Can carbon dioxide be used as an environmentally neutral molluscicide for mitigation of zebra and quagga mussel macrofouling? Carbon dioxide is a natural chemical that does not require a separate or specialized production (e.g. fermentation), is already produced in large quantities, is recycled from initial combustion waste streams for good environmental stewardship, has an indefinite shelf life, nonflammable, is easy to handle and store, does not require electrical or mechanical power to deliver, and can be distributed easily and evenly in water, including hard-to-reach confined water. Through the carbonic acid/bicarbonate buffer, the change in pH of the water is limited. Addition of carbon dioxide also reduces the bioavailability of calcium in the water, thereby inhibiting shell growth. Only species that has taken up residence in the confined water (i.e. Dreissinids) would be exposed long enough to reach mortality levels. Once the water is freely exposed to the air at the outlet, purged, or the CO2 is stripped and reused, equilibrium is quickly re-established and PCO2 goes back to ambient pressure, so that it will not affect the downstream water ecology.
