Lab Exam Flashcards
What is the Canadian drinking water guideline maximum for Total Dissolved solids?
500mg/L
Bottled “mineral water” usually exceeds ____mg/L of TDS
500mg/L
Tapwaters with high TDS cause what problems?
Undesirable tastes, form deposits on pipes/fixtures, may cause gastrointestinal problems and kidney strain
If high TDS is due to calcium and magnesium minerals, the water is referred to as ____
hard
What are benefits of hard drinking waters?
Have reduced heavy metal toxicity and are a good source of dietary calcium
What is the hard, but most accurate way of estimating TDS?
Filter a known volume of water into a preweighed container, evaporate the water, weight the residue
What is the easy and most common way to estimate TDS? What is the benefit of this?
Using an electronic probe. It is helpful because it can be performed on site
If Total Suspended Solids (including small particles like viruses) must be measured, how can one do this?
Specialized micropore filters must be used, but only if the residue does not exceed 200mg. Residue is dried out at 100 degrees C
Waters with a lot of suspended solids come from what situations?
Where there is a great deal of turbulence or where effluent is discharged into the water body
What precautions must one take when collecting a water sample for suspended solids analysis?
Must be low enough that floating matter is avoided but high enough that there is no contamination with bottom sediment
Where are there high saline groundwaters in MB?
Southwestern MB
Precambrian shield waters contain ____ amounts of chloride
low low low
If Precambrian shield waters have chloride present, what does that indicate?
Contamination from human activity (ex. salt on roadways, effluents)
The Canadian drinking water guideline for chloride is ____mg/L
250mg/L
Chloride concentration is usually associated with a salty taste. Is this always the case?
No, as the salty taste comes from the major cations being sodium. Sometimes they are instead calcium or magnesium, and the salty taste is not detected.
What are some nitrogen and phosphorous sources in human sewage
Body wastes, dish soaps, phosphate/ammonia cleaners, household products, garburators, industrial effluents, lawn/garden fertilizers, municipal tapwater treatment plants, pet waste, illegal chemical disposal
Why does the city of winnipeg deliberately add phosphorous to our pipes?
To reduce leaching of lead from pipes downtown
What do urban sewage treatment plants consist of?
We have lagoons where the sewage sits until we decided to treat it for ONLY PHOSPHOROUS
What is the most commonly used method of chloride detection in water samples? What does this involve?
Argentometric method. This involves the titration of chloride with silver nitrate. This forms a red precipitate (potassium chromate is used to indicate end point)
What do community sewage lagoons consist of?
Large lagoons where waste is eventually released into the river or stream
What do rural (farm) residents do with their wastes?
Have a septic field. BAsically there is a large tank underground where the crap settles out, and septic pump brings liquids to the surface into the field. Over time this can create “ponding” of the liquid sewage
Cottage residents have _____ to hold their waste
Holding tanks
In-non potable waters, some substances are present in high enough concentrations to interfere with argentometric chloride detection. What are some of these substances?
Bromide, iodid, cyanide, orthophosphate in high concentrations (precipitates some silver), iron in high concentrations (interferes with end point detection)
Analysts prefer the _____ method of chloride quantification because the end point is more obvious
Mercuric nitrate method
Describe the potentiometric method of chloride quantification
Used when samples are highly coloured/turbid. A silver electrode is used to measure changes in potential difference as silver nitrate is added
What is the formula for chloride concentration?
mg chloride/L = (A-B) x N x 35450/mL sample
A = mL silver nitrate added to produce end point in sample B = mL silver nitrate added to produce end point in blank N = normality of silver nitrate (0.0141 N)
By what formula can NaCl be estimated?
mg NaCl/L = (mg chloride/L) x 1.65
Briefly describe the in-water nitrogen cycle
Ammonia is converted to nitrite in the presence of oxygen, which is in turn oxidized to nitrate.
