Morchella esculenta and Stropharia coronilla, respectively.     

进口锆英砂放射性γ能谱分析

利用γ能谱分析技术对2个产地共17个进口锆英砂样品中的放射性核素226Ra、232Th和40K进行了定量分析,并提出了一种新的样品自吸收修正方法。结果:产地1样品中226Ra的比活度均值为2399.75Bq/kg,232Th的比活度均值为422.72Bq/kg;产地2样品中226Ra的比活度均值为1852.91Bq/kg,232Th的比活度均值为455.45Bq/kg;2个产地样品中40K的比活度均很低。研究表明,锆英砂样品中放射性主要来源是226Ra、232Th。两产地样品中232Th的放射性比活度相差较小,而226Ra的放射性比活度差别明显。同一产地样品中放射性核素比活度也存在较大差异。样品自吸收对分析结果的影响可达10%—30%,须进行自吸收修正。     

Radioactivity of sand, groundwater and wild plants in northeast Sinai, Egypt

The radioactivity levels are poorly studied in non-coastal arid regions. For this reason, 38 locations covering an area of about 350 km(2) in northeast Sinai, Egypt, were investigated by γ-ray spectroscopy. Moderately significant correlations among (238)U, (234)Th, and (226)Ra isotopes and low significant correlations between the concentrations of (238)U-series and (232)Th in sand were obtained. No evidence of correlation was found between the concentrations of radioisotopes and pH, grain size, total organic matter content, bicarbonate or calcium carbonate concentrations of the sand samples. The mean values of soil-to-plant transfer factor were 0.15, 0.18, 1.52 and 0.74 for (226)Ra, (232)Th, (40)K, and (137)Cs, respectively. The range of concentrations of (226)Ra,( 232)Th, and (40)K in water samples collected from five wells were<0.4-0.16,<0.4-0.13, and<0.15-1.62?Bq?l(-1), respectively. The mean absorbed dose rate in outdoor air at a height of 1?m above the ground surface for the sand samples was 19.4?nGy?h(-1). The Ra(eq) activities of the sands are lower than the recommended maximum value of 370 Bq kg(-1) criterion limit for building materials.     

Studies of natural radionuclides and dose estimation from soil samples of Kumaun Himalaya, India

In the present study, the distribution of natural radionuclides in soil samples collected from different geological units of Kumaun Himalayas are assessed using gamma ray spectrometer with Nal(Tl) detector. The naturally occurring radioactivity concentration of ²²⁶Ra, ²³²Th and ⁴⁰K were found to vary from 36.4 Bq/kg to 166.6 Bq/kg, 15.3 Bq/kg to 94.7 Bq/kg and 645.9 Bq/kg to 1378.9 Bq/kg, respectively. The total absorbed gamma dose rate was found to vary from 80 nGy/h to 179.6 nGy/h. The resulting dose due to the presence of these radionuclides was estimated from radiation protection point of view. The significance of this investigation is also discussed in details.     

Natural radioactivity measurements in Pahang State,Malaysia

This study was aimed at providing the baseline data of terrestrial gamma dose rates and natural radioactivity to assess the corresponding health risk in the ambient environment of the Pahang State. Terrestrial gamma radiation (TGR) from 640 locations was measured with the mean value found to be 176?±?5 nGy h^?1. Ninety-eight soil samples were analysed using a high-purity germanium detector (HPGe), and the mean concentrations of the radionuclides ²²⁶Ra, ²³²Th and ⁴⁰K are 110?±?3, 151?±?5 and 542?±?51 Bq kg^?1, respectively.²²⁶Ra and ²³²Th concentrations were found to be three times the world average, while that of ⁴⁰K is quite higher than the world average value. The acid-intrusive geological formation has the highest mean concentrations for ²²⁶Ra (215?±?6 Bq kg^?1), ²³²Th (384?±?12 Bq kg^?1) and ⁴⁰K (1564?±?153 Bq kg^?1). The radium equivalent activities (Req) and the external hazard index (Hex) for the various soil types were also calculated. Some of the soil types were found to have values exceeding the internationally recommended levels of 370 Bq kg^?1 and the unity value, respectively.     

