Drinking water quality Flashcards
what are main minerals in hard water
calcium and magnesium
where does hard water get its minerals
as it passes through rocks and soil
Why does soft water have low mineral content
- Hasn’t passed through rock and soil yet
- Rocks/soil passed through have little soluble minerals
USGS CaCO3 guidelines
soft- 61
moderately hard - 61-120
hard - 121-180
very hard - more than 181
what per cent of homes in America have at least moderately hard water
75%
What is limescale
deposits of calcium carbonate
when hard water is heated or sits for too long and evaporates
why need to remove the limescale
dull/dry hair
irritate skin
grow bacteria
more heating costs, loss of energy
dirty clothes even after wash
low water pressure
how to remove limescale
- soften water, replaces Ca and Mg with Na or K
- Chemical inhibitors
- Carbon filters: helps soften water
- Softener tablets
is hard water injurious to health
-no
- increased hard water drinking, reduced cardiovascular disease due to protective effect of magnesium
- more calcium less blood pressure
who supplies water to north of city
Bearspaw plant, Bow River
who supplies water to south of city
Glenmore plant, Elbow River
where do bow river and elbow river go
South Saskatchewan River -> lake winnipeg -> Hudson’s Bay
source of Bow River water
20% : rain/groundwater/glacier melt
80%: snowmelt
where is most Bow River water used
irrigation - 76%
municipal water -18%
when is water least hard
spring snowmelt
when is water the hardest
December and February
North calgary water hardness rating
mostly hard range
south calgary water hardness rating
extremely hard
what is maximum lead (BLL) exposure for children
5ug/dL
how has lead in children changed over past 40 years
dramatically decreased
2 main sources of lead for children
- Leaded gasoline
- Leaded paint
Health effects of lead poisoning in children
Learning disabilities
attention deficits
ADHD
Anemia
Current BLL of US adults
1.09 ug/dL
how many percent of adults in indoor firing ranges have BLL
34%: over 25
20.8%: 10-24
what is BLL
blood lead levels
spending 2 days every month at outdoor firing range can
quadruple BLL
how to reduce lead exposure
showering and changing into new clothes after
Gout, severe painful arthritis, BLL level
1.2 ug/dL
Where is most lead in body
Bones, 90%
Persistent source of toxicity, how?
gradual release from bones
after lead was taken away from gasoline, what happened to IQ levels
increased by 4-5 points
why was lead added to gasoline?
- tetra ethyl lead reduced engine knocking due to pre ignition
- more powerful high compression engines
problems with lead
health and environmental damage of Pb
incompatibility of Pb with catalytic convertors
