An algorithm for source checking continuous air monitors using radon progeny

Department of Energy requirements contained within 10CFR835 require that continuous air monitors be periodically checked for operability. The DOE air monitoring implementation guide for 10CFR835 allows the use of radon progeny to perform the recommended weekly source check. The Defense Waste Processing Facility located at the Savannah River Site has demonstrated that, through the use of the Hypotheses Concerning Two Means, diurnal change in the radon progeny detected by the monitors meets the requirements for weekly source checks. The use of the diurnal change in radon progeny has replaced the person-hours expended performing direct weekly source checking with an automated system requiring minimal person-hour expenditure.     

Biokinetics of embedded surrogate radiological dispersal device material

The terrorist use of a radiological dispersal device (RDD) has been described as "not if, but when" (). Exposures from such an event could occur by a number of routes including inhalation, wound contamination, or embedded fragments. Several of the radionuclides thought to be potential RDD components are metals or ceramic material. The use of such material would increase the potential for wounds from embedded fragments of radioactive material. To date, most research in this area has focused on inhalation exposures, while the consequence of embedded fragment exposure has not been investigated. This study modified a previously used rodent model in order to determine the biokinetics of intramuscularly implanted nonradioactive surrogate RDD material. Cobalt, iridium, or strontium titanate was embedded into the gastrocnemius muscle of Sprague Dawley rats. The rats were euthanized at 1, 3, or 6 mo post-implantation. Tissue metal analysis showed that iridium did not solubilize from the implanted pellet, while cobalt and strontium did so rapidly. Cobalt was found in all tissues analyzed, but it was localized mainly to kidney and liver as well as being excreted in the urine. Strontium was found in lung, liver, and spleen, as well as being deposited in bone. However, the greatest strontium concentrations were found in the popliteal lymph nodes, the lymph nodes responsible for draining the area of the gastrocnemius. These results indicate that, depending upon the material, a variety of treatment strategies will be needed when dealing with embedded fragment wounds from a radiological dispersal device event.     

锶与人体健康

锶是人体中必需微量元素之一,它与人体骨骼的形成密切相关,是骨骼、牙齿的主要成分,身体所有组织中都有锶,在肠内它与钠竞争吸收部位,使人体降低对钠的吸收,有利于心血管正常活动。锶可用来治疗一些由于副甲状腺功能不全导致的抽搐症状,缺锶会引起龋齿,锶过量则可引起骨骼的生长发育过快,表现为关节和骨骼变形、粗大、脆弱、疼痛,肌肉萎缩及贫血等。     

In vitro dissolution of respirable aerosols of industrial uranium and plutonium mixed-oxide nuclear fuels

Dissolution characteristics of mixed-oxide nuclear fuels are important considerations for prediction of biological behavior of inhaled particles. Four representative industrial mixed-oxide powders were obtained from fuel fabrication enclosures. Studies of the dissolution of Pu, Am and U from aerosol particles of these materials in a serum simulant solution and in 0.1M HCl showed: (1) dissolution occurred at a rapid rate initially and slowed at longer times, (2) greater percentages of U dissolved than Pu or Am: with the dissolution rates of U and Pu generally reflecting the physical nature of the UO2-PuO2 matrix, (3) the temperature history of industrial mixed-oxides could not be reliably related to Pu dissolution except for a 3-5% increase when incorporated into a solid solution by sintering at 1750 degrees C, and (4) dissolution in the serum simulant agreed with the in vivo UO2 dissolution rate and suggested the dominant role of mechanical processes in PuO2 clearance from the lung. The rapid initial dissolution rate was shown to be related, in part, to an altered surface layer. The advantages and uses of in vitro solubility data for estimation of biological behavior of inhaled industrial mixed oxides, such as assessing the use of chelation therapy and interpretation of urinary excretion data, are discussed. It was concluded that in vitro solubility tests were useful, simple and easily applied to individual materials potentially inhaled by humans.     

Trace minerals in commercially prepared baby foods.

