Blame the Discharger! Must Dischargers Bear the Entire Responsibility for Mercury in Wastewater?

Wastewater discharge permits holders across Indiana will probably be requesting mercury variances — many due to background levels of mercury — as a result of changes in technology and regulations.

First, on July 8, 1999, EPA approved a new assay method for mercury. This assay is 200 times more sensitive than the old assay. As a result, levels of 1 ppt can be reliably measured compared to 200 ppt previously. With this new assay, dischargers are likely to see the background levels of three to twenty parts per trillion (ppt) that were undetectable with the old assays. IDEM is requiring use of the new assay in permits it issues.

The costs for the new assay are significant — well over $1000 per sample — primarily because of sampling precautions. But the benefit of getting a better understanding of mercury in our environment is enormous.

Second, IDEM must set a mercury limit on 1.3 or 1.8 parts per trillion for discharges into the Great Lakes basin in wastewater discharge permits it issues. The Great Lakes Initiative rule adopted by Indiana in 1996 mandates it. Outside of the Great Lakes Basin, the limit should be 12 ppt based on 1990 regulations. However, IDEM has drafted a rule to lower the limits statewide to match the Great Lakes standards.

To dischargers, the prospect of violating their permit due to mercury is unnerving. Much of the mercury appears to come from rainfall (see related story), consumer products, and a legacy of past use. Finding solutions will take time and strong coordinated action at the federal, state, and local level.

Ohio and Michigan are among several states to adopt strategies or rules to streamline the process for the dischargers with only background levels of mercury to get a variance. The variance would provide time for the discharger to comply with the limits. To get the variance, the discharger must do everything short of causing widespread and substantial social and economic impacts to the community.

Indiana is considering a similar approach. In fact, an amendment was proposed to HB-1901 (see discussion on page 3) that would establish such a program by statute. While the amendment died due to a lack of consensus, the issue remains.

Unfortunately, the approach in other states puts the responsibility for achieving the permit limit squarely on the shoulders of the discharger — effectively leaving it to the discharger to address background levels of mercury. IKE believes that the state has a role to play beyond setting limits and issuing variances. The state, in coordination with EPA, must take aggressive actions to reduce the background levels. And the state has the responsibility to give dischargers clear and simple directions to address the mercury legacy in the sewer collection system and from their indirect dischargers. Action, not extensive local planning, is critical. Variances make sense if properly crafted. But state and national action on air deposition and consumer products is essential.