Ammonia and nitrate may attain higher levels in _____ waters and ____ waters
Ground waters and polluted waters
What happens when water containing ammonia is chlorinated?
Chlorine reacts with ammonia to produce carcinogenic mono and dichloramines
The Canadian drinking water guideline for nitrate is _____mg/L nitrate or _____ mg/L Nitrate-N
45mg/L, 10mg/L
Nitrate toxicity results in water symptoms?
Gastric and prostate cancer, non-Hodgkin’s lymphoma, spontaneous abortion, affects on human behaviour
What is the primary concern with nitrite in groundwater?
There is almost no O2 in groundwater so nitrite cannot be converted to nitrate. This may lead to Methemoglobinemia: Blood vessels dilate, oxygen supply to brain/extremities reduced. Hemoglobin is converted to methemoglobin and blue skin, lips, nails (cyanosis) can occur. May lead to “blue baby disease”.
What kind of water guidelines are there for ammonia in Canada?
No drinking water guideline for ammonia, though there is a maximum set out for “aquatic life”
____ and ____ are used to extract gold in Manitoba
Arsenic, cyanide
Waters with low organic content can be analyzed for nitrate using what method?
UV spectrophotometric method
What is another common method for analyzing Nitrate concentrations?
Selective sensor which develops electric potential difference across membrane
What happens to waters that have undergone “reverse osmosis”?
Reduces stuff inside the water by about 90%
What is the problem with distilled drinking water?
Water molecules are not attached to anything and therefore attacks anything they can
are water bottle distribution companies required to provide chemical analysis?
No, it is voluntary
What is the International Bottled Water Association?
A board in Virginia that mostly serves to yell at people who say bottled water is bad
What does it mean to say a water is distilled?
HAs been vaporized and condensed, all the minerals have been removed
What does it mean to say a water is “purified”?
Processed in some way to remove some of the minerals, most often by reverse osmosis
What does it mean to say something is “mineral water”?
Natural water that has a lot of dissolved minerals in it (therefore more flavour). Includes hard water
The classification for mineral water is ____mg/L TSS
500mg/L
What does it mean to say water is “natural”?
Untreated.
What does it mean to say something is “spring water”
Comes from an artesian well
What does it mean to say that something is “bottled drinking water”
IT’s literally just tap water put in a bottle
What does it mean to say something is “sparkling water”?
Carbonated (naturally or not)
What does it mean to say water is “mineralized”
Minerals were artificially added (after being removed somehow)
How does one determine whetehr a bottled water brand has been decontaminated in some way?
Must be either ozonated or carbonated (bacteria and fungi can grow otherwise)
What is an ideal maximum for mineral content in water
300mg/L
Why is it important to worry about heavy metal contamination in bottled water?
Concentrations on bottled water are listed in ppm when in fact standards for these things are in ppb, so obviously it will always show up as “0” after rounding - totally unsafe. Therefore you can exceed guidelines and still be labelled as 0ppm
Generally the best bottled water source is what?
Water valley, Alberta
Why is it important to have expiry dates on water?
Because you have no idea how long it has been on the shelf (how long the plastic/glass/packaging has been leaching into the water)
What packaging is it best to avoid when buying bottled water and why?
Coloured bottles - because they may contain lead or uranium
Glass bottles - often have additives like lead, boron, cobalt
Plastic bottles - often leach metal stabilizers, plasticizers, breakdown products (ex. vinyl chloride) and styrene substances
Which is generally better for health, domestic or international/imported water?
domestic. International usually sucks
Where can radioactivity come from in MB surface waters? What radioactive compounds are present?
Usually from substances in Precambrian Shield rock but also comes from nuclear reactor coolant, nuclear weapons/reactor accidents, wastewater from labs/universities - includes radium (radon gas), uranium, thorium
Radionuclides of ____ atomic weight may bioaccumulate in living tissues
HIGH
When analyzing the level of nitrates in a sample, what UVwavelenths are used?
220nm subtracted by 275nm
What was used in the lab to examine radioactivity of samples? What types of radiation does it analyze?
