A chemical solution to an underwater weed problem has some in Collingwood raising their eyebrows.
Signs posted at the Collingwood Yacht Club notifying people of 'pesticides' applied to the water have raised some concern among residents, particularly those who swim nearby at Millennium Park.
According to Dean Collver, director of parks, recreation, and culture, for the town, the application is done annually or every other year, and is used to control the aquatic vegetation that grows from the bottom of the harbour to near the surface and gets tangled in boat rudders.
This year, the contractor, Green Stream Lawn Vegetation Management, was hired by the Collingwood Yacht Club for weed control in the travel corridors among the slips. Collver said the town has also used chemical control for weeds in the town-run portion of the harbour in previous years, but did not use any this year.
A sign posted on the Collingwood Yacht Club door indicates the chemical was added to the water on July 8.
Chris MacFarlane, the vice-commadore at Collingwood Yacht Club, said the herbicide is something that gets applied every year to keep the weeds down. The weeds present a danger when they wrap around the boat rudders and prevent steering. MacFarlane said the club uses Green Stream to obtain government licencing through environmental agencies, and waits for fish to finish spawning before applying the herbicide.
The signs posted around the yacht club grounds and on the gate warn against swimming for 24 hours after application and against human consumption and use of the water for irrigation for five days following the application.
Green Stream confirmed it applied an aquatic herbicide called Reward.
Reward is manufactured by Syngenta Canada, but the formula is held by Univar.
Jon Froese, director of the environmental sciences division for Univar, said the herbicide is ionically charged, which attracts the chemical to green organic material as soon as it is sprayed in the water.
“It breaks down relatively quickly in the water,” he said.
The spread of the chemical is dependent on environmental factors such as currents, and movement of the water. However, Froese said the applicator is aware of what conditions are ideal and the ionic charge of the formula means it sticks to the first green organic material it comes across.
Information prepared by Univar about Reward states the chemical is absorbed by the leaf’s cuticle, and interferes with the plant’s photosynthesis.The active ingredient is diquat dibromide, and it works by desiccating green organic material.
As for danger to fish, Froese said it won’t harm fish in a lake.
“As the plants break down, they consume oxygen,” said Froese, suggesting in a small body of water like a pond or a farm dugout, that could suffocate the fish. “In a lake, it’s not a concern, the fish will just move to other places with oxygen.”
The same goes for human consumption. If someone was using Reward to treat well water or a small body of source water, Froese recommends waiting five days after application. In a lake, where swimmers may swallow some water while bathing, you won’t get any adverse effects from the treatment.
There are signs posted prohibiting swimming in the Collingwood harbour. However, nearby, there are often swimmers jumping from the pier at millennium park.
Froese was familiar with Green Stream and said the company is “quite experienced.”
The Collingwood Yacht Club leases its harbour space long-term from the town.
The town provided a letter of permission to Green Stream for the application of chemical treatment to manage aquatic weeds in the yacht club area of the harbour.
“It is expected that Green Stream will strictly follow all protocols established by provincial ministries for the protection of the environment and public health,” states the letter issued by the town to Green Stream.
The company was also required to provide a certificate of insurance and a WSIB clearance certificate before completing the works, as is required of all the town’s contractors.
According to the information posted on the Univar website (pestweb.ca), Reward is formulated for aquatic use, and is ideal for lakes, ponds, and farm dugouts.
The site states the chemical “quickly becomes biologically inactive,” and again warns users to wait one day before swimming and five days before drinking the treated water.
The chemical information states it is not harmful to fish, birds, livestock, or wildlife.
The product label for Reward states it is for the control of weeds such as Coontail, Duckweed, Canada Water Weed, Pondweeds, Water Milfoil, Water Soldier, Water Chestnut, and Flowering Rush.
The label also states the product must be applied (diluted at a 1:4 ratio with water) only after weeds are visible and in an active state of growth, which is dependent on water temperatures.
The warnings on the concentrated formula suggest it is harmful or fatal if swallowed, and harmful if inhaled. The undiluted formula can also cause eye injury and skin irritation.
