Study on the effect of Fresh Air Ventilation system for reducing indoor ^(222)Rn

Objective:To explore the reduction effect for the indoor ^(222)Rn(Rn)by Fresh Air Ventilation(FAV)system,a novel commercial ventilation device in China.Methods:The indoor concentrations of Rn and its decay products(RnD)in three residential rooms,two in Beijing and one in Hefei city,Anhui province,before and after FAVS functioned were measured using an active continuous method.The air exchange rate was monitored by measuring CO_(2) concentration using the tracer gas method.Results:In the three rooms,the FAVS reduced the Rn concentrations from(162±80)Bq/m^(3) to(63±22)Bq/m^(3) and decreased the RnD concentrations from(64±35)Bq/m^(3) to(13±6)Bq/m^(3) on average,a decrease of(59±25)% in the Rn concentrations and a drop of(77±18)%in the RnD concentrations.Considering dose conversion factors of Rn and RnD,FAVS decreased the exposure dose by(76±20)%.Besides,FAVS increased the air exchange rates from 0.17 h^(-1) to 0.56 h^(-1) on average.Conclusions:FAVS can effectively reduce indoor Rn and RnD concentrations by improving the air exchange,serving as a valuable supplement to existing radon mitigation methods,especially in extreme climates.

Relationships between blood chromium exposure and liver injury:Exploring the mediating role of systemic inflammation in a chromate-exposed population

Hexavalent chromium and its compounds are prevalent pollutants,especially in the work environment,pose a significant risk for multisystem toxicity and cancers.While it is known that chromium accumulation in the liver can cause damage,the dose-response relationship between blood chromium(Cr)and liver injury,as well as the possible potential toxic mechanisms involved,remains poorly understood.To address this,we conducted a follow-up study of 590 visits from 305 participants to investigate the associations of blood Cr with biomarkers for liver injury,including serum alanine aminotransferase(ALT),aspartate aminotransferase(AST),total bilirubin(TBIL),and direct bilirubin(DBIL),and to evaluate the mediating effects of systemic inflammation.Platelet(PLT)and the platelet-to-lymphocyte ratio(PLR)were utilized as biomarkers of systemic inflammation.In the linear mixed-effects analyses,each 1-unit increase in blood Cr level was associated with estimated effect percentage increases of 0.82%(0.11%,1.53%)in TBIL,1.67%(0.06%,3.28%)in DBIL,0.73%(0.04%,1.43%)in ALT and 2.08%(0.29%,3.87%)in AST,respectively.Furthermore,PLT mediated 10.04%,11.35%,and 10.77%increases in TBIL,DBIL,and ALT levels induced by chromate,respectively.In addition,PLR mediated 8.26%and 15.58%of the association between blood Cr and TBIL or ALT.These findings shed light on the mechanisms underlying blood Cr-induced liver injury,which is partly due to worsening systemic inflammation.

Analysis of tritium activity concentrations in urine and internal dose assessment for nuclear power plant workers

Objective:To investigate the activity concentration of tritium in urine of nuclear power plant(NPP)workers,in order to evaluate the occupational exposure levels.Methods:Three chosen NPPs were respectively located in southern,southeastern and northeastern China.Workers involved in operating,service,nuclear cleaning,chemical analysis,health physics,technical support,among others were randomly selected as the research targets,and 69 urine samples of no less than 50 mL were collected.The oxidative distillation method was used to pretreat the urine samples,and the activity concentration of tritium in distillate was then measured using liquid scintillation counter.The formula for the committed effective dose was also applied used to estimate the internal doses.Results:The highest tritium activity concentrations in urine samples from three NPPs were 2412.7,6351.4,and 478.7 Bq/L,respectively.Correspondingly,the internal doses due to tritium intake were 1.8,4.8 and 0.4μSv,respectively.Conclusions:The urine tritium activity concentration of workers varied greatly dependent on their job categories.The values for urine tritium radioactivity concentrations of workers involved in health care,nuclear cleaning and maintenance were generally higher than those for other job categories.The difference in urine tritium activity concentration mainly came from the different exposure time and tritium concentrations.From the dose assessment results,the internal dose caused by tritium intake did not exceed the public annual effective dose limit.

Uncertainty evaluation for determination of ^(14)C in urine samples by wet oxidation method

Objective:To figure out the source of uncertainty in the determination of ^(14)C activity concentration in urine samples,and to establish a complete expression of analysis results,in order to improve the accuracy of ^(14)C monitoring method.Methods:Four urine samples of normal people were collected,and wet oxidation method was used in the pretreatment of the samples,then the activity concentration of ^(14)C was determined by liquid scintillation counting(LSC).After the mathematical model was established,the uncertainty components were determined,the standard uncertainty was combined,and the extended uncertainty was calculated.Results:The relative uncertainty of 4 samples was 22.5%,17.0%,17.3%and 18.2%.The activity concentration of urine was(0.32±0.14),(0.60±0.20),(0.86±0.30)and(0.74±0.27)Bq/L,respectively.In the relative uncertainty of 22.5%,17.7%was from sample counting,13.6%from detection efficiency,2.1%from recovery rate,0.58%from sample volume,and 0.01%from sample weight.Conclusions:The main factors affecting the uncertainty include the error or deviation of sample counting,detection efficiency and recovery rate.The error of volume and weight also contributes to the measurement uncertainty.

