Contents Chapter 3 Acronyms

S. Baloga, E. T. Collins, S. G. Cortelyou, L. V. Hamilton, K. G. Hanzelka, J. M. Loar, D. M. Maguire, H. B. McElhoe, M. J. Peterson, R. A. Rich, E. M. Schilling, I. D. Shelton, R. S. Sherles, L. R. Shugart, G. R. Southworth, M. M. Stevens, and P. T. Stevens

ABSTRACT

Effluent monitoring is a major activity on the ORR. Effluent monitoring is the collection and analysis of samples or measurements of liquid and gaseous effluents to determine and quantify contaminants and process-stream characteristics, assess any chemical or radiological exposures to members of the public, and demonstrate compliance with applicable standards.

4.1 AIRBORNE DISCHARGES

Airborne discharges from DOE Oak Ridge facilities, both radioactive and nonradioactive, are subject to regulations issued by EPA, the TDEC Air Pollution Control Board, and DOE orders. Radioactive emissions are regulated by EPA Region IV under the CAA, NESHAP, 40 CFR 61, Subpart H. (See Appendix A for a list of radionuclides and their radioactive half-lives.) Nonradioactive emissions are regulated under the rules of the TDEC Division of Air Pollution Control.

The NESHAP regulations limit the amount of annual radioactive exposure or dose to the nearest or most affected member of the public. In December 1989, the NESHAP regulations were reissued. Negotiations between EPA and DOE were initiated to bring the ORR into full compliance with the new regulations. As a result of those negotiations, an FFCA was signed in May 1992 by the DOE-ORO manager and was implemented at the ORR facilities. The ORR fulfilled all of its FFCA commitments and came into compliance with the regulations by December 1992. On March 26, 1993, EPA Region IV certified that DOE-ORO had completed all actions required by the FFCA and is considered to be in compliance with the radionuclide NESHAP regulations. An updated Rad-NESHAP Compliance Plan was sent to EPA Region 4 in May 1994.

DOE requirements for airborne emissions are established in DOE Order 5400.1, DOE Order 5400.5, 40 CFR 61 Subpart H, and the Environmental Regulatory Guide for Radiological Effluent Monitoring and Environmental Surveillance (DOE 1991 ). The criteria in NESHAP regulations and DOE orders define major effluent sources as emission points that have the potential to discharge radionuclides in quantities that could cause an EDE of 0.1 mrem/year or greater to a member of the public. Potential emissions are calculated for a source by assuming the loss of pollution control equipment while the source is otherwise operating normally.

Each ORR facility has a comprehensive air pollution control and monitoring program to ensure that airborne discharges meet regulatory requirements and do not adversely affect ambient air quality. Air pollution controls at the three Oak Ridge facilities include exhaust gas scrubbers, baghouses, and exhaust filtration systems designed to remove airborne pollution from exhaust gases before their release to the atmosphere. Process modifications and material substitutions are also made to minimize air emissions. In addition, administrative control plays a role in regulating emissions. Each installation has developed an emissions inventory program that includes stack sampling as necessary to determine the amounts of pollutants that are not removed by the air pollution control equipment.

4.1.1 Y-12 Plant Radiological Airborne Effluent Monitoring

As of January 1, 1995, the Y-12 Plant had a total of 68 stacks, 63 of which were active and 5 were temporarily shut down. During 1995 five additional stacks were placed into temporary shutdown. Thus, during the course of the year 63 stacks were monitored, and there were 58 stacks being monitored at the end of 1995.

Radionuclides other than uranium are handled in millicurie quantities as part of ORNL and Y-12 Plant laboratory activities at facilities within the boundary of the Y-12 Plant. The releases from these activities are minimal, however, and have negligible impact on the total Y-12 Plant dose. Emissions from unmonitored process and laboratory exhausts, categorized as minor emission sources, are estimated according to EPA -approved calculation methods. Emissions from room ventilation systems are estimated from health physics data collected on airborne radioactivity concentrations in the work areas. Areas where the monthly average concentration exceeded 10% of the DOE derived air concentration (DAC) worker protection guidelines were included in the annual emission estimate.

4.1.1.1 Sample Collection and Analytical Procedure

In 1995, 62 emission points were identified from unmonitored radiological processes and laboratories. In addition, one ventilation area from a building that houses depleted uranium operations was identified from health physics data, where one or more average monthly concentration exceeded 10% of the DAC. For the area, the annual average concentration is used, with design ventilation rates, to arrive at the annual emission estimate. No areas from buildings that house enriched uranium operations met these criteria.

4.1.1.2 Results

4.1.2 ORNL Radiological Airborne Effluent Monitoring

Airborne discharges are unique because of the wide variety of research activities performed at ORNL. Radiological gaseous emissions from ORNL typically consist of solid particulates, adsorbable gases (e.g., iodine), tritium, and nonadsorbable gases. The major radiological emission point sources for ORNL consist of the following four stacks located in Bethel and Melton valleys (Fig. 4.3):

• 2026 High Radiation Level Analytical Laboratory;
• 3020 Radiochemical Processing Plant;
• 3039, central off-gas and scrubber system, which includes 3500 and 4500 areas cell ventilation system, isotope solid state ventilation system, and 3025 and 3026 areas cell ventilation system; and
• 7911 Melton Valley complex (HFIR and REDC).

Each stack and vent was assessed for its potential to discharge regulated air pollutant emissions. Those with no potential for regulated air pollutant emissions, such as steam vents, do not require any further documentation. The first phase of the stack and vent survey focused primarily on radioactive emission sources. These sources are updated annually. In 1995, there were 18 minor point/group sources, and emission calculations/estimates were made for each of these sources.

4.1.2.1 Sample Collection and Analytical Procedure

All ORNL in-stack source sampling systems comply with American National Standards Institute N 13.1 (1969, R-1982) criteria. The sampling systems generally consist of a multipoint in-stack sampling probe, sample transport line, a particulate filter, activated charcoal cartridges, a silica-gel cartridge (if required), flow measurement and totalizing instruments, a sampling pump, and a return line to the stack. In addition to that instrumentation, the system at Stack 7911 includes a high-purity germanium detector with a NOMAD analyzer, which allows continuous isotopic identification and quantification of radioactive noble gases present in the effluent stream. To ensure that all radioactive particulates are accounted for, end-of-the-year samples are collected and analyzed by cleaning the in-stack sampling probes. This program requires annual removal, inspection, and cleaning of sample probes.

Velocity profiles are performed following the criteria in EPA Method 2. This profiling ensures that the continuous samplers are sampling at acceptable isokinetic conditions and are obtaining accurate stack flow data for subsequent emission-rate calculations. An annual leak-check program is carried out to verify the integrity of the sample transport system, including the sample components.

In addition to the major sources, ORNL has a number of minor sources that have the potential to emit radionuclides to the atmosphere. Minor sources are composed of any ventilation systems or components such as vents, lab hoods, room exhausts, and stacks that do not meet the criteria for a major source but are located in or vent from a radiological control area. A variety of methods were used to determine the emissions from the various minor sources. All methods used for minor source emission calculations complied with criteria agreed upon by EPA and/or included in the NESHAP Compliance Plan for the ORR. These minor sources are evaluated on a 1- to 3-year basis, depending on the source type. All emissions, both major and minor, are compiled annually to determine the overall ORNL source term and associated dose.

4.1.2.2 Results

Annual radioactive airborne emissions for major sources are presented in Table 4.2. All data presented were determined to be significantly different from zero at the 95% confidence level. Any number not statistically different from zero was not included in the emission calculation. Historical trends for ³H and ¹³¹I are presented in Figs. 4.4 and 4.5, respectively.

The tritium emissions for 1995 are approximately 200 curies. The primary contributor was off-gas from the Tritium Facility, even though it has been inoperative since 1989. Emissions from the central off-gas system, Stack 3039, were highest in 1991 (16,000 Ci); emissions have decreased sharply since then (Fig. 4.4). The ¹³¹I emission for 1995 are 0.16 curies, which is higher than the past years (Fig. 4.5). The emissions are attributable to operations that exhaust through Stack 7911.

4.1.3 K-25 Site Radiological Airborne Effluent Monitoring

4.1.3.1 Sample Collection and Analytical Procedure

Various techniques were used to generate all other radiological point source emissions. Representative grab sample techniques were used to generate emission estimates for the K-1015 Laundry. Material balance calculations were used to generate emission estimates for the K-1004-A through D laboratories. The remaining active sources were calculated using surrogate sample techniques as described in the EPA-approved NESHAP compliance plan, or from emission factors specified in 40 CFR 61, Appendix D. Both techniques are conservative methods of estimating emissions based on the physical form of the radionuclides and the maximum operating temperature of the process.

