Skin dose contamination conversion coefficients. Benchmark with three simulation codes

Handling of radioactive material by operators can lead to contamination at the surface of the skin in case of an accident. The quantification of the dose received by the skin due to a contamination scenario is performed by means of dedicated dose coefficients as it is the case for other radiation protection dose quantities described in the literature. However, most available coefficients do not match realistic scenarios according to state-of-the-art of science and technology. Therefore, this work deals with dedicated dose conversion factors for skin contamination. Since there is an increasing demand on dose coefficients in general, these specific coefficients can be used for various calculations in radiation protection. In this work a method to evaluate such coefficients for the skin contamination dose related to photons, electrons, positrons, alpha and neutron particles is proposed. The coefficients are generated using Monte-Carlo simulations with three well established calculation codes (FLUKA, MCNP, and GEANT4). The results of the various codes are compared against each other for benchmarking purposes. The new dose coefficients allow the computation of the skin received dose, in the case of skin contamination scenario of an individual, taking into account the decay radiation of the radionuclides of interest. To benchmark the quantity derived here, comparisons of radionuclide contamination doses to the skin using the VARSKIN code available in the literature are performed with the results of this work.

Digestive disorders induced by the accumulation of arsenic in the human body

Exposure to arsenic is common, but unconscious, inducing major imbalances especially in the digestive tract, lungs, skin. Contamination is achieved by exposure to arsenic in the air, soil, groundwater, food. It is noted the use of arsenic in pesticides, herbicides, paints, wood preservatives, drinking water, various foods with a wide range of consumption (seafood, rice – including rice milk, rice bran, rice cereals, rice syrup rice, rice crackers). The diagnosis of arsenic poisoning is an important step in establishing the diet and detoxification treatment, focusing on the cause, not the symptoms. We present the case of a 45-year-old patient with symptoms manifested in the digestive tract for 4 years: abdominal bloating, cramps, vomiting, weekly episodes of acute diarrhea. During these period the patient received multiple treatments depending on the symptoms, without a significant improvement, without performing specific investigations of arsenic poisoning. The personalized diet and treatment plan, used in the case of this patient, for a period of 4 months was distinguished by a total solution of the manifestations presented in the anamnesis stage.

Hygienic assessment of the skin-resorptive effect of xenobiotics (literature review)

The basis of safety for working with chemicals, including pesticides, is to minimize contact with them and prevent them from entering the body by inhalation and dermal route, sometimes in actual production conditions, the skin pathway can be more dangerous. The most studied inhalation route of harmful substances entering the body of a working person is confirmed by an extensive evidence base, the presence of regulatory and methodological documents, experimentally established and approved MPC in the air of the occupational area for 2484 substances, and 601 substances included in SanPiN 1.2.3685-211. The maximum permissible levels (MPL) on the skin are presented for only 26 substances in the same document. Identification and evaluation of the skin-resorptive effect of xenobiotics have methodological features due to the properties of the skin, which performs a barrier-protective function, and the physico-chemical, toxic properties of substances. The main stages of development in the domestic hygienic science and practice of research on the study and assessment of the skin-resorptive effect of xenobiotics in industrial contact with them are presented. The continuity of research on the study and evaluation of the skin-resorptive impact of chemicals used in various industries and agriculture is shown, making it possible to develop methodological approaches to the identification and risk assessment of dermal absorption of xenobiotics, including pesticides, within the organisms of workers. Evaluating the risk of skin contamination is the main argument for the development of measures for the primary prevention of skin resorptive action. Establishing the priority of the dermal route of toxicant intake is an evidence-based justification for making decisions about the possibility of using, for example, pesticides on the territory of the Russian Federation. The literature review is based on open sources hosted on virtual database platforms: Scopus, Web of Science, MedLine, Global Health, e-LIBRARY, Electronic Fund of Legal and Regulatory Documents, etc.