An Analysis of Targeted Serum Lipidomics in Patients with Pneumoconiosis—China,2022

Introduction:Pneumoconiosis emerges as the most critical and prevalent occupational disease in China at present,according to research.Studies indicate that pneumoconiosis may indeed impact the body’s phospholipid metabolism.Methods:In this study,serum samples were taken from 46 paired participants,which included patients with pneumoconiosis and dust-exposed workers.We employed ultra-performance liquid chromatographytandem mass spectrometry(UPLC-MS/MS)technology in targeted lipidomics to investigate serum target phospholipids.Initially,a pilot study was conducted with a selection of 24 pneumoconiosis patients and 24 dust-exposed workers,using both univariate and multivariate statistical analyses to preliminarily identify significant differences in phospholipids.Subsequent to this,the remaining subjects were engaged in a validation study,wherein receiver operating characteristic(ROC)analysis was performed to further substantiate the screening potency of potential lipid biomarkers for pneumoconiosis.Results:The pilot study revealed significantly reduced serum levels of 16∶0 lysophosphatidylcholines(Lyso PC),18∶0–18∶1 phosphatidylglycerol(PG),18∶0–18∶1 phosphatidylethanolamine(PE),18∶0 PE,and 18∶1 lysophosphatidylethanolamine(Lyso PE)in the case group in comparison to the control group.Additionally,18∶0 PE,18∶0–18∶1 PE,and 18∶1 Lyso PE emerged as significant phospholipids with superior diagnostic values[area under the curve(AUC)>0.7].A diagnostic model was established,built on 16∶0 PC and 18∶0 PE(AUC>0.8).In the ROC analyses of validation studies,the 18∶0–18∶1 PE and this diagnostic model demonstrated excellent screening efficiency(AUC>0.7).Discussion:A significant divergence in phospholipid metabolism has been observed between pneumoconiosis patients and dust-exposed workers.The 18∶0–18∶1 PE present in serum could potentially function as a lipid biomarker for pneumoconiosis.Additionally,diagnostic models were developed relying on 16∶0 PC and 18∶0 PE,proving to have superior screening efficiency.

Analysis of gamma-emitting radionuclides in soils around high energy accelerators

Objective To investigate the specific activities of gamma radionuclides in the soils around high energy accelerators,and to analyze the influence of rays emitted by nuclides with characteristic peaks at similar energy points on nuclide measurement results,in order to provide reference for the accurate identification of radionuclides.Methods GR5021 high-purity germanium gamma spectroscopy system was used to measure the specific activities of gamma-emitting radionuclides 226Ra,232Th,238U,40K and artificial radionuclides 54Mn,52Mn,7Be,22Na,59Fe,95Zr in six soil samples around three kinds of high energy accelerators,and the theoretical counts of the characteristic peak of 835.7keV were compared with the measured counts of the characteristic peak of 54Mn.Results The specific activity ranges of gamma-emitting radionuclides 226Ra,232Th,238U and 40K in the soils around three kinds of high energy accelerators were 55.5–171,34.9–99.9,21.9–79.3 and 247–680 Bq/kg,respectively.The specific activities of artificial radionuclides 52Mn,7Be,22Na,59Fe and 95Zr were basically lower than the minimum detection limit.A characteristic peak was found at the energy point of 835.7keV in six soil samples,and the corresponding total absorption peak counts were from 228Ac of 232Thdecay daughter.Conclusions The specific activities of gamma-emitting radionuclides were at the normal natural background levels.The specific activities of artificial radionuclides were basically lower than the minimum detection limits.For 232Th,when its specific activity is above 40 Bq/kg,characteristic peak of its decay daughter 228Ac could be misjudged as characteristic peak of 54Mn.

Fast analysis method of strontium-90 after separation using crown ether resin

Objective:To explore the separation condition for 90Sr using crown ether resin,in order to establish a fast method for analysis of 90Sr in food and environmental samples.Methods:Stable strontium isotope(88Sr)was used to simulate the radioactive 90Sr,and the concentration of 88Sr in elution solution was detected using inductively coupled plasma mass spectrometry(ICP–MS).The separation conditions were investigated through batch experiment.Results:Under the optimized experimental conditions,the maximum adsorption capacity of crown ether resin was 22.28 mg/g.4.0–8.0 mol/L nitric acid made it easier for the Sr2þto load on the resin,and 20 mL ultrapure water was used to rinse the chromatographic column to achieve a good separation effect,by which the recoveries of Sr2þwere nearly close to 100%.The average recovery rates of 4 samples were 60.25%,69.26%,75.09%and 66.33%,respectively.Conclusions:Crown ether resin has very good selectivity and adsorption for 90Sr.The optimized conditions were high-efficiency and easy to operate.The separation method has great potential for the fast analysis of 90Sr in food and environmental samples.

Direct analysis method of^(14)C radioactivity concentration in urine samples

Objective:To establish a rapid analysis method for the activity concentration of carbon-14(14C)in urine,in order to estimate the internal dose of 14C exposure,and to protect the health of occupational population.Methods:Liquid scintillation counting(LSC)combined with the function of transformed spectral index of the external standard spectrum(tSIE)was used to measure the quenching level and counting rate,and the spiked urine samples with different shades of color were measured by LSC.After establishing the efficiency-quenching curve,the quenching correction and activity concentration analysis of the actual samples were carried out.Results:By LSC and the data fitting,the relationship between efficiency and quenching index could be represented using the equation y=0.0013x-0.0177(R^(2)=0.978).Three actual spiked samples were tested to verify this method,with recoveries of 97%,102%,and 89%,respectively.14C activity concentration of 4 actual urine samples were 0.12,0.11,0.10 and 0.08 Bq/mL,respectively,while the corresponding extended relative uncertainties were 0.0652,0.0929,0.0893 and 0.1043,respectively.Conclusion:The direct analysis method of 14C activity concentration in urine samples was established using LSC.The recovery of 14C activity concentration in urine samples showed that the proposed method had relatively high accuracy.By studying on the source of uncertainty,the uncertainty of the analysis results mainly came from the statistical error of LSC,and the uncertainty component of counting efficiency.