Three new minor point sources were approved for operation in 1995: (1) a container-processing facility located in K-1423 to wash potentially contaminated empty drums and to operate in conjunction with a drum crusher, (2) a HEPA vacuum-cleaning facility located in K-1310-DC for servicing vacuums containing potentially contaminated debris, and (3) the K-1037 metal-cutting activities in a HEPA-filtered room to cut up a radiologically contaminated transport cart and associated equipment. K-1423 and K-1310-DC did not initiate operations in 1995.

The following minor sources were inactive during 1995: the K-304-5 Deposit Removal Project activities to mechanically remove radiological materials from the interior of cascade components and the K-1420 valve shop. The Pond Waste Management Project (PWMP) drum crusher and dry material repackaging project, and the K-31/33 cascade equipment removal project minor sources completed work in 1994 and discontinued operations.

4.1.3.2 Results

4.1.4 Y-12 Plant Nonradiological Airborne Emissions Monitoring

The Y-12 Plant annual emission fee was calculated by TDEC personnel based on 9,499 tons per year of allowable emission of regulated pollutants, with an annual emission fee of $61,982.45, as defined in TDEC regulations, Chapter 1200-3-26-.02(9)(i). In calculating the annual emission fee, Schedule III of Chapter 26 was used, where the adjusted emissions equal the total emissions minus carbon monoxide and exempt emissions, and a 4,000-ton cap for SO₂ and NO_x. The emission fee rate is based on $18.55 per ton of regulated pollutant allowable emissions. In addition, the Y-12 Plant received a prorated credit for annual emission fees paid during the FYs 1993/1994 and 1994/1995 in the amount of $114,224 pursuant to Rule 1200-3-26-.02(9)(i). When the major source operating permit is issued, the emission fee rate will increase to $32.20 per ton of regulated pollutant.

The level of pollutant emissions is expected to decline in the future because of the changing mission of the Y-12 Plant and downsizing of production areas. More than 90% of the pollutants are attributed to the operation of the Y-12 Steam Plant; however, as a best management practice, Y-12 Plant personnel also monitor emissions from four areas that process beryllium.

In anticipation of permitting requirements and implementation of maximum achievable control technology (MACT) standards under Title V of the CAA amendments, an effort is under way to improve the stack and vent survey, criteria pollutant emission inventory, and hazardous air pollutant emission inventory. A draft of the Oak Ridge Y-12 Plant Title V permit application is expected to be prepared in 1996.

Planning for compliance with anticipated and newly issued requirements under Title VI of the CAA amendments is a major effort. In accordance with the Y-12 Plant CAA implementation plan, a stratospheric ozone protection plan has been issued to outline actions necessary to comply with the new limitations on the release of ozone-depleting chemicals and with the 1995 production ban on these chemicals. The Y-12 Plant Environmental Management Department personnel and refrigeration maintenance personnel successfully implemented work practices required to minimize releases of ozone-depleting refrigerants to the atmosphere. Requirements for refrigeration-system and motor-vehicle air-conditioner maintenance compliance are being met. To accommodate the production ban on ozone-depleting chemicals, studies are proceeding to find suitable replacements, and plant refrigeration equipment is being modified as needed. The Retrofit Heating, Ventilation, and Air Conditioning and Chillers for Ozone Protection project, currently in conceptual design, will eliminate the use of chlorofluorocarbon (CFC) refrigerants in chillers, direct expansion air conditioners, and process coolers, either by replacement with new equipment that operates on ``ozone-friendly'' refrigerants or by retrofit of existing equipment with new components to operate on ``ozone-friendly'' refrigerants.

4.1.4.1 Sample Collection and Analytical Procedure

Currently, four exhaust stacks that serve beryllium processing areas are sampled continuously by extracting a portion of the stack gas and filtering out particulate matter. The samples are then analyzed for beryllium, and emission rates are calculated.

4.1.4.2 Results

Beryllium stack sampling results indicated that \math{<}1 g of beryllium was released during 1995; most readings on the filters were less than the plant laboratory detectable level. Thus, emission rates of beryllium are well below the NESHAP limit of 10 g/day. Emissions of other materials have been estimated and are provided in Table 4.4. The TDEC annual inspection, conducted in July 1995, found no noncompliances.

The Y-12 Plant has reduced CFC emissions by more than 91% since 1992, and improvements are continuing (Fig. 4.9). The efforts of Y-12 Plant management and personnel to minimize emissions of ozone-depleting substances earned the Y-122 Plant a White House ``Closing the Circle'' Award for waste prevention in 1995. The Y-12 Plant was one of 18 organizations to receive the award, which recognizes outstanding achievements in federal waste prevention, recycling, and affirmative procurement.

4.1.5 ORNL Nonradiological Airborne Emissions Monitoring

In 1995, ORNL paid $101,150 in annual emission fees to TDEC; it is estimated that ORNL will pay approximately $100,000 in annual emission fees in 1996. These fees are based on allowable emissions (actual emissions are lower than allowable emissions). In early 1995, TDEC inspected all permitted emission sources to ensure compliance; no noncompliances were noted.

ORNL is currently preparing the permit application that will be required under the Title V permit program. It is anticipated that this application will be due to TDEC in the summer of 1997. To facilitate the preparation of this application, an existing survey of all emission points at ORNL was updated. This survey located all emission points and evaluated their compliance status. Survey results provided information regarding small sources that are currently exempt from air permit requirements. The survey will also assist with compliance efforts that may be required under Title III, Hazardous Air Pollutants.

Actions have been implemented to comply with the prohibition against releasing ozone-depleting substances under Title VI. Also, service requirements for refrigeration systems (including motor vehicle air conditioners), technician certification requirements, and labeling requirements, have been implemented. ORNL has taken actions to phase out the use of Class I ozone-depleting substances. The most significant challenge is the replacement or retrofitting of large chiller systems that require Class I refrigerants.

4.1.5.1 Results

4.1.6 K-25 Site Nonradiological Airborne Emissions Monitoring

Title VI of the CAA amendments addresses stratospheric ozone protection. This section provides a number of regulations to phase out the production and to eliminate the intentional release of ozone-depleting substances to the atmosphere. Ozone-depleting substances have been used at the K-25 Site, primarily as refrigerants in gaseous diffusion processes and for office comfort cooling. Because the K-25 Site is no longer involved in UE, its stockpile of process refrigerants was shipped in 1993 to the operational gaseous diffusion plants in Portsmouth, Ohio, and Paducah, Kentucky, for reuse. Purging of the residual CFC-114 from process equipment continued until February 1995. Releases of CFC-114 for 1995 are shown in Table 4.8. The K-25 Site has eliminated the use of CFC-114 and there will be no future atmospheric emissions of this ozone-depleting substance (also reflected in Table 4.8).

Additional refrigeration equipment service practices were implemented in 1993 in response to the refrigerant recycling and emissions reduction rule. This rule focused on record keeping, a leak repair program for equipment with refrigerant capacity of 50 lb or more, and a safe equipment/refrigerant disposal program.

EPA regulations also require maintenance personnel to recover and recycle refrigerants used in air-conditioning/refrigeration equipment. It also requires that these personnel be trained and certified on the use of approved refrigerant recovery equipment and be certified through the EPA certification program for refrigerant recycling and emissions reduction.

As a result of a well-implemented and focused Ozone-Depleting Substances Program, emissions from air-conditioning/refrigeration equipment have been greatly reduced. It should be noted that the main contributor to the release of R-22 was a 45-year-old air-conditioning system that is being replaced in 1996.

4.1.6.1 Results

The TSCA Incinerator is also a major source of air emissions from the K-25 Site. Emissions from the incinerator are controlled by extensive exhaust-gas treatment. Estimated emissions from the incinerator are significantly less than the permitted allowable emissions (Table 4.10 ).

