The Iowa Department of Natural Resources (IDNR) is currently proposing to amend Iowa ambient water quality standards for chloride, sulphate and total dissolved solids (TDS). In addition, they are proposing a change to the default hardness value used to calculate ambient water quality standards for many chemicals, especially metals.
The changes being proposed include the following:
- Establish numerical water quality criteria for chloride for the protection of aquatic life uses.
- Establish numerical water quality criteria for sulfate for the protection of aquatic life uses.
- Remove TDS criteria and implementation approach
- Revises default hardness level used for hardness dependent chemical criteria from 100 mg/l (as CaCO3) to 200 mg/L.
IDNR will be accepting comments on these proposed changes until August 14, 2009.
Caltha LLP provides expert consulting services to public and private sector clients nationwide to address water quality standards, wastewater permitting and assessing potential impacts of chemicals in the aquatic environment.
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