Transfer of radioactivity from soil to vegetation in Rechna Doab, Pakistan

In Rechna Doab, samples of the most common vegetation, perennial grass Desmostachya bipinnata (dab), were collected along with soil samples from 29 sites. Natural radioactivity of 22?Ra, 232Th/22?Ac and ??K was measured by using high purity germanium-based gamma ray spectrometer. Activity concentration levels of 22?Ra, 232Th/22?Ac and ??K in soil were found to be 46.8 ± 6.2 (36.0-57.6), 61.4 ± 5.9 (48.2-73.2) and 644.8 ± 73.9 (537.7-868.4) Bq kg?1 (dry mass), respectively, and those in vegetation were 2.74 ± 1.70 (1.00-6.39), 2.24 ± 0.59 (1.56-2.61) and 172.72±113.37 (53.14-469.24) Bq kg?1 (dry mass), respectively. The measured values of the activity concentration in vegetation are comparable with some other international data. Calculated soil to vegetation transfer factors of 22?Ra, 22?Ac and ??K were 0.06 ± 0.03 (0.02-0.14), 0.04 ± 0.01 (0.03-0.04) and 0.26 ± 0.16 (0.09-0.69). The mean outdoor absorbed dose rate in air for the area under study was determined as 8.22 nGy h?1 and the mean indoor absorbed dose rate in air was 11.52 nGy h?1. The total annual effective dose to the general public from the vegetation was found to be (0.02-0.16) mSv, which is below the recommended limit value of 1 mSv y?1 for the general public. The dab vegetation under study was found to be radiologically safe for the population and environment.     

Statistical relationship between activity concentrations of radionuclides 226Ra, 232Th, 40K,and 137Cs and geological formations in surface soil of Jordan

An extensive study was conducted to determine the activity concentrations of natural and artificial radionuclides ²²⁶Ra, ²³²Th, ⁴⁰K, and ¹³⁷Cs in soil samples of each governate of Jordan. A total of 370 samples have been measured using a high-purity germanium detector. The activity concentration for ²²⁶Ra, ²³²Th, ⁴⁰K, and ¹³⁷Cs has mean values of 42?±?3, 23?±?3, 309?±?21, and 3.7?±?0.9 Bq kg^–1, respectively. The highest mean activity concentration for ²²⁶Ra was found to be 138?±?4 Bq kg^–1 in the Alkarak governate. In the Ajloun and Jarash governates, the highest mean activity concentration was 35?±?3 Bq kg^–1 for ²³²Th, and 14.2?±?1.9 Bq kg^–1 for ¹³⁷Cs, respectively. Geological influence on the activity concentrations was investigated using the one-way analysis of variance (ANOVA) and independent samples. The ANOVA results indicate that there are strong significant differences between the activity concentrations of ²³²Th, ⁴⁰K, and ¹³⁷Cs based on geological formations the radionuclides occur. The main contribution to gamma dose rate was due to ²²⁶Ra activity concentration. Radium equivalent and external hazard index are associated with a mean value of 98 Bq kg^–1, and 0.266, respectively.     

Assessment of natural radionuclides and their radiological hazards in commercial granite produced in Xinjiang,China

