The good news is that a
simple validation protocol is now available on a real time basis and
does not necessitate expensive lab work. This is great as by the
time it is obvious it is already risky. Too bad other problems
demanding testing cannot be handled as easily.
At least now those
recreational lakes out there that are always old favorites can be
monitored easily. Their condition has been progressively impacted
over the years and problems can simply sneak up on you. This is
particularly true in terms of fertilizer application.
It is a nice fix.
Practical Tool
Can 'Take Pulse' Of Blue-Green Algae Status In Lakes
by Emily Caldwell
Columbus OH (SPX) Jun 07, 2012
The research also
showed that 26.4 percent of water samples taken from seven Ohio lake
beaches in 2009 showed that microcystin levels exceeded the lowest
threshold for health risks as determined by the World Health
Organization (WHO). This finding alone suggests that Ohio's inland
lakes need better protection from potential threats to water quality,
the scientists say.
Scientists have
designed a screening tool that provides a fast, easy and relatively
inexpensive way to predict levels of a specific toxin in lakes that
are prone to blue-green algal blooms.
Blue-green algae is not your average pond
scum - rather than
consisting of plant-like organisms, blue-green algae actually are
cyanobacteria, and some species are linked to the production and
release of the toxin microcystin into the water. Human
exposure to the toxin through drinking or recreational water contact
can threaten public health by causing liver damage, neurological
problems and gastrointestinal illness in humans.
The Ohio State University researchers devised a tool that would
allow inland lake beach managers to test water
samples for the existence
of a pigment called phycocyanin - the substance that gives blue-green
algae their distinctive color. Measures of the pigment level combined
with an assessment of the water's transparency provide strong clues
as to whether microcystin is at high enough levels to threaten
health.
According to Tim
Buckley, "Using this tool is kind of like taking the vital
signs of a lake. Phycocyanin measurements coupled with transparency
measurements can give you the pulse of the blue-green algae situation
in a lake at any given moment in time," said Jason Marion,
lead author of the study and a postdoctoral researcher in
environmental health sciences at Ohio State.
If the screening
suggests that microcystin levels may be high enough to threaten
public health, additional testing could be done for confirmation. In
the meantime, beach managers would be better able to inform the
public of the risk from swimming or fishing in tested waters,
researchers say.
Jiyoung Lee added,
"That's really the power of this work. Beach managers have all
of the tools readily at their fingertips, and they have the necessary
skill level. It's an important step toward better protection of Ohio
residents," said Timothy Buckley, associate professor and chair
of environmental health sciences at Ohio State and senior author of
the study.
The research also
showed that 26.4 percent of water samples taken from seven Ohio lake
beaches in 2009 showed that microcystin levels exceeded the lowest
threshold for health risks as determined by the World Health
Organization (WHO). This finding alone suggests that Ohio's inland
lakes need better protection from potential threats to water quality,
the scientists say.
"Population
growth and urbanization in general, lacking or failing infrastructure
for managing storm water and wastewater, managing agricultural runoff
- all of those things come together to raise additional concern about
the future for these recreational water resources and public health,"
Buckley said.
"This screening
tool is only a solution in that it provides a means for a feedback
loop, but it's not going to decrease the threats to our surface
waters. It's just going to help us figure out how to better manage
the resources. Unfortunately, manage means limit public access, which
is not a good outcome."
This study focused
on lakes in Ohio that tend to contain significant amounts of organic
pollution and high nutrient levels, also known as eutrophic lakes.
Nutrients such as phosphorus find their way to lakes from a variety
of sources - among them farm fertilizers and failing septic systems -
which are known to contribute to the production of blue-green algae.
Precise testing for
the presence of microcystin itself in water is costly, time-consuming
and available only at specially equipped labs, and often is prompted
by public or agency reports of suspected blue-green algal blooms. The
researchers came up with a system that could be used for regular
surveillance of lakes so beach managers are better able to
immediately predict when conditions might be poor for swimming,
boating and other recreational uses.
The equipment
required for screening of phycocyanin levels is a portable, handheld
fluorometer, which costs about $2,300. Water transparency is measured
by a simple $25 tool called a secchi disk, which is submerged in
water until it can no longer be seen to determine the lake's clarity.
"Phycocyanin
has been used as a proxy for this type of algal bloom for a long
time, but we have really validated the predictive nature of
phycocyanin, especially in this type of water," said Jiyoung
Lee, an assistant professor of environmental health sciences and food
science and technology at Ohio State and corresponding author of the
study. "With the low cost and ready availability of these
instruments, I think more routine testing at lakes would be a good
use of this field-applicable, rapid and first-line screening tool so
managers can have an early warning that water may have a dangerous
level of toxin."
In the summer of
2009, the scientists collected 26 samples each from public beach
areas in lakes at seven Ohio state parks: Buck Creek, Delaware, Alum
Creek, Madison Lake, Deer Creek, Lake Logan and East Fork. "We
focused mostly on beaches where people swim and the opportunity for
water contact is the greatest," Marion said.
They documented
several characteristics of the water, including temperature; measures
of oxygen, chlorophyll, pH, organic pollution, phycocyanin and
microcystin; and transparency as determined by secchi disk depth.
Of those
characteristics, the combined levels of phycocyanin and water
transparency were shown to be highly predictive of levels of
microcystin. According to the model designed by the researchers,
beach managers could enter values for phycocyanin and secchi depth
into a spreadsheet or a simple mathematical formula and receive an
automatic calculation of whether microcystin levels are likely to be
high enough to pose at least minimal health risks.
For this study, the
researchers created a model that would predict a microcystin level of
at least 4 micrograms per liter of water, which equates to
approximately 20,000 cyanobacteria cells per milliliter. According to
the WHO, this represents the low end of risk for short-term health
problems such as skin irritation or gastrointestinal illness after
exposure to the water, and warrants an advisory to the public as well
as additional testing of the water.
"Our study
shows that as phycocyanin increases, the amount of blue-green algae
is likely to be increasing, and the amount of toxin production is
also likely to be increasing in this type of water," Marion
said. "When tested for effectiveness, this screening tool gives
very good to excellent reliability."
Lee is continuing
this work, conducting a new research project this summer to explore
environmental factors that affect microcystin production by
cyanobacteria and rapid detection of microcystin at Ohio beaches.
The research is
published in a
recent issue of the journal Environmental Science and Technology.
This study was supported by a grant from the Ohio Water Development
Authority. Additional co-authors include J.R. Wilkins and Cheonghoon
Lee of the Division of Environmental Health Sciences; Stanley
Lemeshow, dean of the College of Public Health
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