4.2 LIQUID DISCHARGES

4.2.1 Radiological Liquid Discharges

DOE Order 5400.5 also established DCGs for radionuclides in water. (See Appendix A for a list of radionuclides and their half-lives.) The DCG is the concentration of a given radionuclide for one exposure pathway (e.g., drinking water) that would result in an EDE of 100 mrem (1 mSv) per year to reference man, as defined by International Commission on Radiological Protection (ICRP) publication 23 (ICRP 1975 ). The consumption of water is assumed to be 730 L/year at the DCG level. DCGs were calculated using methodologies consistent with recommendations found in ICRP publications 26 (ICRP 1977 ) and 30 (ICRP 1978 ). DCGs are used as reference concentrations for conducting environmental protection programs at DOE sites, as screening values for considering best available technology for treatment of liquid effluents, and for making dose comparisons. Radiological data are determined as percentages of the DCG for a given isotope. In the event that a sum of the percentages of the DCGs for each location ever exceeds 100%, an analysis of the best available technology to reduce the sum of the percentages of the DCGs to less than 100% would be required as specified in DOE Order 5400.5.

4.2.1.1 Y-12 Plant Radiological Summary

The following parameters are monitored routinely under the plan:

• alpha and beta activity,
• americium (²⁴¹Am),
• neptunium (²³⁷Np),
• plutonium (²³⁸Pu and ^239/240Pu),
• radium (²²⁶Ra and ²²⁸Ra),
• strontium (⁹⁰Sr),
• technetium (⁹⁹Tc),
• thorium (²²⁸Th, ²³⁰Th, ²³²Th, ²³⁴Th, and total thorium),
• tritium (³H), and
• uranium (²³⁴U, ²³⁵U, ²³⁶U, ²³⁸U, total uranium, and percentage of ²³⁵U).

\noindent The revised plan also requires that a gamma scan be performed routinely for 1 year. The resultant data will be reviewed to determine the applicability of this measurement.

In addition, the Y-12 Plant is permitted to discharge domestic wastewater to the city of Oak Ridge Sewage Treatment Plant STP under Industrial and Commercial User Waste Water Discharge Permit No. 1-91. Radiological monitoring of this discharge is also conducted and is reported to the city of Oak Ridge. The following parameters are monitored routinely:

• alpha, beta, and gamma activity;
• plutonium (²³⁸Pu and ^239/240Pu); and
• uranium (²³⁴U, ²³⁵U, ²³⁶U, ²³⁸U, total uranium, and percentage of ²³⁵U).

Results

The Central Pollution Control Facility (Outfall 501) is the only treatment facility that has exceeded maximum allowable DCGs in the past; however, improvements in the treatment process have resulted in effluent data consistently well below DCGs. This improvement can be seen in Fig. 4.11, which shows ²³⁸U concentrations since 1989.

Additional radiological monitoring at kilometer 12.4 (mile 7.7) on Upper Bear Creek was historically conducted in response to Section IV, Part 4, of a 1983 memorandum of understanding agreed to by DOE, EPA, and TDEC. The monitoring continued as a best management practice until July 1995. Monitoring at kilometer 11.97, which has been proposed as a replacement site, continued throughout the year. These changes were proposed with ORR Environmental Monitoring Plan for implementation in 1995. Analytical data are reported monthly to TDEC as an attachment to the discharge monitoring report required by NPDES. For each of these in-stream locations, all radiological results for 1995 were below 10% of the DCGs.

In 1995, the total of uranium and associated curies released from the Y-12 Plant at the easternmost monitoring station, Station 17 on Upper East Fork Poplar Creek (UEFPC), and the westernmost monitoring station, at Bear Creek kilometer (BCK) 4.55 (NPDES Outfall 304), was 105 kg, or 0.135 Ci (5.0E+9 Bq) (Table 4.12). Figure 4.12 illustrates a 5-year trend of these releases.

The City of Oak Ridge Industrial and Commercial User Waste Water Discharge Permit allows the Y-12 Plant to discharge wastewater to be treated at the Oak Ridge Wastewater Treatment Facility through the East End Sanitary Sewer Monitoring Station (EESSMS), also identified as SS-6 (Fig. 4.10).

No single radionuclide in the Y-12 Plant contribution to the sanitary sewer exceeded 1% of the DCG. Summed percentages of DCGs calculated from the Y-12 Plant contribution to the sewer are essentially zero. Results of radiological monitoring were reported to the city of Oak Ridge with the quarterly monitoring report (Table 4.13 ).

Potential sources of radionuclides discharging to the sanitary sewer had been identified in previous studies at the Y-12 Plant as part of a best management practices initiative to meet the ALARA goals of the Y-12 Plant. These data show that levels of radioactivity are orders of magnitude below regulatory levels established in DOE orders and are not thought to pose a safety or health risk. A 1995 report, Update Summary of the 1991 Discharge of Enriched Uranium to the Sanitary Sewer (DEUSS) Report (Energy Systems 1995 ), was issued in 1995 to further document radionuclide discharges to the sanitary sewer. Figure 4.13 illustrates the 5-year trend of total uranium discharges from the Y-12 Plant Sanitary Sewer.

4.2.1.2 ORNL Radiological Summary

DOE DCGs are used in this document as a means of standardized comparison for effluent points with different isotope signatures. The average concentration is expressed as a percentage of the DCG when a DCG exists and when the average concentration is significantly greater than zero. The calculation of percentage of the DCG for ingestion of water does not imply that effluent points or ambient water sampling stations at ORNL are sources of drinking water. For 1995, only three radionuclides had an average concentration greater than 5% of the relevant DCG; they were ³H, total radioactive strontium, and ¹³⁷Cs. The largest percentage was the ³H concentration at Melton Branch 1, at 21% of the DCG (Fig. 4.15). Following guidelines given in DOE Order 5400.5, fractional DCG values for the radionuclides detected at each monitoring point are summed to determine whether radioactivity is within acceptable levels. In 1995, the sum of DCG percentages at each effluent point and ambient water station was less than 100%, and therefore within acceptable levels.

The discharge from ORNL of radioactive contaminants to the Clinch River is affected by stream flows. Clinch River flows are regulated by a series of TVA dams, one of which is Melton Hill Dam. The flow in Melton Branch is usually less than one-third of that in WOC. In 1995, the monthly ratio of flow in WOC (measured at WOD) to flow in the Clinch River (measured at Melton Hill Dam) ranged from 0.0016 to 0.023, thus providing significant dilution of any radioactivity released into the Clinch River from WOC.

Amounts of radioactivity released at WOD are calculated from concentration and flow. As shown in Figs. 4.16, 4.17, 4.18, 4.19, 4.20, and 4.21, the total discharges, or amounts, of radioactivity released at WOD during the past 4 years have remained in the same range of values but showed a slight decrease in 1995 from 1994.

Categories of Effluents

In 1995, only one Category II gross beta result triggered a total radioactive strontium analysis; none of the Category I gross beta results exceeded the strontium trigger level. The maximum gross beta value of 3200 pCi/L occurred at Category II Outfall 204, which discharges into WOC west of Building 3544. The next highest value was considerably lower, 500 pCi/L, at Category II Outfall 207, which discharges into WOC east of Building 3534.

4.2.1.3 K-25 Site Radiological Summary

Sample Collection and Analytical Procedure

Results

Uranium discharges to surface waters over a 5-year period were investigated to observe their trend (Fig. 4.23). The effluent point having the greatest DCG percentage was the K-1407-J outfall. Uranium isotopes contributed to this percentage as shown in Fig. 4.24. The increase in uranium discharges is attributed to TSCA Incinerator wastewater, which is sent to the CNF for treatment before discharging at K-1407-J (Outfall 011).

4.2.2 Nonradiological Liquid Discharges

The CWA requires that EPA establish limits on the amounts of specific pollutants that may be discharged to surface waters. The standards, called effluent limitations, are written into NPDES permits issued to all municipal and industrial dischargers. The Y-12 Plant, ORNL, and the K-25 Site are each required to monitor discharges at frequencies specified in their permits to ensure compliance with the NPDES effluent limitations. The TDEC Division of Water Pollution Control has the authority to issue NPDES permits and to monitor compliance with the permits in the state of Tennessee under the Tennessee Water Control Act and according to the rules and regulations of the Tennessee Water quality control (QC) Board. DOE waste treatment facilities have formal wastewater acceptability control and surveillance programs that ensure the protection of the facilities and the proper treatment of wastes. Among other things, these programs define pretreatment requirements and waste acceptance criteria. Discharges are regulated under NPDES permits.

The CWA also created the Federal Pretreatment Program to regulate industrial discharges to sanitary sewer systems, which are also referred to as POTW. Under the Federal Pretreatment Program, industries are required to monitor and regulate their discharges to a POTW. The state of Tennessee has created the Tennessee Pretreatment Program, which requires municipalities to develop their own municipal POTWs for their local industries. Municipal POTWs issue permits to industries, spelling out the responsibilities of the industries for pretreatment and compliance with the sewer-use ordinance. These responsibilities include the monitoring of their waste streams to determine pollutant concentration limits.

