Bacterial Pollution in Poquoson by qcr20525

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									Bacterial Pollution in
    Poquoson

 Actions to find the sources.
       Tom Meree 12 February 2007
         High Pollution Areas
• The following chart shows where the highest
  pollution in Poquoson is – near population
  densities.
• Data is for a given sampling point averaged over
  1986 to 2006 (21 years). Many readings are
  much higher than the average. The are about 50
  locations measured each month in Poquoson
  waters.
• The only pollution measured is fecal coliforms;
  not nutrients, sentiments or hazardous materials.
         Pollution Over Time
• The trend for bacterial pollution has
  increased slightly in Back River and
  Bennett’s Creek and stayed about the same
  in the Poquoson River over the last 21 years.
• The installation of City wide sewers has not
  decreased bacterial pollution.
• Levels of concern are 49 for oyster
  harvesting and 400 for beach swimming.
• In 2006, there were 12 samples over 400 in
  Poquoson creeks.
                                                 Fecal Coliform (MPN) Sample Data




                                           100
                                                      200
                                                                300
                                                                         400
                                                                                    500
                                                                                          600




                                       0
                            1/2/1986
                            7/2/1986
                            1/2/1987
                            7/2/1987
                            1/2/1988
                            7/2/1988
                            1/2/1989
                            7/2/1989
                            1/2/1990
                            7/2/1990
                            1/2/1991
                            7/2/1991
                            1/2/1992
                            7/2/1992
                            1/2/1993
                            7/2/1993
                            1/2/1994
                            7/2/1994
                            1/2/1995




Average Single Day Sample
                            7/2/1995
                            1/2/1996
                            7/2/1996
                            1/2/1997
                            7/2/1997
                            1/2/1998
                            7/2/1998
                                                                                                Back River Average Fecal Coliforms




                            1/2/1999
                            7/2/1999
                            1/2/2000
12 Past Sample Average      7/2/2000
                            1/2/2001
                            7/2/2001
                            1/2/2002
                            7/2/2002
                            1/2/2003
                            7/2/2003
                            1/2/2004
                            7/2/2004
                            1/2/2005
                            7/2/2005
                            1/2/2006
                            7/2/2006
                                                 Fecal Coliform (MPN) Sample Data




                                            50
                                                  100
                                                         150
                                                                200
                                                                       250
                                                                              300
                                                                                    350
                                                                                          400




                                        0
                            1/23/1986
                            7/23/1986
                            1/23/1987
                            7/23/1987
                            1/23/1988
                            7/23/1988
                            1/23/1989
                            7/23/1989
                            1/23/1990
                            7/23/1990
                            1/23/1991
                            7/23/1991
                            1/23/1992
                            7/23/1992
                            1/23/1993
                            7/23/1993
                            1/23/1994
                            7/23/1994
                            1/23/1995




Average Single Day Sample
                            7/23/1995
                            1/23/1996
                            7/23/1996
                            1/23/1997
                            7/23/1997
                            1/23/1998
                            7/23/1998
                                                                                                Bennett Creek Average Fecal Coliforms




                            1/23/1999
                            7/23/1999
                            1/23/2000
12 Past Sample Average
                            7/23/2000
                            1/23/2001
                            7/23/2001
                            1/23/2002
                            7/23/2002
                            1/23/2003
                            7/23/2003
                            1/23/2004
                            7/23/2004
                            1/23/2005
                            7/23/2005
                            1/23/2006
                            7/23/2006
                                                  Fecal Coliform (MPN) Sample Data




                                            100
                                                  200
                                                        300
                                                              400
                                                                    500
                                                                          600
                                                                                700
                                                                                      800
                                                                                            900




                                        0
                            1/23/1986
                            7/23/1986
                            1/23/1987
                            7/23/1987
                            1/23/1988
                            7/23/1988
                            1/23/1989
                            7/23/1989
                            1/23/1990
                            7/23/1990
                            1/23/1991
                            7/23/1991
                            1/23/1992
                            7/23/1992
                            1/23/1993
                            7/23/1993
                            1/23/1994
                            7/23/1994
                            1/23/1995




Average Single Day Sample
                            7/23/1995
                            1/23/1996
                            7/23/1996
                            1/23/1997
                            7/23/1997
                            1/23/1998
                            7/23/1998
                                                                                                  Poquoson River Average Fecal Coliforms




