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The Maryland Department of the Environment has purchased state-of-the art equipment that allows the agency to more quickly assess public health threats associated with some algae blooms. Harmful algae blooms are a combination of natural events (such as weather/temperature and salinity) combined with nutrient overload. Algae blooms are a symptom of an impaired Bay – the Bay and our waterways have too much nitrogen, which the state of Maryland is taking aggressive steps to address.
MDE purchased the Enzyme Linked Immuno Sorbent Assay equipment (ELISA) this year with grant money from the U.S. Centers for Disease Control. MDE laboratory staff is now capable of performing timely algae toxin analysis, which has proven highly effective in detecting Microcystin, a toxin produced by the blue-green algae Microcystis aeruginosa.
The World Health Organization provides guidelines for Microcystin levels in both drinking water (less than 1.0 parts per billion) and recreational waters (less than 10 parts per billion). The toxin can be particularly harmful to both humans and animals that drink or have contact with contaminated surface water. It can cause skin, gastro-intestinal and liver problems, and, in rare cases, death. ELISA testing has significantly sped up the process of getting information needed to make timely management decisions to protect public health.
The ELISA test employs a micro-titer, multi-plate system. It is based on the recognition of the toxin by specific antibodies. A series of enzyme/protein reactions are induced into the multi-plates and a color signal is generated. The intensity of the color is read with the use of a spectrophotometer. A standard curve is prepared along with each run, and sample concentrations are determined by comparison to set standards.
Maryland uses these standards as guidelines for protecting its citizens. This summer MDE staff investigated more than 40 algae blooms from the Eastern Shore to western Maryland. Routine monitoring or citizen reports led to the discovery of more than a dozen significant blue-green algae blooms, of which eight were discovered to contain high levels of Microcystis aeruginosa and were subsequently screened for the toxin using ELISA.
Five events warranted public health advisories. One event was initiated by a citizen who reported a “green scum” on Broadford Lake, a drinking water reservoir in Garrett County. Samples contained both elevated Microcystis cell counts and toxin levels that significantly exceeded standards for drinking water.
Another significant blue-green algae bloom occurred in Higgins Mill Pond in Dorchester County. It persisted throughout the late summer and fall seasons. ELISA revealed that high levels of Microcystin toxin were present. The Dorchester County Health Department subsequently issued public health advisories. Monitoring continued into November as unprecedented levels of Microcystin persisted.
A citizen reported a late-season, blue-green algae bloom in Lake Needwood, in Montgomery County. Again, ELISA revealed high levels of Microcystin and an advisory was posted at the Lake. MDE expects that toxin levels will decrease as the cold weather sets in.
MDE encourages citizens to report algae blooms, fish kills, and other water quality issues by calling 1-877-224-7229.
With cooperation from citizens and other state agencies, the expansion of MDE’s capabilities for rapid quantification of algae toxins provided timely scientific analysis that allowed for quick management decisions to protect public health.
For more information on algae bloom advisories, visit http://www.marylandhealthybeaches.com/ or
http://mddnr.chesapeakebay.net/eyesonthebay/index.cfm.
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