REHS Study Flashcards
Most important phase in bacterial growth
Lag Phase
Exponential growth of bacteria
Log Phase
Environmental conditions and food may become restrictive, causing leveling of bacterial growth
Stationary Phase
Bacteria start accumulating waste products and toxins that kill each other
Death phases
Bacteria Growth Factors
Food, Acidity, Time, Temperature, Oxygen, Moisture
Bacteria require nutrients such as proteins and carbohydrates to reproduce
Food
Most microorganisms grow best at this pH
4.6pH to 7.0pH
This pH is considered out of potentially hazardous zone
<4.6 pH
With the right conditions bacteria reproduce…
every 15 - 30 minutes
What is the temperature danger zone
41F - 135F
Bacteria grow in aerobic and anaerobic conditions
Oxygen
Bacteria require water to survive
Moisture
Oxidation reduction potential provides…
ideal environment for anaerobes
Sous vide means…
Excluding air from the product
Key role in controlling lag phase of bacterial growth
Temperature and Time
Maximum hot food cooling time limits are as follows:
From 135F to 70F within first 2 hours. From 70F to 41F or below within 4 hours.
Hot Food Preservation
Do not put cold food in steam table. Steam table is used to keep hot food hot (135F- 165F), not to cook foods or warm foods. Fridge foods should be reheated to at least 165F (w/in 2 hours) prior to putting in steam table.
What is the purpose of canning?
To destroy organisms and not provide environment for which they can grow. Damaged cans introduce air, activation aerobic bacterial activity
Sodium nitrate
Malicious food additive, used to meat prevents growth of botulism and retains quality of food
Methemoglobinanemia
Infant ingestion of sodium nitrates causes Blue Baby Syndrome
Monosodium Glutamate (MSG)
Food additive produced naturally by use of bacterial decomposition. Known as flavor enhancer and meat tenderizer
Generally Regarded as Safe (GRAS)
FDA requires testing to certify if element is safe. Ex: ketchup, pepper, salad oil, vinegar
Ethylene Diamine Tetra Acetate (EDTA)
Common additive to prevent botulism growth. Known to work better than nitrates, but unlike nitrates, does not stop oxidation of meat and color changes
Sulfurs (Sulfites)
Stops enzyme reaction in fruit/veggies, preserves food, prevents discoloration. Approved in manufacturing, must be labeled for use. Illegal to add in restaurants
Malachite Green
Can be used to detect addition of sulfites in food
Phosphoric Acid
Common in soft drink sodas to produce acidic reaction to enhance carbonation
Three categories for hamburger fat (%)
Regular Grade (no more than 30% fat)
Lean Grade (no more than 22% fat)
Extra Lean Grade (no more than 15% fat)
3 categories should not exceed 6-8% difference
Vending Machines
If vending machine holding temperature falls below minimum state required holding temp, then there is an automatic mechanism or switching device that locks the unit from further use until properly serviced
Food Illness Outbreak- CDC definition
- Two or more persons have the same disease, have similar clinical features or have the same pathogen
- A single case of suspect botulism
- A single case of mushroom poisoning
- A single case of ciguatera or paralytic shellfish poisoning or rare disease (Vibrio vulnificus)
Confirmed Case
Laboratory test conducted on the suspect bacteria or virus
Presumptive Case
Laboratory test showed negative on the suspect bacteria or virus
Suspect Case
No laboratory samples submitted
Secondary Case
Infected person was in contact with a primary case
Cal Code Definition AGI
Cal Code 113733- Acute gastrointestinal illness
a.) Diarrhea
b.) Vomiting in conjunction with diarrhea or two other gastrointestinal symptom such as fever or abdominal cramps
Foodborne Illness team consists of:
1.) Environmental Health
2.) Public Health Department
3.) Laboratory
What are the Seven Principles of the HACCP Plan?
1.) Conduct Hazard Analysis
2.) Identify Critical Control Points
3.) Establish Critical Limits
4.) Establishing Monitoring Procedures
5.) Establish Corrective Actions
6.) Establish Verification Procedures
7.) Record Keeping Procedure
Determine the Food Safety Hazardous and then identify the preventive measures that apply to control these hazards
Conduct Hazardous Analysis
Procedure in a food process (from its raw state through processing) at which control can be applied and as a result a food safety hazard can be prevented, eliminated, or reduced.