Hygienic evaluation of diflubenzuron-based pesticides in various application technologies

Introduction. In connection with the widespread introduction of new preparative forms of pesticides and methods of their introduction into the environment, the urgent task of the modern period is to minimize the risk of exposure to pesticides on the health of workers and the population-the use of diflubenzuron of low and medium toxicity increases. Therefore, a mandatory criterion for assessing risk is registration tests, carried out during several stages - as hazard identification, hazard characterization, exposure assessment, risk characterization. Purpose of work. To assess the regularities of the formation of the risk of diflubenzuron by exposure and by the absorbed dose, depending on the type of preparative form of pesticides with different technologies of their introduction and regulating safe use measures. Materials and methods. The obtained exposure levels of insecticides based on diflubenzuron in the air and on the skin were compared with the hygienic standards calculated and experimentally established as follows: MPC (mg/m3) in the air of the working area and approximate admissible level (AAL) (mg/cm2) of skin contamination. The exposure level risk was determined by the safety level (SL) SLsumm value. The risk of exposure to insecticides based on diflubenzuron for the operator / user / refueller / pilot / signaller based on the absorbed dose, determined by the safety factor - SLp, and the exposure -SBsumm, is considered acceptable when SLsumm and SLp <1. Results. The paper presents the risk analysis results of the impact of diflubenzuron-based insecticides studied in natural conditions using 27 drugs with different preparative forms and methods (technologies) of their introduction into the environment. The risk of exposure to insecticides (SLsumm) for all technologies is acceptable SL. The risk of absorbed dose (SLp) was more significant regardless of the type of formulation. Wettable powder formulations are more unfavourable to use than other formulations. Conclusion. The conditions for the use of preparations based on diflubenzuron in the technologies of ground boom spraying and fan spraying of field and horticultural crops, in the treatment of field and forest crops by the aerial method, in the treatment of field and horticultural crops in private household plots, in the treatment of champignons in protected ground, compliance with regulations and measures safety meet hygienic requirements.

Personal protective equipment does not sufficiently protect against virus aerosol unless combined with advanced air purification or ventilation techniques

ABSTRACTBackgroundHealthcare workers (HCWs) are at risk from nosocomial transmission of SARS-CoV-2 from virus laden aerosols. This study aimed to: 1) quantify the degree of protection from virus aerosol provided by different types of mask (surgical, N95, fit-tested N95) and personal protective equipment (PPE); 2) determine if the use of a portable HEPA filter can enhance the effectiveness of PPE; 3) determine the effectiveness of a decontamination shower to remove virus aerosol contamination of a HCW.MethodsVirus aerosol exposure experiments were conducted using bacteriophage PhiX174 (108copies/mL). A HCW wearing PPE (mask, gloves, gown, faceshield) was exposed to nebulised viruses for 40mins in a sealed clinical room. After exiting, the HCW doffed PPE. Virus exposure was quantified via skin swabs applied to the face and nostrils, forearms, neck, and forehead. Experiments were performed with and without the presence of a portable HEPA filter (set to 470m3/hr).FindingsSwabs quantified significant virus exposure under the surgical and N95 mask. Only the fit-tested N95 resulted in lower virus counts compared to no mask control (p=0.027). Nasal swabs demonstrated very high virus exposure, which was not mitigated by the surgical or N95 masks, although there was a trend for the fit-tested N95 mask to reduce virus counts (p=0.058). The addition of HEPA filtration substantially reduced virus counts from all swab sites, and to near zero levels when combined with a fit-tested N95 mask, gloves, gown and faces shield. Virus counts were substantially reduced to near zero levels following a shower.InterpretationThese data demonstrate that quantitatively fit tested N95 masks combined with a HEPA filter can offer protection against high virus aerosol loads at close range and for prolonged periods of time. Skin contamination from virus aerosol can be effectively by removed by showering.FundingEpworth Hospital Capacity Building Research Grant ID: EH2020-654

Point of emission air filtration enhances protection of health care workers against skin contamination with virus aerosol

