Chemistry PostGrad

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Information about Chemistry PostGrad

Published on January 22, 2008

Author: Carmela


Safety at NUS:  Safety at NUS Radiation Hazards:  Radiation Hazards What is radiation? :  What is radiation? Matter is composed of atoms. Some atoms are unstable. As these atoms change to become more stable, they give off invisible energy waves or particles called radiation. 2 types -Non-ionizing -Ionizing What is radiation? (cont’d):  What is radiation? (cont’d) Non-ionizing radiation: radiant energy is NOT capable of stripping electrons from atoms - E.g. infrared, visible light Ionizing radiation: radiant energy is capable of removing electrons from their atomic structures (approx. >10-12eV) - E.g. x-rays, gamma rays Ionizing Radiation:  Ionizing Radiation Two fundamental types -Particulate: radiation in the form of particles, e.g. alpha, beta, neutrons -Wave: radiation in the form of electromagnetic wave, e.g. Gamma rays, X-rays Types of Radiation:  Types of Radiation Alpha Identical to a helium nucleus (2 p and 2 n in one tightly bound particle) Beta Energetic electron ejected from the nucleus of an atom One neutron is converted to one proton and one electron Types of Radiation (cont’d):  Types of Radiation (cont’d) Gamma Electromagnetic radiation from nucleus X-ray Electromagnetic radiation from orbital electrons Neutrons Sources of radiation :  Sources of radiation Naturally-occurring radiation accounts for approx. 80% of our exposure. Most of our exposure is to indoor radon, followed by radiation from outer space and from the earth’s crust. Since the discovery of radiation, people have benefited from the use of radiation in medicine and industry. Man-made sources of radiation account for about 20% of our total exposure to radiation. Sealed vs Unsealed sources:  Sealed vs Unsealed sources Sealed source Radioactive materials sealed inside metal/plastic. Most sealed sources can be handled without concern that the radioactive material will be dispersed onto hands or clothing Unsealed source Unsealed sources are usually liquids that are applied directly and not encapsulated during use. The contents of these unsealed sources are readily accessible to the user. Most come in liquid form, with potential for spills, splashes, aerosolization, and vaporization. Stock vials may not provide adequate shielding. Diff. between radiation & radioactivity:  Diff. between radiation & radioactivity Radiation is the emission of energy from a source, either by particles or photons. There is a difference between Radiation and Radioactivity Radioactivity is radiation that is from a change in the nucleus of an atom, other forms of radiation are usually the emission of energy from a change in the electron orbits. Radioactivity:  Radioactivity The rate of radioactive decays is described by the nuclear disintegrations per unit time: Amount of radioactive in Becquerels (Bq) 1 Bq = 1 disintegration/second (SI unit) 1 Ci = 3.7X1010 disintegrations/second (Older unit) Half-Life (T1/2) :  Half-Life (T1/2) Time taken for the activity of a sample to halve as a result of radioactive decay A = A0/2n Ao = Original Activity A = Activity at time t N is the number of half lives expired in time, t Activity of a vial of Tc-99m was 80 GBq, T1/2 for Tc-99m is 6 hours After 6 hours, one half life, A = 40GBq… After 12 hours, two half life, A=20GBq After 24 hours, four half lifes, A=5GBq Measurements of Radiation:  Measurements of Radiation Common units or special units (US) -Roentgen (R) -RAD (Radiation Absorbed Dose) -REM (Roentgen Equivalent Man) -Curie (Ci) International units – SI -Gray (Gy) -Sievert (Sv) -Becquerel (Bq) Two areas where units are used:  Two areas where units are used Units of activity -Quantity amount of radiation emitted from a radiation source Units of exposure (dose) -Quantity amount of radiation absorbed or deposited in a material Activity :  Activity Quantity of a radioactive material present at a given time -It is the number of disintegrations or transformations of a given quantity of material in a given period of time Units: Ci = 3.7X1010 disintegration per second (dps) 1 Bq = 1 disintegration/sec 3.7X1010Bq=1 Ci 1 Ci=2.22X1012 disintegration/min (dpm) ~ amount of radioactivity in 1 gm of Ra 226 Half-Life:  Half-Life T½ = Measure of radioactive decay Half-life -Physical -Biological -Effective Examples, Carbon-11 (20min), Sulfur-35 (88 days), Calcium-45 (165 days), Tritium (3H) (12.46 yrs), Carbon-14 (5730 yrs), Uranium-238 (4.5X109 yrs) Examples of Half-life:  Examples of Half-life If …..was worth only 36 billion dollars, and if he were to lose ½ his money each year, how long before he is only a millionaire? (t½ = 1 yr) Dose :  Dose Units (US) -Roentgen (R), RAD; radiation absorbed dose, REM; radiation equivalent man -1 R=1 RAD=1 REM if radiation weighting factor=1 Units (SI) -1 Gy = 1 joule/kg = 100 rads -1 Si = 100 rem Exposure :  Exposure Photon flux related to amount of energy transferred to unit mass of air Dose unit -Roentgen (US) -No. of unit; C/kg=>Coulomb -Quantity of gamma or x-rays producing ions carrying a charge of 2.58X10-4C/kg air Absorbed dose:  Absorbed dose Charge per unit mass -Any type of radiation -Any type of material Dose units - rad=62.4X106 MeV/g - Gy=100 rads Dose calculations:  Dose calculations D=La/d2 where D=absorbed dose in rad/hr L=gamma ray constant (from table) a=activity in millicuries d=distance Calculate the absorbed dose in mrad per hr at 150 cm from a 250 millicurie Cesium-137 source - D=La/d2=3.3X250/1502=36.7 mrad/hr at 150 cm Equivalent dose:  Equivalent dose Absorbed dose multiplied by the radiation weighting factor (RWF) or quality factor (QF) RWF is the biological effectiveness of a radiation type Accounts for the type of radiation and its biological effects in human Units-rem Calculating rem:  Calculating rem Rem=rad X QF where QF = 1 for x-rays, gamma rays and beta rays = 3 for neutrons (fast) = 10 for neutrons (slow) = 20 for alphas A source of radium-226 produces 0.15 mrad per hr in a worker. Calculate rem dose in an 8-hr shift. Rem= rad X QF=0.15X20 (alpha)X8=24 rem/8-hr shift Summary :  Summary Gy and rad measure Absorbed Dose Si and rem Equivalent Dose Bq and Ci Radioactivity Ionising radiation measurement :  Ionising radiation measurement Monitoring instruments -A large variety available -None universally applicable -Selection of appropriate detector is important Monitoring methods:  Monitoring methods Film badges -Worn on the outside of clothes -Consists of small piece of photographic film Thermoluminescence detectors -Used in finger dosimeters -Amount of light given off is related to the absorbed amount of radiation Pocket dosimeter -Direct reading portable unit -Allows individual to determine radiation dose as they are working Ionising chambers:  Ionising chambers Measure gamma, x-, beta-, alpha radiation Very useful and popular Convenient and accurate Geiger Mueller Counter:  Geiger Mueller Counter Used for beta, gamma, x-ray radiation measurement Capable of detecting very small amount of radiation Uses an ionising chamber but filled with a special gas and greater voltage is supplied How Radiation Harm You?:  How Radiation Harm You? Ionizing properties of radiation Lead to molecular changes and form chemical species that are harmful to the chromosome material Harm can come from changes in construction and function of the cells. Radiation can cause: Early death of the cell or prevention or delay of cell division Permanent modification which is passed on to daughter cells Biological Effects:  Biological Effects chromosome Cell Radiation Chemical bond break Biological effects of different radiation:  Biological effects of different radiation Deterministic Effects:  Deterministic Effects Below a certain dose, the proportion of cell damage from the exposure is not sufficient to affect the function of the organ or body and no observable effects as a whole Severity increases with dose Eg. 1 Gy can cause nausea and vomiting 5 – 10 Sv is sufficient to cause Bone Marrow Damage Stochastic Effects:  Stochastic Effects Probability of an effect occurring increase with dose Effects include cancer induction and hereditary effects in future generations This means that even low dose can potentially have ill effects – it’s a statistical probability “Zero threshold” concept Working Safely with Radiation:  Working Safely with Radiation ALARA principle Time, distance and shielding Safe work practices ALARA :  ALARA Exposures are kept As Low Achievable As Reasonably Achievable / Allowable Formal ALARA program Keeping all doses, releases, contamination and other risks low Achieve 10% of applicable legal limits Methods of Achieving ALARA:  Methods of Achieving ALARA Time Distance Shielding Basic Radiation Protection:  Basic Radiation Protection Justification Benefit must outweigh risk Limitation Dose limits must not be exceeded Optimization ALARA, social and economic factors considered External radiation dosage:  External radiation dosage - Explanation The dose accumulated by a person working in a area: Dose = Dose rate X Time External radiation dosage:  External radiation dosage Calculation Dose limit is 400 uSv Dose rate is 20 uSv h-1 Dose = dose rate X time 400 = 20 X t t = 20 hours Time Example:  Time Example Annual dose limit for rad worker is 20mSv/year. Assume 50 weeks/year, how much is the hourly exposure? Ans: 0.01 mSv/hour How many hours can a worker spend in a week an area with a dose rate of 20 