RM-60 Radiation counter. Suitable for broad spectrum monitoring of alpha, beta, gamma, and X-rays
What are alpha radiation particles?
Positively charged helium nuclei emitted at high speeds. They can be stopped by air and do not travel far but can do damage to living tissue.
How does one determine if radiation emissions are alpha?
Put a sheet of paper over the sample and monitor for a drop in radiation
What are beta radiation particles?
Electrons originating at very high speeds from the nucleus of radioactive elements. Smaller than alpha particles (less ionizing power)
What does it mean if radiation particles are smaller?
Can penetrate deeper into tissues
What are gamma rays?
High energy electromagnetic radiation (photons) - not particles. Penetrate better than X-rays, and can damage tissue (can ionize DNA).
Once radiation was measured in the lab, what calculations were performed? What do the results then reflect?
We corrected for the background radiation. Results reflect levels comparative to the background, not total radiation.
How would one study total radiation of a water sample?
Run sample through charcoal filter, the total radiation on the filter reflects total ration in the unit volume
Why are coliform counts in water important?
Often they are the only routinely monitored parameter - influencing safety of both ingestion and skin contact with water.
What are the two different counts used when referring to coliforms?
Total coliforms and fecal coliforms.
What does a total coliform count indicate?
All coliform types, regardless of their origin. May be innocuous, free-living, but may also be intestinal inhabitants. This count is broadly indicative of pollution level
What does the fecal coliform count indicate?
Organisms coming from feces of warm blooded animals/birds.
How are fecal coliforms distinguished from total coliforms?
By their ability to ferment lactose (and porduce CO2) at 44.5 degrees C
What is the limit of total coliforms in Manitoban waters? Fecal coliforms?
10 per 100mL. No fecal coliforms.
At what point in coliform count are beaches closed in MB?
> 200 total coliforms/100mL
How must water for microbial examination be collected?
Collected using sterile, preservative-lined containers. Samples must be analyzed within 48 hours, without touching the inside of the bottle or cap.
What are the three basic tests use to detect coliform bacteria in water?
- Presumptive
- Confirmed
- Completed
What is the presumptive test for fecal coliforms?
Grown on medium containing lactose (for production of gas), as well as bile salts to suppress non-coliforms. Development of gas in the tubes indicates that coliforms are likely present
Lactose broth for the presumptive test is incubated at ____ degrees C, whereas bile green is incubated at _____
37 degrees C, 44.5 degrees C
What is the confirmed test for coliform detection?
Selective media like EMB or Endo agar are used to determine if the organisms grown during the presumptive test are in fact coliforms.
What is a positive result for coliforms on EMB agar?
Colonies with dark centers and a green metallic sheen
What is a positive result for coliforms on Endo agar?
Fuchsin dye in the presence of acid produces a dark pink colour
What is the completed test for coliform detection?
Colonies from the confirmed test (Endo or EMB agar) are inoculated onto lactose broth and nutrient agar slants, then gram stained the next day to determine if they are gram negative bacilli.
Ingesting bacteria or protozoa in the water is hazardous for people with what conditions?
high stomach pH (ex. taking antacids), people who have had tonsillectomies, are malnourished, very young or very old
Why is it that high stomach pH may result in higher susceptibility to water-borne pathogens?
stomach acid won’t kill them
Washing yourself with pathogen-contaminated water can result in what conditions?
eye, ear, skin, urinary, vaginal infections
The group “total coliforms” can be described as what?
all aerobic and facultatively anaerobic, gram negative non-spore forming bacilli that ferment lactose with gas formation
Strains of E. coli that invade the intestinal epithelium are referred to as _____. What symptoms are caused by these? How do these symptoms arise?
enteroinvasive E. coli. Cause fever and dysentery-like symptoms, as a result of tissue invasion
If enteroinvasive E. coli gets in the eye, what happens?