Sanitary wastewater from the Y-12 Plant is discharged to the city of Oak Ridge POTW. Both ORNL and the K-25 Site have on-site sewage treatment plants.

4.2.2.1 Y-12 Plant Surface Water and Liquid Effluents

The water quality of surface streams in the vicinity of the Y-12 Plant is affected by current and past operations. Discharges from Y-12 Plant processes affect water quality and flow in EFPC before entering the Clinch River. In past years, discharge of coal bottom ash slurry to the McCoy Branch Watershed from the Y-12 Steam Plant occurred. This practice has been stopped, and coal ash is currently collected dry and is being used for recycle or for filler to support landfill operations.

Bear Creek water quality is affected by area source runoff and groundwater discharges. Discharges to surface water allowed under the permit include storm drainage, cooling water, cooling tower blowdown, and treated process wastewaters, including effluents from wastewater treatment facilities. Sumps that collect groundwater inflow in building basements are also permitted for discharge to the creek. The monitoring data collected by the sampling and analysis of permitted discharges are compared with the appropriate NPDES limits when a limit exists for each parameter. Some parameters are ``monitor only,'' with no limits specified.

During the first 6 months of 1995 the Y-12 Plant operated under a permit that had been issued in 1985. In 1989 an application for permit renewal was submitted to TDEC. Earnest consideration of the permit renewal request began in 1992 with information meetings conducted between representatives of the TDEC, DOE, and Lockheed Martin. The Y-12 Plant submitted a storm water permit application in 1992, and an update or addendum to the 1989 permit application was filed in early 1993. A new permit was issued on April 28, 1995. Compliance monitoring in accordance with new permit conditions was initiated on the permit effective date (July 1, 1995). The effluent limitations contained in the permit are based on the protection of water quality in the receiving streams. The permit places emphasis on storm water runoff and biological, toxicological, and radiological monitoring. Some of the more significant changes in the new permit are as follows.

• toxicity limitation for the headwaters of EFPC,
• quarterly toxicity testing at the wastewater treatment facilities,
• a compliance schedule to reduce mercury in EFPC,
• a compliance schedule for chlorine limitations at outfalls containing cooling water,
• chlorine limitations of water quality criteria at the headwaters of EFPC,
• a compliance schedule for correction of elevated ammonia concentrations discharged to EFPC from a groundwater spring,
• a requirement to manage the flow of EFPC such that a minimum flow of 7 million gal per day is guaranteed by adding raw water from the Clinch River to the headwaters of the creek,
• sampling of storm water at a minimum of 25 locations per year,
• a storm water pollution plan, and
• in-stream pH limitations on tributaries to Bear Creek and various other tributaries on the south side of Chestnut Ridge.

4.2.2.2 Sanitary Wastewater

Prior to June 28, 1994, samples from the sanitary sewer were collected from two sites to monitor compliance to the permit: the City Monitoring Station (SS4) and the Union Valley Station (SS5). The Y-12 Plant contribution was calculated by subtracting the loading of the Union Valley Station from the loading of the City Station. The Union Valley Station does not have any Y-12 Plant waste streams associated with it. Two additional in-plant monitoring points (SS1 and SS2) were monitored as a best management practice. In July 1994, the EESSMS (SS-6) (Fig. 4.10) was put into service. Completion of the monitoring station and rerouting of the associated sewer line combined all Y-12 Plant sanitary sewer effluent into one discharge line. The EESSMS is capable of monitoring all Y-12 Plant sanitary sewer effluent. Thus no additional sampling sites are required and back-calculation of contaminant releases based on two monitoring location is no longer necessary.

The Industrial User Permit expired at the end of August 1995. As required by the city, a sanitary sewer permit application and questionnaire form were submitted in July 1995. The questionnaire is used by the city's Department of Public Works staff to set limits for industrial and commercial discharges. Reissuance of the Y-12 Plant permit is in part contingent on review of permits issued to other industrial customers and on the issuance of an NPDES permit for the city's wastewater treatment facility.

Results

The PCB Monitoring Plan for the Y-12 Plant specifies sampling locations and frequencies of sampling for PCBs. All results for the year were less than the analytical detection limit, which is 0.0005 mg/L (Table 4.17).

Monitoring of nonradiological parameters at kilometer 12.4 (mile 7.7) on Upper Bear Creek continued until July 1995, as it did for radiological parameters, to monitor the influence of seepage from the S-3 ponds site. Because of decreased flow at this site since closure of the S-3 ponds, a new site at kilometer 11.97 has also been monitored as a replacement site. Analytical data from both sites have been compared, and changes in the monitoring routine were implemented in July 1995. Analytical data are reported monthly to TDEC in an attachment to the discharge monitoring report required by NPDES. These sites were monitored once per week for nonradiological parameters. Surface water in the upper reaches of Bear Creek contains elevated trace metals and nitrate concentrations.

Table 4.18 summarizes Y-12 Plant contributions to the sanitary sewer system for 1995.

Progress in Implementing Corrective Actions and Significant Improvements

Two dechlorination systems that began operating in December 1992 continued to provide dechlorination for 75% of EFPC flow (20% of EFPC flow is estimated to be groundwater). In-stream levels of total residual chlorine were typically about 0.01 mg/L during 1995 as compared with outfall discharge levels before 1993 of about 0.3 to 1.0 mg/L. Fish populations and density have increased significantly. Additional dechlorination has been achieved by installation of five tablet dechlorinators during 1995 (which now total 38) at chlorine-discharge sources. Outfall 125, the next largest nondechlorinated outfall, began treatment in 1995, following installation of a dechlorination system in late 1994.

Ecological recovery of EFPC is continuing, with some significant recent trends. Pollution-intolerant fish species are being found below Lake Reality, and there has been substantial reduction in toxicity above Lake Reality. However, both fish and benthic macroinvertebrate communities in UEFPC are dominated by pollution-tolerant species, especially above Lake Reality. Additional recovery may occur in response to reductions in mercury levels in EFPC. Complete recovery may not occur because water temperatures are elevated, inadvertent discharges/spills may occur, and availability of habitat is limited above Lake Reality.

Flow Management (or Raw Water) Project

Discharges to EFPC have decreased in volume from about 10 million gal/day (38 million L/day) in the early 1980s to about 3.5 million gal/day (13.2 million L/day) currently, primarily because of reductions in plant operations. These reductions have increased concern about maintaining water quality and stable flow in the upper reaches of EFPC. Accordingly, the new NPDES permit requires addition of Clinch River water to the headwaters of EFPC (North/South Pipe-Outfall 200 area) by March 1997 so that a minimum flow of 7 million gal/day (26.5 million L/day) is maintained at the point where EFPC leaves the reservation. Design of this project was completed in early 1995. Construction is planned to be completed in 1996.

Ammonia Reduction at Outfall 17

A urea pile was maintained above Outfall 17 for about 10 years; the urea was used for deicing roads and sidewalks. Elevated levels of ammonia nitrate in EFPC were traced to Outfall 17 as a result of a fish kill in December 1992. The urea pile was removed at that time; however, the soil in the area of the pile remains contaminated. The sudden toxic effect on fish was attributed to the start-up of dechlorination efforts on EFPC in the preceding month, which reduced available chlorine that apparently was reacting with and neutralizing the ammonia.

A feasibility study completed in late 1994 defines possible corrective actions. The new NPDES permit contains compliance requirements for Outfall 17, which are being achieved (since early 1993) as a result of natural flushing of contaminants from the site.

Non-Point-Source Studies

Storm water runoff is required to be periodically sampled and analyzed for a large number of contaminants by the Y-12 Plant Stormwater Pollution Prevention Plan . The plan was issued in September 1995 in accordance with provisions of the NPDES permit. The plan presents (1) programmatic and physical best management practice controls implemented at the Y-12 Plant, (2) surveillance programs, and (3) a monitoring plan for characterizing storm water discharges. Storm water runoff data from previous years were analyzed and the Feasibility Study of Best Management Practices for Non-Point Source Pollution Control at the Oak Ridge Y-12 Plant (CDM 1993 ) was issued in 1993. Additional studies were initiated on the basis of this report. Sampling of parking lots, the metal scrap yard, and selected building roofs was completed in 1994. The data will help determine whether the areas are specific sources of contaminants observed in storm water flow in EFPC . These types of investigations will continue as necessary to ensure compliance with the NPDES permit and other regulatory requirements.

