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(Updated
8:30 p.m., March 25)
Changes
likely in wake of Petrie Island water study
By Fred Sherwin
Orléans Online
A study
aimed at trying to identify the source of higher than usual e-coli
counts at the Petrie Island beach in the summer of 2006, will likely
result in the automatic closure of the beach following a rainfall.
The study
conducted by Environment Canada’s National Water Research Institute
last summer, found that e-coli levels were consistently higher following
a moderate rainfall than they were normally.
All fresh
water contains e-coli, either from animal sources or humans. The federal
Ministry of Environment and most provinces including Quebec use a
standard of 200 parts per million per 100 ml of water in determining
what is safe and what isn't. Ontario's standard and the standard used
by the City of Ottawa's recreation department is 100 parts per million.
In 2006,
the beach at Petrie Island was closed 45 days due to e-coli counts
in excess of 100 parts per million. Although a large number of the
closures followed excessive rainfalls, a high number did not, which
prompted the city to call in the Ministry of Environment.
In 2007,
the beach was only closed six days following moderate to heavy rainfalls.
The Ministry of Environment study found that the water quality at
Petrie Island was well within provincial and federal standards for
most of the summer. The only exceptions were following moderate rainfalls
on June 28, July 9 and Aug. 7. In those instances, 50 per cent of
the water samples taken contained bacteroid markers consistent with
human fecal matter.
By comparison,
on the 13 so-called "dry sampling days", only two of the
51 water samples taken contained the same bacteroid DNA marker. Unfortunately,
the study failed to quantify the number or level of the bacteroid
DNA marker present in the samples.
In general,
the bacteroid DNA marker consistent with human fecal matter was present
in 11 per cent of the water samples taken during the swimming season
from June 1 to Aug. 31, from a high of 22 per cent in ankle deep water
in June, to as low as zero per cent in chest deep water in August.
During
that same period of time the average level of e-coli in chest deep
water was well below both federal and and provincial standards at
all four testing points on Petrie Island, and slightly above provincial
levels but still below federal levels in ankle deep water in July
and August.
In general,
the study confirmed much of what the city's parks and recreation department
already knew, says parks and recreation manager Dan Brisebois.
"We
were confident that the water is generally safe to swim in except
after a heavy rainfall which is usually accompanied by a spike in
e-coli. One of the recommendations coming out of this is that the
beach should automatically be closed following a rainfall in excess
of five millimetres which is already the case at Westboro Beach. But
to say that the beach should be closed permanently or that it should
never have been created in the first place is a stretch. The beach
at Petrie Island is no worse or no better than any other beach in
the city," says Brisebois.
Several
of the more alarming findings made by the study can easily be explained
by the annual spring flooding which leaves debris such as condoms,
tampon applicators and syringes along the beach.
During
a walk along the beach following the spring flooding last April, researchers
found 37 tampon applicators, five condoms, and two syringes. The study
suggests the debris was the result of untreated municipal waste water,
but fails to indentify where the untreated municipal waste water may
have originated from.
The study
also uncovered evidence that sea gulls are contributing to the level
of e-coli in ankle deep water at the beach and in the damp sand near
the water's edge which contains virtually no bacteroid DNA markers
for human fecal matter. The findings are consistent with nearly every
other beach where similar studies have been down.
Brisebois
says the city will likely cut down on the amount of grooming along
the water's edge so as not to stir up the wet sand.
The final
recommendation coming out of the study is that it be expanded to determine
the source of the e-coli, whether it is human or not, and the level
of and type of waterborne pathogens commonly associated with certain
strains of the e-coli bacteria.
(This
story was made possible thanks to the generous support of our local
business partners.)
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