Conjuctivitis
Noninvasive E. coli usually cause infection by what means?
by toxin production - enterotoxigenic bacteria - similar to cholera toxin
If enterotoxigenic E. coli is inhaled, what illness can occur?
Pneumonia
what are standards for total coliforms in Canada?
10/100mL (none must be fecal)
Water with less than ____ total coliforms per 100mL is considered suitable for swimming
200
The organism Shigella dysenteriae causes what illnesses?
Bacillary dysentery/shigellosis
How many Shigella cells are needed to induce infection and how long is the incubation period?
Very few cells (less than 5), incubation period of around 12-50 hrs
What is the incubation period for standard E. coli infection?
24 hrs
Most deaths due to shigellosis occur in whom?
children under 9 yrs old
How do Shigella bacteria produce symptoms?
Bacteria multiply in the epithelium of the colon and release endotoxins. This triggers inflammation and diarrhea. If bacteria enter the bloodstream, the endotoxin causes a fever.
What is the incubation period for Salmonella incubation?
6-36 hrs
What is Salmonella often reported as?
Gastroenteritis, “food poisoning”
What is the causative agent of salmonellosis?
Salmonella enteritidis
How do Salmonella bacteria produce symptoms?
Invade mucosa of intestines, produce cramps, nausea, fever, diarrhea.
How long do salmonella infection symptoms usually last?
2-4 days
Where is one most likely to acquire a salmonella infection?
Places where lakewater is used for consumption/washing stuff. Or, from undercooked meat, raw eggs, dairy.
What happens when Salmonella bacteria enter the bloodstream?
Cause a potentially deadly illness called enteric fever
IS Klebsiella pneumoniae a resident bacterium? Can it cause illness?
Common in normal gastrointestinal flora. Produced bacterial pneumonia and illness in the upper respiratory tract, ear, and urinary tract.
Klebsiella bacteria are particularly dangerous for what group of people?
Alcoholics.
Where is Klebsiella often found?
Pulp/paper mills
What aspect of Klebsiella makes it resistant to the immune system?
Capsule, makes it hard for white blood cells to phagocytize it
Where is Pseudomonas aeruginosa often found?
Extremely wide range of environmental conditions, in any type of water (surface, swimming pools, distilled water, even bottled water), found in disinfectants, medications,
Why is it that Pseudomonas aeruginosa can be found even in bottled water?
It is an obligate aerobe (but can use CO2), and can survive on the oxygen dissolved in the water from the time of bottling, or ozone breakdown if the water was ozonated.
What infections can P. aeruginosa produce?
wound infections, respiratory, ear, eye infections.
Is P. aeruginosa part of the normal human flora?
Part of the GI tract in about 5% of the pop’n.
Clostridium botulinum can proliferate where?
It is an obligate anaerobe and can grow in sealed containers such as canned food.
How does C. botulinum cause infection? How is it treated?
Through a toxin, one of the most potent known to man. IT can’t be treated with antibiotics, instead needs antitoxin for specific strain
How is that Clostridium cells can endure the boiling process needed to can things like jam?
Produces endospores that can survive 5 hrs of boiling, with germination inhibited at pH of
How quickly do symptoms/death occur in botulism poisonings?
symptoms start in 12-36 hours, death occurs in 3-6 days
In what cases may Clostridium botulinum live in the body?
For some reason it can live in the intestines of infants but not children or adults. Can establish itself then start producing toxins and kill the baby.
Where is Clostridium found in the natural environment?
Can be found in water, especially during winter when O2 is depleted. May kill waterfowl.
Corynebacterium diptheriae is a ______ bacterium related to what organism?
Actinomycete, related to Mycobacterium tuberculosis
Where does C. diptheriae reside in the body and what types of infections does it produce?
Lives in throat, produces an exotoxin which can damage nerves, heart, liver, kidneys
Describe the difference in appearance between Entamoeba coli and Entamoeba histolytica? Why is it important to know the difference?
