Hazardous Agents Research Articles

Review for Retrospective Exposure Assessment Methods Used in Epidemiologic Cancer Risk Studies of Semiconductor Workers: Limitations and Recommendations.

This article aims to provide a systematic review of the exposure assessment methods used to assign wafer fabrication (fab) workers in epidemiologic cohort studies of mortality from all causes and various cancers. Epidemiologic and exposure–assessment studies of silicon wafer fab operations in the semiconductor industry were collected through an extensive literature review of articles reported until 2017. The studies found various outcomes possibly linked to fab operations, but a clear association with the chemicals in the process was not found, possibly because of exposure assessment methodology. No study used a tiered assessment approach to identify similar exposure groups that incorporated manufacturing era, facility, fab environment, operation, job and level of exposure to individual hazardous agents. Further epidemiologic studies of fab workers are warranted with more refined exposure assessment methods incorporating both operation and job title and hazardous agents to examine the associations with cancer risk or mortality.

Comprehensive Evaluation of Hazardous Chemical Exposure Control System at a Semiconductor Manufacturing Company in South Korea.

The goal of this study was to evaluate the hazardous chemical exposure control system in a semiconductor manufacturing company and recommend an appropriate exposure surveillance system for hazardous agents. We reviewed compliance-based chemical exposure data compiled between 2012 and 2014 by the study company. The chemical management system, characteristics of chemical use and hazardous gas monitoring system were also investigated. We evaluated the airborne isopropyl alcohol (IPA) and acetone generally used as cleaning solvents, volatile organic compounds and metals levels using internationally recommended sampling and analytical methods. Based on the results of past working environment measurement data and of our investigation, the overall current exposure to chemicals by semiconductor workers during routine production work appears to be controlled below occupational exposure limits. About 40% of chemical products used were found to contain at least one unidentifiable trade-secret substance. There are several situations and maintenance tasks that need special attention to reduce exposure to carcinogens as much as possible. In addition, a job-exposure matrix as a tool of surveillance system that can examine the exposure and health status of semiconductor workers according to type of operation and type of job or task is recommended.

A novel thiol-ene click reaction for preparation of graphene quantum dots and their potential for fluorescence imaging

Graphene quantum dots (GQDs), as a kind of carbon dots with the structure of graphene, possess fascinating properties of both carbon dots and graphene have attracted increasing attention for various applications especially in the biomedical fields. It is therefore, many methods for preparation of GQDs have been developed over the last decade. However, most of the previous reports are required tedious experimental procedure and hazardous agents. In this study, we developed an unparalleled preparation method for preparation of GQDs from graphene oxide through a one-step thiol-ene click reaction. More importantly, many carboxyl groups have been introduced on the surface of GQDs during this procedure. The characterization results demonstrated that these GQDs display small size, uniform morphology, high water dispersibility and strong green fluorescence. Biological assays suggested that these GQDs are of low cytotoxicity and efficient cell uptake performance. More importantly, many other GQDs could also been fabricated through the thiol-ene click reaction owing to the universality of thiol-ene click reaction. Therefore, this novel strategy based on thiol-ene click reaction should be of great importance for advancing the preparation and biomedical applications of GQDs.

One-pot construction of cellulose-gelatin supramolecular hydrogels with high strength and pH-responsive properties

Inspired by the supramolecular structure of cellulose, cellulose-gelatin supramolecular hydrogels with high strength and pH-sensitivity were constructed in a basic-based solvent system, ethylene diamine/potassium thiocyanate (EDA/KSCN) with the aid of cyclic freezing-thawing. The investigation on the characteristics of supramolecular hydrogels revealed that repeated freezing-thawing cycles played an important role in the formation of the physical cross-linked supramolecular network structure between cellulose and gelatin. The mechanical properties of supramolecular hydrogels were much higher than pure cellulose and gelatin hydrogel, and the compressive strength was 9.6 times higher than that of pure gelatin hydrogel. The synergistic effect between hydrogen-bonding interaction and the reinforcement of regenerated cellulose nanofibrils (CNF) contributed to the superior mechanical performance. Furthermore, the swelling kinetics tests showed that the supramolecular hydrogels exhibited excellent pH-responsibility, indicating potential applications in biomedical fields. Thus, a straightforward route to construct natural polymer-based hydrogels with supramolecular structure through physical crosslinking strategy without employing hazardous crosslinking agents was developed, paving the way for the design of new types of hydrogels.