Rationale: We recently demonstrated that a patient hood with a high efficiency particulate air filter eliminates virus aerosol contamination when very large quantities of bacteriophage virus are aerosolised into a clinical room. While this containment method is relatively low cost, it is unclear whether similar efficacy can be achieved with lower cost/commercial grade air purifiers, or if such an approach protects healthcare workers against virus aerosol contamination. Method: A total of 109 (10 ml of 108) PhiX174 bacteriophages was nebulized into a sealed clinical room. Surface contamination was detected by settle plates left uncovered during exposure. A healthcare worker remained in the room, personal exposure was determined by skin swabs after exiting the room, following doffing of personal protective equipment (PPE). Four skin areas were swabbed: forearms/hands, neck, forehead, under N95 mask. Three conditions were tested, 1) hood with hospital grade air purifier (IQ Air Health Pro 250), 2) hood with commercial air purifier (Philips 1000i), and 3) control (no hood/air-purification). Findings: The control condition demonstrated extensive environmental and limited skin contamination underneath PPE, which was highest under an N95 mask. The commercial air purifier and hood provided environmental control of virus aerosol and almost zero skin contamination. In comparison, the hospital grade purifier provided complete environmental and skin contamination protection, despite a lower clean air filtration rate (240m3/hr vs 270m3/hr). Virus counts on plates and swabs were significantly lower for both air purifiers and across neck, forehead, and under the N95. There were no statistically significant differences in detected virus counts between air purifiers. Conclusion: This cheap and scalable method may be an effective way to reduce the spread of COVID-19 in hospitals by enhancing the effectiveness of PPE worn by health care workers who care for COVID-19 patients and who are exposed to virus aerosol.

A Collaborative Experience: Implementation of an Optimised Tc-99m Generator Assembly Process

Technetium-99m (Tc-99m) has a six-hour half-life making customer transportation times a challenge. ANSTO (Australia's Nuclear Science and Technology Organisation) Health Products group has overcome this by delivering the parent isotope Molybdenum-99 (Mo-99), which has a half-life of sixty-six hours, in shielded GENTECH™ generators. As part of ANSTO's questioning attitude, an augmented risk assessment was undertaken to identify any potential exposure risks of the GENTECH™ assembly process. The evaluation identified potential areas of improvement in contamination control for the manual handling of the generator leads. Upon further analysis, contamination events from the generator leads had the potential for skin doses above the threshold for skin tissue reactions. Additional substitution and administrative controls were designed to mitigate the risks identified. The effectiveness of the new controls was assessed for efficiency in the manufacturing process through mock trials and fitness for use in a pharmaceutical cleanroom environment. The implemented controls were monitored, and data from each run was gathered. This data included; changes in radiological conditions and dosimetry results. Upon implementation, there was an observable decrease in glove contamination. The decrease verified that there was a reduction in the risk of skin contamination events. The data analysis was used to model the dose averted, which revealed a reduction in potential extremity dose to production workers. This paper aims to show the optimisation within an approved process through the implementation of engineering and administrative controls, resulting in a dose reduction to workers.

Update on Coagulase-Negative Staphylococci—What the Clinician Should Know

Coagulase-negative staphylococci (CoNS) are among the most frequently recovered bacteria in routine clinical care. Their incidence has steadily increased over the past decades in parallel to the advancement in medicine, especially in regard to the utilization of foreign body devices. Many new species have been described within the past years, while clinical information to most of those species is still sparse. In addition, interspecies differences that render some species more virulent than others have to be taken into account. The distinct populations in which CoNS infections play a prominent role are preterm neonates, patients with implanted medical devices, immunodeficient patients, and those with other relevant comorbidities. Due to the property of CoNS to colonize the human skin, contamination of blood cultures or other samples occurs frequently. Hence, the main diagnostic hurdle is to correctly identify the cases in which CoNS are causative agents rather than contaminants. However, neither phenotypic nor genetic tools have been able to provide a satisfying solution to this problem. Another dilemma of CoNS in clinical practice pertains to their extensive antimicrobial resistance profile, especially in healthcare settings. Therefore, true infections caused by CoNS most often necessitate the use of second-line antimicrobial drugs.