microSv/hour 20 mSv = 20 mSv/year * 1 year 20 mSv = 20 µ Sv/hour * time Time = 1000 hour Hours/week = 1000/50 = 20 hours Time Example:  Time Example If rad worker spends 35 hours per week in the area, what is the max allowable dose rate per week? 0.01 mSv/hr*40 hr/week = 0.4 mSv/week 0.4 mSv/week * 1week/35 hr = 0.114 mSv/hr =11.4 microSv/hr Time Example:  Time Example Dose limit for individual member of the public is 1mSv/year. What is the max dose rate in the area which could be continuously occupied by the members of the public? ~ 0.11 micro Sv/hour 1mSv/year * 1 year/365 days * 1 day/24 hour Distance:  Distance Inverse square law D1r12 = D2r22 D = Dose rate at distance, r R = Distance from the radiation source Dose rate at 2m from a gamma source is 500 micro Sv/hour. Distance that will give dose rate of 10 micro Sv/hour? ~ 14.1m Shielding:  Shielding Safe Work Practices (cont’d):  Safe Work Practices (cont’d) Rehearse operations without radioactive material Inform others in the area of the use of radioactive material Minimize the time spent near radioactive materials. Use remote handling tools like tweezers or forceps to handle stock vials. Safe Work Practices (cont’d):  Safe Work Practices (cont’d) Do not handle the stock vial for a extended period of time Use appropriate shielding Minimize the amount of material handled. Only use what you need, put the rest away Safe Work Practices (cont’d):  Safe Work Practices (cont’d) Make sure the material is properly contained. Drip trays lined with absorbent material Stabilize glassware to prevent it from tipping Dry powder use a glove bag or box Transport items in shielded secondary containers. Safe Work Practices (cont’d):  Safe Work Practices (cont’d) Do not contaminate writing materials Segregate items used with radioactive materials with those used with non-radioactive materials. Protective clothing shall be worn when handling contamination may be expected. Safe Work Practices (cont’d):  Safe Work Practices (cont’d) Personal with tears/breaks in skin should wear waterproof tape to seal such breaks or not manipulate radioactive material Personnel shall monitor themselves (and their work surfaces) for contamination after each use of radioactive material. Safe Work Practices (cont’d):  Safe Work Practices (cont’d) Eating, drinking, smoking and mouth pipetting is prohibited Items that are routinely contaminated (centrifuges, water baths, tongs, etc) should be clearly labeled. Hands should be monitored and washed before leaving the lab. Waste Handling Process:  Waste Handling Process Store in a safe location with proper shielding until the waste has decayed to a low level Must be < 1 microSv/hr or 0.1 mrem/hr Proper shielding: Beta emitters – Perspex enclosure Gamma emitters – Lead shielding Waste Handling Process (cont’d):  Waste Handling Process (cont’d) Place in secondary containers Proper labeling and designate the storage area with clear signages Radiation Waste Disposal in NUS:  Radiation Waste Disposal in NUS Permitted types: C14 (Licensing exemption limit (LEL) 100microCi) Tritium (1000microCi) I-125 (10microCi) P-32 (10microCi) S-35 (10microCi) Radiation Waste Disposal in NUS:  Radiation Waste Disposal in NUS If mixtures of radioisotopes: Sum of An/Mn is less than the LEL of the most active radionuclides An – Activity of nuclide n, Mn – LEL of nuclide n Radiation Waste Disposal in NUS :  Radiation Waste Disposal in NUS Place waste inside Red Bag (can be obtained from Ms. Lisa Lui @ oshsec) Tape opening with Red Tapes (From Lisa) Fill up Yellow label and paste onto the Bag Fill up Form RAD01-01 Low level biological-incineration Chemical + Biological Radiation Waste Disposal in NUS :  Radiation Waste Disposal in NUS Liquid Radiation Waste Absorbed into vermiculite at point of use and dispose off as solid waste All radioactive bags must be kept in secure and safe area OSHE will organize central collection every 4 to 6 months depending on level at the departments Cost of disposal is borne by OSHE but this may be charged to individual departments in the near future Radiation Protection Act (Cap 262):  Radiation Protection Act (Cap 262) Regulated by Centre for Radiation Protection (CRP) under Health Sciences Authority Subsidiary legislations - Radiation Protection (Non-Ionising) Regulations - Radiation Protection (Ionising) Regulations - Radiation Protection (Transport of Radioactive Materials) Regulations Radioactive Protection Act:  Radioactive Protection Act CRP has Director appointed by the minister Radiation Advisory Committee- to advise Minister Act focuses on Use, Manufacture, Sale of and Dealing with Radioactive Materials and Irradiating Apparatus You require to have a license Duties of licensees Disposal of radioactive waste Powers of Director & Authorised Officers Radiation Protection (Ionising) Regulations :  Radiation Protection (Ionising) Regulations Exemptions-details Licenses Age limit Condition for engaging in radiation work Arrangements for protection of workers Medical and radiological supervision Labeling of irriadiating apparatus and radioactive materials Storage What Is NIR?:  What Is NIR? Energy waves of oscillating electric and magnetic fields traveling at the speed of light Energy levels not great enough to cause the ionization of atoms Includes spectrum of UV, IR, microwave (MW), radio frequency (RF), extremely low frequency (ELF) and visible light Why Is It Dangerous?:  Why Is It Dangerous? Wide range of occupational settings Can pose a considerable health risk to exposed workers if not properly uncontrolled Examples of Non-Ionizing Radiation:  Examples of Non-Ionizing Radiation Extremely Low Frequency (ELF) Radiofrequency (RF) / Microwave (MW) Laser Hazards Infrared Radiation (IR) Visible Light Radiation Ultraviolet Radiation (UV) ELF:  ELF Refers to an electromagnetic field having a frequency much lower than the frequencies of signals typically used in communications (From 1 Hz to 300 Hz). Includes alternating current (AC) fields Most common ELF field is 60 Hz produced by power lines, electrical wiring, electrical equipment Two forms: Static and ELF fields Health Hazards:  Health Hazards Potentially significant due to widespread use of electrical power at 50 – 60 Hz Much concern over consequence of long-term exposure to these fields One area is in computing applications where cathode-ray tube (CRT) displays are used Health Hazards:  Health Hazards ELF fields known to interact with tissues by inducing electric fields and currents Research has suggested possible carcinogenic, reproductive  and neurological effects Other health effects could include cardiovascular, brain and behavior, hormonal and immune system changes Safety and Precautions:  Safety and Precautions Inform about possible hazards Increase the worker's distance from the source (radiation fields often drop off dramatically within about 1m of the source) Stand back from electrical equipment, and work station CRT should be at least 0.5m away from eyes Safety and Precautions:  Safety and Precautions Use low-radiation designs wherever possible (for the layout of office power supplies, for example) Reduce exposure times. No action should be taken to reduce exposure if it increases the risk of a known safety or health hazard such as electrocution RF and MW Radiation:  RF and MW Radiation Electromagnetic radiation RF - any frequency within the electromagnetic spectrum associated with radio wave propagation Microwaves are a specific category of radio waves that can be defined as radiofrequency energy where frequencies range from several hundred MHz to several GHz. From 3 kHz - 300 GHz (MW: range from several hundred MHz to several GHz) Sources of RF and MW:  Sources of RF and MW Traffic radar devices Heaters and sealers Wireless communications/cellular phones Radio transmission Radio antennas / masts Magnetic Resonance Imaging (MRI) Health Hazards:  Health Hazards RF and MW will damage tissue through heating at high intensities MW radiation is absorbed near the skin RF radiation may be absorbed throughout the body Parts of body most prone are the eyes and testes due to the relative lack of blood flow to dissipate the heat Health Hazards:  Health Hazards Levels encountered by the general public are far below levels deemed significant Workers working near transmission towers / antennas are exposed to large amounts of radiation Safety and Precautions:  Safety and Precautions Engineering Controls Sources of radiation should be properly shielded Devices which can produce acute thermal injuries (e.g., industrial MW ovens) should have interlocked doors Devices which produce high levels of stray RF radiation (e.g., induction heaters and dielectric heaters) should be operated remotely whenever possible Safety and Precautions:  Safety and Precautions Administrative Controls Exposure should not exceed the recommended exposure limits Areas where worker exposure is suspected to exceed the recommended limits should be surveyed to determine the exposure levels Needless exposure should be avoided Exposure times should be kept as short as reasonably possible Safety and Precautions:  Safety and Precautions Administrative Controls Potentially hazardous devices should be appropriately labeled Areas of excessive exposure around them clearly demarcated Notices with warnings and the necessary precautions should be posted Electrically-activated explosive devices should not be placed near sources of RF/MW radiation Safety and Precautions:  Safety and Precautions Administrative Controls