E. coli - Benign. Has about 8+ nuclei bigger
E. histolytica - Smaller, causes crazy disease. Have 1-4 nuclei.
What symptoms does E. histolytica cause?
Produces amoebic dysentery in humans, dogs, cats. Ranges from mild to severe dysentery, fever, intestinal bleeding. May also enter blood and cause abscesses in liver, brain, lungs.
How is E. histolytica transmitted? How does it travel through the body?
Via cysts in water, shed with feces (some people are unsymptomatic carriers). Cysts can be viable for up to 150 days and live in up to 50 degrees C. Travels through body using single pseudopodium.
Giardia lamblia is the causative agent of what?
Beaver fever/giardiasis
How do Giardia parasites cause symptoms? How long do symptoms last?
Adhere to the lining of the duodenum + small intestine, damaging the mucosa and causing irritation and bleeding. Symptoms last 6-7 weeks.
Who often acquires Giardia infection?
bikers/ canoeists
Are algal toxins destroyed by chlorination?
No, may become even MORE toxic!
What happens when algal toxins contact skin?
May get an allergic reaction called contact dermititis
The algal genus oscillatoria produces what kind of toxins?
alkaloid neurotoxins
What does the genus oscillatoria look like?
homogenous filaments with no heterocysts
What types of toxins are produced by Gloeocapsa and Lyngbya. To what phylum do they belong?
Contact dermititis is caused by them. Belong to cyanobacteria
What health problems can be caused by dinoflagellates?
toxic “red tides”, produce neurotoxins such as saxitoxins that can be accumulated in shellfish
What is the colloquial name of the Bacillariophyta?
Diatoms
Synura is a colonial alga from what group? Describe this species.
Chrysophyta. Produces bad tastes in water and usually occurs during early spring ice break up
Describe the diatoms (bacillariophyta)
Made of two halves made of mostly silica. May make things taste oily and “fishy”. May proliferate in water during cooler periods (early spring, late fall)
What are the charophyta?
Large algae resembling aquatic macrophytes. They occur in large groups that may exclude others (plants or algae) using allelopathic chemicals.
What is the reason for the name “Skunkgrass”? What does this mean for humans?
Smells like sulphur, secreted by the alga. Enough of this can taint a water body
In MB, what are the major problems surrounding Helminths?
Associated with livestock operations, or sewage entering water in cottage areas
nematodes are from the phylum _____
Aschelminthes
flatworms are from the phylum ______
platyhelminthes
tapeworms are from the class _____
cestoda
flukes are from the class _____
trematoda
What do Ascaris eat and where do they live?
Live in the small intestines of humans and hogs, feed on chyme
Ascaris infection is called _____
Ascariasis
What is the primary concern in Ascaris infection?
Can physically obstruct the intestine because they can be over 30cm long. The fluid in the worms is under pressure and can burst and be highly toxic
Where can ascaris be found in MB?
Can be found in groundwater aquifers near hog barns - eggs can survive up to five years.
What do Ascaris eggs look like?
oval in shape, thin transparent shell
Describe the lifecycle of ascaris
Eggs hatch into a zygote, but only develop in a temperature lower than body temp (outside of host). After 10-14 days, larvae are present. Larvae molt inside the egg to become infective. Eggs hatch in the small intestine, burrowing through the wall to enter blood vessels and being carried to the liver. They are then transported to the right side of the heart, to the lungs via arteries. They then move up the bronchioles, bronchi, and trachea to the epiglottis. They are swallowed and move to the small intestine
What is the genus and species of the human whipworm?
Trichuris trichiura
Where does the human whipworm live?
Appendix area
Describe the life cycle of the whipworm Trichuris
Eggs develop slowly after being released into the environment - larva is fully formed in the egg after 3-6 weeks. When eggs are swallowed they burrow into the wall of the small intestine, remain there for a few days, then come out into the lumen and mature to adults
Where are flukes (trematodes) found in MB?