Identify Critical Control Points
Maximum or minimum value to which a physical, biological, or chemical hazard must be controlled at a critical control point to prevent, eliminate, or reduce it to an acceptable level
Establish Critical Limits
Procedure to monitor the control points
Establishing monitoring procedures
Are taken when monitoring indicates a deviation from a critical limit has not been met
Establish corrective actions
Ensures that the HACCP plan is adequate
Establish verification procedures
Written HACCP plan, records, documenting and monitoring of critical control points, critical limits
Record Keeping Procedures
Modern Sewer System
At most 2 days to reach plant. Travels at rate of at least 2ft/sec
Waste Water
Manholes placed 300-500 ft apart
Heaviest flow of sewage through wastewater treatment plan is between 3-9PM
Sanitary waste out of home, general business & institution from toilet, showers, sink, etc
Domestic Waste
Waste water discharged from manufacturing plant (restaurant, hospitals, canning, meat processors, refineries, etc)
Industrial Waste
Can infiltrate sewer system by cracks in sewer pipe
Ground Water
Certain amount of water infiltration from leaky pipes. High water table can be introduced into system by open drain
Storm Drain Runoff
Prohibiting draining of any type of wastewater onto public streets
National Pollution Discharge Elimination System
Liquid waste coming out of the ground at refuse landfills. Can be from rainfall seeping into landfill, or liquid waste intentionally dumped
Leachate
Fresh wastewater is 99.8% water and 0.2% solid concentration
Physical Characteristics of Waste Water
Fresh water water is also called..
Gray Water
Hot Zone at 113-158F
Thermophillic Zone
Medium Zone. Grows at 59-112F
Mesophillic Zone
Cold Zone. Grows at 35-50F
Psychrophillic Zone
Pipes drain liquid onto land
Surface Disposal
Shallow underground collection of pipes, title segmented loosely to allow water to percolate
Tile Field Disposal
Leach lines laid 2-5’ underground, perforated pipes (4” thick)
Subsurface Disposal
No longer accepted, Dispose of waste water into large water body, river, stream, etc
Dilution Disposal
Waste water being treated. Waste water going into a treatment plant
Effluent
Something that is taken into material
Absorption
Something that adheres to the material
Adsorption
Standard weight of one gallon of water
8.34 lbs
One cubic feet of water contains
7.48 gallons
Bar Screening (removes large objects), Grit Removal (sand/gravel), Pre-aeration (introduces oxygen, helps remove oil/scum), Flow Meter (measures rate of flow), Chlorine (optional)
Preliminary Treatment
Sedimentation (Clarification Tanks, removes solids that can settle, floating debris)
Primary Treatment
Collects raw sludge and relocates for sludge digestion, Bio/Chemical/Physical Treatment (Further removal of solids and dissolved solids of the waste water)
Secondary Treatment
Filtration (Filters to remove particles/color/odor), Disinfection (Destroys pathogenic bacteria), Used mainly for reclaimed water
Tertiary Treatment
Activated sludge, trickling filter, oxidation ponds, composting subsurface disposal field (Biological Treatment Process)
Aerobic Treatment Process
Sludge digestion, methane production, septic tanks, composting
Anaerobic Treatment Process
Holds volume of water for period of time at shallow depths (3-5’) to promote aerobic activity and purification water. Remains for 45-60 days before use.
Stabilization Pond (Lagoonization)
Solid portion of waste water
Sludge
Most biologically active, high potential to turn septic
Raw Sludge
Contains biological agents that digest sludge into inorganic materials, aka “Mixed Liquor”
Activated Sludge
Product of total anaerobic digestion, most stable
Digested Sludge
Simple hole dug, only used in past, now only used for emergencies
Pit Privy
Wastewater designed to seep into ground from _____ vault
Cesspool
If cannot connect to sewer, then next best option is ______. Water water retained in multi-compartment tank for ~24 hours where 60-70% of sludge settles.
Septic Tanks
What pipe color is reclaimed water?
Purple
What pipe color is steam, gas, oil?
Yellow
What pipe color is sewer?
Green
What pipe color is potable water?
Blue
What pipe color electrical?
Red
What pipe color are leach lines?
White
The concentration of a contaminant that, if exceeded, triggers treatment or other requirements that a water system must follow
Action Level (AL)
The highest level of a contaminant that is allowed in drinking water.
Maximum Contaminant Level (MCL)
Set as close to the public health goal or Maximum contaminant level goal as economically or technological feasible
Primary MCL
Set to protect the odor, taste, and appearance of drinking water
Secondary MCL
The level of a contaminant in drinking water, below which there is no known or expected health risk
MCL Goal
The level of disinfectant added for water treatment that may not be exceeded at the consumer’s tap
Maximum residual disinfectant level (MRDL)
The level of a disinfectant added for water treatment below, which there is no known or expected health risk.
Maximum residual disinfectant level goal (MRDLG)
The level of a contaminant in drinking water below, which there is no known or expected health risk.
