Presented by:
Heather Florence
Island Health
April 16, 2015
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Assess risk to consumers
Manage/Reduce risk to consumers
Detect trends over time
Establish system historical reliability
Evaluate system performance and management
◦ is current treatment/disinfection effective
◦ will additional methods be required
Requirement under the Drinking Water Protection Act
Without monitoring you really never know what the
water quality is…
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Refer to Operating Permit/Sampling Program
Discuss with DWO
Consider Provincial, Federal and International
Standards
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Drinking Water Protection Regulation
BC Surface Water Quality Objectives
Guidelines for Canadian Drinking Water Quality
US EPA, WHO
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Raw water – where, why and how often and
for what parameters
Finished water – where, why, how often and
for what parameters
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Fecal contamination from
humans and animals
 Wildlife
 Farm/pets
 Improper sewage systems
 Runoff
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Chemical Contamination
from humans
 Accidents and spills
 Long term impacts from
industry and agriculture
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Inadequate treatment
Treatment system failure
Cross connection (backflow)
Infiltration through water line
breaks/leaks
Naturally Occurring
Chemicals
 Arsenic
Source Water
Water Works
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Microbiological
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Chemical/Physical
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Operational
Pathogens versus Chemicals
Pathogens pose the greatest risk
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Can change from day to day.
Not evenly distributed in the water
What is not here today may be here tomorrow.
Single exposure can result in illness
Chemistry changes slowly over time.
 Evenly distributed in the water supply e.g. iron
http://www.nccph.ca/docs/SDWS_Water-borne_EN.pdf
46 of 48 events investigated were due to microbial
causes. Only 2 were chemical.
Pathogens; Three distinct groups
 Protozoa size 8000 nm
 Bacteria size 500 nm
 Viruses size 20-90 nm
There are many different types of bacteria,
viruses and protozoa but only a few are
disease causing (pathogenic). Some are
actually helpful.
PROTOZOA
400x
8000 nm
BACTERIA
VIRUSES
25x
500 nm
20 – 90 nm
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i.e. Giardia and Cryptosporidium
Multiply only in the intestine of animals and
humans (not in water)
2 forms:
◦ Active/feeding/reproducing stage (trophozoite)
◦ Dormant stage (cyst)- withstand harsh
conditions to infect new hosts (lengthy survival
times)
As few as 10 cysts can cause illness
Can be filtered by soil due to organism size
versus the size of soil pore spaces
Not destroyed by chlorination
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Campylobacter, E. coli 0157, Salmonella
Single cell , size 500 nm
Multiply in the gut of animals and humans
Doses to cause illness;
• Salmonella 100 MO’s 10%-20% 1,000,000 MO’s
60%-80%
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May survive for a while in water but will not
multiply
Destroyed by chlorination and UV disinfection
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Tiny, 20 nm – 70 nm -> Can travel through soil
pore spaces (silt 200- 50,000 nm)
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Genetic material surrounded by a protein or lipid
based coat (Not cellular microorganisms)
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Can only reproduce inside a living cell (obligate
intracellular parasite)
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Human to human transmission very common
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Low numbers to cause illness (18 for Norovirus)
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Inactivated by chlorination and UV disinfection
Microorganism
Freshwater
Ground Water
Viruses
11 days – 304 days
11 days – 1 year
Salmonella
1 day – 2 months
Vibrio Cholera
5 days – 25 months
Protozoan cysts
176 days, 18+ months 2 – 6 months
E. Coli indicator group
30 days, 90 days
10 days – 35 days
40 days
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Giardia $210 (analysis) + 100 litres + filter
Salmonella $35
Campylobacter $40
Virus $1000
Generally…No
(Cost prohibitive, time consuming, impractical, and
overly specific)
During an outbreak… Yes
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Relatively simple and inexpensive to monitor
Concentrations can be correlated to extent of
contamination.
Requirements for survival are similar to
pathogens of concern
Indicator organisms coexist with pathogens
(but tend to be more plentiful)
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Total coliform bacteria
E. Coli bacteria
Total coliform
Fecal coliform (old term)
E. coli
(multiple strains)
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Live in the environment (water and soil)
Not naturally present in secure ground water
Can reproduce in many places in the
environment
Easily destroyed by simple disinfection
Fast and inexpensive test $25
Standard: no total coliforms and no E. coli detectable per 100 mL
L1/L1
However…
Ability of total coliform’s to predict recent faecal contamination is
very limited, so where more than one sample set is obtained per
month:
No sample should contain Escherichia coli (E. coli).
No consecutive samples from same site or not more than 10% of
samples in a given month with total coliform bacteria.
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We look at the number reported, results of
other same day samples, sample history,
contributing circumstances, and MOST
IMPORTANTLY…location:
Drinking water source?
Well versus surface water?
Finished water supply means?
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Work was performed on the well or well pump?
Sanitation issues with the well?
Well under direct influence of surface water?
Well otherwise susceptible to contamination?
What to do?
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Check well (pooling water, damage, missing cap).
Check maintenance log- was well disinfected after
any work performed?
Resample.
Shock the well with chlorine- use standard
procedures
WHY?
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Disinfection not effective when sample was obtained
Contamination may have occurred within the system.
Operational issues within the distribution system.
What to do?
