Lecture 1 Flashcards
Occupational hygiene
Review controls and effectiveness of hazards to reduce risk
* Perform Measurement and Monitor hazards using systematic
approaches
Area Monitor:
* Airborne contaminants
* Biological materials
* Comfort levels
* Noise
* Radiation
Personal monitor and dosimetry:
* Chemical exposure
* Noise dose
* Ionizing radiation dose
Biological Monitor:
* Chemical and biological exposures
3 classes, to reduce exposure to hazards
Engineering controls: equipment, items, actions to reduce
harmful exposure (most effective)
* examples: ventilation controls, lab design
Administrative controls: actions by administration to reduce
employee exposure
* examples: orientation, training, immunizations,
* Personal protective equipment controls: use of PPE, last line of
defense
* examples: gloves, gown, lab coats,
Whose responsibility is it to keep workers safe ? levels of government
Provincial: Occupational H&S, worker’s
comp (WSIB), WHMIS, TDG
* Federal: Labour Code, WHMIS, TDG
(rail, air, water), Criminal code, Human
Pathogens and Toxins Act, Nuclear
Safety and Control Act
Municipal: fire, building, sanitation and
waste disposal codes
Whose responsibility is it -employer
Provide
o resources to work safely
* Orient and train
o all employees
* Identify
o hazards
* Conduct
o inspections and incident
investigations
* Participate
o in development and
implementation of programs
Whose responsibility is it -employee
- Complete
- Orientation and training
- Implement
- Hazard controls
- Follow
- the rules and safe work
practices - Report
- Uncontrolled hazards and
incidents - Participate
- in the development and
implementation of programs
Safe practice- the
basics
- Before leaving the lab
- Clean, disinfect or decontaminate
- Dispose all hazardous waste
- Return materials and equipment
- Turn everything off
- Remove gloves and lab coat
- WASH HANDS!
- close & lock lab door
Spill clean up
Chemical Spill Kits
* In place in each lab
* Remove all people from the area
* Let faculty know
* If small benchtop spill, we can contain it with spill kit,
let spill team know, they will come to dispose
Allow aerosol to settle
* Wear proper PPE
* Cover spill with paper towel
* Flood with 10% hypochlorite
* Let stand for 30 minutes
* Wipe area with water and allow to air
dry
* Dispose of paper towels in biohazard
waste container
- Hazard:
- Source of potential damage, harm on something or someone
- Risk:
Chance or probability that a person will be harmed or experience an adverse health effect if
exposed to a hazard (i.e low or high risk)
Incident:
- Accident:
a minor event that could have caused harm (under different circumstances)…..”near miss”
a major unplanned event that causes harm to people or damage to property
Hazards-Biological
routes of entry and examples
- Absorption – via body contact can transfer directly across skin
- Injection – contact with needles and sharps
- Ingestion – via direct or indirect consumption
- Inhalation- via the respiratory system (most common)
- Exposure to aerosols may be the greatest biohazard facing laboratory workers
- suspension of particles (bacteria, viruses, parasites, fungi) from manipulations in the
lab, may gain access to respiratory system
- Universal Precautions (UP)
treat all blood specimens, and certain other bodily
fluids, as if contaminated with blood-borne
pathogens such as hepatitis and HIV
* do not apply to feces, nasal secretions, saliva,
sputum, sweat, tears, vomit and urine unless they
contain visible blood
Body Substance Precautions (BSP)
treat all body fluids and substances including
secretions and excretions (not just those associated
with Hep B and HIV) as potentially infectious
Standard Precautions (US, Canada)
applies to blood, all body fluids, secretions (except
sweat), non intact skin, mucous membranes
* Includes hand washing and use of PPE (gloves,
masks, etc.), barrier techniques for entering a
patient’s room, cleaning and disinfecting, training,
etc.