Public Health Goal (PHG). Set by the California EPA
MCLs and MRDLs for contaminants that affect health along with their monitoring and reporting requirements, and water treatment requirements
Primary Drinking Water Standard (PDWS)
When was the Safe Drinking Water Act signed into law?
December 16, 1974
When was the Safe Drinking Water Act amended?
1986 & 1996
What did the Safe Drinking Water Act do?
- Set national standards regulating the levels of contamination in drinking water
- Require public water systems to monitor & report their levels of identified contaminants
- Establish uniform guidelines specifying acceptable treatment technologies
Federal & State Laws
- California Safe Drinking Water Act (SDWA)
- Bulletin 74-90 and 74-81
- Jurisdiction & authority of local construction standards
- Caused by polluting runoff (phosphate detergents, nitrate, fertilizers, sewage)
- Increase in nutrients cause algae blooms, algae, fish die and decompose to bottom creating oxygen loss, and new oxygen produced by living algae towards surface
Algae Blooms (Eutrophication)
Oligotrophic (Young), Mesotrophic (Middle-aged), Eutrophic (Old/Mature Lake)
Lake Age
Drinking Water Treatment
Untreated Water –> Coagulation –> Flocculation –> Sedimentation –> Filtration –> Disinfection –> Treated Water
- Chemical reaction that occurs when a coagulating chemical is added to water.
- Most common is aluminum sulfate (alum)
- Coagulant reacts with water & minerals in the water to form floc particles
- Neutralize negative charge on suspended particles - form larger clumps that are heavy enough to settle
Coagulation
- Process of slow, gentle mixing of the water to encourage tiny floc particles to clump together & grow to a size that will settle quickly
- Flocculent particles at 1.5 mm (1/16 inch) are usually heavy enough to settle within a few minutes
- Mechanical mixers (preferred) or hydraulic mixing
- Primary concern is the degree of mixing
Flocculation
- Process of holding the water in quiet, low-flow conditions so suspended matter & particles can be settled out by gravity to the bottom of the tank & removed as sludge
- Purpose is to remove as much of the flocculent & other suspended material as possible before water flows to the filters
- The final step in pretreatment prior to filtration
- An economic means of clarifying water
Sedimentation
- Variation of gravity filtration
- Uses biological processes as well as physical straining
- Simple, cost-effective
Slow Sand Filters
- Much greater water treatment filtration rate and the ability to clean automatically using back washing
- Complete filtration cycle (filtration and back washing) occurs sequentially
Rapid Sand Filter
_____ are a convenient and economical choice for applications that require gross particulate removal.
Particulates are trapped in the bag for quick disposal. ____ are available for low flow and come in welded styles. They have multiple micron removal efficiencies.
Bag Filter
_____ is a valuable water purification process when mineral-free water is the desired end product.
Most mineral constituents of water are physically larger than water molecules. Thus, they are trapped by the semi-permeable membrane and removed from drinking water when filtered through a reverse osmosis system. Such minerals include salt, lead, manganese, iron, and calcium. ____ will also remove some chemical components of drinking water, including the dangerous municipal additive fluoride.
Reverse Osmosis
The selective destruction or inactivation of pathogenic organisms
Disinfections
Disinfection types:
- Chlorine
- Ozone
- UV light
- Boiling
Chlorine in this form has the highest disinfecting ability
Free available residual chlorine
_______ process of adding chlorine to water until the chlorine demand has been satisfied
Breakpoint Chlorination
Zone of saturation of groundwater, easy to find in flat areas, hard in hills
Water Table
Well bored into aquifer that has enough pressure to bring water to surface without pump
Artesian Well
Aeration Zone, Saturation Zone, Impervious Rock, Aquifer Water
Ground levels
97% of world’s fresh water. Water percolates at 3ft/yr into aquifer
Aquifer
Caused by over drilling of aquifer, creating cone at top of well
Cone of Depression
When constructing, 3 things to consider (expense, depth of water table, type of construction)
Wells
Best type of quality, solid casing installed with perforation at bottom for aquifer. Large kinetic hammer drives casing into ground and past point of saturation. Well uses submergible pumps. Required 50’ well seals
Case Driven Well
Use earth augers, depth is limited to length of auger used
Bored Well
Manually dug by man, machine, finished well lined with concrete, bricks, tile or clay pipes. Not deep
Dug Well
Prevents contaminants from entering the well casing
Sanitary seal
Supports pumping equipment & aids in sealing against surface water
Well Slab
Metal tube placed in the well to keep the well open
Well Casing
Mixture of cement, water, and sometimes sand
Grout
Space between the drilled hole and the casing. Grout seals the well against contamination
Annulus
At the bottom of the casing, penetrating the aquifer. The screen provides enough open spacing for unrestricted water flow. Gravel packing aids in filtering & increases well efficiency.
