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Blue-green algae is not your average pond scum -- rather thanconsisting of plant-like organisms, blue-green algae actually arecyanobacteria, and some species are linked to the production andrelease of the toxin microcystin into the water. Human exposure tothe toxin through drinking or recreational water contact canthreaten public health by causing liver damage, neurologicalproblems and gastrointestinal illness in humans. The Ohio State University researchers devised a tool that wouldallow inland lake beach managers to test water samples for theexistence of a pigment called phycocyanin -- the substance thatgives blue-green algae their distinctive color. Measures of thepigment level combined with an assessment of the water'stransparency provide strong clues as to whether microcystin is athigh enough levels to threaten health. "Using this tool is kind of like taking the vital signs of alake. Phycocyanin measurements coupled with transparencymeasurements can give you the pulse of the blue-green algaesituation in a lake at any given moment in time," said JasonMarion, lead author of the study and a postdoctoral researcher inenvironmental health sciences at Ohio State. If the screening suggests that microcystin levels may be highenough to threaten public health, additional testing could be donefor confirmation. In the meantime, beach managers would be betterable to inform the public of the risk from swimming or fishing intested waters, researchers say. "That's really the power of this work. Beach managers have allof the tools readily at their fingertips, and they have thenecessary skill level. It's an important step toward betterprotection of Ohio residents," said Timothy Buckley, associateprofessor and chair of environmental health sciences at Ohio Stateand senior author of the study. The research also showed that 26.4 percent of water samples takenfrom seven Ohio lake beaches in 2009 showed that microcystin levelsexceeded the lowest threshold for health risks as determined by theWorld Health Organization (WHO). This finding alone suggests thatOhio's inland lakes need better protection from potential threatsto water quality, the scientists say. "Population growth and urbanization in general, lacking orfailing infrastructure for managing storm water and wastewater,managing agricultural runoff -- all of those things come togetherto raise additional concern about the future for these recreationalwater resources and public health," Buckley said. "This screening tool is only a solution in that it provides ameans for a feedback loop, but it's not going to decrease thethreats to our surface waters. It's just going to help us figureout how to better manage the resources. Unfortunately, manage meanslimit public access, which is not a good outcome." The research is published in a recent issue of the journal Environmental Science & Technology . This study focused on lakes in Ohio that tend to containsignificant amounts of organic pollution and high nutrient levels,also known as eutrophic lakes. Nutrients such as phosphorus findtheir way to lakes from a variety of sources -- among them farmfertilizers and failing septic systems -- which are known tocontribute to the production of blue-green algae. Precise testing for the presence of microcystin itself in water iscostly, time-consuming and available only at specially equippedlabs, and often is prompted by public or agency reports ofsuspected blue-green algal blooms. The researchers came up with asystem that could be used for regular surveillance of lakes sobeach managers are better able to immediately predict whenconditions might be poor for swimming, boating and otherrecreational uses. The equipment required for screening of phycocyanin levels is aportable, handheld fluorometer, which costs about $2,300. Watertransparency is measured by a simple $25 tool called a secchi disk,which is submerged in water until it can no longer be seen todetermine the lake's clarity. "Phycocyanin has been used as a proxy for this type of algalbloom for a long time, but we have really validated the predictivenature of phycocyanin, especially in this type of water," saidJiyoung Lee, an assistant professor of environmental healthsciences and food science and technology at Ohio State andcorresponding author of the study. "With the low cost andready availability of these instruments, I think more routinetesting at lakes would be a good use of this field-applicable,rapid and first-line screening tool so managers can have an earlywarning that water may have a dangerous level of toxin." In the summer of 2009, the scientists collected 26 samples eachfrom public beach areas in lakes at seven Ohio state parks: BuckCreek, Delaware, Alum Creek, Madison Lake, Deer Creek, Lake Loganand East Fork. "We focused mostly on beaches where people swimand the opportunity for water contact is the greatest," Marionsaid. They documented several characteristics of the water, includingtemperature; measures of oxygen, chlorophyll, pH, organicpollution, phycocyanin and microcystin; and transparency asdetermined by secchi disk depth. Of those characteristics, the combined levels of phycocyanin andwater transparency were shown to be highly predictive of levels ofmicrocystin. According to the model designed by the researchers,beach managers could enter values for phycocyanin and secchi depthinto a spreadsheet or a simple mathematical formula and receive anautomatic calculation of whether microcystin levels are likely tobe high enough to pose at least minimal health risks. For this study, the researchers created a model that would predicta microcystin level of at least 4 micrograms per liter of water,which equates to approximately 20,000 cyanobacteria cells permilliliter. According to the WHO, this represents the low end ofrisk for short-term health problems such as skin irritation orgastrointestinal illness after exposure to the water, and warrantsan advisory to the public as well as additional testing of thewater. "Our study shows that as phycocyanin increases, the amount ofblue-green algae is likely to be increasing, and the amount oftoxin production is also likely to be increasing in this type ofwater," Marion said. "When tested for effectiveness, thisscreening tool gives very good to excellent reliability." Lee is continuing this work, conducting a new research project thissummer to explore environmental factors that affect microcystinproduction by cyanobacteria and rapid detection of microcystin atOhio beaches. This study was supported by a grant from the Ohio Water DevelopmentAuthority. Additional co-authors include J.R. Wilkins and Cheonghoon Lee ofthe Division of Environmental Health Sciences; Stanley Lemeshow,dean of the College of Public Health; and Evan Waletzko of theEnvironmental Science Graduate Program, all at Ohio State. The e-commerce company in China offers quality products such as Children Jeans Wear Manufacturer , China Knitted Baby Wear, and more. For more , please visit Kids Plaid Shirts today!
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