Many chemicals are toxic to the zebra mussel, but users must exercise great caution due to strict regulations relating to their uses and release into aquatic systems. For example, government agencies are concerned with chlorine because it combines with organic compounds in the water to form trihalomethanes (THM), compounds thought to be carcinogenic. Since chlorine is one of the most effective and widely used methods of zebra mussel control, both proactively and reactively, the increase in regulations and the possibility of hazardous environmental effects will pose quite a problem for many facilities. Disposal of wastewater is likely to become more and more costly as government regulations are increased and enforced.
When forming a mitigation strategy, it is in the best interest of time, money, and efficiency to thoroughly research all avenues of control possibilities. Shift the burden of compliance with these regulations to the vendor. Direct all vendors of chemical control to the local regulatory agency for the information needed to approve the use of their product within your facility. In many cases approval will not be met. This step will save time, money, and the effort of making sure that all compliance regulations are met economically. By doing this, only the truly viable sources of chemical control will be reviewed.
The chemical most commonly used against the zebra mussel is chlorine at 0.3 to 0.5 ppm (300-500 ppb) total residual chlorine (TRC) for 1 to 3 weeks for adults. Chlorine dioxide, bromine, ozone, and potassium permanganate are other oxidizing molluscicides that will be discussed. A list of oxidizing chemicals and brief information on their potential environmental impacts is presented in subsequent sections.
Management and Control Contents
Environmental Impacts of Chemical Control
Chemical Control and the Effects of Molluscicides