Well Screen (intake screen) & Gravel Packing
Allow you to connect your water pipe from your water well pump to an under ground discharge, to go to your house.
Pitless Adaptor
When your well is constructed the hole in the ground is bigger than in the ground is bigger than the well casing
Faulty Annular Seal
CO & O can have corrosive effects, H2S & CH4 can effect odor/taste
Entrained gas
Salts (Ca/Mg/K/Na), bicarbonates, nitrates/phosphates. Effects taste/odor/color/corrosion
Dissolved Minerals
Bacteria, fungi, mold, viruses, algae, clay
Suspended/Colloidal Solids
From mining, improper waste disposal and contamination
Radioactive Waste
Suspended solids, BOD, DO, COD, Nitrates, H2S, pH
Chemical Exam of H2O
Coliform (Most probable number MPN, Colilert Testing), MPN confirmation, membrane filter
Bacterial Exam
Inorganic, has threshold limit value (TLV) of 5 mg/L. High concentration yield metallic taste, can cause vomiting
Zinc
at 250mg/L, can cause health problems (heart disease)
Chlorides
Diff TLV depending on form. NaSO4 (Sodium Sulfate), MgSO4 (Magnesium Sulfate, Epsom salt), CaSO4 (Calcium Sulfate). High levels cause laxative effects to human body.
Sulfate Compounds
Common in detergents. Conc. Limit Value 0.5 mg/l. Common pollution indicator for human domestic sewage. Found carcinogenic. Replaced by LAS (Linear Alkanate Sulfonate)
ABS (Alkyl-Benzene Sulfanate)
Nitrates should not be found in fresh water sources
Limit - 10mg/l
High levels of nitrates can lead to
Blue Baby Syndrome (methemoglobinemia)
common in processed meats to counteract growth of botulism
Nitrates
Copper
1 mg/dl
Iron
3 ppm
Fluoride
0.6 - 1.7ppm
Defluorization
Two methods, Bone char & activated alumina
Nuclides (Radium Ra226):
3 micro-micro curie/l limit
Strontium 90 (Sr90)
10 micro-micro curie/l limit
Most sampling containers (300ml), sterilized w/ leak proof caps. Samples taken at 2ft below water surface.
Water Sampling
Standard for water clarity. Indexes of 5 units can be distinguishable. Soil, Silt, algae, microorganisms can affect…
Turbidity
Used while utilizing light of flame. Sample poured until flame is not seen down tube.
Jackson Turbidity Meter
Used for clarity tests in pools. Clarity= how deep disk seen from surface, should be min 4 feet.
Secchi Disk
- Provides a media that contains specific indicator nutrients for total coliform & E. coli
- As these nutrients are metabolized, yellow color & fluorescence are released confirming their presence
- Noncoliform bacteria are chemically suppressed
- Identified in 24 hours or less
Coli-alert Test
- Uses a cellulose ester filter, called a membrane filter, the pore size is manufactured to close tolerances
- Pore size selectively traps bacteria from water filtered through the membrane
- Nutrients are diffused through the membrane to grow bacteria into colonies
- Colonies are recognizable as coliform because the nutrients contain a dye
Membrane Filter Test
- Standard method for determining coliform since 1936
- Tubes of laurel tryptose broth are inoculated with a water sample
- Coliform density is calculated from statistical probability formulas that predict the most probable number of (MPN) of coliform in a 100-mL sample necessary to produce certain combinations of gas positive (gas-forming) and gas-negative tubes in the series of inoculated tubes
Multiple Tube Fermentation
3 distinct test states
presumptive, confirmed, completed
Group 1: Water found satisfactory (low to no coliform), does not need treatment to be potable
Group 2: Water has low contamination levels but requires disinfection
Group 3-5: Contaminated water. Requires extensive disinfection process
Water Quality Classification
Best type, purest form of water, expensive, time consuming, boiling water then condense steam
Distillation
Use of electric current, + charge placed in H20, dissolved solids ions go through +/- membrane
Electro dialysis
Removes mineral compound (Ca, Mg) by increasing [Na]
Ion Exchange (Water softening)
any connection between piping that carries drinking water and the piping that carry other types of water or substances that may not be safe to drink (non-potable)
Cross Connection
The level of hazard determines the type of cross-connection prevention
Control Devices- Air Gap
Physical separation of drain pipe and drain
Air Gap
Flow of contaminated water into potable water supply caused by back pressure
Backflow
Form of back flow when pressure in potable water drops below pressure in flow of contaminated water
Back Siphonage
Used in toilet tank and commercial sink faucets, uses atmospheric pressure in event of back flow to force a valve to close, preventing waste water from entering potable water
Atmospheric Vacuum Breaker
Safest is Diagonal Jet Fountain. Air gap created when fountain jet used. Schools
Drinking Fountain
Connect to faucets, protects hose siphonage
Hose Bib Vacuum Breaker
Used as protection connection to all non-potable water supplies where line is not subject to back pressure. Under continuous pressure and must be installed above usage point.
