Environmental Impact Statement and Environmental Impact Report for Continued Operation of Lawrence

C.4 PUBLIC HEALTH

Measures are taken to minimize exposures to the public that might occur from operations at LLNL and SNL, Livermore. Both LLNL and SNL, Livermore release tritium to the atmosphere through stacks, primarily at Building 331 at the LLNL Livermore site and at Building 968 at SNL, Livermore. The LLNL Livermore site also releases small quantities of oxygen-15 and nitrogen-13 from accelerator operations at Building 194. Both LLNL and SNL, Livermore discharge wastewater to the sewer system that may contain low concentrations of radionuclides and toxic materials. All releases must be limited to comply with the regulatory requirements of DOE Orders and with Federal laws and regulations identified in section C.1. There are no significant sources of external radiation exposure to the public from site operations at the LLNL Livermore site, LLNL Site 300, or SNL, Livermore (LLNL, 1990b).

The quantities of radionuclides released to the air are minimized through the use of administrative controls (such as worker training and limits on amounts of radionuclides allowed in any single facility at one time) and engineering controls (such as high-efficiency particulate air filters, tritium removal systems). Releases to the sewer system are minimized by administrative controls (such as limiting inventories, worker training, and posting notices on sinks that discharge directly into the sewer system) and engineering controls (such as retention tanks and blocking connections to sewer drains).

C.4.1 Environmental Monitoring

The purpose of this section is to provide an overview of the environmental monitoring program conducted by LLNL and SNL, Livermore. Further details and evaluations of the results are available in the environmental reports that are published by both Laboratories on an annual basis. Some of the results are discussed in section C.4.2.2.

There is a comprehensive environmental monitoring program to assess the effectiveness of effluent control measures, to assess compliance with applicable environmental regulations, and to estimate the impact of operations on the environment. The environmental monitoring programs are conducted in accordance with DOE Orders and other DOE directives. Air and sewage effluent, surface water, rain, ground water, soil, vegetation, and foodstuff samples are collected and analyzed. Also, environmental radiation and noise measurements are taken and evaluated. The results of the monitoring program are reported to DOE and to other appropriate federal, state, and local regulatory agencies on a yearly basis (DOE, 1982). During 1990, over 150,000 environmental sample analyses were made (LLNL, 1991d). Table C-5 presents the environmental monitoring and analysis schedule. This table is not all-inclusive; it is designed to provide the reader with a general idea of what is monitored and the location and frequency of sample collection and analysis. Further details concerning the monitoring program can be obtained from the annual environmental reports.

C.4.1.1 Monitoring at the Combined LLNL Livermore Site and SNL, Livermore

Because of the close proximity of the LLNL Livermore site and SNL, Livermore, the Environmental Protection Department of LLNL and the Environmental Protection Department of SNL, Livermore conduct a joint environmental monitoring program.

Air Sampling

The air at the LLNL Livermore site perimeter and at locations throughout the Livermore Valley is monitored by the environmental monitoring program to measure the concentrations of airborne particulates (radionuclides and metals) and tritiated water vapor. Tritiated hydrogen gas is not monitored because its committed effective dose per unit of exposure is 25,000 times less than that for tritiated water. There are 13 continuously operating high-volume air particulate samplers at offsite locations, and 6 of these samplers are at locations around the combined perimeter of the two sites. SNL, Livermore operates 4 onsite air monitors. All air sampler filters are changed weekly; identified by location, sampling period, and flow rate; and transported to the laboratory for analysis. Filter samples from the LLNL Livermore site perimeter and offsite locations are analyzed on a weekly basis for gross alpha and beta radioactivity. Airborne tritiated water vapor is determined on a biweekly basis. Monthly composites of the filter samples from selected LLNL Livermore site perimeter locations are analyzed for gamma-emitting radionuclides, uranium-235, uranium-238, plutonium-239, and beryllium. Monthly composites of selected offsite filter samples are analyzed for plutonium-239. Replicate samples are taken as a quality assurance measure to confirm the results.

Sewage Sampling

SNL, Livermore monitors sanitary sewage outfall from this site to demonstrate compliance with SNL, Livermore's Wastewater Discharge Permit. Sewage effluent is sampled at the discharge point from SNL, Livermore by a flow-proportional composite sampler. An aliquot of the composite sample is collected weekly and analyzed by a state-certified laboratory for pH, metals, and dissolved solids. These data are reported to the City of Livermore Water Reclamation Plant on a monthly basis. Twice a year extensive sampling and analysis is performed on the sewage outfall and on liquid effluents from the Electroplating Laboratory and the Printed Wiring Laboratory. SNL, Livermore facilities that handle hazardous substances are equipped with a Liquid Effluent Control System which consists of large retention tanks designed to collect liquids at the generating facility. This allows SNL, Livermore to analyze the liquid effluent for potential contaminants before it is discharged into the sewer and ensures that the liquid effluents are within allowable limits before they leave the facility. LLNL facilities that handle hazardous substances are equipped with retention tanks that collect liquids at the generating facility. Contents of these tanks are analyzed to determine whether or not the material meets wastewater discharge guidelines.