Drain Modifications and Reroutes

Extensive drain surveys conducted in years previous to 1993 identified incorrectly connected building drains to either the sanitary or storm sewers. Most of these drains were administratively closed at that time. Permanent and physical changes to provide correct drain routings were designed and initiated in 1993 for 32 ``major'' buildings. One building was completed in 1993, and 25 buildings were completed in 1994. Several changes were made to the initial plans because of the ongoing downsizing of the plant. The remaining buildings will be completed as funding appropriations permit.

An additional design effort, which began in 1993, identified drains (primarily floor drains) that needed to be closed to ensure that accidental or unauthorized discharges are not made to either sanitary or storm sewers. The original scope included 21 buildings but has been reduced to 18 because managers were proactive in closing off drains that were under their control and for which sufficient funding was available. This design was completed in 1994. Work in 6 buildings was completed in 1994 and in the remaining 12 in 1995.

Several additional projects have been initiated to eliminate drains incorrectly discharging to EFPC or the sanitary sewer. Two main buildings in the Biology complex (9208 and 9207) were corrected in 1993 and 1994, respectively, by the rerouting of drains from EFPC to the sanitary sewer. A steam condensate discharge of about 40,000 gal/day (150,000 L/day) to the sanitary sewer from Building 9769 was rerouted to the steam plant in early 1995.

In addition, a project was begun in late 1994 to survey all the remaining and previously unsurveyed building drains at the Y-12 Plant. The survey was completed in early 1995. Incorrectly routed drains have been identified for closure or correction, and many drains were corrected or eliminated. Further corrective actions will be taken as funding appropriations permit.

Reduction of Mercury in Plant Effluent (RMPE): Phase II

The legacy of contamination resulting from use and storage of mercury at the Y-12 Plant has prompted a series of remedial measures. The RMPE II program is structured to serve as a bridge between downstream remediation of EFPC and upstream remedial actions at the Y-12 Plant. These efforts are directed toward meeting the NPDES permit requirements of 5 g/day from the Y-12 Plant by December 31, 1998. Six projects (four building source elimination efforts and two treatment units) have been identified under the RMPE  II program to reduce mercury contamination to UEFPC.

Significant progress was made in 1994 and 1995 toward reduction of mercury in discharges to EFPC. Construction and start-up of the Interim Mercury Treatment Unit (IHgTU) for Building 9201-2 was completed in September 1994. A study was initiated in 1995 to evaluate upgrading the IHgTU to a permanent system. The upgrade will be complete in early 1996. The IHgTU, which continues to operate, treated more than 1 million gal (3.78 million L) of water in 1994 and 4.3 million gal (16.27 million L) in 1995. In addition, rerouting pipes for buildings 9201-2 and 9201-5 was completed to eliminate sources of mercury. Design work was completed in 1994 for reroutes in buildings 9201-4 and 9204-4; construction is expected to be completed in early 1996.

To provide permanent mercury treatment capability, the Central Mercury Treatment System (CMTS) was designed in 1995; construction will be completed in 1996. The facility will be located in the existing Central Pollution Control Facility in Building 9623. Mercury-contaminated groundwater originating from sumps in buildings 9201-4, 9201-5, and 9204-4 will be collected and transported to CMTS for treatment. The system will be sized based on treatability studies such that water released to EFPC is within the NPDES limits (2 parts per billion, monthly average). The discharge of the CMTS will be through a new NPDES outfall.

Fish Kill Summary

Between January 6 and January 8, 1995, approximately 1800 dead fish were retrieved from EFPC. Water quality data thoroughly documents rapid and wide fluctuations in temperature and conductivity following ice and thunderstorms on January 6, 1995. These water-quality changes were a direct result of the unusual weather conditions and the associated application of road de-icer compounds. Toxicity tests and calculations of maximum concentrations of salts suggest that the impact from the road de-icers was far less significant than the effect of the rapid drop in temperature.

On August 3, 1995, an estimated 5 gal (19 L) of wastewater containing an unsaturated polyester resin (43% styrene) was released to the storm sewer system during an in situ pipe-relining operation. A small amount of resin failed to catalyze and harden during the curing process and was released to EFPC at Outfall 109. The discharge resulted in the death of approximately 5500 minnow-sized fish in the upper reaches of EFPC within the Y-12 Plant boundaries. The project plan has been revised to include the use of physical barriers to prevent the release of wastewater associated with this activity.

4.2.2.3 ORNL Nonradiological Summary

ORNL's current NPDES permit requires that point-source outfalls be sampled before they are discharged into receiving waters or before they mix with any other wastewater stream (see Fig. 4.14). Numeric and aesthetic effluent limits have been placed on the following locations:

• X01-Sewage Treatment Plant (STP);
• X02-Coal Yard Runoff Treatment Facility (CYRTF );
• X12-NRWTF;
• X13-Melton Branch;
• X14-WOC;
• X15-WOD;
• CAT1-Category I outfalls (storm drains);
• CAT2-Category II outfalls (roof drains, parking lot drains, storage area drains, spill area drains, once-through cooling water, cooling-tower blowdown, condensate, and disposal demonstration area);
• CAT3-Category III outfalls (drains that at one time included process and/or lab constituents); and
• COOLS-Cooling Systems (cooling water, cooling tower blowdown, and cleaning wastes originating at space cooling facilities).

Permit limits and compliance are shown by location in Table 4.19. Compliance with the NPDES permit for the last 3 years is summarized by major effluent locations in Fig. 4.25. The figure provides a list of the effluent locations and the number of noncompliances at each location. The majority of permit limit excursions in 1995 occurred at the Category II outfalls. All Category II limit excursions in 1995 were associated with total suspended solids, typically residual dust or dirt particles, conveyed in storm water runoff.

In 1995, at X01, no certain cause was established for February and October fecal coliform excursions. Effluent chlorine and suspended solids concentrations were normal at the times of the excursions. ORNL staff investigated whether rainfall could have contributed to the excursions, via rain dropping from a collection-point grate into the sample bottle. In addition, the possibility of STP facility maintenance contributing to the excursions was being investigated. Procedural modifications have been made with regard to these possible causes. The June 1995 chlorine excursion at X01 was attributed to malfunction of an automatic feed valve in the sewage treatment plant's effluent chlorination system. The component was promptly replaced and no subsequent excursions have occurred. At X02, no certain cause was established for oil-and-grease and suspended solids excursions that occurred in June and October, respectively. An ORNL project, Upgrade Coal Yard Runoff Treatment Facility, will be concluded in 1996 and will provide additional removal capability for solids, oils, and greases. At X12, all parameters were 100% in compliance. ORNL had no fish kills in 1995.

At the Category I and II outfalls, exceedences of limits on total suspended solids were attributed to flushing of parking lots or streets by storm water runoff. Category I and II outfalls are not contaminated by any known activity, nor do they discharge through any oil-water separator, other treatment facility, or equipment. During rain events, waters from the parking lots and surrounding areas drain into these outfalls, carrying suspended solids and other residue. This situation may result in total-suspended-solid exceedences. Best management practices (including frequent street sweeping) are in place to help avoid these exceedences. In addition, a plan is currently being carried out to improve sampling points at selected outfalls. At the cooling systems, all parameters were 100% in compliance.

Mercury in the Aquatic Environment

Prior to the stringent regulations now in effect, some contaminants reached various streams primarily as the result of accidental spills or leakages. Most mercury spills occurred from 1954 through 1963, during a period when ORNL was involved with OREX and METALLEX separations processes. Most of this activity occurred in or around buildings 4501, 4505, and 3592 in the main plant area. These processes are no longer in operation at ORNL. During the time of operation, an unknown number of mercury spills occurred. The spills were cleaned up; however, some quantities of mercury escaped and reached the surrounding environment. Sampling locations have been selected in areas surrounding known mercury spills. Additional sampling locations have been selected downstream from the outfalls and drains to determine the extent to which any mercury is being transported in surface water and sediment.

Surface water locations are shown in Fig. 4.26. In 1995 a total of 78 samples were taken from 13 locations. Samples were collected by the manual grab method and placed in 500-mL polyethylene bottles with polyethylene caps. In the laboratory, the samples were analyzed for total mercury content by manual cold vapor atomic absorption. Mercury was detected at 9 of the 13 sampling locations. The highest value reported was 0.44 �g/L near Outfall 207 in WOC, nearly identical to the 1994 high value of 0.43 at the same location. Average concentrations ranged from 0.050 to 0.25. The Tennessee Water Quality Criteria for the protection of fish and aquatic life sets a maximum concentration of 2.4 �g/L for mercury in water. The highest concentration, near Outfall 207, was 18% of the reference value.