Pressure Type Vacuum Breaker
Valve in toilet tank, discharges specific water amount activated by water pressure
Flushometer
Commercial water mains to protect municipal water supply. Must be certified and checked annually by certified backflow plumber
Reduced Pressure Backflow Prevention Device
Used in low hazard situations, where water may be polluted but not contaminated
Double Check Valve
Formed during drinking water chlorination (chlorination by-products). Considered potential human carcinogens
Trihalomethanes (THM)
Pesticide used to control nematode pesticides. Strong carcinogen. Factory workers found to have sterility problems.
1,2-dibromo-3-chlorompropane (DBCP)
Organic solvent, degreasing agent. Carcinogen
Trichloroethylene (TCE)
Similar organic solvent to TCE with toxic effects at 20PPB
Perchloroethylene (PCE)
Toxic to humans at high concentrations, known carcinogen. Used to manufacture chloroflouromethanes for refrigeration, air conditioners, aerosols. Causes ozone depletion in atmosphere
Carbon Tetrachloride
Mosquitos - wiggle horizontally up and down, no breathing tube. Adults stand 45 degree angle on flat surface.
Anopheles larvae (malaria)
Mosquitos- lies at ~45 angle, long breathing tube
Culex larvae (Western St. Louis Encephalitis)
Mosquito- have shorts thick breathing tube, relies on surface tension to stay afloat
Aedes larvale (Yellow Fever/Dengue)
Mosquito Control- Use long Mosquito Larvae Dipper to not scare larvae, count sample
Larval Surveys
Mosquito Control- Utilizes carbon dioxide as attractant for mosquitoes (such as piece of lard)
Dry Ice Traps
If possible, drain water. Floating debris cleared. Larvicide breaks surface tension of water and kills larvae
Large Water Bodies
Gambia Affinis (Mosquitos fish, consumes 200/day), Dragon Fly (larvae eats larvae & adult eats adult)
Natural Enemies
Last resort, pose hazard to environment
Pesticides
Fogging (insecticide), screening, bednet, protective clothing, repellents
Adult Mosquito Control
Fly species
- House Fly
- Blow Fly
- Bottle Fly
- Black Fly
- Fruit Fly
Musca domestica, most dangerous for transfer of germs, breeds in feces (horse, pig, chicken, dog, man, NOT cattle).
Can live up to 60 days.
Common House Fly
Breeds in dead animal flesh. Attracted to substance called mercaptan
Blowfly/ Bottle Fly
Mechanical transmitter of diarrhea and dysentery. Common cause of myaisis in sheep and cattle.
Commonly found in wounds or skin opening scars.
Life cycle is 10-25 days.
Black Blow Fly
Infestation of tissue w/ fly larvae
Myaisis
Second only to mosquitos for blood sucking characteristics (primarily female).
Eggs laid in free flowing, fast moving water (river/streams)
Larvae attach to submerged rocks
Can transmit human onchocerciasis (filariasis disease known as river blindness)
Black Fly
Chrysops discalis, bites often painful/remain swollen.
Lay eggs in vegetation near still water (ponds, lakes)
Larvae develop in wet soil/water.
Known to transmit Tularemia
Deer Fly
Drosophilidae Family. Breed in decaying fruit.
Nuisance in bars for fruit liquor bottles.
Fruit Fly
- Sanitation
- Larvae Control
Fly Control
Introduce natural enemies
Biological/Physical Control
Conducted with airplane, helicopter. Fixed amount per target area.