* combines requirements of UP and BSP
Routine Practices and types of transmission
how to decontaminate
Standards and strategies to protect workers from
exposure to infectious disease
* 3 types of transmission-based precautions for patients
implemented: contact, droplet and airborne
* Routine practices include: a risk assessment, hand
hygiene, control of the environment or location,
administrative controls, and PP
Decontamination:
* Sterilization and disinfection
* chemical disinfectants
* autoclave
* gas sterilizers (ETOH)
* incineration
* Infection Control
* Routine practices to protect both you and the
patient
Three program elements in WHMIS
*Labels - supplier and workplace labels
* SDS (Safety Data Sheets) - 15 CATEGORIES
* Training
* Incorporates GHS (Globally Harmonized System) as of 2015
Globally harmonized System (GHS)
Two major elements:
◼ Classification of chemical products
◼ Hazard communication tools:
◼ Format for Safety Data Sheets (SDS)
◼ Content for label and SDS with
hazard/precautionary statements,
symbols and signal word
WHMIS-Labels
- Product Identifier
- Initial supplier identifier (name, address, phone)
- Pictograms
- Signal words
- Hazard statement
- Precautionary statement
- Supplemental label information
Categories of Hazards
Biological * eg., pathogenic microorganisms,
biological tissues
* Chemical * eg., flammables, corrosives, toxics
* Physical * eg., radiation, noise
* Equipment * eg., machinery with moving parts, high
voltage apparatus
* Ergonomic - repetitive motion injuries, carpal tunnel (exercise, take breaks, rotate tasks)
* Psychosocial/Psychological * eg., emotional stress, Workplace conflict, violence, and harassment , job changes/security, noise,
CLASSES OF FIRE
A: paper, wood, cloth, rubbish
* B: gasoline, oil, paints, grease, other
flammable liquids
* C: overloaded or short-circuited live
electrical equipment (e.g. mixers,
incinerators, large equipment
* D: flammable metals (e.g. sodium,
potassium)
* K: flammables containing a fat (e.g.
cooking oils)
Dry chemical (use on A,B or C)
anhydrous - solutes
No water present in their structures
hydrates- solutes
Proportion of water in their structures
the water in a hydrate is called water of crystallization or water of hydration attached with loose chemical bonding
when heated hydrates lose their water and become anhydrous
Hygroscopic - solutes
Chemicals that absorb water with air exposure
Used as dessicants
* Examples: anhydrous calcium chloride, anhydrous magnesium
perchlorate, silica gel
if they absorb too much water is it deliquescent
S O L V E N T S
Substances in which solutes are dissolved
present in the largest concentration
* Examples: solid, liquid or gas
- Most common solvent is water referred to as aqueous solutions when used to prepare a solution
- Water= polar solvent
- polar covalent bonding of oxygen and hydrogen atoms it will dissolve all other polar and ionic compounds
- Organic solvents= nonpolar
- Examples: chloroform, xylol, and benzene
S T A N D A R D S O L U T I O N S
Requires a high degree of accuracy
* Standard= solution of exact known concentration
* Used as a reference to determine the
concentration of solutions of unknown
concentrations
* Equipment: analytical balances and volumetric glassware
volumetric (quantitative) transfer preparation
Primary Standards-dissolving an exact amount of pure dry chemical in a solvent and diluting to an exact, known volume so concentration is determined by the weight of solute in an exact volume of solution.
- be at least 0.9995 (w/w) [99.95% (w/w)] pure
* have a stable and definite composition
* be non-hygroscopic and remain unchanged in composition when dried in hot air oven at 105-110C (before use) and put in a dessicator
* preferably have a high molecular weight
* react stoichiometrically* in a single, rapid, complete reaction
potassium acid phthalate
sodium chloride
TRIS
Secondary Standards- all criteria from primary cannot be met .The concentration of a secondary standard is determined by analysis against a primary standard by
* titrametric analysis
* spectrophotometry
Sodium hydroxide (NaOH)
Concentrated Acid/Base or Viscous Fluid
Biological Standards- bili, chol, hormones
primary and secondary are different in how their concentrations are determined
Appropriately label the container with
- Reagent name and concentration
- Date of preparation
- Initial of person who prepared the solution
- Expiry date (if applicable)
- WHMIS label
be sure to check the shelf life
reagent water
Water treated to remove impurities
Special reagent water used for clinical lab applications meeting clinical laboratory reagent water (CLRW) specifications. Prepared by distillation, deionization, reverse osmosis, UV light treatment
Testing water purity:
Includes specific guidelines and specifications from CLSI
* CLRW: resistivity (≥10 Mohm
Type I-water (CLRW)
highest purity, used for maximum accuracy and precision
use immediately - no storage instructions
Type II (CLRW)
- less pure than Type I, used for general laboratory procedures
Distilled water:
* water collected from the process of vapourizing water to steam and condensed back to liquid
* Free from all non-volatile materials, some volatile organic matter, dissolved gases and trace amounts of ions, ex: Na+ , K+ , CO3 * pH 6.5-7.0
Deionized water:
* Water collected from an ion exchange column tightly packed with chemically attached resin beads that act like a cation and anion exchanger.
* Free of ionic impurities
* pH 7.0
Type III
- least pure of the three, used for qualitative procedures
Two main types of WHMIS labels
supplier labels
* workplace labels
- A workplace label is required when:
- a hazardous product is prepared
- a hazardous product is decanted (e.g., transferred or poured) into another
container, or - a supplier label becomes lost or illegible (unreadable)
W H E N I S A W H M I S W O R K P L A C E L A B E L N O T
R E Q U I R E D ?
