Virtually all heavy metals are naturally occurring to a small extent, mostly as a result of their geologic presence. Therefore, all of the heavy metals for which the DNR and Environmental Protection Agency have water quality criteria are present in the water and sediment. The following table summarizes some applicable concentrations. For most heavy metals, the magnitude of the water quality criteria for aquatic life protection is dependent upon the hardness of the water. The water quality criteria indicate the concentration of the substance in the water at which adverse effects to aquatic life, wildlife, or humans would not occur.
Acute concentration refers to a level which protects against mortality.
The effluent concentration numbers in the table would be used to determine the need for a water quality based effluent limit according to s. These numbers are from Hat Rapids dam and could change pending collection of additional data. From the bench scale treatability pilot study collected April 26, 1995. Additional parameters can be found in Appendix B . 3 WQC refers to ambient water quality criteria.