Aerial Spraying
Chemical vaporizes which causes immediate death to nearby flies/insects
Fly Cords and Resin Strips
Doesn’t work well because of depth the larvicide cannot penetrate to kill larvae
Larviciding
Short reproduction cycle, evolve quickly. Regularly switch formulas
Resistance Factors
Economical and effective. Min 16 mesh gauge (16 strands/inch)
Screening
Uses U.V. light Ex: Zap Trap
Electrocution
Fly Exclusion devices/fly fans. Commonly used over delivery doors of food facilities. Strong current of air provides barrier (min 1600 ft/min air)
Air Curtains
To control mass infestation, introduce…
Sterile Male Flies
Non chemical fly capture methods, baited traps fly cone surveys, fly grill surveys
Domestic Fly Survey Techniques
Most common device to determine local fly population and density. Places on natural attractant manure or garbage then count number of flies land on grill in 30 seconds
Fly Grill Survey
Most common to invade home/restaurant. Lays and carries eggs mass of 30-50 eggs called an ootheca
German Cockroach
Radio/TV roach, ootheca contains 18 eggs, hatch in 50-75 days
Brown Banded Cockroach
Screams, “real” water bug, cannot climb (unlike Brown-Banded/German), ootheca cary ~8 eggs which hatch in ~60 days
Oriental Cockroach
Largest. Ootheca contains ~14 - 16 eggs, hatch in 50 days. Flies often
American Cockroach
Cockroach Control:
- Identify cockroach and lifecycle
- Determine level of infestation, in full blown infestation identify source
- Determine type of extermination (tenting with fumigation usually best, or spray/fog each unit)
Rattus norvegicus, most vicious/territorial.
Tails short/thick. Burrow in ground, swim
Norway Rat
Not vicious, agile climbers, long/slender tail live in high places
Roof Rat
Smallest of three, long tail, live in any convenient place, short migration range
House Mouse
What Kind of Rat?
Average length of dropping: 3/4 inch
Rounded ends
Norway Rat
What kind of rat?
Average length of dropping: 1/2 inch
Pointed ends
Roof Rat
What kind of rat?
Average length of dropping: 1/4 inch
Pointed ends
House Mouse
Rodent Control
- Eliminate food source, proper sanitation, rodent harborage site must be removed, Norway rat burrows at 45 angle, plug holes and entrances
- Roof Proofing: Ventilation should be screened/sealed, pipes no larger than 1/4”, trees & branches should not touch building, clean all dropped fruit/veggies/plants
Last method, after proper sanitation technique. Most effective usually most poisonous
Pesticides
Classification of Pesticides -Route of Absorption:
- Stomach Poison (must ingest)
- Contact Poison (touch)
- Fumigant Poison (inhalation)
- Desiccants (release body fluid of insect by removing body silica gel, dries out insect)
chemicals are now classified in relation to lethal dose of chemical amount where 50% tested population dies.
LD50
LD50 toxic levels:
- highly toxic LD50 (5-50mg/kg)
- toxic (50-500mg/kg)
- moderately (500-1000mg/kg)
- slightly (1000-5000mg/kg)
- non-toxic (5000+mg/kg)
LD50 1500mg/kg, natural organic insecticide produced from chrysanthemums
Pyrethrum
Synthesized form of pyrethrum. Moderately toxic.
Allethrin
Mostly banned because stay in environment for long time (DDT)
Chlorinated Hydrocarbons
LD50 150, used in low concentration to treat head lice
Lindane
LD50 500, remains stable in environment for long periods of time
DDT
LD50 5000, used effectively against fleas
Methoxychlor
Ingested, causes internal bleeding. Common anticoagulants are Prival, Warfarin, Fumarin
Anticoagulants
Bait with 25% anticoagulant in box
Bait Box Trap
Extremely toxic, used in single dose applications, limited to pest control professionals
Toxic Poisons
Natural emetics are agents which cause an animal to regurgitate. Cause vomit to enter lungs, leading to drowning
Red Squill
Resembles white sugar and flour. Extremely toxic
1080 (Sodium Fluoroacetate)
Used in sewer systems. Toxicity <1080.
1081 (Sodium Fluroroacetamide)
Safest single dose, highly toxic to Norway rat, low toxicity to other mammals
Nor-Bromide
A pungent garlic, grayish/black powder favored by all domestic rodents
Zinc Phosphide
Arsenic compound
Paris Green
Central Nervous System inhibitor
Organophosphates and carbamates
Concentration exposure (oral/dermal) at which 50% of tested population dies
Lethal Dose 50 (LD50)
Concentration exposure (inhalation) at which 50% tested population dies
Lethal Concentration 50 (LC50)
Chemical concentrations to which workers may be exposed all day without adverse effects. ACGIH sets levels. Levels published by NIOSH. Toxicity exposure is function of time & dose.
Threshold Limit Values (TLV)
Average concentration workers can be repeatedly exposed to during 8 hr day, 40 hr week without developing adverse chronic effects
Time Weighted Average (TWA)
Concentration that cannot be exceeded even instantaneously because of serious health effects. Ceiling Value.