English

Food safety and quality are critical issues that should be given more attention all over the world mainly from nutritional quality and human health point of view. Food safety is a scientific field of study which deals with handling, preparation, and storage of food in ways that prevent food borne illness. Food safety system is often categorized into two, namely traditional and science-based systems. Food can be used as a source of disease transmission from one person to another; it also serves as a nutrient growth medium for bacteria that can cause food poisoning, and hazardous agent for consumers’ health. Factors which can be a source of potential hazards in foods include traditional milk production accompanied with improper agricultural practices and poor hygienic environment at all stages of the food chain. Quality assurance is mandatory before the milk is consumed. It is achieved up on planned and systematic activities performed in each steps of the quality system. Milk and milk products contaminants are classified into two, namely, infectious and non-infectious agents. Food-borne illnesses are generally infectious or toxic in nature and caused by major infectious diseases such as bacteria, viruses, parasites, or chemical substances getting access to enter into the body through contaminated food or water. Milk and milk products heading for export to global market need to pass through the strictest quality standards. Hazard analysis and critical control point system (HACCP) requires a critical examination through every step of food manufacturing process to determine the possibility of having physical, chemical, or microbiological contamination. To achieve this, it is necessary to control the quality of milk at the grass root level. Key words: Milk, contamination, food safety, quality control.

Staphylococcal enterotoxin B (SEB) toxin of Staphylococcus aureus and the detection methods

Staphylococcal enterotoxins (SEs) secreted by Staphylococcus aureus is one of the principal causes of food poisoning. The SEs are superantigens; they are highly stable, resisting most proteolytic enzymes and thus keeping activity in the gastrointestinal tract after being ingestion. In particular, heat-stable enterotoxin is one of the most important property related to food safety. They are not degraded at 100°C for 30 minutes, even at 121oC for 28 minutes, the SEs retain biological activity. Heat resistance of SEs in foods is higher than in the culture medium. Staphylococcus aureus (S. aureus) produces more than 20 different types of enterotoxins, including SEA to SEE, SEG to SER and SEU. Among these, Staphylococcal enterotoxin B (SEB) is a powerful toxin, heat-stable, water-soluble and is a common cause of food poisoning. Moreover, SEB is one of the harmful or hazardous agents used as biological weapons in bioterrorism or biological warfare. Therefore, determining presence of SEB toxin in food is extremely important. In this review, we introduce the most basic features about S. aureus; about SEB toxin and conventional methods for SEB diagnosis, detection. Especially, we focus on rapid detection strip based on an immunochromatography; this technique is an highly sensitive, rapid, easy for use and storage.

Electrochemical Biosensors: A Solution to Pollution Detection with Reference to Environmental Contaminants.

The increasing environmental pollution with particular reference to emerging contaminants, toxic heavy elements, and other hazardous agents is a serious concern worldwide. Considering this global issue, there is an urgent need to design and develop strategic measuring techniques with higher efficacy and precision to detect a broader spectrum of numerous contaminants. The development of precise instruments can further help in real-time and in-process monitoring of the generation and release of environmental pollutants from different industrial sectors. Moreover, real-time monitoring can also reduce the excessive consumption of several harsh chemicals and reagents with an added advantage of on-site determination of contaminant composition prior to discharge into the environment. With key scientific advances, electrochemical biosensors have gained considerable attention to solve this problem. Electrochemical biosensors can be an excellent fit as an analytical tool for monitoring programs to implement legislation. Herein, we reviewed the current trends in the use of electrochemical biosensors as novel tools to detect various contaminant types including toxic heavy elements. A particular emphasis was given to screen-printed electrodes, nanowire sensors, and paper-based biosensors and their role in the pollution detection processes. Towards the end, the work is wrapped up with concluding remarks and future perspectives. In summary, electrochemical biosensors and related areas such as bioelectronics, and (bio)-nanotechnology seem to be growing areas that will have a marked influence on the development of new bio-sensing strategies in future studies.

