Page 1 of 1 AQBEQB CLERK Comments for Triennial Review . From: "Steve White" To: Date: 6/23/2003 3:45 PM Subject: Comments for Triennial Review To: EQB From: Steve White, ACT Foundation RE: Comments on 7Q10 - Harmonic Mean Flow Date: June 23, 2003 Please accept these attached comments regarding both a suggested course of study for reviewing the present 7Q10 method of measuring water ?ow as compared to the less stringent Harmonic Mean ?ow method and why we oppose the change from 7Q10 to Harmonic Mean Flow which would allow more cancer causing chemicals to be discharged into our rivers and streams. Thank You. Steve White, Director Af?liated Construction Trades Foundation 600 Leon Sullivan Way Charleston, WV 25301 345-7570 Suggested Areas of Study On The Preposed Changes To The Water Quality Standards Rule Prepared by Carpenter Environmental Associates, Inc. On behalf of the Af?liated Construction Trade Foundation The West Virginia Deparunent of Environmental Protection Division of Water Resources in a letter dated September 24, 2002 has recommended that changes he made to Section 7.2.b of the Water Quality Standards Rule regarding the design ?ow used to determine compliance with water quality standards. I Speci?cally, the DWR has stated that the following should be added to Section 7.2.b :?except that application of harmonic mean ?ow in the development of ef?uent limitations for Human Health Category criteria for carcinogens. During a meeting on this issue, it was decided that a study plan should be developed to determine the impacts of the proposed change. The following are issues which we believe must be included in the study. 1. Determination of Need for Revisions to Critical Design Flow for Human Health Carcinogens The .West Virginia regulatiOns currently require that the 7Q10 flow be utilized When determining appropriate discharge limitations for pollutants considered human health carcinogens. A review and evaluation of the compliance history of all facilities that currently have permit limitations for carcinogenic pollutants in their National Pollutant Discharge Elimination System (NPDES) permits must be conducted. This evaluation must include a detennination of the number of existing dischargers that are currently unable to consistently meet their permit limits for carcinogenic pollutants and the reasons why the permit limits cannot be met. 2. Determination of Health Impacts The use of harmonic mean ?ow as the design ?ow for carcinogens substances is based upon the assumption that the linear lifetime exposure model for carcinOgens is correct for all cancer causing substances. While the use of the linear lifetime exposure model for cancer may in many cases be conservative, we believe that applying such an assumption across-the~board for all cancer causing substances fails to account for valid alternative models for cancer such as the threshold model. A review of the scientific literature must be conducted to determine for which carcinogens the linear lifetime eitposure model for carcinogens is correct and for which carcinogens a threshold model is more appropriate. The study must include a determination of the number of increased cancer cases likely in West Virginia as a result of the change from 7Q10 to harmbnic mean ?ow. This study should take into account both increased cancer cases associated with carcinogens that follow the linear lifetime exposure model and the non-linear threshold model. We have determined that revising the critical design ?ow would allow, for just three rivers, the Ohio, the Kanawha, and the Greenbriar, the rule as proposed would allow, respectively, the discharge of 7.4, 5.4, and 7.8 times as much cancer causing substances as is currently allowed, which would equate to people being exposed live to eight times as much cancer causing substances. The study must evaluate whether this increase would result in a concomitant increase in cancer cases for carcinogens that follow both the linear lifetime exposure model and the non?linear threshold model. 3. Determination of the Economic Impact of Revising the Critical Design Flow a. Realized savings for new and existing dischargers: This analysis must include a determination of the cost associated with meeting discharge limits associated with the 7Q10 ?ow and harmonic mean ?ow. b. Impacts to ecOnomic growth in West Virginia: A study must be conducted to determine if the current requirement of 7QIO ?ow has resulted in industries not locating in West Virginia because they were unable to meet discharge permit requirements because the cost would be prohibitive to doing business. 