RF/MW devices should not be used in flammable or explosive atmospheres Equipment sensitive to RF/MW should not be installed near sources of radiation Maintenance of devices used to produce RF/MW radiation should be done by qualified personnel. The equipment should be turned off whenever possible Safety and Precautions:  Safety and Precautions Controlling RF Shocks and Burns Metallic structures producing contact shocks should be electrically grounded and/or insulated Insulating platforms or shoes can be used to reduce energy absorption and currents to ground Workers should wear insulating gloves Safety and Precautions:  Safety and Precautions First Aid Remove worker from exposure area to a cool environment and provide cool drinking water Apply cold water or ice to burned areas Seek immediate medical attention Severe MW or RF overexposure may damage internal tissues without apparent skin injury, so a follow-up physical examination is advisable Lasers :  Lasers Stands for Light Amplification by Stimulated Emission of Radiation Produces an intense, highly directional beam of light is emitted Monochromatic – one specific wavelength Coherent - each photon moves in step with the others Types of Lasers :  Types of Lasers Commonly designated by the type of lasing material employed: Solid-state lasers - lasing material distributed in a solid matrix Gas lasers – use gases like helium and helium-neon Excimer lasers - (the name is derived from the terms excited and dimers) uses reactive gases, such as chlorine and fluorine, mixed with inert gases such as argon, krypton or xenon Types of Lasers :  Types of Lasers Commonly designated by the type of lasing material employed: Dye lasers - complex organic dyes, such as rhodamine 6G, in liquid solution or suspension as lasing media Semiconductor lasers - sometimes called diode lasers, are not solid-state lasers. Generally very small and use low power. Laser Classes:  Laser Classes Class I Laser systems that do not pose a hazard under normal conditions Examples include enclosed / interlocked lasers or lasers with low power output No warning label is required Laser Classes:  Laser Classes Class II Low power visible lasers or laser systems Not usually hazardous as natural human body reflexes reduces this Hazardous if viewed for prolonged periods of time (like many conventional light sources) If manufactured after 1976, will usually have a sign “Caution – Laser Radiation – Do not stare into beam” Sign must be clearly visible Laser Classes:  Laser Classes Class IIIA Lasers of laser systems that do not usually pose a hazard if viewed momentarily with the unaided eye Hazardous if viewed using collective optics Laser Classes:  Laser Classes Class IIIA Clearly visible sign with words “Caution – Laser Radiation – Do not stare into beam or view directly with optical instruments” Eye protection should be worn Laser Classes:  Laser Classes Class IIIB Lasers or laser systems that are hazardous if viewed directly, including viewing of reflections from smooth surfaces (diffused reflections are not hazardous) A clearly visible sign “Danger – Laser Radiation Avoid Direct Exposure to Beam” must be in place Eye protection must be worn Slide89:  Laser Classes Class IIIB A clearly visible sign “Danger – Laser Radiation Avoid Direct Exposure to Beam” must be in place Eye protection must be worn Laser Classes:  Laser Classes Class IV Lasers or laser systems that produce a hazard not only from direct viewing and reflections, but also from diffused reflections May produce fire and skin hazards A clearly visible which reads “Danger – Laser Radiation –Avoid Eye or Skin Exposure to Direct or Scattered Radiation” Laser Classes:  Laser Classes Class IV Capable of causing serious eye injury Should be enclosed if possible and operated remotely Health Hazards :  Health Hazards Common cause of laser-induced tissue damage is thermal in nature Tissue proteins are denatured / destroyed due to the temperature rise following absorption of laser energy Exposure can result in damage to the eye and skin Human eye is most vulnerable to injury than human skin Associated Hazards:  Associated Hazards Hazards that are not associated with the beam itself Electrical: Lethal electrical hazards from high power lasers. Chemical: Eximer, dye and chemical lasers, and welding or cutting fumes Non-Beam Optical: UV, Infra Red, or Visible Light Safety and Precautions:  Safety and Precautions Special Safety and Control Measures for Medical Applications Special training requirements Special equipment testing requirements Special medical surveillance requirements Laser treatment controlled areas Patient eye protections Evaluation of fiber delivery systems Ventilation systems Safety and Precautions:  Safety and Precautions