pH

The concentration of hydrogen ions in the water (pH) can significantly impact aquatic life. The following table, adapted from Claudi and Mackie (1994), illustrates the survival and growth potential of zebra mussels in waters with different pH values.

Population Characteristic pH

• Threshold value for adult survival 6.5
• Threshold value for veliger survival 6.9
• Incipient lethal level for veligers 7.4
• Value for massive infestation 8.0

Values used for determining risk for pH values by the Risk Assessment Calculator are as follows:

• < 6.7999999 - low risk of infestation
• 6.8 to 7.3999999 – moderate risk of infestation
• 7.4 to 8.999999 – high risk of infestation
• 9.0 to 10 – low risk of infestation

Risk Assessment Contents

Habitat and Water Chemistry Tolerances