ABSTRACT

The specific activities of ²²⁶Ra, ²³²Th and ⁴⁰K of 26 samples of granite produced in Xinjiang of China were measured by a high-purity germanium detector, and their radiological hazards of radium equivalent, external hazard index, internal hazard index, absorbed dose rate, annual effective dose rate, gamma index and alpha index were evaluated. The results indicate that the overall average specific activities of ²²⁶Ra, ²³²Th and ⁴⁰K obtained in the investigated samples are below the world’s average granite values. The average radium equivalent is within the recommended limit of 370?Bq?kg^?1. The results obtained further show that the mean values of external hazard index, internal hazard index, absorbed dose rate, annual effective dose rate, gamma index and alpha index are 0.65, 0.77, 111.7?nGy?h^?1, 0.55 mSv?y^?1, 0.89 and 0.23, respectively. These mean values established that radiological hazards are also found to be below the international recommended values. The results are compared with granite samples from other countries or China-Taiwan province. It can be noticed that the specific activity values of granite samples produced in China are lower or similar to that of other countries or China-Taiwan province, however there are higher specific activity values for ²²⁶Ra and ²³²Th in individual samples, which need to provide proper radiation monitoring before use considering the long term health effect.     

Creating a baseline radiological standard for the waste isolation pilot plant underground

The Waste Isolation Pilot Plant (WIPP) is a deep underground geological repository for defense transuranic wastes. The creation of a full baseline radiological standard for the WIPP underground is essential in order to evaluate and account for the influence of the naturally occurring radioactive materials, and to prepare for any suspected contamination or the very unlikely event of a real accident scenario. In this report, we describe the establishment of the baseline information using the gamma background dose rate measurements and the salt rib smears of surface removable alpha and beta activities throughout the WIPP underground. The average background gamma dose rate in the WIPP underground is 8.27 x 10(-9) +/- 1.65 x 10(-9) Gy/h while the gamma dose rate on the WIPP surface is 3.46 x 10(-8) +/- 1.65 x 10(-9) Gy/h. The overall surface average alpha activity in the underground is 8.52 x 10(-5) +/- 1.22 x 10(-4) Bq/cm2 (at 1sigma level) with the minimum detectable activity (MDA) of 4.81 x 10(-4) Bq/cm2. The overall surface average beta activity is 8.25 x 10(-4) +/- 8.17 x 10(-4) Bq/cm2 (at 1sigma level) with the MDA of 3.19 x 10(-3) Bq/cm2. This baseline standard will be beneficial to the overall WIPP operational facility, ensuring the worker safety and adding to public confidence in the operation of the WIPP.     

Analysis of 226Ra, 232Th and 40K in soil samples for the assessment of the average effective dose

The activity concentrations of the natural radionuclides namely ²³⁸Ra, ²³²Th and ⁴⁰K are measured for soil samples collected from different locations of Faridkot and Mansa districts of Punjab. HPGe detector, based on high-resolution gamma spectrometry system is used for the measurement of activity concentration. The range of activity concentrations of ²²⁶Ra, ²³²Th and ⁴⁰K in the soil from the studied areas varies from 21.42 Bq kg⁻¹ to 40.23 Bq kg⁻¹, 61.01 Bq kg⁻¹ to 142.34 Bq kg⁻¹ and 227.11 Bq kg⁻¹ to 357.13 Bq kg⁻¹ with overall mean values of 27.17 Bq kg⁻¹, 95.22 Bq kg⁻¹ and 312.76 Bq kg⁻¹, respectively. Radium equivalent activities are calculated for the analyzed samples to assess the radiation hazards arising due to the use of these soil samples in the construction of dwellings. The absorbed dose rate calculated from activity concentration of ²²⁶Ra, ²³²Th and ⁴⁰K ranges between 9.87 and 18.55, 38.01 and 88.68 and 9.40 and 14.79 nGy h⁻¹, respectively. The total absorbed dose in the study area ranges from 61.10 nGy h⁻¹ to 112.86 nGy h⁻¹ with an average value of 84.80 nGy h⁻¹. The calculated values of external hazard index (H _ex) for the soil samples of the study area range from 0.36 to 0.68. Since these values are lower than unity, according to the Radiation Protection 112 (European Commission, 1999) report, soil from these regions is safe and can be used as construction material without posing any significant radiological threat to population. The corresponding average annual effective dose for indoor and outdoor measured in the study area are 0.42 mSv and 0.10 mSv respectively.