TLV-C
Short term exposure limit (STEL) is allowable exposure concentration for short time period. A 15 min average exposure period, repeated no more than 4 times per day, with a minimum of 1 hr between exposures, provided 8 hr TWA not exceeded
TLV-STEL
Cal-OSHA mandated values to enforce workplace violations
Permissible Exposure Limits (PEL’s)
Maximum exposure concentration at any time
Ceiing
Standard for Acute Toxicity Ratings:
Acute Oral LD50 < 5,000 mg/kg single dose
Dermal LD50 < 4,300mg/kg in 4 hour period
Inhalation LC50< 10,000PPM gas vapor
Standard for Extremely Toxic Ratings
Oral LD50 < 50mg/kg single dose
Dermal LD50 < 43mg/kg in 4 hr period
Inhalation LC50 < 100PPM gas vapor
Consists of face piece connected to hose and regulator to air source (compressed air/oxygen or oxygen-generating chemical). Recommended in atmospheres that are Immediately Dangerous to Life and Health (IDLH). Avg usage time is 30 minutes, limited to air supply/usage
Self Contained Breathing Apparatus (SCBA)
supplies air, never oxygen. Not for use in IDLH environments
Supply Air Respirators (SAR’s)
remove airborne contaminants.
Not for IDLH, oxygen deficient, unventilated, confirmed, and unidentified contaminant atmospheres.
Types include particulate filters, cartridges, canisters which contain sorbents for gas, vapors, or a combination of both.
Air-Purifying Respirators
PPE Levels: Offers highest level of protection for both respiratory & dermal. Used when handling extremely hazardous chemicals, in unventilated areas or working with unknown substance
Level A
PPE Levels: Offers highest level of protection for both respiratory & dermal. Used when working in unventilated area or low O2 environment with little to no splash hazards
Level B
PPE Levels: Lower level of respiratory and dermal protection, used when working in known airborne contaminants. Offers no chemical or splash hazards
Level C
PPE Levels: Offers little to no respiratory or low dermal protection. Used when working in known low level contaminants. Offers no chemical or splash hazards
Level D
Mixture of organic and inorganic materials
Refuse
Inorganic material component of refuse, does not break down by decomposition (bottles/cans)
Rubbish
Organic Waste material component of refuse, readily breaks down. Makes up 50% of refuse
Garbage
Commonly used in level terrain. Large earth moving equipment digs trenches through excavation, solid waste filled into trench, backfilled, and compacted. “cut and fill” method
Trench Method
Uses side of hill or sloped area, refuse dumped and covered with dirt. Most common method in the US and is continued until the entire slop is leveled
Area method
Landfill located in area with large depressions or slopes such as a valley or ravine. Refuse dumped, filled with dirt and compacted. Once leveled or exhausted, can be used as golf course or parks. Commonly used by large cities.
Valley or Ravine Method
Hazardous Materials accepted for disposal
Class 1 Landfill
Low level hazardous material accepted for disposal
Class 2 Landfill
No hazardous materials accepted
Class 3 Landfill
Sandy Loam is soil choice
Landfill Soil
Minimum daily cover is 6” compacted to prevent fly larvae emergence. Min final cover is 24”
Landfill Cover
Ideal Slope for Landfill (1:2, 50%, 26.3 degrees)
Final Closing Slop (1:3), 33%, 18.3 degrees)
Slope of Landfill Cell
Methane, CO2, Hydrogen Sulfide
Decomposition Gases Produced via Anaerobic Decomposition
Aerobic State is between 4-60 days, Anaerobic State is after 60 days.
State of a Landfill
Any liquid waste that comes out of a landfill
Leachate
Rows of compost piles positioned to allow air to flow through promoting aerobic decomposition
Windrows
Burning of waste products. For smokeless incineration, temperature should be maintained at 1500-1800F
Incineration
Landfills must be min ____ feet from lakes/streams, and min ____ feet from human habitation (communities)
200’;500’
Citing landfill sites should be for duration of at least ______
30-40 years
Soil Science (most absorptive to least absorptive)
Sand –> Sand Loam –> Loam –> Silt Loam –> Clay Loam –> Clay
Results in good water absorption
Red/Brown Color
Usually bad PERC results
Blue/Black Color (slow water absorption)
Not very good soil for water absorption
Mottled Soil
Sampling Collection Methods
- Grab Samples
- Composite (Batch) Sampling
- Number of Samples
- Preservation and Storage of Samples
Emergency Inspections without a Warrant
- Authorized if seizure of Hazardous Food
- Sewage overflow
- Vaccination against Small Pox
- Quarantine of Communicable Disease
- Destruction of diseased animals
Minimum PPM for Chlorine
minimum 100ppm for 30 seconds in cool water.
Too much chlorine causes odor/tarnish. Loses effectiveness if water is too dirty or too warm.
