Contact: Robin Tyler, Environmental Laboratory Section, phone: (302) 739-9942
or Melinda Carl, Public Affairs, phone: (302) 739-9902

Blue-Green Algae Bloom Reported on Silver Lake in Dover

Scientists from DNREC’s Division of Water Resources report a blue-green algae bloom on Silver Lake in Dover. The bloom consists of microscopic colonies of algae cells which give the water a murky “pea green” color. The bloom frequently catches the attention of observers when it forms a “paint-like” scum on the water surface.

Blue-green algal blooms occur annually throughout Delaware on ponds and lakes of all sizes and some tidal-fresh waters. They begin forming during summer and are often particularly vigorous in early autumn. As these blooms die and decay, the floating scum may have a multi-colored appearance of various shades of blue, green, and white. In addition, natural oils released into the water from the dying cells may be interpreted as an oil spill from a human source. The blooms usually disappear after the first strong cold front of the autumn causes a large decrease in water temperature. Therefore, the blooms in Silver Lake and other waterways throughout the state are expected to persist for a period which could range from the next several days to a few weeks.

Some blue-green algae, including types found in Delaware, are known to produce toxins that can be harmful to other living things. Animals which ingest the water containing toxins are most vulnerable, most notably wildlife and domestic animals. Not all blue-green algae blooms are toxic, and for any waterbody with such a bloom, the level of toxin can vary from undetectable to high at different places around the lake and on different days. Thus, all blooms should be treated with caution.

Therefore, the following common sense precautions are recommended for waterways:

• Don’t let pets or livestock drink, or get into water where algal scum is present.
• Don’t feed waterfowl in or near algae scum areas.
• Avoid exposure to water with blue-green algae scum or wear gloves if unavoidable.
• Fish caught in waterways where blooms are present often have an undesirable taste. Some waterways in Delaware including Silver Lake in Dover have fish consumption advisories. Visit DNREC’s web site, www.fw.delaware.gov/Fisheries/adivisories.htm for consumption advice.
• People prone to hay fever and asthma from environmental sources should avoid algae bloom areas.

For more information contact, Robin Tyler, Division of Water Resources, 302-739-9942.
 

-30-