                            1/23/1999
                            7/23/1999
                            1/23/2000
12 Past Sample Average
                            7/23/2000
                            1/23/2001
                            7/23/2001
                            1/23/2002
                            7/23/2002
                            1/23/2003
                            7/23/2003
                            1/23/2004
                            7/23/2004
                            1/23/2005
                            7/23/2005
                            1/23/2006
                            7/23/2006
        When Pollution Occurs
• The next chart shows pollution levels by the orange
  squares for 2005 and 2006. The red dots show days of
  heavy rain and the three floods of 2006 are shown. The
  blue diamonds show the amount of sewage pumped
  from Poquoson each day.
• Higher pollution is usually preceded by a heavy rain
  or flooding. Sometimes there is a heavy rain or
  flooding and there is not high pollution. It seems
  that the source may have been “cleaned out”.
• One can see that usually when there is flooding or heavy
  rain, the sewage flow from Poquoson goes up. This is
  probably due to infiltration into the sanitary sewer
  system.
                                                                                        2005- 2006 Poquoson Sewage Flow, Rainfall and Pollution
                                                         3,000                                                                                                                                     600.0
HRSD Poquoson Sewage Flow - Average Gallons Per Minute




                                                                                                                                                                       Ernesto   Nor'Easters
                                                                     Red Dots show days of rainfall over an inch.
                                                         2,500                                                                                                                                     500.0



                                                         2,000                                                                                                                                     400.0




                                                                                                                                                                                                           Fecal Coliforms
                                                         1,500                                                                                                                                     300.0



                                                         1,000                                                                                                                                     200.0



                                                          500                                                                                                                                      100.0



                                                            0                                                                                                                                      0.0
                                                            1/1/05            4/11/05                 7/20/05       10/28/05           2/5/06             5/16/06      8/24/06           12/2/06
                                                                                                                      Sewage Avg Flow
                                                                                                                      High Rainfall Days
                                                                                                                      Average Fecal Coliforms - High Pollution Areas
   Consequences of Pollution
• Pollution impairs the health of the Bay and
  puts the public at risk.
• Since the high fecal coliform levels in our
  waters are apparently coming from the
  land after heavy rains or flooding, there
  may be higher concentrations of fecal
  coliforms on land. If true, this is not
  healthy for people on land either.
Some Possible Causes of Pollution
•   Sewer system overflows / leakage.
•   Septic system leaching / flooding.
•   Ponds concentrating pollutants.
•   Animal waste.
•   Boats at marinas.
Probably a combination of the above varying for different
  rain and flooding conditions.
Need to test to determine source to be able to prioritize
  cleanup actions!
               Sewer System
• The sewer system has been observed to overflow during
  extreme flooding (Isabel, Ernesto, Nor’Easters).
• Sewer system has infiltration as shown by increased
  sewage pumping volumes and system pressure during
  heavy rains and flooding.
• Is there leakage out at the higher system pressure?
  There are not consistently high pollution levels
  following periods of high sewage pumping, so the
  sewer system may not be the principal cause.
• Leaking sewage water can be “seen” by either putting
  marker dye in the sewage or by looking for washing
  machine chemicals. The City does some testing but
  more testing is needed.
            Septic Systems
• In Poquoson, there are 59 or fewer septic
  systems still in known use.
• Septic tanks are supposed to be emptied and
  filled when disconnected. So pollution from
  septic systems should have decreased.
• The City Public Works checks properties for
  proper hookup and leaks when there is another
  reason to check. The City should aggressively
  check for improper sewage discharges.
                BMP Ponds
• Almost all of the BMP (Best Management
  Practice) ponds in Poquoson are designed for
  sediment capture and water volume retention,
  not bacterial treatment. Do these ponds
  concentrate and nurture fecal coliforms?
• Heavy rains and extreme flooding could then
  easily flush contaminated BMP water into the
  Bay.
• Also our ditches with stagnant water could
  contribute.
• It would be easy to test by sampling in several
  seasons for fecal coliforms.
              Animal Waste

• Animal waste is thought by some to be a
  principal contributor. But it is not clear that
  animal waste is present in the quantities needed
  for the high pollution readings we see.
• We can test for this source by a process called
  “speciation”. Speciation is where individual
  samples are examined to see which species of
  animal the fecal coliform comes from. For our
  purposes, it would be important to know only
  whether the waste is human or animal.
           Boats At Marinas
• There are two large marinas on Bennett’s Creek
  and the sampling point between them has a high
  average fecal coliform reading.
• There have been people living on board their
  boats at both marinas.
• But the fecal coliform sample at this point is
  often below 10. The samples are much higher
  after flooding or heavy rainfall, so the fecal
  coliform pollution from the boats is probably
  not a major contributor to the peak pollution
  levels at this one sampling point.
                             Action

•   The City needs to get the Va Dept of Health, Dept of
    Environmental Quality and Hampton Roads Sanitation
    Department fully involved to take advantage of their expertise.

1. Test BMP ponds and stagnant ditches for fecal coliforms and
   other pollutants.
2. After intense rains or floods:
   1. Sample areas around highly polluted areas to determine
      source.
   2. Do a “speciation” of a limited number of samples to
      determine whether human or animal waste is the primary
      cause of high pollution readings.
3. Continue to search for sewer system leaks and improper
   hookups. Evaluate methods to prevent sewer system
   overflows during flooding conditions.

								
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