“Is it safe to swim in the river?” is one of the most common questions ShoreRivers’ staff are asked by community members. Fecal bacteria and toxic algae in waterways pose threats to both water quality and public health. People who come in contact with bacteria- or toxin-laden water can contract eye, ear, and respiratory diseases, skin rashes, gastrointestinal issues, or brain or liver damage. In order to better understand the health of our rivers and potential risks to human health, ShoreRivers regularly monitors bacteria pollution at 28 sites throughout the mid and upper Eastern Shore and works closely with government agencies to monitor toxic algal blooms when they occur.
The Swimmable ShoreRivers program is designed to test the waters for bacteria at popular swimming locations, marinas, yacht clubs, and towns on a weekly or bi-weekly basis from Memorial Day through Labor Day on all the rivers in the ShoreRivers region. The program follows EPA’s standard protocols for collecting and analyzing samples and uses a pass/fail system to determine if bacteria levels are safe or unsafe for swimming. You can view the results from all of our sites at theswimguide.org and get updates during swim season by following #SwimmableShoreRivers on social media.
Additionally, the Swimmable ShoreRivers program works with local and state government health agencies to monitor toxic algal blooms and inform the public of serious potential health risks to humans and pets. Algal blooms occur naturally, but increased levels of nutrient pollution in our waterways from fertilizers, septic systems, and wastewater plants fuel larger, more toxic, and longer-lasting blooms. In the ShoreRivers region, toxic blooms occur most frequently on the Sassafras River due to its lower salinity levels. This summer we dealt with a toxic algal bloom on the Sassafras that lasted for almost three months and was the largest and most toxic bloom ever recorded on the river.
The results from our monitoring in 2020 show that bacteria and algal conditions vary based on location, weather, and other factors so systematic, scientific analysis is vital. The majority of our bacteria monitoring sites passed more than 60% of the time. A few of our sites, however, failed more than 40% of the time; meaning, the bacteria levels in the water exceeded the EPA threshold for safe water contact the majority of the times we sampled. Specifically, Hambrooks Bay Beach, Crouse Park, Denton, Broad Cove Claiborne, Morgan Creek Landing, and Duck Neck .
“Bacteria pollution most commonly comes from leaking sewer lines and septic systems, stormwater runoff, domestic and wildlife droppings, and land application of manure and sewage,” says Matt Pluta, ShoreRivers Choptank Riverkeeper. “Our results show that bacteria levels increase after rainfall, and after a wet summer like the one we just had, we expected bacteria levels to be high at many sites.”
Now that we have baseline data showing which sites frequently have elevated levels of bacteria, ShoreRivers will focus on the next most popular question from the public: “where does the bacteria pollution come from?” ShoreRivers is currently exploring partnerships and innovative technologies to help us identify specific sources of bacteria pollution at specific testing locations.
“Once we know where the bacteria is coming from – whether it’s leaking sewer lines, failing septic systems, over-application of fertilizer, or people not picking up after their pets – we can start implementing real solutions,” Pluta says. “Monitoring techniques such as DNA sampling and bacteria source tracking are improving and becoming more reliable. It’s another tool in our Riverkeeper toolbelt to help improve water quality conditions so Eastern Shore waterways are always safe and swimmable.”