Other Special Control Measures Laser demonstrations involving the general public or exposure of the general public to any laser beam hazards. Laser installation procedures Federal, state, or local requirements Personal protective equipment Warning signs, labels, and signal words in accordance with local standards. Electrical installations in compliance with local standards. Radiation Protection (Non-Ionising) Regulations :  Radiation Protection (Non-Ionising) Regulations Controlled apparatus (a) Ultraviolet sunlamps (b) Microwave ovens (c) Medical and industrial ultrasound apparatus (d) Magnetic resonance imaging (MRI) apparatus (e) Entertainment lasers (f) High power lasers Radiation Protection (Non-Ionising) Regulations (cont’d):  Radiation Protection (Non-Ionising) Regulations (cont’d) Licenses (4 types) Age requirement 18 years and + Requirements for apparatus as mentioned Requirements for labeling Examples of label in laser apparatus (warning signs) (transparencies) Biological Hazards:  Biological Hazards What are biohazards?:  What are biohazards? Any material of biological origin capable of causing harm to human and its environment Examples: Viruses Bacteria Fungi Human source material Animal source material, etc. Viruses Biosafety Protection Principles:  Biosafety Protection Principles “Containment” Safe methods for managing infectious materials in the laboratory to reduce or eliminate exposure of laboratory workers, other persons, and the outside environment. Include three elements: 1. Laboratory practice and technique 2. Safety equipment (Primary containment) 3. Facility design (laboratory design) (Secondary containment) Safety Equipment:  Safety Equipment Primary Barriers Includes: BSC, Centrifuge cups, Personal protective equipment, enclosed containers, etc. Will only be effective if they are used properly Facility Design and Construction:  Facility Design and Construction Labs must be designed and constructed based on the usage requirement Many design and construction factors : ventilation, plumbing, access, work flow, construction material, treatment system, etc. Design and construction are not the most important factor but still an essential factor in biosafety Risk Assessment for Work with Biohazardous Agents or Materials :  Risk Assessment for Work with Biohazardous Agents or Materials What is known about the agent or material? Is it associated with infections, toxicity, or allergies? What role does physical environment and work activity play in assessing risk? Are preventive measures available? Do barriers, personal protective equipment (PPE), pre- or post-exposure prophylaxis or immunizations offer protection? Biological Agent Characteristics:  Biological Agent Characteristics Pathogenicity Virulence - degree of pathogenicity Host range Communicability Method of Transmission:  Method of Transmission Direct Contact: Direct transmission to receptive portal of entry Indirect Contact: Vehicle-borne such as inanimate materials or objects (fomites) Vector-borne (arthropods) Airborne: Dissemination of microbial aerosols to a suitable portal of entry Routes of Transmission:  Routes of Transmission Ingestion Inhalation Absorption Penetration of skin or membranes Other Risk Assessment Criteria:  Other Risk Assessment Criteria Concentration of material to be used Quantity to be used Potential for aerosol generation Infectious dose Stability in the environment Ability to avoid host defence Type of work Other Risk Assessment Criteria:  Other Risk Assessment Criteria Toxicity (microbial toxins) Enzymes (microbes produce coagulase, hemolysins, hyaluronidase) Allergenicity (agent or by-products; animal dander, urine) Genetic modifications Biological/chemical/radiological mixtures and interactions Risk Group Classification (WHO):  Risk Group Classification (WHO) Pathogenicity Infectious dose Mode of transmission Host range Availability of effective preventive measures and treatments Risk Group 1:  Risk Group 1 Severity of Disease Unlikely to cause human or animal disease Host Range Human (healthy adult) and animals Individual Risk Low Community Risk Low Risk Group 2:  Risk Group 2 Severity of Disease Can cause disease, unlikely to be serious Effective treatment and preventive measures are available Host Range Human (healthy adult) and animals Individual Risk Moderate (potential hazard) Community Risk Low Risk Group 3:  Risk Group 3 Severity of Disease Can cause serious disease Does not ordinarily spread from one person to another Other criteria – effective treatment and preventive measures are usually available Exposure route – inhalation (often) Risk Group 3:  Risk Group 3 Host Range Human (healthy adult) and animals Individual Risk High Community Risk Low Risk Group 4:  Risk Group 4 Severity