South Carolina 303d List Public Notice Description Title: EPA Decision to add Four (4) waterbody-pollutant combinations to South Carolina's 2020 and 2022 section 303(d) Lists Summary of Proposed Action: The EPA Region 4 is requesting public comment on its decision to add four waterbody-pollutant combinations to South Carolina's 2020 and 2022 303(d) Lists. Section 303(d)(2) of the Clean Water Act requires that states submit, every two (2) years, lists of waters within its boundaries for which existing pollution controls fail to achieve or maintain state water quality standards. The EPA must approve or disapprove each list, referred to as a 303(d) list or list of impaired waters. The EPA partially approved South Carolina's 2020 and 2022 303(d) Lists; agreeing with the State's addition of 329 waterbody-pollutant combinations to the List, as well as the removal of 173 waterbody-pollutant combinations. However, the EPA independently determined that four (4) waterbody-pollutant combinations should have been included and has added those to the list. Comments must be submitted no later than February 17, 2023, to smith.elizabeth@epa.eov. Description: The EPA Region 4 has decided to add four (4) additional waterbody-pollutant combinations on South Carolina's 2020 and 2022 303(d) Lists. These waterbodies are not being listed by SCDHEC due to biological confirmation language within their state regulation; despite exceedances of lead, cadmium, and turbidity found that otherwise would have required the State to list these waters. South Carolina refers to South Carolina Regulation 61-68 Section E. 14 d. (2), which states that if the ambient concentration is higher than the numeric criterion for toxic pollutants, the criterion is not considered violated if biological monitoring has demonstrated that the in-stream indigenous biological community is not adversely impacted. South Carolina's rationale for this is "The goal of the Standards is the protection of a balanced indigenous aquatic community. Therefore, biological data are the ultimate deciding factor, regardless of chemical conditions." This regulation was not reviewed or approved by EPA for CWA purposes. The EPA views biological criteria as one (1) component of a comprehensive water quality standards program that works in concert with - not in place of - the use of water quality criteria. The EPA's reasoning is that biological assessments have limited ability to predict and prevent impacts - they can only observe harm after it has occurred. In cases where biological assessment has not detected an impact, it is possible that impairment is projected and plausible but has not yet occurred or that the biological assessment was not sensitive to the impact. The four (4) additional waterbody-pollutant combinations to be added by the EPA on South Carolina's 2020 and 2022 303(d) Lists are described below. All stations had biological assessments with scores in the "good" (3.5-4.4 out of 5) range completed during the listing period, while other station data show impairments for at least one parameter: ------- Station BL-001 was on the 2018 303(d) List for lead impairment and was found to be impaired for turbidity on the 2020 List. SCDHEC omitted it from the 2022 303(d) List due to a biological assessment that scored at least 3.7. Station B-136 was on the 2018 303(d) List for a biological impairment and was found to be impaired for turbidity in 2020. SCDHEC omitted it from the 2022 303(d) List due to a biological assessment that scored at least 3.7. Station RS-18426 has not been on the 303(d) List previously, and the EPA found it to be impaired for cadmium in 2020 and 2022. SCDHEC omitted it from the 2020 and 2022 303(d) Lists due to a biological assessment that scored over 3.3 (unlisted sites remain unlisted unless they score 3.3 or less). ------- |