Environmental Management Systems and Hazardous Waste in the Health Service Providers in the City Of Barranquilla

Objectives: There is, in Colombia, a stark weakness in the state entities as to planning and executing projects related to environmental hazardous waste management, so some local entities do not comprehensively manage this type of processes or adequately dispose of such waste deemed as hazardous to the environment and human health. This study focuses on an analysis of the Environmental and hazardous waste Management Systems (EMS) within the healthcare providers (IPS) (Healthcare Providers) in the city of Barranquilla. Methods: The design of the research is descriptive, not experimental and it develops from the implementation of a closed questionnaire. Findings: It concludes that the (IPS) (Healthcare Providers) generally do not have a good degree of control over their personnel’s exposure to hazardous agents as they are regularly in direct or indirect contact with hazardous materials such as biological fluids. Application/Improvements: Their internal and external stakes and conserve the environment, but also have a bigger market share, improve their image and grow in a sustainable way. Keywords: EMS, Hazardous Waste, ISO 140001, Prevention Plan

Tracking of a Fluorescent Dye in a Freshwater Lake with an Unmanned Surface Vehicle and an Unmanned Aircraft System

Recent catastrophic events in our oceans, including the spill of toxic oil from the explosion of the Deepwater Horizon drilling rig and the rapid dispersion of radioactive particulates from the meltdown of the Fukushima Daiichi nuclear plant, underscore the need for new tools and technologies to rapidly respond to hazardous agents. Our understanding of the movement and aerosolization of hazardous agents from natural aquatic systems can be expanded upon and used in prevention and tracking. New technologies with coordinated unmanned robotic systems could lead to faster identification and mitigation of hazardous agents in lakes, rivers, and oceans. In this study, we released a fluorescent dye (fluorescein) into a freshwater lake from an anchored floating platform. A fluorometer (fluorescence sensor) was mounted underneath an unmanned surface vehicle (USV, unmanned boat) and was used to detect and track the released dye in situ in real-time. An unmanned aircraft system (UAS) was used to visualize the dye and direct the USV to sample different areas of the dye plume. Image processing tools were used to map concentration profiles of the dye plume from aerial images acquired from the UAS, and these were associated with concentration measurements collected from the sensors onboard the USV. The results of this project have the potential to transform monitoring strategies for hazardous agents, enabling timely and accurate exposure assessment and response in affected areas. Fast response is essential in reacting to the introduction of hazardous agents, in order to quickly predict and contain their spread.

Choline Azide: New Reagent and Ionic Liquid in Catalyst‐Free and Solvent‐Free Synthesis of 5‐Substituted‐1H‐Tetrazoles: A Triple Function Reagent

AbstractAn efficient and green route for the synthesis of 5‐substituted‐1H‐tetrazoles using choline azide as a new azidation reagent in solvent‐free and catalyst‐free conditions, is reported for the first time. The noteworthy aspects of this high‐yield and cost‐effective reaction are simple methodology, mild reaction conditions, easy work‐up procedure, low reaction time, and specially using choline azide as an effective alternative to hazardous azidation agent.

Iron-montmorillonite clays as active sorbents for the decontamination of hazardous chemical warfare agents.

A class of heterogeneous catalysts based on commercial bentonite from natural origin, containing at least 80 wt% of montmorillonite clay, was designed to transform selectively and under mild conditions toxic organosulfur and organophosphorus chemical warfare agents into non-noxious products with a reduced impact on health and environment. The bentonite from the natural origin was modified by introducing iron species and acid sites in the interlayer space, aiming to obtain a sorbent with strong catalytic oxidising and hydrolytic properties. The catalytic performance of these materials was evaluated in the oxidative abatement of (2-chloroethyl)ethyl sulfide (CEES), a simulant of sulfur mustard, in the presence of aqueous hydrogen peroxide as an oxidant. A new decontamination formulation was, moreover, proposed and obtained by mixing sodium perborate, as a solid oxidant, to iron-bentonite catalysts. Solid-phase decontamination tests, performed on a cotton textile support contaminated with organosulfide and organophosphonate simulant agents revealed the good activity of the solid formulation, especially in the in situ detoxification of blistering agents. Tests carried out on the real blistering warfare agent, sulfur mustard (HD agent), showed that, thanks to the co-presence of the iron-based clay together with the solid oxidant component, a good decontamination of the test surface from the real warfare agent could be achieved (80% contaminant degradation, under ambient conditions, in 24 h).