Five categories of strained baby foods were analyzed for iron, copper, zinc, magnesium, manganese, strontium, and cadmium. Meats, egg yolk, and cerals tended to have the highest concentrations of iron, copper, and zinc. Fruits and vegetables had lower contents of these minerals. Cereals and vegetables were the best sources of magnesium and manganese. Strontium and cadmium levels were consistently low.     

STRONTIUM, OTHER TRACE ELEMENTS AND DENTAL CARIES

Strontium has received special attention for its possible relation to dental caries. The current data on the strontium concentration in enamel and in drinking water supplies suggest that a relationship may exist to dental caries experience of children who have been lifelong residents of the areas studied. The situation is obviously too complex to evaluate because of the numerous trace elements that have been shown to be significantly associated with caries prevalence.     

A physiologically based pharmacokinetic model for chloropentafluorobenzene in primates to be used in the evaluation of protective equipment against toxic gases.

Chloropentafluorobenzene (CPFB) has been proposed as an innocuous simulant for the uptake of toxic gases. Exposure to CPFB in a training exercise could be inferred afterwards from a measurement of CPFB in expired breath. To understand the relationship between exposure and measurement, we have developed a physiologically-based pharmacokinetic (PB-PK) model for CPFB in primates. To test the model, inhalation exposures were conducted on anesthetized rhesus monkeys. CPFB concentration in expired breath was measured during and after exposure. Simulations of CPFB uptake and clearance agreed with experimental measurements in seven of eight monkeys. A human version of the model was used to simulate exposures consisting of a single breath or a few breaths. By showing a measurable CPFB concentration in expired breath after several hours of clearance, simulations with the human model indicated the suitability of CPFB as a simulant for toxic gases.     

The impact of recirculating industrial air on aircraft painting operations

The 1990 Clean Air Act Amendments resulted in new environmental regulations for hazardous air pollutants. Industries such as painting facilities may have to treat large volumes of air, which increases the cost of an air control system. Recirculating a portion of the air back into the facility is an option to reduce the amount of air to be treated. The authors of this study developed a computer model written in Microsoft Excel 97 to analyze the impact of recirculation on worker safety and compliance costs. The model has a chemical database with over 1300 chemicals. The model will predict indoor air concentrations using mass balance calculations and results are compared to occupational exposure limits. A case study is performed on a C-130 aircraft painting facility at Hill Air Force Base, Utah. The model predicts strontium chromate concentrations found in primer paints will reach 1000 times the exposure limit. Strontium chromate and other solid particulates are nearly unaffected by recirculation because the air is filtered during recirculation. The next highest chemical, hexamethylene diisocyanate, increases from 2.6 to 10.5 times the exposure limit at 0 percent and 75 percent recirculation, respectively. Due to the level of respiratory protection required for the strontium chromate, workers are well protected from the modest increases in concentrations caused by recirculating 75 percent of the air. The initial cost of an air control system is $4.5 million with no recirculation and $1.8 million at 75 percent recirculation. The model is an excellent tool to evaluate air control options with a focus on worker safety. In the case study, the model highlights strontium chromate primers as good candidates for substitution. The model shows that recirculating 75 percent of the air at the Hill painting facility has a negligible impact on safety and could save $2.7 million on the initial expenses of a thermal treatment system.     

Pathogenesis of foot-and-mouth disease: clearance of the virus from the circulation of cattle and goats during experimental viraemia.

Viraemia is an important aspect of the pathogenesis of infectious diseases, but the mechanisms of entry and removal of virus from the vascular system particularly in natural hosts are poorly understood. The results of this study showed that the clearance of foot and mouth disease virus (FMDV) from the circulation of cattle and goats followed the general rules for the clearance of inert particulate materials and other viruses from the circulation. High doses of infused FMDV were cleared less efficiently than low doses, probably as a result of a depletion of the reticulo-endothelial system by the higher doses. FMDV was cleared from the circulation of cattle at a considerably slower rate than from the circulation of goats, but in both species significant individual variation in clearance was observed. These results could explain individual as well as species variations relative to the onset and duration of viraemia.     

深圳市"十一五"生活垃圾收运处理设施建设规划

分析了深圳市生活垃圾产生量、清运处理量及组成,垃圾收集设施、运输设施和处理设施的现状及其存在的问题.结合深圳市"十一五"社会经济发展的总体目标和规划的基本原则,提出了深圳市"十一五"生活垃圾收运处理设施建设规划与保障措施.     