Sediment sampling locations are shown in Fig. 4.27 . In 1995, a total of 54 sediment samples were taken from nine stream locations. Samples were collected by the manual grab method and placed in glass containers. In the laboratory, the samples were analyzed for total mercury content by manual cold vapor atomic absorption. The highest value reported was 880 �g/g near Outfall 261 on Fifth Creek. Average values at the other sites ranged from 0.019 to 16 �g/g. In general, results from samples collected in 1995 were similar to those for 1994.

PCBs in the Aquatic Environment

In 1995, duplicate samples of sediment were collected at ten locations in streams at and around ORNL (Figs. 4.28 and 4.29). Samples from each location were analyzed by the analytical laboratory for Aroclors 1016, 1221, 1232, 1242, 1248, 1254, and 1260. Only one location had results above detection limits. Four additional locations had laboratory-estimated values below the detection limit. The single maximum concentration above detection limit, 330 �g/kg for Aroclor-1254, was reported at the confluence of Fifth Creek and WOC. Detected Aroclor levels are similar or slightly lower than those detected in 1994. Results for most samples collected in 1995 were either below laboratory detection limits or were estimated by the laboratory.

4.2.2.4 K-25 Site Surface Water Effluents

The following are the five permitted major outfalls at the K-25 Site (Fig. 4.22):

• 005 (K-1203 Sewage Treatment Plant),
• 009 (K-1515 Sanitary Water Treatment Facility),
• 011 (K-1407-J CNF discharge to Poplar Creek),
• 013 (K-1513 Sanitary Water Intake Backwash Filter), and
• 014 (K-1407-J CNF discharge to the Clinch River).

In accordance with the compliance schedule in Part I, Section E, of the NPDES permit, the discharges through Outfalls 010 and 012 ceased permanently on December 30, 1993. These outfalls were removed from the permit in 1995. Although no monitoring is required at Outfall 013, routine inspections are conducted to ensure that no unsightly debris or scum is discharged through this point as the result of backwash operations at the K-1513 sanitary intake filter. Outfall 014 is a permitted outfall for the discharge of effluent from the CNF to the Clinch River. Part I, Section E, of the permit required that CNF discharges through Outfall 011 cease and CNF discharges through Outfall 014 be fully operational no later than April 30, 1996. Discharges through Outfall 014 began in November 1995. During operational startup and testing, discharges from CNF were routed concurrently through both Outfalls 011 and 014. The project is on schedule to meet the compliance deadline.

Part I, Section E, of the permit also requires that K-1515 sanitary water plant (Outfall 009) discharges be rerouted to the Clinch River by September 30, 1995. Discharges from the new K-1515-F treatment lagoon to the Clinch River began on June 12, 1995, and all phases of operational and postoperational testing were completed by September 18, 1995. By September 30, 1995, the Outfall 009 compliance schedule was completed and notification of completion was submitted to TDEC.

Results

The K-1203 Sewage Treatment Plant (Outfall 005) experienced a total residual chlorine (TRC) noncompliance in February 1995 during an upset condition caused by excessive rainfall and infiltration into the sewage collection system. During the upset condition the chlorine disinfection system and the ultraviolet (UV) light disinfection system were operated concurrently in accordance with operating procedures for upset events to provide maximum disinfection. TRC concentrations prior to an on subsequent days following the upset were well below the permit limit. Because this noncompliance was during an excessive rainfall event, the receiving water for Outfall 005 (Poplar Creek) was at a high flow rate, thus minimizing any potential for the TRC concentration in the effluent to have a negative impact to the environment. Observations of the receiving water confirmed that there were no adverse environmental impacts.

The sewage plant was placed in service in 1976, and many factors, including age, have contributed to degradation of the sewage collection system network. The degradation has allowed infiltration of storm water and groundwater into the system, which has contributed to influent volumes exceeding the plant design capacity. A sanitary sewer upgrade project to minimize infiltration was initiated in 1990. Phase I of this project, which has been completed, included raising the on-site manholes. Phase 2 of the project, which started in November 1994, includes relining the sanitary sewer system pipes. Relining activities continued through 1995 and point-source repairs for seriously damaged sections were initiated.

The K-1203 Sewage Treatment Plant (Outfall 005) experienced a BOD noncompliance with the NPDES Permit in February 1995. A thorough investigation into this event was conducted, including consultation with the Operator Training Center in Murfreesboro, Tennessee. The investigation revealed that there had not been a BOD shock to the treatment system because the microorganisms would not have recovered without operational reseeding. Furthermore, there would have been evidence of the plant going septic as a result of the microorganisms dying, and no such evidence existed. All other NPDES parameters measured at the time of the incident were well within permit limits and indicated proper operation of the system.

Outfall 009 is the discharge point for the K-1515 sanitary water plant, which provides sanitary water to the K-25 Site to be used for drinking, fire protection, and other purposes. It also provides water to two industries in the Bear Creek Road Industrial Park through an arrangement with the city of Oak Ridge. Raw water is taken from the Clinch River and treated at K-1515. In accordance with the NPDES permit, the K-1515-F settling lagoon was constructed and began discharging to the Clinch River in June 1995. Successful completion of the operational and postoperational testing phase was completed before the September 1995 compliance schedule date. The K-1515 sanitary water plant exhibited 100% compliance with the K-25 NPDES permit during 1995.

The K-25 Site CNF, Outfalls 011 and 014, has provisions for the treatment of nonhazardous and hazardous wastes. Nonhazardous flow entering the CNF consists of steam plant effluents and various small-quantity or infrequent streams from waste disposal requests. Hazardous streams include effluents from the TSCA Incinerator, the steam plant hydrogen softener waste stream, and various small-quantity or infrequent streams from waste disposal requests. The NPDES permit requires termination of CNF discharges to Poplar Creek through Outfall 011 by April 30, 1996. Installation of a new pipeline from CNF to Outfall 014 in the Clinch River was completed in October 1995, and TDEC approval to begin operation was received. All postoperational testing of the pipeline and termination of Outfall 011 discharges to Poplar Creek were completed by January 1996 and the compliance schedule for this outfall was met four months ahead of schedule. CNF exhibited 100% compliance with the K-25 NPDES permit during 1995.

The K-25 NPDES Permit includes 137 storm drain outfalls that are grouped into four categories based on their potential for pollutants to be present in their discharge. Category I storm drains have intermittent flow and drain storm water runoff from areas remotely associated with plant activities and subsurface runoff; Category II storm drains have intermittent flow and drain stormwater runoff from building roof drains and paved areas associated with plant activities; Category III storm drains have intermittent flow and drain storm water runoff from areas associated with concentrated storage areas, roof drains, coolant systems, and parking lots; and Category IV storm drains have continuous flow and drain cooling water discharges and runoff from industrial areas. Monitoring at storm drain outfalls is conducted semiannually, quarterly, monthly, or weekly for Categories I through IV, respectively, with those storm drains that have the highest potential for pollution being sampled most frequently.

The remaining three K-25 site NPDES noncompliances for 1995 occurred at storm drain outfalls. These noncompliances occurred at Outfall 120, Outfall 480/490, and Outfall 100.

In February 1995 a sewage bypass pump failed during a relining operation as part of the sanitary sewer upgrade project at the low point of system, causing sewage to back up and overflow from a manhole. As a result, approximately 100 gal (378 L) of raw sewage spilled onto a parking area and flowed into a nearby storm drain catch basin leading to Outfall 120. The bypass pump was immediately brought back on line and the sewage remaining in the parking area was washed back into the sanitary sewer system.

A visible sheen was observed emanating from Outfall 480/490 on May 1, 1995. Oil-absorbent booms and pads were utilized to contain and remove the sheen and a walkdown of the complete storm drain system was initiated to find the source of the sheen. Areas of specific concern were not identified in the investigation.

In December 1995 freezing conditions caused a sanitary water line break, resulting in a discharge of chlorinated water through Outfall 100, which is a Category IV storm drain. The discharge caused the TRC limit at Outfall 100 to be exceeded. As the water line was being repaired a temporary dechlorination system was installed in the storm drain network to ensure that chlorine levels at the outfall were maintained within NPDES permit limits. The temporary dechlorination system was removed from the storm drain network after repairs on the sanitary water line were completed.