The application of stand-off infrared detection to identify air pollutants

Fourier-transform infrared spectroscopy (FT-IR) enables the passive detection and identification of chemical agent clouds from distances. It can be used for the monitoring of large spaces and protection of industrial installations outside buildings. The aim of the study was show the possibilities and limitations of passive FT-IR. In studies done by the Faculty of Fire Safety Engineering at the Main School of Fire Service were used spectrometer RAPID (Remote Air Pollution Infrared Detector), Bruker Daltonics Company. Hazardous substances such as acetone, methanol, ammonia was identified on-line from several observation points at 25 m, 50 m and 75 m. The tests were carried out at various meteorological conditions. The results indicate that remote infrared detection allows detecting hazardous chemical agents in the atmosphere from a distance. Nevertheless, meteorological and terrain conditions have a big impact on the measurement results. During measurements, the detector indicated the presence of other substances. Moreover, it was found that under cloudy and windy weather, remote detection is not possible.

Evaluation of the Combined Effects of Heat and Lighting on the Level of Attention and Reaction Time: Climate Chamber Experiments in Iran.

Heat exposure and unsuitable lighting are two physical hazardous agents in many workplaces for which there are some evidences regarding their mental effects. The purpose of this study was to assess the combined effect of heat exposure and different lighting levels on the attention rate and reaction time in a climatic chamber. This study was conducted on 33 healthy students (17 M/16 F) with a mean (±SD) age of 22.1 ± 2.3 years. The attention and reaction time test were done by continuous performance test and the RT meter, respectively, in different exposure conditions including the dry temperatures (22°C and 37°C) and lighting levels (200, 500, and 1500 lux). Findings demonstrated that increase in heat and lighting level caused a decrease in average attention percentage and correct responses and increase in commission error, omission error, and response time (P < 0.05). The average of simple, diagnostic, two-color selective, and two-sound selective reaction times increased after combined exposure to heat and lighting (P < 0.05). The results of this study indicated that, in job task which requires using cognitive functions like attention, vigilance, concentration, cautiousness, and reaction time, the work environment must be optimized in terms of heat and lighting level.

The use of genetic engineering constructions as control samples on evaluation of diagnostic kits for reveal of rna of hazard and extremely hazard agents of virus infections by reverse transcription - polymerase chain reaction.

The reverse transcription - polymerase chain reaction method (RT-PCR) has leading position on diagnostic infections, caused by RNA-containing viruses. This method presents severe requirements to carrying out of everybody stages of analysis (extraction of nucleic acid, carry out reverse transcription, amplification of DNA). It is necessary to account the possibility of false positive or false negative results appearance. The use on RT-PCR only positive (PCS) and negative (NCS) control samples is insufficient for the control of stages of RNA extraction and reverse transcription. That is way there is necessity the construction of inner control sample (ICS) to control of these stages. The main goal of present is the ground of use genetic engineering constructions (GEC) as control samples (PCS and ICS) on evaluation of diagnostic kits for reveal of RNA of hazard and extremely hazard agents of virus infections by RT-PCR. The vector recombinant plasmids, containing the insertion of cDNA of agent´s genomic RNA are used as PCS, RNA was packed in membrane protein of MS2 bacteriophage, is used as ICS. It is demonstrated that ICS does no influence on sensitivity of RT-PCR both for use of native agents and for use of synthetic nucleic acids of Ebola, Marburg, Lassa, Machupo, Venezuelan encephalitis equine (VEE), Rift Valley fever and rabies viruses. The possibility of use of PCS and ICS for standardization of diagnostic kits is discussed.

PEDOT:PSS–MODIFIED PLATINUM MICROELECTRODES FOR MEASUREMENTS IN AQUEOUS MEDIA: EFFECT OF POLYMER SURFACE AREA ON LONG-TERM ANODIC PEAK CURRENT STABILITY