The removal of strontium from the mouse by chelating agents

The effects of the chelating agents monosodium glutamate, Tiron, tartaric acid, ascorbic acid, 1,4,7,10,13,16-hexaoxacyclooctadecane (18-crown-6), 2,3-dimercaptosuccinic acid (DMSA), succinic acid, malic acid, ethylendiaminetetraacetic acid (EDTA), ethylenglycol-bis-(-amino-ethylether)-N,N tetraacetic acid (EGTA), cyclohexanediaminetetraacetic acid (CDTA) and diethylentriaminepentaacetic acid (DTPA) on the distribution and excretion of intraperitoneally injected strontium were investigated in male Swiss mice. Strontium nitrate was given at a dose equal to 3.78 mmol/kg and ten minutes after, chelators were administered intraperitoneally at doses approximately equal to one-fourth of their respective LD₅₀ values. DTPA, followed by CDTA, EDTA and tartaric acid, was consistently the most effective in increasing the urinary excretion of strontium. Only ascorbic acid increased significantly the fecal excretion of strontium. CDTA, DTPA and ascorbic acid were also the most effective chelators in reducing the concentration of strontium found in various tissues. CDTA, DTPA and tartaric acid are the most effective agents of those tested in the removal of strontium after a single administration.Supported by a fellowship from the Fondo de Investigaciones Sanitarias de la Seguridad Social, Spain.     

The removal of protein-bound solutes by dialysis

Protein-bound solutes that accumulate in plasma when the kidneys fail are poorly cleared by conventional dialysis. Means have been developed to reduce the levels of such solutes, either by modifying the dialysis procedure to increase their clearance or by limiting their production. A trial testing whether reducing bound solute levels clinically benefits dialysis patients is required to determine whether these measures should be adopted in routine clinical practice.     

The pulmonary effects and clearance of intratracheally instilled Ni3S2 and TiO2 in mice

The effects and clearance of intratracheally instilled nickel subsulfide (Ni3S2) and titanium dioxide (TiO2) were compared. Instilled Ni3S2 was acutely toxic to mice. Blood was recovered from the lungs during lavage, pulmonary polymorphonuclear leukocyte cell levels were increased, body weights decreased, and mice appeared clinically sick. These effects were in contrast to TiO2-instilled animals, which appeared similar to phosphate-buffered saline-instilled controls. The clearance of instilled particles from the lungs was examined for both Ni3S2- and TiO2-exposed mice. Particles were rapidly cleared to the gastrointestinal (GI) tract within 15 min; this clearance was nonspecific for Ni or Ti and appeared to be due to the coughing reflex. Significantly less Ni was present compared with TiO2 in mouse lungs at 3 and 7 days postexposure (P less than 0.05), with halflifes for the later clearance phase of 119 and 462 hr, respectively. Much of the early Ni lung burden was cleared to the GI tract, and Ni levels in the kidney and blood peaked at 1 hr. Longer-term Ni clearance rate constants were similar for lung, kidney, and blood and were consistent with the hypothesis that 63Ni was first solubilized in the lung then transported through the blood.     

Skin permeation of polycyclic aromatic hydrocarbons: A solvent-based in vitro approach to assess dermal exposures against benzo[a]pyrene and dibenzopyrenes

Consumer products with high contents of polycyclic aromatic hydrocarbons (PAHs) were repeatedly identified by market surveillance authorities. Since several of the individual compounds have been identified as genotoxic carcinogens, there might be health risks associated with the usage of these items. It therefore becomes reasonable to argue to reduce PAH contents in consumer products to a level as low as possible. This study presents data on the migration of PAHs from consumer products into aqueous sweat simulant or aqueous ethanol and on its combined migration and penetration into human skin. Product specimens were either submerged in simulant, or placed directly on test skins in Franz cell chambers to simulate dermal contacts. Migration of hexacyclic dibenzopyrenes became detectable by using ethanolic simulant, but not in aqueous sweat simulant. Similarly, migration of the pentacyclic model carcinogen benzo[a]pyrene (B[a]P) into aqueous sweat simulant was significantly lower when compared with human skin or skin models. The results point to a gross underestimation (about two orders of magnitude) when using aqueous sweat simulant instead of human skin for assessing PAH migration. On the other side, the usage of 20% ethanol as simulant revealed good agreement to the actual exposure of human skin against B[a]P migrating out of contaminated products. Our results underline that aqueous sweat simulant is not suitable to study dermal migration of highly lipophilic compounds.     