Minimum PPM for Quaternary Ammonia
minimum 200ppm. Less effected by dirty water, stays effective for longer time, less affected by hard water, safe to use with bare hands
Minimum PPM for Iodine
Minimum 12.5 ppm, less effected by dirty water, stays effective for longer time, less affected by hard water, metallic odor, brownish color.
What is the set up for Manual/Hand Washing
3 compartment sink, wash –> rinse –> sanitize
Lithium (Li)
Pharmaceutical; used to treat mental disorders as an anti-depressive
Potassium (K)
Naturally occurring radioactive isotopes.
Occurs in all soils, essential in plant growth and human/animal nutrition.
Can ignite spontaneously in moist air, extinguish with soda ash or graphite
Sodium (Na)
Peroxides are irritants & corrosives. Pure Na is fire risk (reacts w/ any form of water, ignites spontaneously in dry air when heated, extinguish using soda ash, salt, lime)
Radioactive forms used in tracer studies/medicine
Barium (Ba)
Causes respiratory problem in lungs when dust is inhales (baritones pneumonitis)
Used as digestive tract survey in medicine
Beryllium (Be)
Highly toxic (inhalation of dust)
Tolerance 0.002 mg/m^3 of air, known carcinogen
Magnesium (Mg)
Central element of the chlorophyll molecule, component of red blood capsules
Strontium (Sr)
Radioactive Sr is bone seeking element (collects in bones),
Byproducts from nuclear reaction
Chromic Acid (CRO5)
Highly toxic and corrosive to skin
Cobalt (Co)
Important trace element in soils, animal nutrition, radioactive Co cancer treatment
Copper (Cu)
Necessary trace element in human diet
Factor in plant metabolism
Nontoxic in elemental form
Noncombustible except as powder. Cu pipe with soda water.
Iron (Fe)
Siderosis (disease caused by inhalation of metallic particles)
Gives water metallic taste.
Manganese (Mn)
Fumes.
Dust/powder is flammable.
Exposure has caused spastic/psychological symptoms, pneumonitis
Nickel (Ni)
Flammable/toxic as dust or fume, carcinogen, exposure can cause dermatitis
Tin (Sn)
All organic tin compounds are toxic, stenosis (tin poisoning), block tin used in coating copper cooking utensils and lead sheets
Zinc (Zn)
Fume fever (dust), flammable, fire and explosion risk
Arsenic (As)
Known carcinogen, dermatitis, gastrointestinal, possible teratogen, respiratory impairment.
Highly toxic ingestion/inhalation
OSHA employee exposure 10ug/m^3 air
ACGIH is 0.2mg/m^3 air
Common industrial waste product considered as hazardous waste
Cadmium (Cd)
Kidney, testes necrosis, poisoning, vomiting, diarrhea, cramps, fumes, pneumonitis, emphysema, food poisoning
Lead
FDA regulations 0 Pb in food, 0.05% in house paint
Lead Poisoning
Avg adult blood level 5-10ug/dl
Children 10-15ug/dl should be monitored for lead poisoning
Subclinical 20-35ug/dl
Moderate/High Toxic >35ug/dl
Treatment may include chelation using Ethylene Diamine Tetra Acetic acid or EDTA
Tool to assess lead
X-ray Fluorescence Refractor (XFR)
Mercury (Hg)
Gastrointestinal impairment, inflamed mouth/gums, CNS tremors, psychological symptoms (tolerance 0.05mg/m^3)
Asbestos
OSHA PEL-TWA is 0.2 fibers/cc for fibers
>5um in length
Carbon Monoxide (CO)
Highly toxic inhalation, highly flammable, fire/explosion risk, flammable limits in air (12-75% by volume
Carbon Monoxide tolerance
50ppm (industrial), U.S. standard is 35ppm
Liquid waste coming out of the ground at refuse landfills.
Leachate
Fresh wastewater is 99.8% water and 0.2% solid concentration
Physical Characteristics of Waste Water
Fresh water is also called
Gray Water
Hot Zone at 113-158F
Thermophillic Zone
Medium Zone. Grows at 59-112F
Mesophillic Zone
Cold Zone. Grows at 35-50F
Psychorophillic Zone
____ pipes drain liquid onto land
Surface Disposal
Easy to use and cost efficient for pools
Hyperchlorous Chlorine (HOCl)
Samples should be taken at 12-18” depth with forward sweeping motion for pools
Testing for Chlorine
Measures total residual chlorine, heat sensitive
Orthotoludene (Ortho Test)
Measures free & combined levels, not heat sensitive, more accuratee
D-P-D (Diethyl-Phenylene-Diamine)
Minimum turnover rate for pool
6 hours
Minimum turnover rate for a spa
0.5 hour
Minimum turnover rate for a wading pool
1 hour