Contamination of drinking water by hazardous agents is becoming a serious global threat, so it is necessary to develop more efficient sensing technologies for applications in liquid media. The limited working lifetime of electrochemical biosensors, especially when measurements are made continuously in liquid media, remains an unsolved challenge. We studied the effect of PEDOT:PSS surface area on platinum microelectrodes with respect to electrode ability to conduct reversible ion-to-electron transduction in liquid media. Electropolymerization of 3,4-ethylenedioxythiophene:poly(styrene sulfonate) EDOT:PSS to poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) was conducted on microplatinum electrodes 5 and 10 mm long using a galvanostatic mode. Cyclic voltammetry was used to determine capacitive peak current; higher peak current indicates higher redox capacitance. Field-emisison scanning-electron microscopy was used to study the surface morphology of the PEDOT:PSS transucer layer after measurement in liquid media. The anodic capacitive peak currents did not differ significantly between the two electrodes at day one (~0.20 mA); however, peak current decreased by ~ 20% and ~ 80% at day six for 10- and-5 mm electrode lengths, respectively. The results imply that PEDOT:PSS surface area plays a role in transduction of PEDOT:PSS in aqueous media.

Microplastic potentiates triclosan toxicity to the marine copepod Acartia tonsa (Dana)

ABSTRACT Microplastics (MP) are contaminants of environmental concern partly due to plastics ability to sorb and transport hydrophobic organic contaminants (HOC). The importance of this “vector effect” is currently being debated in the scientific community. This debate largely ignores that the co-exposures of MP and HOC are mixtures of hazardous agents, which can be addressed from a mixture toxicity perspective. In this study, mixture effects of polyethylene microbeads (MP) and triclosan (TCS) (a commonly used antibacterial agent in cosmetics) were assessed on the marine copepod Acartia tonsa. Data indicated that MP potentiate the toxicity of TCS, illustrating the importance of understanding the mixture interaction between plastics and HOC when addressing the environmental importance of the vector effect.

تقييم الوعي بالوقاية من الإشعاع المؤين بين العاملين في مجال الإشعاع في مستشفيات أربيل

الإشعاعات المؤينة هي عوامل خطرة في مكان العمل وجميع أشكال الإشعاع المؤين تنتج نوعًا من الإصابات غير القابلة للشفاء. لذلك ، فإن تطبيق الحماية من التعرض للإشعاع المؤين يمكن أن يلعب دورًا مهمًا في صحة العمال. الهدف من هذه الدراسة هو تقييم تطبيق الحماية من الاشعاع بين العاملين في قسم الاشعة في مستشفيات اربيل. المنهجية: أجريت دراسة مقطعية مع ستة مستشفيات (عامة وخاصة) وتم اختيار عينات من 110 عامل عشوائياً من بين 135 عامل إشعاع. تم جمع البيانات من خلال استبيانات منظمة. تم ترميز البيانات التي تم مسحها وإدخالها في برنامج MS Excel. تم تصدير المزيد من البيانات إلى SPSS 18 لتحليلها. تم إجراء التحليل عن طريق توزيعات التردد والجداول المتقاطعة. النتائج: بينت النتائج ان هناك 47 (42.7٪) اناث و 63 (57.3٪) ذكور. الغالبية العظمى من العمال 51 (46.4٪) تتراوح أعمارهم بين 21-30 سنة وحاملي الدبلوم 68 (61.8٪). خضع 49 فقط (44.5٪) للفحص الأولي بينما لم يخضع 47 (42.7٪) للفحص الدوري قط. وفقًا للوائح ICRP للحماية من الإشعاع ، من الضروري للعاملين في مجال الإشعاع ارتداء أجهزة الكشف الشخصية أثناء العمل. لكن الغالبية 89 (80.9٪) لم يتم تزويدها بمثل هذه الأجهزة. وكشفت الدراسة أيضًا أن الغالبية العظمى من العاملين في مجال الإشعاع يعملون أكثر من 40 ساعة في الأسبوع. لم يتم إجراء معايرة جهاز الأشعة السينية والمسح الإشعاعي لمكان العمل بانتظام. 30 عينة فقط ليس لديهم وعي ومعرفة بالإشعاع المؤين بينما قيل أن 95 (86.4٪) ليس لديهم فيزيائي صحي. الخلاصة: من خلال دراسة وتحليل البيانات ، تبين أن الغالبية العظمى من العاملين في مجال الإشعاع في المستشفيات الستة التي زرناها لم يكن لديهم وعي كافٍ بأساس الحماية من الإشعاع ولم يمتثلوا للتوصيات الدولية للحماية من الإشعاع.

Airway Epithelial Barrier Dysfunction in Chronic Obstructive Pulmonary Disease: Role of Cigarette Smoke Exposure.

