Potable Water - Saraniecki Flashcards
Nitrates
Significant disease?
MCL?
Water treatment?
Sources?
relatively non-toxic except to infants under 6 months
higher pH in intestinal tract allows bacterial conversion of nitrates to nitrite
nitrite attacks heme, no oxygen carry in blood, baby turns blue, treated with methylene blue
MCL 10 ppm
Water treatment: distillation, reverse osmoses, ion exchange, boiling
Sources: ammonia fertilizers, animal feedlots, human wastes
How is benzene a risk in water?
VOC
chomosomal aberrations
increased risk of cancer
What does toluene cause?
VOC
pronounced nervous disorders, spasms, tremors
impaired speech, hearing, vision, memory
kidney and liver damage
Where is perchloroethylene from? How is it consumed and what does it cause?
MCL?
used in dry cleaning of fabrics and metal degreasing
inhalation risk or ingestion of contaminated food or water, skin absorption
PERC is stored in animal fatty tissues
Group 2A human carcinogen - reasonably anticipated to be a human carcinogen
damages CNS
MCL 0.005 mg/l
What does lead in water cause?
implicated in stroke and kidney disease
increased risk of cancer
childhood delayed mental development
What does cadmium in water lead to? Sources?
kidney damage
sources - galvanized pipe, cisterns, pesticides
What does fluoride in water do?
mottled teeth/bone disease
4.0 ppm action level
Where does arsenic come from to be found in water?
found in natural rock formations, industrial wastes, pesticides, fertilizers
10 ppm MCL
What is atrazine and what might it cause?
synethetic organic chemical
man made pesticide
may cause weight loss, cardiovascular damage, retinal damage, increase risk of cancer
What is alachlor and what might it cause?
synthetic organic chemical
man made pesticide
eye, liver, kidney, spleen problems, anemia, increased risk of cancer
What are radionuclides and are the MCLs?
naturally occurring particles, possible from nuclear fallout
emit alpha and beta radiation
alpha particles from Radon is the major preventable cancer concern - action level 300 pCi/l
uranium poisoning linked to kidney toxicity
MCL alpha - 15 pCi/l
MCL beta - 4 millirems/year
MCL gamma is zero
What contaminants would cause acute health effects?
pathogens and nitrates
What contaminants would cause chronic health effects?
VOCs
IOCs
SPCs
radionuclides
What is Crenothrix?
nuisance microorganism
iron bacteria that does not usually cause disease
causes severe fouling or plugging of pipes
reddish-orange slimy deposits
adds iron flavor to water
How must water and sewer lines be separated?
must be laid below frost level
must be kept 10’ horizontal separation, 18” vertical separation
Describe a dug well
shallow, 10-35 ft
watertight casing material
sealed in cement grout or bentonite clay
mounded ground for runoff
Describe a bored well
does not penetrate bedrock
relies on ground water that is filtered by local soil
large diameter, 20”-36”, 30’ to 100’ deep
Describe a driven well
30-50+ ft deep
pulls water from saturated zone
usually sand screen point
2” to 4” pipe
pump at top of well in an access pit below the frost line or in the house
Describe a drilled well
100-400ft into bedrock fractures
6” well casing extends into bedrock and 1-2’ above ground
sealed with cement or bentonite to avoid contamination
most sanitary type of system
What soil formations indicate good water sources?
sedementary- weathered or eroded rocks and decomposed organic material
sand, gravel, peat, shale, sandstone
basalt
What soil formations indicate poor water sources?
igneous - formed by cooling and hardening of molten rock, granite, diorite
metamorphic - heat and pressure treated, sedimentary and igneous rock
What are Karst areas?
fast moving underground water through very porous limestone that forms caves, sink holes, tunnels
usually contaminated
What does a positive fecal coliform test indicate in regards to polution?
fresh pollution
What does a positive Clostridium perfringens indicate in regards to pollution?
previous pollution
What is the stream zone of degradation?
near point source pollution
decreased O2
increased suspended solids
fish diminish
snails and worms pervade
What is the stream zone of active decomposition?
O2 near zero
high turbidity
foul ordors
no fish
only worms and larvae
most polluted zone
Describe the stream zone of recovery
gradual reversal
first more O2
less odors
then clams, snails, crawfish, bugs, flies
later fish
What are ABS and LAS pollutants?
detergents contain surfactants that lower the surface tension of water that allows adhered grease and dirt to be washed off
ABS - Alkyl Benzene Sulfonates
LAS - Linear Alkyl-benzene Sulfonates
What do surfactant pollutants do to surface water?
reduce O2 transfer at water surface
remove natural oils from fish gills - suffocation
contain nitrogen and phosphates, provoking algae blooms and eutrophication
biodegrade slowly
indicate sewage pollution
What do surfactant pollutants do to well water?
not harmful
indicate sewage pollution
How do you remove surfactants from drinking water?
carbon absorption
What is MBAS assay?
methylene blue active substance - any compound that reacts with the indicator chemical methylene blue
this detects surfactants, which indicates sewage pollution
What are some methods for emergency water treatment?
boil clear water for 1-2 mins
pressure cook water for 250F for 15 min
chlorinate - 6-8 drops chlorox per gallon, 1 pint chlorox per 1000 gallons, 30 min contact time, double amount of bleach if turbid
At what amount can hydrogen sulfide exposure be fatal?
300 ppm
What does hard water do to typical house chores
makes it difficult to produce suds or rinse laundry, dishes, food equipment
