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List of State Officials - Martin O'Malley, Governor; Anthony Brown, Lt. Governor; Robert Summers, MDE Secretary

Volume IV, Number 10 

June 2011

Come on in, the water's fine (most of the time): Helping swimmers stay healthy on Maryland beaches
By Kathy Brohawn, Heather Merritt, and Charlie Poukish, Science Services Administration 

Click on photo to view larger image

    The beach at Ocean City. Maryland’s beaches, on the coast and inland, offer beauty and the promise of summer fun.

During the 2010 beach season, Maryland beaches were not under an advisory 96 percent of the time.

The beach at Sandy Point State Park in Anne Arundel County, with the Bay Bridge in the background.

The beach at Cunningham Falls State Park, in the picturesque Catoctin Mountains in Frederick County.

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Maryland’s beaches, on the coast and inland, offer beauty and the promise of summer fun. But natural waters can sometimes hold unseen dangers – so the Maryland Department of the Environment works to help keep swimmers healthy.

MDE joins with partners in other federal, state, and county government agencies to check for signs of pollution and monitor water quality at beaches. And on the relatively rare day when there is a problem – with, say, harmful algae or signs of elevated levels of bacteria – the word goes out to alert people to the risk.

The work begins before the first swimmer dips a toe into the water. Prior to the start of beach season on Memorial Day, local health departments collect water samples from beaches and perform surveys to identify any nearby pollution sources that might adversely affect water quality.

The health departments continue to collect water samples during the season. Samples are sent to the Maryland Department of Health and Mental Hygiene laboratory for analysis.  When fecal bacteria standards are exceeded, the results are reported to local health departments so that beach managers can issue an advisory. An advisory is a recommendation against swimming or water sports. During the 2010 beach season, Maryland beaches were not under an advisory 96 percent of the time. Beaches are only closed when the waters are affected by a sewage spill or overflow or other harmful contaminants.

You are less likely to be exposed to polluted water at beaches that are monitored regularly and posted for health hazards.  Swimming in other natural waters could present a health or safety risk from bacteria or such physical dangers as submerged debris.  There are several things you can do to reduce the likelihood of getting sick from swimming in natural waters.  First, you should find out if the area you want to swim in is monitored regularly and posted for closures or swimming advisories.  In areas that are not monitored regularly, choose swimming sites in less developed areas with good water circulation, such as beaches along more open waterways rather than in enclosed creeks. Avoid swimming at beaches where you can see discharge pipes or at urban beaches after a heavy rainfall.

The status of any swimming beach is posted on the Maryland Healthy Beaches website. The site includes a Google Earth application that provides color-coded status of beaches throughout the state and daily updates on rainfall at individual beaches, because stormwater runoff can be as source of bacteriological contamination. The site also provides tips on staying healthy at the beach.

How the Maryland Beaches Program works

In connection with the Beaches Environmental Assessment and Coastal Health (BEACH) act, the U.S. Environmental Protection Agency provides funding to improve beach monitoring in coastal states. MDE administers Maryland’s Beaches Program.

The bacteria used in the beach monitoring program are called indicator bacteria.  These bacteria are not necessarily harmful but they are commonly found in the gut of humans and warm-blooded animals in very high numbers, and are quick, easy, and inexpensive to identify in the laboratory. If these bacteria are present, then potentially harmful human pathogens may also be present. 

The standards used for recreational waters and for issuing advisories were developed by EPA following several studies where indicator bacteria were sampled and beachgoers were surveyed about their general health and illnesses the day they went swimming and through additional questions three days and then a week after they visited the beach.

The standards are based on risk analysis and the probability of the potential risk of illness. When the bacteria standard is exceeded at your local beach, the risk of illness from full water contact is increased. When it is not exceeded, the risk of illness from water contact is low. There is no guarantee that you will get sick when an advisory is issued and no guarantee that you will not get sick when there is no advisory.


What you should know about vibrio bacteria

Vibrio are bacteria that occur naturally in estuarine and marine waters worldwide. Vibrio vulnificus and Vibrio parahaemolyticus are two species that can cause infection if someone has an open wound while swimming, wading, or fishing (including crabbing). Not all strains of vibrio bacteria cause illness or infection, and since their presence is not necessarily due to pollution the indicator bacteria used for beach advisories is not useful for determining the presence of vibrio. The primary environmental factors controlling vibrio concentration are temperature, salinity and chlorophyll. Vibrio bacteria are not commonly found in the winter when water temperatures are low but are common in the summer and early fall when water temperatures are warm. When open wounds are exposed to warm seawater with vibrio, a skin infection may result; these infections may lead to skin breakdown and ulcers. People with weakened immune systems are at higher risk for very serious illness from V. vulnificus. Though rare, cases do occur sporadically. Anyone who suspects this type of infection following contact with marine or estuarine waters should see a doctor as soon as possible.

Scientists with the National Oceanic & Atmospheric Administration have been monitoring the abundance and distribution of V.vulnificus and V. parahaemolyticus in the Chesapeake Bay since 2006. They have developed models that can predict the likelihood of V.vulnificus and V. parahaemolyticus in the Chesapeake Bay. The models are not suitable for determining the individual risk for vibrio-related illness and should not be used to guide decisions about swimming or other activities in the Bay. The models are useful for estimating the likely extent of vibrio bacteria in Maryland waters during the summer.

Due to the complex relationship between exposure, dose, and an individual’s vulnerability for infections, there is no known threshold or standard that determines risk of infection from vibrios. People can take precautions to avoid or reduce the risk of infection. These precautions include: covering wounds with waterproof bandages; having hand sanitizer or access to soap and water to cleanse wounds that occur while swimming, fishing, or crabbing; and showering following swimming in natural waters and washing hands before eating. 


Harmful Algal Program

The Maryland Departments of the Environment, Natural Resources, Health and Mental Hygiene, and other investigators collaborate to manage a State-wide Harmful Algae Bloom surveillance program to protect public health and the environment. The agencies coordinate with the MDE Shellfish Sanitation Program, MDE Water Supply Program, local health departments, the U.S. Food and Drug Administration, researchers at regional universities, and the Center for Disease Control and Prevention to assure that swimming and recreational waters are monitored, that shellfish waters are free of bioaccumulating algae toxins, and that drinking water supplies are protected. 

One potentially toxic algae associated with fresh water lakes, ponds, tidal fresh waters and swimming beaches is Microcystis aeruginosa, a blue-green algae. This algae is easy to identify because when a bloom is present it looks like someone spilled a can of bright green paint in the water. Through coordination with the state agencies and local health departments, MDE assesses the risk to swimmers, pets, and livestock by determining when toxin is being produced and when toxin levels are absent. If there is a known risk in swimming water the local health department will issue a beach closure.   


Tips for staying safe

• Be sure to avoid swimming within 48 hours of a heavy rain event.
• Try not to swallow beach water.
• Avoid swimming if you feel ill or have open cuts or sores. If water contact can’t be avoided, cover your open cut or sore with waterproof bandages.
• If they are available, use diaper-changing stations in restroom facilities, or change diapers away from the waters’ edge. Remember to properly dispose of used diapers.
• Wash your hands with soap and warm water after using the bathroom or changing diapers.
• Pick up your trash.
• Remember not to feed seagulls or other wildlife.
• When boating, use an approved marina pump-out station for boat waste disposal.
• If you have a septic tank, keep it maintained and in good working order.
• If you see any unsafe or unhealthy conditions, be sure to report them to a lifeguard or beach manager.

Remember to check the Google Earth Beach Notification System on, or your county website, for water quality information about your beach.



This Issue's Featured Articles :: For the Record