In vivo and in vitro susceptibility of Plasmodium falciparum to sulphadoxine/pyrimethamine in Liberia, West Africa

The in vivo response of Plasmodium falciparum to standard treatment with sulphadoxine/pyrimethamine was studied in 19 hospital patients from Yekepa town with hypoendemic malaria and in 28 children, two to nine years old, living in a village with holoendemic malaria. In vitro tests were performed on eight isolates. In the hospital patients all parasites cleared with mean clearance time of 2.2 (range one to three) days and no recrudescence occurred during a 28-day follow-up period. In the village children, despite a high sporozoite inoculation rate, recurrent parasitaemias were only recorded after 28 days, suggesting a rather long-lasting prophylactic effect against reinfection by the drug combination. In vitro, inhibition of parasite multiplication was achieved by 3 X 10(-7) M sulphadoxine and 3.8 X 10(-9) M pyrimethamine.     

Deposition, retention, and clearance of inhaled particles.

The relation between the concentrations and characteristics of air contaminants in the work place and the resultant toxic doses and potential hazards after their inhalation depends greatly on their patterns of deposition and the rates and pathways for their clearance from the deposition sites. The distribution of the deposition sites of inhaled particles is strongly dependent on their aerodynamic diameters. For normal man, inhaled non-hygroscopic particles greater than or equal to 2 micrometers that deposit in the conducting airways by impaction are concentrated on to a small fraction of the surface. Cigarette smoking and bronchitis produce a proximal shift in the deposition pattern. The major factor affecting the deposition of smaller particles is their transfer from tidal to reserve air. For particles soluble in respiratory tract fluid, systemic uptake may be relatively complete for all deposition patterns, and there may be local toxic or irritant effects or both. On the other hand, slowly soluble particles depositing in the conducting airways are carried on the surface to the glottis and are swallowed within one day. Mucociliary transport rates are highly variable, both along the ciliated airways of a given individual and between individuals. The changes in clearance rates produced by drugs, cigarette smoke, and other environmental pollutants can greatly increase or decrease these rates. Particles deposited in non-ciliated airways have large surface-to-volume ratios, and clearance by dissolution can occur for materials generally considered insoluble. They may also be cleared as free particles either by passive transport along surface liquids or, after phagocytosis, by transport within alveolar macrophages. If the particles penetrate the epithelium, either bare or within macrophages, they may be sequestered within cells or enter the lymphatic circulation and be carried to pleural, hilar, and more distant lymph nodes. Non-toxic insoluble particles are cleared from the alveolar region in a series of temporal phases. The earliest, lasting several weeks, appears to include the clearance of phagocytosed particles via the bronchial tree. The terminal phases appear to be related to solubility at interstitial sites. While the mechanisms and dynamics of particle deposition and clearance are reasonably well established in broad outline, reliable quantitative data are lacking in many specific areas. More information is needed on: (1) normal behaviour, (2) the extent of the reserve capacity of the system to cope with occupational exposures, and (3) the role of compensatory changes in airway sizes and in secretory and transport rates in providing protection against occupational exposures, and in relation to the development and progression of dysfunction and disease.     

