Use of quaternary ammonium to control the spread of aquatic invasive species by wildland fire equipment

Wildland firefighting equipment moves large volumes of raw water during fire incidents in order to extinguish flames or control fire growth. This water movement may serve as pathways for aquatic invasive organisms to be moved between water bodies and watersheds. The equipment used may become contaminated and serve as vectors for future invasions across large geographic areas. New guidelines used by federal firefighting agencies recommend the application of sanitation solutions using quaternary ammonium compounds for decontaminating wildland fire equipment to prevent the spread of aquatic invasive species that may foul the equipment. While quaternary ammonium compounds have been tested on other aquatic organisms, the effectiveness of such compounds has not been systematically tested on dreissenid mussels. We tested the survival of quagga mussel veligers after exposure to a 3% solution of Sparquat 256 ® for 5 and 10 minutes. We assessed survival immediately after treatment and then after 60 minutes in fresh water. We found that a 5 minute exposure duration was insufficient to kill 100% of tested veligers. However a 10 minute exposure, as prescribed in the interagency operational guidelines for preventing spread of aquatic invasive species, was effective in killing all tested veligers, but not immediately after treatment. An additional 60 minutes were required after the quaternary ammonium solution was removed before 100% mortality was achieved. This work highlights the need for more rigorous evaluation of the effectiveness of various sanitation solutions in killing quagga and zebra mussels under different ambient temperatures in order to validate and refine the sanitation protocol for firefighting equipment and other applications.