A Storm Water Pollution Prevention Program (SWPPP) is another requirement of the NPDES permit. The K-25 SWPPP was initiated in October 1993 and addresses the following components:

• the storm water monitoring program;
• a site assessment;
• best management practices;
• development of a site map;
• inspections, evaluation, and record keeping; and
• definition of organizational responsibilities.

The sampling program is conducted to evaluate and characterize storm water runoff. Storm drains were monitored for various contaminants, depending on the types of areas drained by the system. PCBs, chemical oxygen demand, and radioactivity are sampled in all areas of the site. Through the evaluation of storm water effluent, further sampling or investigation was defined, and pollutant sources and areas for corrective actions were identified.

The FY 1995 sampling and analysis plan was developed with the information from the 1987 and 1994 sampling results, knowledge of various processes and functions conducted at the K-25 Site, material storage and handling practices, and waste disposal practices in the drainage areas for each outfall. Storm drains that drained similar areas were grouped to minimize the number of storm drains to be sampled. Thirty storm drains were placed into six groups located at the powerhouse area. One storm drain from each group and all other outfalls were sampled according to the plan. Dry- and wet-weather samples are planned to be collected in FY 1996 at continuous-flow storm drains in conjunction with water and sediment sampling to be conducted within the piping systems.

An assessment of the K-25 Site was conducted to determine which areas, activities, or materials may be contributing pollutants to the storm drain system. When a potential source was identified, management practices were reviewed to determine if there was a risk of pollutants entering storm water. If there was a risk, either corrective actions were identified or best management practices were applied. Best management practice plans were developed for the TSCA Incinerator, the CNF, the K-1501 Steam Plant, and the K-1414 Garage. These facilities were considered to be at risk because of the nature of the activities and because they are operating facilities. In 1995, best management practice plans were developed for the K-1417 Drum Storage Yard and for construction activities because contaminants may reach storm water. There are also three ongoing activities that are considered to be site-wide best management practices because they provide the site with information on contamination, transport of storm water, and effects of contamination. These three best management practices are the storm drain survey, radiological survey, and BMAP.

An SWPPP site map was developed as a visual aid to bring all of the site data together. Knowing the location of all identified potential pollutant sources in relation to the storm drain system (and sensitive environmental areas) gives the user an idea of potential pollutants that can be expected to be found at a particular outfall. By using the map, pollutants can be traced from an outfall to a source or from a potential source to its respective outfall.

Two semiannual inspections were performed in 1995. The first site inspection, performed in January 1995, comprised an assessment of compliance at various facilities with existing CWA best management practices, a site-wide dry-weather inspection, and a site-wide inspection during a storm event. The second inspection was performed in August 1995. Inspection criteria included evaluation of erosion-control methods employed during construction projects at the site, and the extent to which control guidelines were followed.

4.3 TOXICITY CONTROL AND MONITORING PROGRAM

4.3.1 Y-12 Plant Toxicity Control and Monitoring Program

Effluent from the Groundwater Treatment Facility was tested in April and June using Ceriodaphnia and fathead minnows. In April, the effluent's NOEC was 0.5% for Ceriodaphnia and 10% for fathead minnows. The calculated IWC was 2.09%. In June, the effluent's 48-hour LC₅₀ was 100% for both Ceriodaphnia and fathead minnows. The calculated IWC was 0.73%.

Effluent from the Central Pollution Control Facility was tested in May and June using Ceriodaphnia and fathead minnows. In May, the treated effluent from the Central Pollution Control Facility had an NOEC of 100% for both Ceriodaphnia and fathead minnows. In June, the treated effluent from the Central Pollution Control Facility had a 48-hour LC₅₀ of \math{>}100% for both Ceriodaphnia and fathead minnows. The calculated IWCs of Central Pollution Control Facility effluent in EFPC were 0.23% in May and 0.40% in June. Because the IWCs were less than the NOEC and the LC₅₀, it is unlikely that treated effluent from that facility adversely affected the aquatic biota in EFPC.

Water from the in-stream monitoring point, Outfall 201, was tested seven times during the period using Ceriodaphnia and fathead minnows. Four tests were conducted in May and the NOECs were 100%, 80%, \math{<}80%, and 80% for Ceriodaphnia ; the NOEC s were each 100% for fathead minnows. The 96-hour LC₅₀s for Ceriodaphnia and fathead minnows were all \math{>}100%. (The 96-hour LC₅₀s were developed during the chronic tests.) Three tests were conducted in June and the NOECs were 80%, 100%, and 100% for Ceriodaphnia , and were 100%, 80%, and 100% for fathead minnows. The June LC₅₀s for both Ceriodaphnia and fathead minnows were all \math{>}100%.

Storm sewer monitoring began in June at four locations in the storm system via the Surface Water Hydrological Information Support System (SWHISS), which include Buildings 9422-11, 9422-12, 9422-15, and 9422-16. The water from the storm sewer at Building 9422-11 had a 48-hour LC₅₀ of 38.5% for Ceriodaphnia and \math{>}100% for fathead minnows. The water from the Building 9422-12 storm sewer had 48-hour LC₅₀s of 37.3% and 74.8% for Ceriodaphnia and fathead minnows, respectively. Water from the storm sewer at Building 9422-15 had a 48-hour LC₅₀ of 77.2% for Ceriodaphnia and \math{>}100% for fathead minnows. The water from the Building 9422-16 storm sewer had a 48-hour LC₅₀ of \math{>}100% for both Ceriodaphnia and fathead minnows. During the toxicity tests, total residual chlorine was measured in storm sewer water samples from Buildings 9422-12 and 9422-15; therefore, chlorine may have contributed to the mortality of the Ceriodaphnia and fathead minnows in these tests. Later tests include toxicity testing of dechlorinated storm sewer water to evaluate the effects of chlorine on the test results.

4.3.2 Y-12 Plant Biomonitoring Program

4.3.3 ORNL Toxicity Control and Monitoring Program

Full-strength wastewater from the NRWTF was not toxic to Ceriodaphnia during the April and October tests; therefore, no IWC was calculated on the NRWTF for 1995. Fathead minnow testing for this facility was discontinued as allowed in the NPDES permit guidelines. The STP wastewater's NOEC for Ceriodaphnia ranged from 6% to 50% during 1994. The NOEC for the STP was 6% in April, 12% on two occasions (April and November), 50% in July, and 25% in September. Per guidelines in the NPDES permit, no fathead minnow tests were conducted for the STP. Because the IWC exceeded the NOEC for both tests conducted in April, a Toxicity Control Plan for the STP was developed and implemented in July, and toxicity testing for this facility was increased to every other month.

During 1994 the Melton Branch (X13) site was tested 11 times, and the WOC (X14) site was tested 10 times. Water from X13 reduced fathead minnow survival on five occasions (April, May, October, November, and December) and Ceriodaphnia reproduction on two occasions (February and December). Confirmatory tests conducted in May and November again resulted in reduced fathead minnow survival. Follow-up confirmatory tests conducted in June and December showed the water to be nontoxic; thus the toxicity appeared to be transient. Confirmatory tests using Ceriodaphnia were conducted in February and December. Both confirmatory tests resulted in NOECs of 100%. Water from X14 reduced fathead minnow survival on two occasions (April and May) and Ceriodaphnia reproduction on two occasions (August and December). A confirmatory test of fathead minnows, conducted in May, again resulted in reduced fathead minnow survival. A secondary confirmatory test conducted in June showed the water to be nontoxic; thus the toxicity appeared to be transient. Confirmatory tests using Ceriodaphnia were conducted in September and December. Both confirmatory tests resulted in NOECs of 100%. To determine whether fathead minnow mortality in the ambient water samples might be caused by a fungal or bacterial pathogen, water from X13 and X14 was exposed to UV light for a 20-min period. Tests of water from sites X13 and X14 showed improved fathead minnow survival or growth in water treated with UV light (NOECs were 100%).

4.3.4 K-25 Site Toxicity Control and Monitoring Program

The results of the toxicity tests of wastewaters from K-1407-J and K-1203 conducted during 1995 are given in Table 4.26. This table provides the month the test was conducted, the wastewater's no-observed-effect level (NOEL), and 96-hour lethal concentration for 50% of the test organisms (LC₅₀) for fathead minnows and Ceriodaphnia for each wastewater. Average water quality measures obtained during each toxicity test are shown in Table 4.27.

