The federal Clean Water Act requires states to periodically review and update their water quality standards. In its most recent review, Indiana started the process of changing its standards for the concentrations of metals in lakes and rivers to match national recommendations. HEC submitted comments.

For Indiana’s segment of the Ohio River, it uses the standards established by the multi-state compact for the river known as ORSANCO. Over the past 70 years, ORSANCO scientists have carefully calculated the concentrations of several hundred chemicals that the river could tolerate and still remain healthy for aquatic species and for people. Indiana uses those standards in writing permits for discharges to the Ohio River.

In 2018 there was a proposal to eliminate ORSANCO’s standards. HEC partnered with more than a dozen organizations from the Ohio River states to advocate for preservation of ORSANCO’s pollution control standards, and we were successful!

Photo: Plume approaching Evansville (photo credit: copyright BlairPhoto EVV)