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Check disinfection
Check maintenance history
Check flushing history- stagnant water?
Check operational procedures- disinfection of pipes?
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Subset of the total coliform bacteria group
Live only in the intestinal tract of animals and
humans
Do not survive long in the environment
Indicator of recent fecal contamination
Destroyed by chlorination and UV disinfection
Fast and inexpensive test $25
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Consider results of other same day samples,
sample history, operational circumstances,
and MOST IMPORTANTLY…
will the water receive disinfection prior to
consumption??
Unless water will be disinfected after the
sample site and before it reaches the
consumer, risk must be evaluated and
managed….COMMUNICATION
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Fill in time and date on bottle label and from,
seal form in bag.
Wash hands
Remove aerator
Run water for 2 minutes
Remove sample bottle cap and hold without
touching inside surfaces or putting down
Fill sample bottle to fill line (no overflow)
Firmly replace cap, and bag holding the form
Pack on ice and promptly ship out
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Chemical/Physical
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Operational
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Alkalinity
Aluminum
Arsenic
Barium
Biochemical oxygen
demand
Chemical oxygen demand
Boron
Calcium
Chloride
Chlorophyll a
Copper
Fluoride
Iron
Lead
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Magnesium
Manganese
Nitrogen, ammonia
Nitrogen, nitrate
Nitrogen, nitrite
pH
Phosphorus
Potassium
Selenium
Sodium
Sulphate
Total dissolved solids
Total suspended solids
Zinc
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Aesthetic Objective (AO): colour, pH, sodium
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Maximum Allowable Concentration (MAC)
◦ Potential Health Effects associated – arsenic, fluride
◦ All water supply systems must be in compliance
with health related requirements (the MAC’s).
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Contact Lab
Obtain bottles and instructions on sample
collection
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pesticides, herbicides, hydrocarbons,
pharmaceuticals, trihalomethanes, haloacetic
acids
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Chlorine demand and residual
Temperature
Turbidity
Conductivity
pH
Treatment/Disinfection system performance
TOC
Consumer complaints (taste, odor,
appearance)
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Real time measurement
May aide in the interpretation of sample
results/determination of corrective actions
Provides clues to other water quality issues
not just microbiological concerns
Inexpensive
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Share them with the consumers (annual
report, communications regarding required
upgrades etc.)
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Share them with the HA
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Compare results over time
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Compare results between sample sites
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Clear and complete
Centrally located
Easily accessible
Compliance= meeting the requirements plus
demonstrating that compliance has been met.
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Total Coliform-abundant in environment, not
necessarily an indicator of fecal contamination
E. coli - indicative of recent fecal contamination
(so pathogens may be present)
E. coli reproduce only in gut of humans and
animals (Do not persist in environment)
Both are destroyed by UV and chlorination
Both are bacteria (as opposed viruses or
protozoa)
Total coliform and E. coli test is not a test for
protozoa or viruses
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Untreated Surface Water (lake)
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Dug Well 25 ft deep in an unconfined sand and gravel
aquifer. Water table 10 ft below ground’s surface
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Drilled well 135 feet deep into a confined aquifer. Water
table 100 ft below ground’s surface
For each of these water sources consider three different
sample results.
Sample A) L1 total coliform and L1 E. coli per 100 ml
Sample B) est. 15 total coliform and L1 E. coli per 100 ml
Sample C) 53 total coliform and est. 12 E. coli per 100 ml
Note: L = less than and est. = estimated
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Raw water
Treatment/disinfection will occur so positive
results are not of concern
All samples are useful for monitoring source
water quality
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Untreated Surface Water (lake)
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Dug Well 25 ft deep in an unconfined sand and gravel
aquifer. Water table 10 ft below ground’s surface
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Drilled well 135 feet deep into a confined aquifer. Water
table 100 ft below ground’s surface
For each of these water sources consider three different
sample results.
Sample A) L1 total coliform and L1 E. coli per 100 ml
Sample B) est. 15 total coliform and L1 E. coli per 100 ml
Sample C) 53 total coliform and est. 12 E. coli per 100 ml
Note: L = less than and est. = estimated
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25 ft. deep, unconfined aquifer, water at 10ft
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Under direct influence of surface water (GUDI)
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At risk of containing pathogens (GARP)
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Irregular results not unusual (dependent on
weather, chance contamination)
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Disinfection required (or existing disinfection
may be ineffective)
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Untreated Surface Water (lake)
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Dug Well 25 ft deep in an unconfined sand and gravel
aquifer. Water table 10 ft below ground’s surface
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Drilled well 135 feet deep into a confined aquifer. Water
table 100 ft below ground’s surface
For each of these water sources consider three different
sample results.
Sample A) L1 total coliform and L1 E. coli per 100 ml
Sample B) est. 15 total coliform and L1 E. coli per 100 ml
Sample C) 53 total coliform and est. 12 E. coli per 100 ml
Note: L = less than and est. = estimated
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135 ft. deep, confined aquifer, water at100 ft.
Potentially a secure ground water source-so
why the bad samples?
◦ Physical problem with the well?
◦ Maintenance performed without shock chlorination?
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Inspect well for damage, shock chlorinate,
consider GUDI/GARP assessment
Heather Florence
[email protected]
3rd floor 6475 Metral Drive Nanaimo
(250) 755-6215