mercury 2019 eqc staff report_0.41

DETP/20/239

''Wednesday, February 19, 2020 at 9:23:51 AM (GMT+08:00) Goldstein, Meyer:'' deq 3-2020 willamette basin mercury multiple discharger variance 340-041-0059, 340-041-0345 adpoted 1/24/2020 filed 1/24/2020 effective 1/24/2020 The proposed rule amendments ensure the state variance authorization rule is consistent with the more recently promulgated federal variance rule (2015). In addition, the amendments clarify the variance rules by providing authority to the Environmental Quality Commission to grant multiple discharger and waterbody variances. A variance is a regulatory tool under the Clean Water Act to address circumstances in which a water quality standard is not currently attainable and limits derived based on the applicable standards are not currently achievable for dischargers, but it is possible to make incremental progress toward meeting the standard. A variance is a temporary designated use and criterion for a specific pollutant that applies to a specific discharger or dischargers or waterbody. In cases where multiple dischargers cannot attain water quality based effluent limits for the same pollutant and due to the same justification factor, DEQ may develop a multiple discharger variance. A MDV is an amendment to water quality standards rules that provides a variance for multiple eligible dischargers. Once the U.S. Environmental Protection Agency approves the MDV, DEQ can include requirements associated with the MDV in permits for eligible facilities without additional EPA approval. DEQ is proposing rule amendments that establish a multiple discharger variance for mercury in the Willamette Basin for individual NPDES permittees that cannot currently meet mercury water quality based effluent limits. This rule is needed because human-caused sources of mercury, primarily due to atmospheric deposition of global mercury, currently prevent attaining the human health water quality criterion for mercury. The purpose of the variance is to create a transparent tool, as authorized under the Clean Water Act, that allows incremental progress in reducing mercury. This document describes DEQ’s justification for the MDV and proposed procedures for issuing permits and establishing variance requirements, as federal and state rules for variances require. The federal government adopted variance regulations (40 C.F.R. §131.14) in 2015. DEQ last substantially revised Oregon regulations regarding variances (OAR 340-041-0059) in 2011. In addition to adopting a specific rule to authorize and describe the process for granting MDVs to dischargers in the Willamette Basin, DEQ is proposing amendments to the state’s general variance rules to make them consistent with the federal regulations.