The measurement of radioactivity in Italian drinking waters

Drinking waters generally contain variable amounts of radioactivity. Many radionuclides, like ⁴⁰K and those belonging to the natural decay series of ²³⁸U, ²³⁵U and ²³²Th, are transferred to the water from the aquifer rocks by erosion and dissolution mechanisms.In recent years, a great interest arose towards the natural radioactivity in drinking water. The European Council Directive 98/83/EC, subsequently enforced in Italian law, pushed public authorities to organize tap water surveys. Parameter values for radioactivity levels in water are given, according to World Health Organization recommendations. Maximum concentration values for radon are separately proposed in a European Commission Recommendation.For this reason, during the latest years, the Regional Environment Protection Agency (ARPA) has been performing an extensive monitoring of tap waters in the Lombardia district of Italy. Natural radioactivity content was measured to check the compliance with recent European and Italian rules.Analyses were performed by an ultra-low level scintillation counter equipped with an alpha-beta discrimination device. Specifically arranged procedures, requiring quick and easy pre-treatments, allowed to measure gross alpha and beta activity, ²²²Rn, ²²⁶Ra, and uranium isotopes concentrations in a relatively short time. Subsequently, more complex procedures, involving radiochemical separation of radionuclides, are currently being studied for ²¹⁰Pb, ²¹⁰Po and ²²⁸Ra. Method performances were carefully tested by both internal validation procedures and international intercomparison exercises.These procedures have been employed for a wide range screening in the Lombardia district in Italy. Obtained results showed that in most cases gross alpha activity was lower than the parameter value given by the cited regulations. When these values were exceeded, a more detailed survey was planned: at present three of them, in the western and south-western part of Lombardia and in the city of Milan have been carried out.     

Capillary electrochromatography-applicability to the analysis of pesticides and compounds of environmental concern and the theory of electroosmosis

Summary The applicability of capillary electrochromatography to the automated analysis of pesticides and phthalate esters that are of environmental concern was assessed. Reversed phase packing materials were compared. Column to column and run to run reproducibility was established. Peak height with an internal standard gave the best reproducibility. Faster analysis than alternative HPLC methods was demonstrated for a mixture of the insecticide pirimicarb and related pyrimidines. The relationship between the concentration of an analyte in a sample and at the detector was determined by the use of radio-labelled¹⁴C-pirimicarb. The volume fraction of the liquid zone was 0.64. The possibility of electroosmosis through the pores is discussed with reference to the Rice-Whitehead model for electroosmotic flow in a capillary. A new parameter, the effective pore size is used in equations for electroosmosis through porous packings.     

The g-factor of the72+[404] ground state of 177Ta

With the technique of nuclear magnetic resonance on oriented nuclei the hyperfine splitting $\text{ν}{}_{\mathrm{<mtext>M</mtext>}}\text{= ¦gμ}{}_{\mathrm{<mtext>N</mtext>}}\text{B}{}_{\mathrm{<mtext>HF</mtext>}}\text{/h¦}\text{of}{}^{177}\text{Ta}\text{(j}{}^{\mathrm{\pi }}\text{7}\text{2}{}^{\mathrm{+}}\text{; T}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{= 56.6h)}$ in Fe has been measured With the known hyperfine field $\text{B}{}_{\mathrm{<mtext>HF</mtext>}}\text{(}\text{Ta}\text{Fe}\text{) = ?648 (13)}\text{kG the}\text{g-}\text{factor of the}\text{7}\text{2}{}^{\mathrm{+}}\text{[404]}$ ground state of ¹⁷⁷Ta is deduced to be $\text{¦g¦ = 0.643 (13)}$.     

The decay of 101Ag

The decay of ¹⁰¹Ag have been studied using β- and γ-spectrometers in singles and coincidence modes. A half-life of 11.4 ± 0.3 min was obtained and a decay scheme was proposed. The first excited state was established at 80.3 keV and a half-life of 4.8 ± 0.5 ns was suggested. The resultant level structure of ¹⁰¹Pd is compared to a theoretical calculation with strong band mixing.     

Spins of the levels and multipole mixing ratios of transitions in 125Sb determined from γ-γ directional correlation and polarization-directional correlation measurements

In order to resolve several discrepancies in spin assignments to levels in ¹²⁵Sb, directional correlations and polarization-directional correlations have been measured for several γ-γ cascades in ¹²⁵Sb populated from the decay of ¹²⁵Sn. Earlier results obtained from using NaI and Ge(Li) and NaI detectors were difficult to interpret due to the complex structure of the decay scheme. To improve the experimental situation, we have used two coaxial Ge(Li) detectors for the angular correlation measurements and a coaxial Ge(Li)-planar Ge(Li) combination for the polarization-directional correlations. Combination of the results of these measurements give unique spin assignments of $\text{11}\text{2}$^?, $\text{11}\text{2}$^?, $\text{9}\text{2}$⁺, $\text{11}\text{2}$⁺ and $\text{9}\text{2}$⁺ to the 1982 keV, 1890 keV, 1420 keV, 1089 keV and 1067 keV levels, respectively. The determined E2/M1 mixing ratios are : δ(470) = 0.010±0.027, δ(1067) = ?0.86±0.18, and δ(916) = ?0.02±0.01.     

K, L and M electron directional correlations in Te

Directional correlations of the cascade in ¹²³Te involving K, L and M electrons from the 89 keV M4 transition have been measured in order to determine the δ(E2/M1) value for the 159 keV transition. The result agrees with that from older correlation measurements, but is in conflict with values derived from Coulomb excitation and lifetime measurements as well as from L subshell ratios.     

Hyperfine interactions of Rn and Ra implanted into Fe,Al, Cd and Bi metals

The interactions on radon and radium nuclei implanted into metals have been studied by means of α-γ angular correlations. The influence of source preparation and of surface oxide layers have been studied in sources prepared by evaporation and isotope separator implantation. The interactions in iron are found to have contributions from static magnetic fields as well as static quadrupole interactions. The magnetic fields for radon and radium in iron were determined to be +920±85 kOe and −380±35 kOe, respectively. The theoretical models used to describe the perturbations due to mixed interactions and their importance in internal field determinations are discussed.     

The decay of 31Ga34

Ge(Li) single γ-ray measurements and a NaI(Tl)Ge(Li) coincidence experiment were performed in a reinvestigation of the decay of 15 min ⁶⁵Ga. Eighty-nine γ-rays were attributed to this decay. In the proposed decay scheme 32 of these γ-rays (representing about 99.5 % of the total intensity of the γ-rays) were placed. The intensity of the annihilation radiation was determined using also a mass-separated source.     

Excited levels of 233Pa by alpha decay of 237Np

α-spectrometry using Si(Au) detectors has been performed with thin samples of ²³⁷Np; αγ bi-parametric coincidences have permitted an analysis and unfolding of the spectrum and give data about the level scheme. Direct and α-coincident γ-spectra have been measured using Ge(Li) and Si(Li) detectors, obtaining the characteristic electromagnetic transitions in ²³³Pa. Nine new γ-transitions are found, relative to the most recent compilation made by Ellis. In the level scheme, the existence of a level at 306.1 keV is confirmed. A level at 257.1 keV, previously suggested, is evidenced. The level at 300.5 keV is proposed as the $\text{7}\text{2}{}^{\mathrm{?}}$ component of the $\text{5}\text{2}\text{(523)}$ band, hence proposing the 306.1 keV level as the $\text{7}\text{2}{}^{\mathrm{+}}$ term of the $\text{5}\text{2}\text{(642)}$ band.