The risk assessment for employees working under different technologies of application of pesticides

Introduction. In recent years, agricultural production in Russia has increased at the expense of farms and personal subsidiary plots; farmers use chemical protection means - pesticides to protect crops. Farmers and users of private household plots are considered the leading risk group most exposed to pesticides during their application, transportation, and loading. At the same time, farmers and users do not have special training in the safe handling of pesticides. They do not undergo periodic medical examinations, which increases the risk of exposure to pesticides on their health. Purpose of work. Study of exposures of pesticides in the air of the working area and on the skin of workers when they use pesticides in private farms, farms on-field, and high garden crops; justification of the requirements for the safe use of pesticides in private farms and farms. Material and methods. The established exposure levels of pesticides in the air and on the skin were compared with hygiene standards calculated or experimentally set: MPC / OBUV (mg / m3) in the atmosphere of the working area and MPC/ODU (mg/cm2) of skin contamination. The exposure level risk was determined by the KBsumm. The risk of exposure to pesticides for the operator/farmer/user based on the absorbed dose, determined by the value of the safety factor - KBp, and exposure - Kbsumm, is considered acceptable when the value of KBsumm and KBp < 1. Results. The authors presented generalized results of the analysis of the risk of exposure to pesticides in terms of both exposure (KBsumm) and absorbed dose (KBp) in natural conditions when using 20 drugs on field and garden crops in private household plots and farms. The absorbed dose for farmers, calculated taking into account the work for 6 hours, when compared with ADI, in some cases, exceeded the permissible values. The risk of using two preparations in suspension concentrates and one preparation in the form of a nanoemulsion concentrate in terms of the absorbed dose during knapsack spraying of field crops in farms was higher than the acceptable one. Conclusion. The hygienic assessment of the risk of using pesticides of different hazard classes for all land application methods into the environment convinces us the actual hygienic situation to be determined mainly by the state of the equipment used, compliance with hygiene regulations. The degree of professional skills of operators, as well as the culture of pesticide use, are significant. In the future, the risk, especially in terms of the absorbed dose, must be calculated for users of private household plots and farmworkers, taking into account the differences in cultivated areas’ volumes.

A Case of Dimethoate Poisoning Requiring Prolonged Skin Decontamination

Background Decontamination is a critical medical counter measure in reducing toxic exposure following poisoning. Little is known on the effectiveness of this procedure and its impact in the context of preventing secondary exposure of healthcare workers and secondary contamination of facilities. Presented here is a case of dimethoate poisoning that required a prolonged period of skin decontamination to remove residual skin contamination. Case Report A young gardener consumed dimethoate at the workplace witnessed by a colleague who called the emergency services immediately. Paramedics noted the patient to be drowsy with stable vital signs and 100% oxygen saturation. En-route to the hospital the patient vomited multiple times and was drenched in vomitus with a pungent odour. Upon arrival at the emergency department (ED), vital signs remained stable with a Glasgow Coma Scale (GCS) of 10. Due to gross external contamination from the vomitus and pungent odours emanating suggestive of chemical fumes off-gassing, the hospital decontamination shower was activated for patient decontamination. Staff donned protective suits and proceeded to disrobe and bag all the patient’s clothing before showering the patient for 10-minutes using soap and water. Post-decontamination a chemical agent monitor (CAM) were used to screen for residual chemicals following the hospital’s decontamination protocol. The chemical alarm was triggered twice, first around the left mastoid region and again just below the left breast. This required targeted re-showering for a further 10-minutes before patient was finally cleared of contamination. Subsequently, the patient was given atropine (2.4 mg) and pralidoxime (1 g) followed by an infusion at the intensive care unit (ICU). The patient made an uneventful recovery and was discharged 5-days later. Conclusion This case of dimethoate poisoning is notable for the prolonged period of skin decontamination to remove residual skin contamination and illustrates potential implications to patient and health care worker safety. Past mass casualty incidents involving chemicals, such as the sarin attack in Tokyo, highlight the high incidence of secondary exposures amongst healthcare workers due to the lack of casualty decontamination. As a result, many hospitals have developed capacity to conduct rapid and timely decontamination at their premises to prevent further complications from secondary chemical exposure. However, the effectiveness of this process of decontamination needs further evaluation.