Situation Analysis and Issues in Management of Biomedical Waste in Select Small Health Care Facilities in a Ward Under Bruhat Bengaluru Mahanagara Palike,Bangalore, India

Smaller health care facilities especially clinics though believed to generate lesser quantum/categories of medical waste, the number of clinics/small health care settings are considerable. The movement to manage biomedical waste in a safe and scientific manner has gathered momentum among the medium and large hospitals in Bangalore, but there has been a little understanding and focus on the smaller health care facilities/clinics in this aspect. It is important to gather evidence regarding the current situation of bio-medical waste (BMW) management and issues in smaller health care settings, so as to expand the safe management to all points of generation in Bangalore and will also help to plan relevant interventional strategies for the same. Hence an exploratory study was conducted to assess the current situation and issues in management of BMW among small health care facilities (sHCF). This cross sectional study was conducted in T. Dasarahalli (ward number 15) under Bruhat Bengaluru Mahanagar Palike (BBMP) of Bangalore. Data was collected from a convenient sample of 35 nursing homes (<50 beds) and clinics in December 2011. The results of this study indicate that 3 (20 %) of nursing homes had a Policy for Health Care Waste Management, though committees for Infection control and Hospital waste management were absent. Recording system like injury and waste management registers were non-existent. In our study the Common Bio-medical Waste Treatment Facility operator collected waste from 28 (80 %) of the sHCF. Segregation at the point of generation was present in 22 (62.9 %) of the sHCF. Segregation process was compliant as per BMW rules 1998 among 5 (16.1 %) of the sHCF. 18 sHCF workers were vaccinated with hepatitis B and tetanus. Deficiencies were observed in areas of containment, sharps management and disinfection. It was observed that though the quantum and category of waste generated was limited there exist deficiencies which warrant initiation of system development measures including capacity building.     

饮水中的锶对学龄儿童发育的影响

就高锶饮水对学龄儿童的形体发育、骨龄发育、龋齿和氟斑牙患病率的影响进行了流行病学调查。调查结果表明，饮水中含锶量在１０ｍ ｇ／ Ｌ时对学龄儿童的骨龄发育，尤其是对女童骨龄发育有一定促进作用，对学龄儿童的形体发育没有明显的影响。饮水锶与儿童龋齿率的关系在调查结果中不十分明确，但锶的防龋齿作用有必要做进一步的流行病学调查来证实。     

Effect of haemoperfusion on plasma paraquat concentration in vitro and in vivo

This study was to observe the paraquat (PQ) reduction rate after haemoperfusion (HP) on the groups of a relatively large number: 50 survivors out of 105 patients with acute PQ poisoning. We started off by measuring the clearance of haemodialysis (HD) and HP for the PQ in vitro. At the blood flow of 250 mL/min, the PQ clearance was greater in HP than in HD during the first 90 minutes: 215 versus 175 mL/min at 30 minutes, 213 versus 201 mL/min at 60 minutes, and 199 versus 179 mL/min at 90 minutes. The clearance in HP decreased rapidly after two hours. By the end of the dialysis, however, the final concentration in container decreased to 5.7 microg/mL in HD and 1.5 microg/mL in HP, which implied that although HD was cleared more effectively during the later stages, the overall elimination was greater in HP. Following this preliminary investigation, we performed HP on all the patients in order to assess the extracorporeal elimination. One hundred and five patients who had swallowed one to three mouthfuls of PQ (24.5% w/v) solution were subjected to the in vivo study. The reduction rate of PQ was checked out by measuring the PQ concentration in plasma before and after four hours of HP. Seeing the reduction rate was significantly higher in the survivors group than in the nonsurvivors group (80.3+/-19.9 versus 67.2+/-19.2%, P <0.01), we concluded that adequate HP appears to be an indispensable treatment for patients with acute PQ poisoning.     

三峡工程湖北段二期库区卫生清理及蓄水后人畜共患病监测

目的探讨三峡库区湖北段卫生清理过程中的经验和问题,掌握蓄水后库区病媒生物和人畜共患病的变化动态,分析蓄水后环境改变对库区人群健康的影响。方法依据长江三峡库底卫生清理技术规范,统计分析库区内人畜共患病发病情况。结果卫生清理工作符合国家标准规定要求,顺利通过验收,满足了蓄水的需要;蓄水后库区监测点肾综合征出血热、钩端螺旋体病和流行性乙型脑炎均为散发。结论三峡库区卫生清理有效地清除了库区污染源,蓄水后库区内未出现病媒生物异常及人畜共患病的流行暴发,至今尚未发现三峡库区蓄水对库区人群健康产生显著影响。