Disclosure Statement Regarding The Application of
Aquatic Herbicides (including Pond Dyes)

The Maine Board of Pesticides Control (BPC) and the Maine Department of Environmental Protection (DEP) have requested that pesticide dealers present this statement to all persons who purchase an herbicide that is labeled for use in surface waters. The two agencies want to ensure that every purchaser is clearly aware of the restrictions on aquatic herbicides (including pond dyes) as outlined below.

Permits Required for “Waters of the State”
The DEP requires anyone applying any pesticide to “Waters of the State” to first obtain a Maine Waste Discharge License (WDL). Maine statutes define “Waters of the State” as:

“…any and all surface and subsurface waters that are contained within, flow through, or under or border upon this State or any portion of the State, including the marginal and high seas, except such waters as are confined and retained completely upon the property of one person and do not drain into or connect with any other waters of the State, but not excluding waters susceptible to use in interstate or foreign commerce, or whose use, degradation or destruction would affect interstate or foreign commerce.” 

Only treatments conducted on private ponds and which follow the Best Management Practices (BMPs) described below can be conducted without a permit.

Purchase and Application of Aquatic Herbicides 
Persons wishing to purchase and apply an aquatic herbicide—except for the pond dyes listed below—must first obtain a pesticide applicator’s license from the BPC. BMPs have been developed that must be followed by those planning to treat private ponds with any aquatic herbicide (including pond dyes)—see “Best Management Practices for The Application of Aquatic Herbicides in Private Ponds” below.

Purchase and Application of Certain Pond Dyes 
Persons wishing to purchase and apply pond dyes such as Aquashade, Admiral or Pondmaster Blue (containing the active ingredients erioglaucine [Acid Blue 9] and tartrazine [Acid Yellow 23]) are exempt from applicator licensing requirements. However, while these products are exempt from licensing requirements, the requirement for obtaining a WDL still applies, if applicable (see “Waters of the State” definition above).

Purchasers should be aware that the State has a policy of minimizing reliance on pesticides and that herbicides used to control common aquatic weeds may have adverse effects on the environment. Purchasers are therefore encouraged to learn more about aquatic weed identification and nonchemical control measures by visiting http://www.state.me.us/dep/blwq/topic/invasives/index.htm. 

Information on invasive aquatic plants, permits and aquatic herbicides may also be obtained by contacting the DEP at 207-287-3901. Information on pesticide applicator licensing may be obtained from the BPC at 207-287-2731 or go to http://www.thinkfirstspraylast.org/cert/questions.htm.

Best Management Practices for The Application of
Aquatic Herbicides in Private Ponds
Effective: June 15, 2007

Common algae and plants can thrive in private Maine ponds when ideal conditions are provided. Ample sunlight, fertilizers and nutrients from surrounding areas and—especially for algae—groundwater recharge can hasten growth, creating a nuisance that compromises recreation, aesthetics and other pond uses. 

Pond owners faced with algae or plant infestation may consider using products, namely pesticides, which claim to control these species. Maine laws place conditions on how these products may or may not be used because of the risks they pose to human health, as well as to nearby streams, wetlands, lakes or groundwater that are legally regarded as “Waters of the State.”

Pesticides that claim to kill or control vegetation in water—algae and other aquatic plants—are called aquatic herbicides. Pond dyes or colorants are aquatic herbicides that prevent algae and weed development by limiting light and restricting photosynthesis.

Generally, aquatic herbicides, other pesticides or any pollutant may not be discharged into any water of the state without a WDL from the DEP.

Further, the BPC restricts the sale and application of aquatic herbicides to BPC-licensed applicators. Initially this restriction also included pond dyes.

In March 2007, the BPC relaxed regulations affecting the sale and use of pond dyes only if used within a private pond contained on one person’s property. While BPC sale and use restrictions for other aquatic herbicides and DEP discharge licensing requirements remain in force, the private pond owner may now purchase and use BPC-registered pond dye products for private pond use. 

The rationale for easing rules on pond dye purchase and use is that these products are able to meet algae and plant control needs of private pond owners while posing minor risk to Maine’s aquatic habitats.

Minor risk, however, is not the same as zero risk. Pond dye products can have biological and other environmental consequences in the event they escape from the pond and move into waters of the state. The DEP prohibits the discharge of any material to waters of the state that change the color, clarity, chemistry or temperature of the receiving waters without a WDL.

Therefore, application of pond dye products must be conducted in a manner that demonstrates the highest standards of conduct, namely in accordance with the BMPs.

The following BMPs must be followed by both licensed and unlicensed pond dye users. Licensed pesticide applicators certified for aquatic vegetation control who intend to treat private ponds with any aquatic herbicide must also follow these BMPs. While close attention to these BMPs will prevent an illegal discharge in most cases, good judgment should always prevail. 

Maine BMPs for Use of Aquatic Herbicides In Private Ponds for 
Control of Algae and Other Aquatic Plants 

•	Aquatic herbicides and pond dyes may be used without a WDL only under the following conditions:
o	Use of aquatic herbicides and pond dyes must not result in a discharge to groundwater or surface waters of the state (such as ponds, lakes, wetlands, streams and rivers).
o	Aquatic herbicides and pond dyes may only be used in private ponds contained wholly on a single property.
o	Aquatic herbicides and pond dyes may only be used in ponds that have no outflow while these products are active.
o	Aquatic herbicides and pond dyes may only be applied after any seasonal high water outflow has ceased.
o	Aquatic herbicides and pond dyes may only be used in ponds that generally have a seasonal high water outflow if:
•	there is no defined channel exiting the pond such as a drainage swale or a mineral bottom channel;
•	there is no year-round surface water body (such as lakes, ponds, streams and rivers) within 100 feet down gradient of the pond;
•	any seasonal outflow does not occur as channeled flow, but occurs only across a dense vegetated area at least 50 feet in length, as measured along the gradient.
o	Aquatic herbicides and pond dyes may only be applied during the months of May, June, July and August.
o	Aquatic herbicides and pond dyes may only be applied after spring runoff and when the water level has stabilized or has been drawn down at least 6 inches below the point of discharge.
o	Aquatic herbicides and pond dyes should not be applied when weather forecasts predict significant rainfall during the five-day forecast period following application. 
o	Aquatic herbicides and pond dyes must be applied at the minimum effective rate and in accordance with label instructions. 

For more information, contact the following: 

Robert Stratton
Bureau of Land and Water Quality
Maine Department of Environmental Protection
State House Station 17, Augusta, ME 04333 
tel.: 800-452-1942, e-mail: robert.d.stratton@maine.gov

Henry Jennings
Maine Board of Pesticides Control
State House Station 28, Augusta, ME 04333
tel.: 287-2731, e-mail: henry.jennings@maine.gov

John Jemison
University of Maine Cooperative Extension Water Quality Office
495 College Avenue, Orono, ME 04473
tel.: 800-870-0270, e-mail: jjemison@umext.maine.edu

rev 6/08