The liquid herbicide paraquat is widely used throughout North America as an effective herbicide and pre-harvest crop defoliant but can be fatal if accidentally ingested in small quantities as well as cause eye damage and irritation to skin.
In response to the risks associated with paraquat, the Environmental Protection Agency has already pursued significant manufacturer labeling and training changes. For growers, the next step in the process is to address changes required to safely dispense the restricted-use pesticide.
They should quickly get up to speed on what the EPA has mandated in terms of new closed transfer systems required to safely dispense the herbicide and avoid potential fines.
By September 2020, new container standards for paraquat will take effect, with “closed-system packaging for all non-bulk (less than 120 gallon) end-use product containers of paraquat,” according to the EPA.
The agency will require “new closed-system packaging designed to prevent transfer or removal of the pesticide except directly into proper application equipment. This will prevent spills, mixing, pouring the pesticide into other containers or other actions that could lead to paraquat exposure,” according to EPA’s website (https://bit.ly/2r4qFml).
Paraquat containers from manufacturers will need to be completely sealed with no screw caps, adaptors or other ways to open and decant the chemicals. To prevent accidental exposure or spills while transferring the liquid herbicide to smaller containers (for mixing or use), certified applicators must also use a closed transfer system that connects to the sealed container and cannot be easily circumvented.
Are All Systems In Compliance?
Closed transfer systems are specifically designed to transfer liquids safely while preventing accidental exposure to the concentrated/diluted pesticide or rinse solution. Although many types of closed transfer systems exist, many do not satisfy the new EPA mandate because they can be breached or circumvented.
Within this category are gravity-assisted inversion systems, which are inserted into containers using adapters and flipped upside down.
The adapter depresses a valve so the chemical flows freely out of the container. However, this type of system can be easily circumvented and the chemicals decanted if the valve is pressed when the container is not properly seated in the adapter.
Container breaching systems are another alternative. With this approach, sealed 1- to 2.5-gallon containers of product would be placed in an enclosed system and then pierced so the liquid contents drain to the bottom before being fed through hoses to the application equipment. A water input valve can also be used to safely rinse out the enclosure.
Probes inserted into containers for fluid extraction are also commonly used for volumes ranging from 10 to 120 gallons. However, when the probe is extracted, it is a breach of the closed system. Also, there is no safe or compliant way for growers to rinse the container after use.
Hand-Operated Pressure Pumps
GoatThroat Pumps, a Milford, Connecticutt.-based pump designer and manufacturer, is developing a system to specifically comply with EPA paraquat use requirements.
The small, versatile, hand-operated pressure pumps are engineered to work as a system, complete with everything needed to move liquids from the source container through measuring and into the mix tank with a simple triple-rinse set-up.
The hand pump version functions essentially like a beer tap.
The operator attaches the pump, presses the plunger several times to build up a low amount of internal pressure and then dispenses the liquid. A one-touch valve allows growers and pesticide handlers to execute a controlled, steady transfer of liquids from one container to another, and the flow rate can be adjusted from gallons to drops based on their needs.
Other systems can be connected through no-spill connectors to extraction devices such as the Chem Traveler.
According to the company, because the pumps use very low pressure (<6 PSI) to transfer fluids through the line and contain automatic pressure relief valves, they are safe to use with virtually any closed container. The hand-operated pump also works with no access to electricity.
“Using a hand-operated, closed-transfer pump system will not only help growers meet the new EPA paraquat standards by September, 2020 but also enhance the safety and ease of use of many other chemicals growers are pouring and mixing every day,” says Dr. Kerry Richards, director of Delaware’s Pesticide Safety Education Program.
GoatThroat Pumps provided this article. For more information, visit www.goatthroat.com.