“So what do I need to Know?”

Plant nutrients such as PHOSPHATES and NITRATES stimulate the growth of aquatic plants, algae, and bacteria. Summer heat, ever-increasing as a result of climate change, fuels this growth. At the end of their life-cycle the plants, algae, and bacteria decompose using the dissolved oxygen in the water.

Dissolved oxygen helps capture and contain PHOSPHATES in the decomposed plants, algae, and bacteria as well as in the naturally occurring sand and rock. If/When the dissolved oxygen level is too low, the PHOSPHATES are released and in turn the additional phosphate may fuel the growth of ever-present bacteria in the water. Of particular concern is the growth of CYANOBACTERIA.

CYANOBACTERIA is one of the building blocks of life on our planet. In the right conditions, cyanobacteria can become toxic and bloom; these blooms will be bright green, they look slimy, and can be picked up (but please don’t!!!). If ingested, toxic Cyanobacteria blooms are a health danger to children and dogs in particular and humans in general. Exposure can cause liver and nerve damage, and at the very least may cause diarrhea, eye irritation, or rashes. Dogs seem to be particularly affected due to the volume of water they might ingest drinking water; sadly, the risk of death is high. Wildlife living near the pond are at equal risk from drinking the water during a bloom, and aquatic life are not immune to the effects of a toxic Cyanobacteria bloom. Finally, the National Institutes of Health published a study showing that Cyanobacteria can become airborne and cause health issues. https://pmc.ncbi.nlm.nih.gov/articles/PMC12300373/

Our Call to Action:

1. DONATE to the Clear Pond Water Association!

We currently dedicate the majority of the funds raised toward additional water testing that we provide to the town. We are currently reviewing several intervention options to mitigate the cyanobacteria; the options currently under consideration are natural treatments such as barley straw or Alum treatment, mechanical aerators, and a solar-powered ultra-sound device. Any of these interventions will require additional funds.

2. Refrain from using commercial fertilizer on your lawn.

Water run-off from storms carries phosphates and nitrates into the pond directly, but these also leach into the aquifer, which is the main water supply for our spring-fed pond. The simplest thing you can do is to use the mulching function on your mower to let the grass clippings naturally feed your lawn.

3. Maintain your septic system

Faulty septic systems are another primary source of phosphates and nitrates. Proper maintenance of septic systems, and replacement as necessary, will help reduce the phosphates and nitrates that run into the pond.

For more information from the Town of Plymouth about Pond Closures and FAQ’s about Cyanobacteria:

Beach & Pond Water Quality Testing | Plymouth, MA (plymouth-ma.gov)

If you see what looks like a cyanobacteria bloom:

Stay out of the water! Contact the Plymouth Public Heath Department at 508-322-3339, or click the following link to make an on-line report: https://www.plymouth-ma.gov/938/Report-A-Concern . If confirmed, the pond will be closed to swimming and other in-water activities while the blooms are occurring and for 2 weeks afterward.

To receive Town of Plymouth text or email alerts about pond closures:

https://www.plymouth-ma.gov/list.aspx

If the town closes the pond, a notice is usually posted at the entrance to the Clear Pond Conservation Area on Surrey Drive. Additionally, the CPWA will post the closure (and eventual re-opening) on the homepage.

Sign-up below to receive pond closure and re-opening notifications.