0. Economic impacts of increased cancer cases in West Virginia: This eValuation must take into account the expected increase in cancer cases due to the proposed change and the expected associated costs: health care costs as well as lost earnings associated with removing cancer stricken individuals from the work force. ATTACHMENT 1: CALCULATION OF HARMONIC MEAN FLOW Carpenter Environmental Associates, Inc. has Carried out the study described below to determine the effect of the proposed'rule change to allow the use of harmonic mean ?ow as the design ?ow for wasteload allocation for carcinogens. Utilizing the harmonic mean flow would represent a change from West Virginia?s usual method of wasteload a110cation Which uses the 7 day mean low ?ow with a 10 year return period (7Q10) expected in a river as the critical design criteria. Use of the harmonic mean ?ow rather than 7Q10 ?ow as the critical design ?ow would result in an increase in the amount of carcinogens that would be allowed to be discharged the waters of West Virginia. The amount of the allowable inerease can be estimated by comparing the harmonic mean ?ow of a river, or river segment, to the low ?ow. Carpenter Environmental Associates, Inc. (CBA) has develoPed the harmonic mean ?ow (Q13) for locations on three rivers in West Virginia. These rivers are the Ohio, Kanawha, and the Greenbrier. These rivers were selected due to their size (large, medium and small, respectively) and nature (controlled or uncontrolled). Daily stream ?ow data for the available periods for rec0rd were obtained from the United States Geological Survey (USGS) website for the Kanawha and Greenbrier. Data for the Ohio River was obtained by CEA from the USGS in 1991. No additional data on daily ?ows was available for the Ohio River. To calculate the harmonic mean ?ow, the total number of-rec0rd ?ows (N) was divided by the summation of each daily ?ow The harmonic mean ?ow was calculated as follows: Qh= harmonic mean ?ow Total number of recorded daily ?ows Inverse of daily ?ow The 7Q10 ?ows were obtained from the USGS Water Resources Division in West Virginia. The 7Q10?s for the gaging stations of interest are as follows: Ohio River at Huntington 4,500 cubic feet per second (CPS) (estimated), Kanawha River at Charleston - 1,250 CFS (estimated), and the Greenbrier River at Hilldale 55 CPS. Due to the regulation of the Ohio and Kanawha Rivers by locks and dams, there are only estimated design 7Q10?s available. CEA was informed by the USGS that these estimated 7Q10?s are currently appropriate to use as the critical design ?ow. The following table compares the calculated harmonic mean flows to the 7Q10 ?ows. . . Harmonic - Harmonic River USGS Mean now 7Q10 (cfs) Mean Flow/ (cfs) 7Q10 Ratio ch16 Huntington . 03206000 53 33,367 4,500 7.4 Charleston 03198000 61 6,781 1,250 5.4 Greenbrier 1 Hilldale 03184000 64 416 55 7.6 Each ratio developed above represents the factor by which the quantity of carcinogens discharged to West Virginia?s Wasters will be increased if the harmonic mean ?ow is used as the design ?ow rather than the 7Q10. Changing the regulations from 7Q10 to harmonic mean ?ow would result in allowing 5.4 to 7.6 times more carcinogens being discharged in the river segments studied. Similar analyses must be performed for other river segments in West Virginia to determine the factor by which allowable discharges of carcinogens would be increased in each river. Based on the limited analyses performed, the propoSed change to using the harmonic mean flow as the Critical design ?ow for determining wasteload allocations will result in signi?cant increases in the amounts of carcinogens that are allowed to be discharged to West Virginia waters. These increased discharges will result in increased cancer risks, the magnitude of which depends upon the particular carcinogen. For some - carcinogens, the impact of the proposed rule change on risk of cancer may be small, for Others the increase in risk may be many times the increase in discharge amount. Given these conclusions, it is prudent and appropriate that the West Virginia State Water Resources Beard determine the increased quantities of carcinogens the proposed rule would allow to be discharged to all river segments in West Virginia and determine the increased cancer risk to West Virginia?s citizens these discharges would represent for each carcinogen. Comments On The Proposed Changes To The Water Quality Standards Rule Pfepared by Carpenter Environmental Associates, Inc. . On behalf of the Affiliated Construction Trade Foundation The West Virginia Department of Environmental Protection Division of Water Resources in a letter dated September 24, 20-02 has recommended that changes he made to Section 7.2.b of the Water Quality Standards Rule regarding the design ?ow used to determine compliance with water quality standards. Speci?cally, the DWR has stated that the following should be added to Section 7.2.b :"except that application of hannomc mean ?ow in the development of ef?uent limitations for Human Health Category criteria for carcinogens and the use of other hydrologically based design flow periods for determining appropriate ef?uent limitatiOns to re?ect representative exposure frequencies and durations for CategOry criteria shall be performed consistent with the guidance offered in Technical Support Document for Water Quality based Toxics Control Orin the alternative, the DWR recommends - adding a new section regarding the applicability of the use of alternative design flows for dew/clotting ef?uent limitations for Human Health and Aquatic Life Criteria based upon the guidance provided in the TSD. We disagree with the DWR preposed change to allow Harmonic Mean Flow to be the critical design ?ow for determining the amount of a carcinogen an industry can legally discharge to the State?s waters. We also believe that the design ?ows should be specifically stated