Naturally Occurring Contaminants In Drinking Water

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Naturally Occurring Contaminants In Drinking
Water

• Arsenic
• Uranium
• Manganese
• Fluoride

Are they in drinking water?
Is contamination a public health concern?
What can health officials do about it?
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Q Where is the problem?
A We dont know because

• The problem could show up anywhere as
  hydrological factors vary locally
• Arsenic, which occurs more frequently in Northern
  New England, tends to be found more often in NE
  CT wells
• Past results suggest that uranium is more often
  found in western CT wells
• High manganese may be caused by nearby activity
  such as excavating and composting
• Though recent reviews conclude that the fluoride
  MCL is high, the impact of fluoride in CT
  groundwater has not been evaluated.

Contaminated wells could be anywhere in the state
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Q Should We Be Concerned?
A Yes, for these reasons

• Arsenic is a known human carcinogen
• Uranium is toxic to kidneys, and EPA recently
  established an MCL based on this endpoint
• There is not enough water data to estimate the
  extent of exposure to the 600 K CT residents with
  private wells
• Because these are natural contaminants, DEP does
  not have the authority to intervene.

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Uranium Isotopes Relative Abundance Radiation

• 238U to 234Th
• alpha
• t1/24.5X109 years
• 235U to 231Th
• alpha
• gamma
• t1/2700X106 years

• U has been surveyed
• Newtown area (2000)
• Brookfield area (2006)

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Case Study Toxicity/Activity of 210Po Relative
to 238U
Should 210Po be more toxic than 238U?
Radiologically, one gram of 210Po is equivalent
to is 13 million killograms 238U
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Heavy Metals (e.g. Uranium) Affect Kidney
Function
E.G mercury, cadmium, lead, uranium, chromium,
platinum, etc.
Toxicokinetics
Toxicodynamics

• Low (
• non-biodegradable
• long half life
• Partial mimicry of nutrients
• (Zn, Cu, Fe)
• Bioaccumulation
• U is hard to get rid of
• Sequestered by SH groups
• Partially resorbed in kidney

• Renal toxicity
• Concentrated in nephron
• Damage to proximal tubule
• Caused by free U ion
• apoptosis

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Uranium in Connecticut Public Groundwater Wells
Frequency of wells with U 10 ug/l
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Uranium in Connecticut Public Groundwater Wells
Average detectable U concentration by town
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Fluoride Health Concerns/Benefits

• 1 mg/l optimal to promote oral health
• 19-13-B102 mandates monthly average of added Fl
• 0.8 to 1.2 mg/l
• WHO guideline is 1.5 mg/l

Higher exposures can cause fluorosis of teeth and
bones
How much is too much?

• Dental fluorosis (children under 8 yrs)
• Rarely serious (i.e. pitted), mostly cosmetic
• NOAEL- ? (maybe below 1 mg/l)
• Moderate and severe forms not seen below 2 mg/l

• Skeletal fluorosis (can be crippling)
• Clear effects at 14 mg/day total exposure
• Suggestive effects at 6 mg/day

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Fluoride in CT Groundwater Wells
It is rare to find fluoride above 1.2 mg/l in CT
groundwater wells
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Arsenic in Groundwater

• New England Region
• ME (statewide)
• 1-3 50 ppb 12-13 10 ppb (Loiselle et al.,
  2001)
• NH (southeastern)
• 10-15 50 ppb (Boudette et al., 1985)
• MA (eastern, i.e. Pepperell)
• 12 50 ppb (Zeuna Keane, 1985)
• CT (northeastern , i.e. South Woodstock)
• 8 50 ppb (ATSDR, 1998)
• 2/20 10 ppb (Brown Chute, 2001

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Arsenic in New England Wells (from Ayotte et al.,
1999)
A Bedrock wells
B Stratified drift wells
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Survey areas
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Results Dissolved Arsenic

• Colchester Area
• All wells below DL

• Woodstock Area
• 8/20 wells above DL
• 6/8 detects near S Woodstock
• 2/20 MCL (10 ug/l)

Localized problem Contamination is not
widespread but also, not predictable.
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What can be done?
Note DEP does not have a role and will not
supply bottled water

• Use compliance information to flag potential
  areas of concern
• Recommend additional testing of wells in areas of
  concern
• Target well owners
• New wells
• Existing wells adjacent to known sources
• Provide information on treatment and health
  effects
• E.g. fact sheets

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