Effluent from K-1407-J (Outfall 011) was tested twice with fathead minnows and Ceriodaphnia . The effluent's NOELs were 75% on both occasions for fathead minnows and 25% and 75% for Ceriodaphnia . The LC₅₀s were \math{>}75% for fathead minnows on both occasions, \math{>}25% in the May tests, and 75% in the November test for Ceriodaphnia . The toxicity tests conducted for this outfall were within the limits specified by the NPDES permit.

Effluent from K-1203 was tested four times with fathead minnows and with Ceriodaphnia . In all four tests, full-strength samples did not reduce survival, growth, or reproduction. Thus the NOELs were 100% and the LC₅₀s were \math{>}100%.

4.4 BIOLOGICAL MONITORING AND ABATEMENT PROGRAM

4.4.1 Monitoring Contaminant Concentrations

From November 1994 to March 1995, the highest mercury concentrations in sunfish on the ORR continued to be in fish from EFPC (Fig. 4.31). Mean mercury concentrations in sunfish from the middle sections of East Fork (from EFK  6.3 to EFK 23.4) were similar, with lower mercury concentrations in fish from areas downstream [EFK 2.1, Poplar Creek kilometer (PCK) 6.9, Clinch River kilometer (CRK) 15.0]. The twofold to threefold higher concentrations in sunfish above Lake Reality suggests that Y-12 Plant discharges continue to be an important source of mercury in fish in the upper reaches of EFPC. In addition to EFPC, elevated concentrations of mercury were clearly evident in fish from Poplar Creek, Bear Creek, and WOC. Overall, mean mercury concentrations in fish in 1994/1995 on the ORR were similar to those observed in 1993-94.

A pattern of decreasing concentration with distance downstream is apparent for PCBs in redbreast sunfish in EFPC (Fig. 4.32). Redbreast sunfish from sites upstream of EFK 23.4 (EFK 23.7, EFK 24.8) contained PCB concentrations in December 1994 substantially higher than those observed in fish from other EFPC sites. The high concentrations in fish at sites in UEFPC indicate the importance of the industrialized portion of the Y-12 Plant as a source in relation to contaminated sediment and soil downstream of Lake Reality. Mean PCB concentrations in sunfish were also elevated in WOC and Bear Creek during the same time period. In general, mean PCB concentrations in sunfish collected in 1993-95 from EFPC and WOC are substantially higher than those observed in fish collected in previous years.

Toxicity tests on effluent from the two major liquid waste treatment plants at the K-25 Site (the K-1203 sewage treatment plant and the K-1407-J CNF) show that discharges from the plants are usually well within the permit limits, and often have no effect on survival, growth or reproduction even at full strength. The single exception occurred in the March 1994 testing of the sewage treatment plant effluent, when the fathead minnow survival was below the permit limit of a minimum No Observed Effect Limit of 4.2%. A confirmatory test conducted later the same month produced results well within the permit limits. Toxicity tests on the CNF effluent have all produced results within the permit limits for the past two years. The tests at this outfall are scheduled to be discontinued, as a new outfall has been constructed directly on the Clinch River. Toxicity testing will not be required under the terms of the NPDES permit at this new outfall as the Clinch River has a much larger flow than Poplar Creek. Because of the consistently good test results, the testing frequency of effluent from the K-1203 sewage treatment plant was reduced to twice per year in July 1995.

While the NPDES permit does not have toxicity testing limits on stormwater discharges, testing is conducted to ensure that these discharges are not inimical to aquatic life. Discharges from two storm drains, SD-170 and SD-190, frequently demonstrate some impact to the test organisms. Some of the reduction in survival of fathead minnows in samples from various K-25 Site locations may be due to a naturally occurring pathogen. Water samples disinfected with UV light often show increased survival compared to untreated samples.

Toxicity tests on water from in-stream locations occasionally exhibit reduction in survival or reproduction of Ceriodaphnia , and reductions in fathead minnow survival also occur occasionally. As is the case for the storm drains, this reduction may largely be explained by the occurrence of a natural pathogen, such as a fungus or virus, as disinfection of the water samples often increase survival.

Bioaccumulation studies have been carried out by collecting fish or caged clams from the subject waters, and analyzing the soft tissue for contaminants of concern. Fish collected from Mitchell Branch and the K-901-A and K-1007-B ponds in 1994 showed elevated levels of PCBs when compared with fish from reference locations. Whole body analysis of prey fish (chiefly shad) likely to be preyed upon by terrestrial piscivores show that many contain levels of PCBs above the concentration shown to be detrimental to some predators, such as mink. Some fish collected from Poplar Creek also contained concentrations of mercury above the levels detrimental to mink. Caged clams placed in the pond and stream also showed detectable levels of PCBs. The results so far seem to indicate that one or more storm drains entering the pond carry PCBs, and that much of the PCBs deposited in the pond so far have remained in the pond, rather than migrating into Poplar Creek. A similar situation appears to exist in Mitchell Branch, but the levels of PCBs involved seem to be significantly lower. However, sunfish collected from various localities along Poplar Creek do not show much variation, indicating that the contribution of PCBs to Poplar Creek from the K-25 Site is small. Waterfowl collected near the Site have not shown detectable levels of PCBs.

Raccoons feed upon fish and other aquatic organisms, so some have been trapped and analyzed. Lead, mercury, and cadmium have been found in the raccoons trapped near the K-25 Site. The mercury concentrations were higher in those raccoons collected along EFPC. This correlates with the elevated mercury levels found in the prey fish. Although no relative contribution can be quantified, all indications are that the K-25 Site is a relatively small contributor of mercury to Poplar Creek. At this time, sources for the lead and cadmium cannot be determined.

Water taken from Mitchell Branch kilometer (MIK) 0.12 was tested on Medaka fish embryos, and proved toxic to them. Other fish health studies conducted on fish from Mitchell Branch show that these fish are stressed relative to the fish collected from the reference sites. This stress is evidenced by elevated levels of liver detoxification enzymes, gill and liver dysfunctions and changes, and by an abnormal population distribution of size and age class. In particular, there were very few individuals from the 1992 brood. However, fish born in 1992 were also scarce at the reference sites. It is possible that this scarcity may therefore reflect some widespread natural disturbance of breeding patterns that occurred in 1992. This, and the trends of the other indicators and the fact that the fish community as a whole seems to be rebounding, suggest that the stress is due to a variety of causes, and that some or all of them may be episodic in nature.

The community studies conducted in Mitchell Branch show that the stream has been impacted. Studies of the benthic macroinvertebrate fauna show that both species diversity and richness are below that of the reference sites. Although there has been considerable variation in the sample results through time, it does appear that Mitchell Branch is recovering. As the studies have progressed, there has also been a gradual increase in the number of fish species present in the creek, as well as in numbers of individuals.

In the summer of 1995, the K-25 Site program was modified. Several tasks were reduced in scope or frequency, and some subtasks were eliminated altogether. Toxicity testing was eliminated from Poplar Creek and the Clinch River, and the frequency was reduced at storm drain 180, which has not historically exhibited toxicity in the effluent. Fathead minnow toxicity tests on storm drain effluent was also discontinued, as Ceriodaphnia tests have proven to be more sensitive. If a problem is found at any of the storm drains, fathead minnow tests will be reinstated. Fish bioaccumulation studies in Mitchell Branch and the K-1007 Ponds were discontinued, as it has already been demonstrated that some contaminants are accumulating in fish from these waters. Similarly, whole body analysis of prey fish has been discontinued, as data sufficient for the present uses has already been collected. The assessment of fish health and the in-stream monitoring of Mitchell Branch have been discontinued for the present. In-stream monitoring will resume on a two year cycle, and the assessment of fish health may be re-instated after further remediation activities on the K-25 Site are completed. All of these modifications were made with the approval of the TDEC.

4.4.2 Toxicity of Lithium Discharges to Oak Ridge Stream Is Mitigated by Sodium

4.4.3 Reduction of Aqueous Mercury Inputs to East Fork Poplar Creek Is Slow To Produce a Corresponding Decrease in Mercury Bioaccumulation in Fish

4.4.4 Sources of Contamination to Stream Biota Are Identified and Evaluated

4.4.5 Fish Communities in Mitchell Branch Are Recovering Following Remedial Actions

4.4.6 Cessation of Fly Ash Discharges to McCoy Branch Leads to Recovery of the Benthic Macroinvertebrate Community

Contents Chapter 5