- Two situations when a workplace label is not necessary:
- When a hazardous product is:
- poured into a container which is going to be used immediately, or
- under the control of the person who decanted it
Note: If the product is not used right away or if more than one person will use the product, a full workplace label is required.
SIGNAL WORD
- Degree or level of hazard of the product
- Two signal words:
- Danger
- Use for high-risk hazards
- Warning
- Used for less severe hazards
efflorescent
when hydrates upon exposure to air give up their water of crystallization
desiccant
Chemicals which are so hygroscopic that they can absorb water from other chemicals
anhydrous calcium chloride
* anhydrous magnesium perchlorate
* calcium sulphate (drierite)
* silica gel
The standards for biological constituents are set by
- Laboratory Centre for Disease Control (Ottawa)
- National Bureau of Standards (NBS)
- World Health Organization (WHO)
- National Institute of Health (NIH).
SATURATED SOLUTIONS
has undissolved solute existing in a state of dynamic equilibrium with dissolved solute
contains the maximum amount of solute that can be dissolved at a given temperature - 20 (room temp)
when making a standard solution determine solubility at room temp, find out how much you need for the solution , WEIGH OUT EXCESS , HEAT solute and solvent until solute is dissolved , remove from heat and cool all extra solute will crystallize at room temp if not then supersaturated just add some crystals to start the process
BUFFER SOLUTIONS
A buffer is a solution which resists changes in pH.
1. a weak acid or a weak base
2. the salt of that weak acid or weak base.
when making a buffer add the acid/base with salt and ALMOST to full volume check the pH make adjustments if needed and then dilute to full volume
MAINTAINING PURITY
Always place the proper lid back on the reagent bottle immediately after use.
Never pipette reagent directly from a stock bottle
Never pour unused reagent back into a stock bottle
Never use your fingers for handling
Never mix tubes
MIX ACID TO WATER
Reagent or Analytical Reagent (AR) Grade
purest grade of chemicals used for routine clinical analysis
qualitative and quantitative analysis in the laboratory
American Chemical Society (ACS) - must meet their specs ACS on label
Chemically Pure Grade (CP)
meet no particular purity specifications
impurity limits not listed some make their own
“highest purity”
not for research but ok for routine analysis
Purified, Practical or Pure Grade
have to be further purified before use
not for analytical procedures
Technical or Commercial Grade
least pure
manufacturing
in the lab ONLY for acid washing glassware, desiccants, neutralize acid spills
Pharmaceutical Grade
safe for injection or ingestion into the human
body. NF, BP, CP, USP
not be used in analytical procedures
three common methods of determining the purity of a chemical.
Determination of Melting Point, Freezing Point, or Boiling Point
Spectrophotometry - Spectral Absorbance Curves- wavelength the chemical absorbs light . chemical after this are spectroanalyzed.
Molar Absorptivity -The absorbance of a one molar solution through a one cm light path
Chromatography- separate mixtures of various components. if something is pure only one thing will show on the graph
STORAGE OF CHEMICALS
Store concentrated acids and bases in separate cupboards, well vented and low to the floor.
Flammable liquids in safety cans for expansion
Poisons such as barbiturates and cyanides should be kept in a locked cupboard
Ethers should be stored in the fume hood in safety cans- explosive
Picric acid is explosive when dry and should always be stored under a layer of water
Radioactive isotopes in lead containers
DISTILLATION
vaporizing water to steam, and condensing the steam on a cold surface back to water which is collected
removes ions , non volatiles,
water stored in polyethylene or pyrex containers to prevent contamination , soda glass will have trace metals
DEIONIZATION demineralization)
removal of ionic impurities but non ions are still in the water
passed through an ion exchange column which is tightly packed with resin (polymer) beads
cations exchange for H+
anions exchange for OH-
if it has both cationic and anionic resin exchangers is called a mixed-bed ion exchange column.
water stored in polyethylene or pyrex containers to prevent contamination , soda glass will have trace metals
OTHER METHODS OF PURIFICATION
Ultraviolet Light -bactericidal
Reverse Osmosis-water is forced at high pressure through a semi-permeable membrane. Cant produce CLRW on its own but good to have
Carbon Adsorption- passing water through a bed of activated carbon,
Filtration- water is passed through a filter which mainly removes solid impurities
TESTING WATER PURITY
should test for resistivity,
microbiological content, organic impurities, and pH.
SPECIFIC RESISTANCE/SPECIFIC CONDUCTIVITY
-measure of the resistance of water to the passage of a current between two electrodes. Ionized material = conductivity increase = low specific resistance. No material high resistance. So the higher the resistance the purer the water
ORGANIC SUBSTANCES
looking for presence of organic material by detecting products of oxidation by UV light, heat, high temp
- can also use permanganate colour test to detect presence of organic substances, The more color that is lost the more substances present.
