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21st Annual Water Quality Report - 2010line breakpdf iconDownload Roslyn Water AWQR - May, 2011

What Does This Information Mean?

A review of the table indicates that our system has no violations. We have learned through our testing that some contaminants were detected; however, these contaminants were detected below the level prescribed by the State.


Although nitrate was detected below the MCL, it was detected at 5.86 mg/l which is greater than one-half of the MCL of 10 mg/l. Therefore, we are required to present the following information on nitrate in drinking water:


“Nitrate in drinking water at levels above 10 mg/l is a health risk for infants of less than six months of age. High nitrate levels in drinking water can cause blue baby syndrome. Nitrate levels may rise quickly for short periods of time because of rainfall or agricultural activity. If you are caring for an infant, you should ask for advice from your health care provider.”
The table also indicates that none of the samples analyzed for lead and copper monitoring exceeded the action levels. If present, elevated levels of lead can cause serious health problems, especially for pregnant women and young children. Lead in drinking water is primarily from materials and components associated with service lines and home plumbing. The Roslyn Water District is responsible for providing high quality drinking water, but cannot control the variety of materials used in plumbing components. When your water has been sitting for several hours, you can minimize the potential for lead exposure by flushing your tap for 30 seconds to 2 minutes before using water for drinking or cooking. If you are concerned about lead in your water, you may wish to have your water tested. Information on lead in drinking water, testing methods, and steps you can take to minimize exposure is available from the Safe Drinking Water Hotline or awww.epa.gov/safewater/lead.

 

TABLE OF DETECTED CONTAMINANTS
 
Contaminant
Violation
Yes/No
Date of Sample or Number of Samples
Level Detected (Range) (Average)
Unit
Measurement
MCLG
Regulatory Limit
(MCL, TT or AL)

Likely Source
of Contamination

 
  INORGANIC CONTAMINANTS/NITRATES
 
Total Alkalinity
NO
9
3.00 to 65.3
18.10
mg/l
n/a
None
 Naturally occurring.  
 
Calcium
NO
9
1.73 to 25.0
7.58
mg/l
n/a
None
 Naturally occurring.  
 
Calcium Hardness
NO
9
4.30 to 62.5
18.94
mg/l
n/a
None
 Naturally occurring.  
 
Chloride
NO
9
4.64 to 40.1
14.78
mg/l
n/a
MCL=250
 Naturally occurring or indicative of road salt contamination.  
 
Total Dissolved Solids
NO
9
18 to 196
74.67
mg/l
n/a
None
 Naturally occurring.  
 
Iron
NO
9
<20 to 60
20
µg/l
n/a
MCL=300(1)
 Naturally occurring.  
 
Magnesium
NO
9
0.78 to 14.6
3.90
mg/l
n/a
None
 Naturally occurring.  
 
Nitrate
NO
29
0.57 to 5.86
4.01
mg/l
10
MCL=10
 Runoff from fertilizer use; Leaching from septic tanks, sewage;Erosion of natural deposits.  
 
Sodium
NO
9
3.70 to 19.10
9.28
mg/l
n/a
(see Health
Effects)(2)
 Naturally occurring; Road salt; Water softeners; Animal waste.  
 
Sulfate
NO
9
<5.0 to 26.0
7.87
mg/l
n/a
MCL=250
 Naturally occurring.  
 
Total Hardness
NO
9
7.5 to 122.0
34.90
mg/l
n/a
None
 Naturally occurring.  
  LEAD AND COPPER
 
Lead
NO
2nd half
of 2008
<1.0 to 6.66
1.57(3)
µg/l
0
AL=15
 Corrosion of household plumbing systems; Erosion of natural deposits.  
 
Copper
NO
2nd half
of 2008
<0.02 to 0.12
0.08(4)
mg/l
1.3
AL=1.3
 Corrosion of household plumbing systems; Erosion of natural deposits, leaching from wood preservatives.  
  VOLATILE ORGANIC CONTAMINANTS  
 
Dichlorodifluoromethane
NO
48
<0.5 to 0.5
0.26
µg/l
n/a
MCL=5
 Used as a refrigerant.  
 
1,1,1 Trichloroethane
NO
48
<0.5 to 0.90
0.37
µg/l
n/a
MCL=5
 Discharge from metal degreasing sites and other factories.  
 
1,1 Dichloroethene
NO
48
<0.5 to 0.7
0.26
µg/l
n/a
MCL=5
 Discharge from industrial chemical factories.  
 