in the regulations. Critical Design Flow For Human Health Carcinogens We believe that adoption of the harmonic mean ?ow as the critical design ?ow for carcinogens is inappropriate for at least two reasoas. First, the State has not adequately investigated the impact on all the streams of West Virginia of abandoning the use of a low design ?ow, such as the 7Q10, in favor of the harmonic mean flow. For example, for just three rivers, the Ohio, the Kanawha, and the Greenbriar, the rule as proposed would allow, respectively, the discharge of 7.4, 5.4, and 7.8 times as much cancer causing substances as is currently permitted (See Attachment 1). The effect of the rule change on our rivers has not been determined. However, the harmonic mean ?ow is greater than the 7Q10 for a particular stream, so that, the adeption of the harmonic mean ?ow as the critical design flow necessarily results in an increase in the amount of cancer causing chemicals allowed in _a_ll_ rivers and streams. The State must detennine the magnitude of the increase in each riVer and stream in order to make a fully informed decision. Second, the rationale for embracing harmonic mean ?ow as the critical design flow is based upon the assumption that the linear lifetime exposure model for carcinogens is correct for all cancer causin substances (see Rationale Document, Water Resources Board of West Virginia, August 19, 1991). While the use of the linear lifetime exposure model for cancer may in many cases be conservative, we believe that applying such an assumptiOn across-the?board for all Cancer causing substances fails to account for valid alternative models for cancer. As developed in the accompanying report to these comments (Attachment 2), which was prepared for the speci?c purpose of providing information about valid alternative cancer models, there are ?a number of circumstances in which a linear model may not be appropriate in that it may underestimate actual risk.? In such circumstances, low ?ow conditions, rather than harmonic mean conditions, can be the critical factor in determining whether- an individual is exposed at a level that results in an acceptable cancer risk. Further, the report concludes that in non-linear models, cancer risk can increase sharply at low doses, so that, ?the actual risk entailed by changing to Harmonic Mean Flow may increase by far more than 8-fold.? (As stated earlier, a Very limited, simple comparison of 7Q10 to harmonic mean ?ow for the rivers investigated showed that as much as 8 times more carcinogens could be discharged). Establishing the harmonic mean ?ow as design flow rather than the 7 Q10 would allow polluters to discharge up to 8 times (and perhaps mere would be determined in needed investigations) more cancer causing substances to West Virginia's rivers and streams and would increase cancer risk. The increased cancer risk which would result by establishing harmonic mean ?ow as the design flow can and must be determined before allowing such a change. Therefore, we believe that the use of harmonic mean ?ow as the critical stream ?ow fer carcinogens should not be anon/ed until it is fully investigated and the legislature determines that the increased cancer risk to the citizens of West Virginia is acceptable. Critical Design Flow for Aquatic Life Criteria and Non-Carcinogenic Human Health Criteria The Division of Water Resources has proposed that the regulations at Section 7.2.b be revised to include the following language "the use of other hydrologically based design ?ow periods for determining appropriate ef?uent limitations to reflect representative exposure frequencies and durations for Category criteria shall be performed consistent with the guidance offered in Technical Support Document for Water Quality based Toxics Control Or in the alternative, the DWR recommends adding a new section regarding the applicability of the use of alternative design flows for developing ef?uent Limitations for Human Health and Aquatic Life Criteria based upon the guidance provided in the TSD. The EPA toxic support document recommends the IQIO for acute aquatic life criteria and the 7Q10 for chronic aquatic life criteria and 30Q5 for non?carcinogenic human health criteria. Rather than providing a vague reference to guidance manual, the regulations should provide explicit requirements for the design flows to avoid inconsistencies or con?ision when developing permit limitations. EPA's recoxnruendations would result in a. more stringent design ?ow for acute criteria for aquatic life (1Q10 rather than the same design ?ow for chronic criteria for? aquatic life (7Q10) and a less stringent design ?ow for non?carcinogenic human health criteria (30Q10 rather than 7Q10). Prior to changing the design ?ow for non- carcinogenic human health criteria from 7Q10 to an analysis must be conducted to? evaluate the increased health risk to citizens of West Virginia of allowing increased ICVels of non-carcinogenic toxic pollutants to be discharged to the waters of West Virginia and the legislature must determine that the increased health risk is acceptable. This evaluation must take into account that the neighboring states of Kentucky and both utilize the 7Q10 flow to determine discharge limitations for these pollutants .