The epithelial lining of the airway forms the first barrier against environmental insults, such as inhaled cigarette smoke, which is the primary risk factor for the development of chronic obstructive pulmonary disease (COPD). The barrier is formed by airway epithelial junctions, which are interconnected structures that restrict permeability to inhaled pathogens and environmental stressors. Destruction of the epithelial barrier not only exposes subepithelial layers to hazardous agents in the inspired air, but also alters the normal function of epithelial cells, which may eventually contribute to the development of COPD. Of note, disruption of epithelial junctions may lead to modulation of signaling pathways involved in differentiation, repair, and proinflammatory responses. Epithelial barrier dysfunction may be particularly relevant in COPD, where repeated injury by cigarette smoke exposure, pathogens, inflammatory mediators, and impaired epithelial regeneration may compromise the barrier function. In the current review, we discuss recent advances in understanding the mechanisms of barrier dysfunction in COPD, as well as the molecular mechanisms that underlie the impaired repair response of the injured epithelium in COPD and its inability to redifferentiate into a functionally intact epithelium.

Aerobiological Stabilities of Different Species of Gram-Negative Bacteria, Including Well-Known Biothreat Simulants, in Single-Cell Particles and Cell Clusters of Different Compositions.

The ability to perform controlled experiments with bioaerosols is a fundamental enabler of many bioaerosol research disciplines. A practical alternative to using hazardous biothreat agents, e.g., for detection equipment development and testing, involves using appropriate model organisms (simulants). Several species of Gram-negative bacteria have been used or proposed as biothreat simulants. However, the appropriateness of different bacterial genera, species, and strains as simulants is still debated. Here, we report aerobiological stability characteristics of four species of Gram-negative bacteria (Pantoea agglomerans, Serratia marcescens, Escherichia coli, and Xanthomonas arboricola) in single-cell particles and cell clusters produced using four spray liquids (H2O, phosphate-buffered saline[PBS], spent culture medium[SCM], and a SCM-PBS mixture). E. coli showed higher stability in cell clusters from all spray liquids than the other species, but it showed similar or lower stability in single-cell particles. The overall stability was higher in cell clusters than in single-cell particles. The highest overall stability was observed for bioaerosols produced using SCM-containing spray liquids. A key finding was the observation that stability differences caused by particle size or compositional changes frequently followed species-specific patterns. The results highlight how even moderate changes to one experimental parameter, e.g., bacterial species, spray liquid, or particle size, can strongly affect the aerobiological stability of Gram-negative bacteria. Taken together, the results highlight the importance of careful and informed selection of Gram-negative bacterial biothreat simulants and also the accompanying particle size and composition. The outcome of this work contributes to improved selection of simulants, spray liquids, and particle size for use in bioaerosol research.IMPORTANCE The outcome of this work contributes to improved selection of simulants, spray liquids, and particle size for use in bioaerosol research. Taken together, the results highlight the importance of careful and informed selection of Gram-negative bacterial biothreat simulants and also the accompanying particle size and composition. The results highlight how even moderate changes to one experimental parameter, e.g., bacterial species, spray liquid, or particle size, can strongly affect the aerobiological stability of Gram-negative bacteria. A key finding was the observation that stability differences caused by particle size or compositional changes frequently followed species-specific patterns.

Remediation of 137Cs contaminated concrete using electrokinetic phenomena and ionic salt washes in nuclear energy contexts

This work describes the first known the use of electrokinetic treatments and ionic salt washes to remediate concrete contaminated with 137Cs. A series of experiments were performed on concrete samples, contaminated with K+ and 137Cs, using a bespoke migration cell and an applied electric field (60V potential gradient and current limit of 35mA). Additionally, two samples were treated with an ionic salt wash (≤400molm−3 of KCl) alongside the electrokinetic treatment. The results show that the combined treatment produces removal efficiencies three times higher (>60%) than the electrokinetic treatment alone and that the decontamination efficiency appears to be proportional to the initial degree of contamination. Furthermore, the decontamination efficiencies are equivalent to previous electrokinetic studies that utilised hazardous chemical enhancement agents demonstrating the potential of the technique for use on nuclear licensed site. The results highlight the relationship between the initial contamination concentration within the concrete and achievable removal efficiency of electrokinetic treatment and other treatments. This information would be useful when selecting the most appropriate decontamination techniques for particular contamination scenarios.