of Disease Likely to cause serious or lethal disease Can be readily transmitted from one individual to another Effective treatment and preventive measures are not usually available Transmission – direct, indirect, inhalation Risk Group 4:  Risk Group 4 Host Range Human (healthy adult) and animals Individual Risk High Community Risk High Biosafety Levels:  Biosafety Levels VERY Important : Biosafety Levels and Risk Groups are not always the same!!! Biosafety level = Containment level Specifies: Facility Safety equipment Microbiological and special practices Biosafety Levels (BSLs) Classification:  Biosafety Levels (BSLs) Classification Biosafety level(s) refer to those conditions under which the biological agents can be safely handled ordinarily. Four laboratory biosafety levels (BSLs) are defined by CDC/NIH biosafety guidelines. Principal Investigator (PI) is specifically and primarily responsible for assessing the risks and appropriately applying the recommended biosafety levels. Biosafety Level 1:  Biosafety Level 1 Agent Well-characterized agents not known to cause disease in healthy adults Escherichia coli K12, Bacillus subtilis Basic lab facility; work on the open bench Use standard microbiological practices No containment equipment is required Biosafety Level 2:  Biosafety Level 2 Agent Agents of moderate potential hazard to personnel and the environment Staphylococcus aureus, Hepatitis B virus, Salmonella species Basic lab facility, plus autoclave is available Use standard microbiological practices plus limit the access Containment equipment is used when aerosols are generated or concentrated preps and large volumes are handled Biosafety Level 3:  Biosafety Level 3 Agent Indigenous or exotic agents with potential for aerosol transmission that may cause serious or potentially lethal disease Mycobacterium tuberculosis, Coxiella burnetii, St. Louis encephalitis virus Containment facility Use standard microbiological practices plus controlled access Containment equipment, such as Class I or II biological safety cabinets (BSCs) are required for manipulations of viable material and additional PPE is required Biosafety Level 4:  Biosafety Level 4 Agent Dangerous and exotic agents that pose high risk of aerosol transmitted LAI and life threatening disease, or related agents with unknown risk of transmission Marburg, Congo-Crimean hemorrhagic fever Biosafety Level 4:  Biosafety Level 4 Maximum containment facility Standard microbiological practices plus clothing change, showers, and decontamination of all materials on exit from the lab Containment equipment, such as Class III BSCs or Class I or II BSCs in combination with one-piece positive pressure suits ventilated by a life-support system protected in conjunction by HEPA filtration Disinfection Procedures:  Disinfection Procedures Why disinfect? to get rid of unwanted pathogenic microorganisms To eliminate - or at least reduce - exposure risk medical waste treatment spill cleanup minimization of nosocomial infections routine surface decontamination To eliminate contamination risk preparation of microbiological media & supplies preparation of pharmaceutical production supplies and equipment preparation of food (surface sanitization) preparation of work area for cleanliness-critical tasks Some key disinfection terms…:  Some key disinfection terms… sterilization - act or process, physical or chemical, that destroys or eliminates all forms of life, especially microorganisms disinfectant - an agent, usually chemical, that inactivates viruses or kills vegetative microbes but not necessarily resistant forms such as spores antiseptic - a substance that prevents or arrests the growth or action of microbes, either by inhibiting their activity or by destroying them (living tissue use) decontamination - disinfection or sterilization of contaminated articles to make them suitable for use sanitizer - an agent that reduces the numbers of vegetative bacteria only Resistance to disinfectants:  Resistance to disinfectants Classes of Disinfectant:  Classes of Disinfectant Chlorine Iodine Alcohol Phenolics Quaternary Ammonium Compounds Glutaraldehyde Formaldehyde Hydrogen Peroxide Chlorhexidine Transport and Storage:  Transport and Storage Transport pointers: Secondary container Planning ahead Spill control Storage Labeling Proper record “Freezer management” Biological Waste Handling:  Biological Waste Handling Must have in place biological waste handling procedures in the lab Mixed waste hierarchy: Waste Handling Pointers:  Waste Handling Pointers Use proper sharps bins Do not overfill – 80% mark Use yellow bag with biohazard symbol Double bagged and seal securely Use secondary containers THE END :  THE END

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