Infecting many birds and animals, invertebrates.
What are types of human fluke infections in MB (and where)? how do they occur?
Swimmer’s itch occurs when metacercaria dig under the skin and result in inflammation/rash - happens in places like Bird’s Hill, Clear Lake.
Fasciola hepatica can infect human livers
Trematodes are otherwise known as ____
flukes
Describe the generalized life cycle of a fluke
Eggs hatch in water into a miracidium. This enters an intermediate invertebrate host (liver). Miracidium transforms into a sporocyst, which then reorganize to form redia. The cercaria form in there, escaping from the intermediate host. Cercaria searches for the next host, such as arthropod. IT encysts and becomes a metacercaria. When the flesh of this host is eaten, the metacercaria are liberated in the intestines of the definitive host and matures into an adult
Which types of trematodes pose the biggest risk to humans in MB? Why is this and what do these trematodes look like?
Fascioloid trematodes - live entire life inside body with no external signs (no dermatitis). These are long (up to 30 cm) and dorsoventrally flattened, leaflike in shape.
Where do human fascioliasis infections come from?
Cattle and deer.
Describe the life cycle of Fasciola hepatica
Eggs pass out of liver through bile to small intestine, shed with feces. After 4-15 days the miracidium emerges and looks for snail host. In the snail the sporocysts, rediae, and cercariae develop. These cercariae escape the snail and swim freely until they encounter aquatic macrophytes, which they encyst on to (lose tails). When they are swallowed with water by definitive host they excyst in duodenum, penetrating the intestinal wall, abdominal cavity, and into the liver, where they mature into adults,
What do eggs of Fasciola hepatica look like?
Have a lid/operculum at one end.
Cestodes are otherwise known as ____. To what phylum do they belong?
Tapeworms. Phylum platyhelminthes
Fasciolopsis buski is a species of _____ that does what?
trematode, infects human and mammal intestines
What do tapeworms look like?
Body consists of a series of sections called proglottids each of which break off at maturity, full of eggs. Tapeworms may become very long and the anterior end anchors into the intestine by means of a scolex (containing hooks and suckerS).
How does one acquire tapeworm infection?
Drink water contaminated with eggs
Echinococcus granulosus is otherwise known as ____
Hydatid worm
Where is Echinococcus granulosus found?
Dogs, hogs, cattle, humans. Adult worms usually found in canids, with hundreds of worms in an intestine.
How can humans acquire Echinococcus infection?
By drinking water containing eggs or allowing dogs to lick your face
Describe the life cycle of Echinococcus granulosus starting from ingestion
Eggs acquired via ingesting contaminated water, hatch into oncospheres in duodenum. These penetrate the intestinal wall, enter the bloodstream and may be carried elsewhere in the body. This is where they develop into hydatid cysts, wherein the host is induced to create a layer of permanent tissue around the cyst. Cysts expand and divide to form brood chambers, where miniature scoleces are formed. Damage to host depends on location and size of cyst.
Where can hydatid cysts be found in the body and what are some treatment methods?
Can be found anywhere, but particularly dangerous in heart and brain. They are usually scattered throughout the body, making surgery lifethreatening and challenging. Drug treatments are toxic to host.
IF cysts are the end of the line for Echinococcus granulosus parasites, how do these diseases live on?
By other organisms eating the flesh of an infected organism. Each tiny scolex in the cysts can become a new organism in the intestine of the next host
Taenia solium is otherwise known as ____
pork tapeworm
Briefly describe the life cycle of Taenia solium
Proglottids with thousands of eggs each are passed daily. When these eggs are ingested by pigs/humans, they hatch and burrow through the intestinal wall, move through blood to muscles where they develop into cysts called cysticerci. These contain a scolex, which, when eaten (under/uncooked), will anchor itself in the intestine. This worm grows for several months.
What symptoms can be caused by Taenia solium?
Depends on location of cystercerci. IN eye or CNS they can cause headaches, blindness, even death
