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Public health awareness bulletin issued for algal bloom in Black Lake, near Onaway

Submitted by on September 16, 2020 – 12:38 amNo Comment


District Health Department No. 4, in consultation with the Michigan Department of Health and Human Services (MDHHS) and Michigan Department of Environment, Great Lakes and Energy (EGLE), is issuing a public health awareness bulletin about an algal bloom in Black Lake near Onaway, Michigan.

People and pets should avoid direct body contact with algae in the lake or with water that is blue-green or water that looks like it has a green sheen or spilled paint on its surface.

The algae layers may contain flecks, foam, or clumps. People and pets should also avoid swallowing the lake water.

The Silver Beach Rd had a bloom and the preliminary testing is indicating >10 ug/L of microcystin, which is above the EPA recommended recreational level of 8 ug/L.

The toxin testing this year suggests that the obvious algal blooms and scums may contain microcystin and should be avoided by people and pets. We generally recommend people look out for cyanobacterial blooms and avoid recreating in and letting pets in water with visible algae on any lake.

The sampling on 9/11/20 came from the citizen report to EGLE, but Black Lake is also part of an ongoing cyanobacterial bloom surveillance project being conducted by EGLE and USGS.

Until last week, cyanobacterial blooms and toxins had not been observed at their sampling locations, however, USGS only has a couple sampling locations on the large lake. It is common for cyanobacterial blooms and toxins to be localized to areas of obvious algal scums or blooms.

Although most algal blooms are not harmful, there are some made of cyanobacteria that can produce toxins – and can result in a harmful algal bloom (HAB). Out of an abundance of caution, District Health Department No. 4 wants residents and visitors to be aware of the algal bloom on Black Lake. Advice may change based on additional testing or as more information becomes available. Also, the amount of algae in the lake can change quickly.

What are Harmful Algal Blooms?
Cyanobacteria (cyꞏaꞏnoꞏbacꞏteꞏriꞏa), also known as blue-green algae, are a natural part of lakes, rivers, and ponds. Unfortunately, some species can produce toxins, called cyanotoxins (cyꞏaꞏnoꞏtoxꞏins), that can make people and animals sick. When conditions are right, these organisms can quickly grow to form cyanobacteria blooms – or harmful algal blooms (HABs). These blooms can last for weeks or longer and are considered harmful because they may contain cyanotoxins. A bloom can start out small and become very large in size and can
give off a foul odor.

What causes HABs to form?
Some factors that can contribute to HABs include sunlight; low-water or low-flow conditions; calm water; warmer temperatures; and excess nutrients (phosphorus or nitrogen). The primary sources of nutrient pollution are runoff of fertilizers, animal manure, sewage treatment plant discharges, storm water runoff, car and power plant emissions, and failing septic tanks.

How dangerous are HABs?
If you touch HABs, swallow water with HAB toxins, or breathe in water droplets, you could get a rash, have an allergic reaction, get a stomach ache, or feel dizzy or light-headed,
depending on the amount and type of exposure. HABs can also cause illness in pets. Always look for HABs before going in the water. Check for any posted HAB advisories.

What should I do if I see a HAB?
 Stay out of water that may have a HAB. Enter and swim in nonaffected areas of the lake.
 Do not let your children or pets play in HAB debris on the shore.
 Never swallow any lake or river water, whether you see HABs or not.
 Do not let pets lick HAB material from their fur or eat HAB material.
 Do not drink or cook with lake water.
 See a doctor if you or your children might be ill from HAB toxins, or call Poison Control at 1-800-222-1222. If your pet appears ill, contact your veterinarian.
 HABs should be reported to EGLE by calling the Environmental Assistance Center at 1-800-662-9278 or emailing AlgaeBloom@michigan.gov.

For more information about HABS
The Michigan Department of Health and Human Services’ website (www.michigan.gov/habs) offers information about algal blooms along with The Center for Disease Control and Prevention’s Harmful Algal Bloom (HAB) – Associated Illness site (https://www.cdc.gov/habs/index.html).