Tetrachloroethene
NO
48
<0.5 to 1.0
0.28
µg/l
n/a
MCL=5
 Discharge from factories and dry cleaners; waste sites; spills.  
  OTHER PRINCIPAL ORGANIC CONTAMINANTS  
 
1,1 Dichloroethene
NO
48
<0.5 to 1.20
0.47
µg/l
n/a
MCL=5
 Released into the environment as fugitive emissions and in waste water during production and use as a chemical intermediate solvent; used in vinyl chloride manufacturing; chlorinated solvent intermediate; coupling agent in anti-knock gasoline; degreasing agent.  
  UNSPECIFIED ORGANIC CONTAMINANTS  
 
Dacthal (DCPA)
NO
16
<1.0 to 2.7
0.86
µg/l
n/a
MCL=50
 Released to the environment through its use and application as an agricultural herbicide used on a wide range of vegetable crop  
  CONTAMINANTS LISTED IN TABLE 16 OF PART 5  
 
Methyl tert-butyl
ether (MTBE)
NO
48
<0.5 to 1.7
0.37
µg/l
n/a
MCL=10
 Released from gasoline storage tanks. MTBE is an octane enhancer in unleaded gasoline. Atmospheric deposition.  
 
Perchlorate
NO
10
<1.0 to 2.1
0.79
µg/l
n/a
MCL=18(5)
 Oxygen additive in solid fuel propellant for rockets, missiles and fireworks.  
  DISINFECTION BY-PRODUCTS  
 
Chloroform
NO
49
<0.5 to 0.70
0.33
µg/l
n/a
(6)
 By-product of drinking water chlorination needed to kill harmful organisms. TTHMs are formed when source water contains large amounts of organic matter.  
 
Bromoform
NO
49
<0.5 to 1.4
0.27
µg/l
n/a
(6)
 By-product of drinking water chlorination needed to kill harmful organisms. TTHMs are formed when source water contains large amounts of organic matter.  
 
Dibromochloromethane
NO
49
<0.5 to 1.30
0.28
µg/l
n/a
(6)
 By-product of drinking water chlorination needed to kill harmful organisms. TTHMs are formed when source water contains large amounts of organic matter.  
 
Total Trihalomethanes
NO
49
<0.5 to 3.4
0.89
µg/l
n/a
MCL=80
 By-product of drinking water chlorination needed to kill harmful organisms. TTHMs are formed when source water contains large amounts of organic matter.  
  RADIOLOGICAL  
Gross Alpha Activity
NO
8(2010)
-0.420 to 0.270
-0.153
pCi/l
0
MCL=15
 Erosion of natural deposits.  
 
Gross Beta Activity
NO
7(2006)
0.294 to 2.15
1.28
pCi/l
0
MCL=50(7)
 Decay of natural deposits and man-made emissions.  
Radium 228
NO
8(2010)
1.03 to 2.74
1.52
pCi/l
0
MCL=5
 Erosion of natural deposits  
 

Notes:

  1. If iron and manganese are present, the total concentration of both should not exceed 500 µg/l.
  2. Water containing more than 20 mg/l of sodium should not be used for drinking by people on severely restricted sodium diets. Water containing more than 270 mg/l of sodium should not be used for drinking by people on moderately restricted sodium diets.
  3. During 2008, 30 point of use samples were collected and analyzed for lead. The level included in the table represents the 90th percentile of the sites tested. The action level for lead was not exceeded at any of the sites tested.
  4. During 2008, 30 point of use samples were collected and analyzed for copper. The level included in the table represents the 90th percentile of the sites tested. The action level for copper was not exceeded at any of the sites tested.
  5. An MCL has not been established for this contaminant. The value represents a State Guidance Level.
  6. Total Trihalomethanes (TTHMs) have a MCL = 80 µg/l. TTHMs consist of Bromoform, Chloroform, Bromodichloromethane and Dibromochloromethane.
  7. The State considers 50 pCi/l to be the level of concern for beta particles.

Definitions:

  • Maximum Contaminant Level (MCL) - The highest level of a contaminant that is allowed in drinking water. MCLs are set as close to the MCLGs as feasible.
  • Maximum Contaminant Level Goal (MCLG) - The level of a contaminant in drinking water below which there is no known or expected risk to health. MCLGs allow for a margin of safety.
  • Action Level (AL) - The concentration of a contaminant which, if exceeded, triggers treatment or other requirements which a water system must follow.
  • Treatment Technique (TT) - A required process intended to reduce the level of a contaminant in drinking water.
  • Milligrams per liter (mg/l) - Corresponds to one part of a substance in one million parts of liquid (parts per million - ppm).
  • Micrograms per liter (ug/l) - Corresponds to one part of a substance in one billion parts of liquid (parts per billion - ppb).
  • N/A - This stands for not applicable. No MCLG has been established for this contaminant.
  • < - This symbol indicates the level is less than the number shown.
  • Picocuries per liter (pCi/l) - Picocuries per liter is a measure of the radioactivity in water.

  

 

 

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