Sewer effluent leaving SNL, Livermore combines with the outflow from LLNL. The effluents mix with sewage from the City of Livermore and go to the Livermore Water Reclamation Plant (LWRP) where the sewage is treated. Administrative and engineering controls at the SNL, Livermore and LLNL Livermore sites prevent potentially contaminated wastewater from being discharged directly to the sanitary sewer. Liquids are discharged to the sanitary sewer only if laboratory results indicate that the pollutant levels are within allowable limits (LLNL, 1991d). If liquids exceed permissible pollutant levels, they are treated to reduce pollutants to the lowest levels practical and below LLNL guidelines, or are shipped to an offsite treatment or disposal facility (LLNL, 1991d).

The combined sewage from LLNL and SNL, Livermore is continuously monitored for pH, selected metals, and radioactivity before leaving the LLNL Livermore site. If established limits are exceeded, an alarm is registered at the LLNL Fire Dispatcher's Station which is attended 24 hours a day. The monitoring system provides a continuous check on sewage control and provides direct notification of the Livermore Water Reclamation Plant in the event that pollutant limits are exceeded. A sanitary sewer spill plan and a trained response team exist to minimize the effects of a potential spill.

Daily composite samples of the combined sewage are analyzed for gross alpha, gross beta, and tritium activity. A monthly composite of the combined LLNL Livermore site and Livermore Water Reclamation Plant effluents is also analyzed for gamma-emitting radionuclides and plutonium-239. Composites of the monthly samples are analyzed quarterly for plutonium and cesium content (LLNL, 1991d). Heavy metals are analyzed on a monthly basis. Once each quarter a 24-hr composite sample of the LLNL sewer effluent is subjected to an extensive set of analyses by an independent offsite laboratory. Analyses include parameters specified on Livermore Water Reclamation Plant's National Pollutant Discharge Elimination System permit.

LLNL has a sewage effluent diversion system to retain wastewater which is unacceptable for release to the Livermore Water Reclamation Plant. This system can retain approximately 200,000 gal of potentially contaminated sewage until it can be analyzed and the appropriate handling methods determined. The diversion system ensures that all but the first few minutes of wastewater flow that trigger an alarm is retained at LLNL until the appropriate actions are taken (LLNL, 1991d).

There are five satellite monitoring stations located at strategic points in the main sewer system of LLNL to isolate the source of any inadvertent contamination (LLNL, 1991d). Four more monitoring stations were installed in 1991 (LLNL, 1991d).

Water Monitoring

LLNL monitors the waters of the LLNL Livermore site and the surrounding areas of the Livermore Valley. The waters monitored in the Livermore Valley include lakes, aqueducts, tapwater, rainwater, and drinking-water supply wells. Stormwater is monitored on the LLNL Livermore site. The samples are analyzed for radioactivity. As part of a study which was initiated in 1977, the concentration of tritium is measured annually in water collected from wells in the immediate vicinity of and in wells downgradient from the Livermore Water Reclamation Plant to determine the extent of tritium migration into the ground water. In 1990, the rainwater and stormwater runoff from four storms were analyzed for radioactivity, metals and volatile organic compounds.

Soil Monitoring

LLNL conducts an annual soil monitoring program to measure the concentration of various radionuclides that occur as a result of the operations at the LLNL Livermore site or as a result of global fallout from past atmospheric testing of nuclear weapons. Soil and arroyo samples are analyzed for plutonium-239 using alpha spectroscopy. Gamma spectroscopy is used to analyze the samples for over 150 radionuclides. Arroyo sediments are also analyzed for tritium, polychlorinated biphenyls, pesticides, metals, volatile organic compounds, and semivolatile organic compounds (LLNL, 1991d).

Vegetation and Foodstuff Monitoring

Native vegetation, honey, goat's milk, and wine from the surrounding area are analyzed to provide input for pathway analyses and to calculate the potential radiation dose from consumption of these materials.

External Radiation Monitoring

Radiation dosimeters are used to monitor the penetrating (gamma and neutron) radiation levels which can neither be measured by collection of material on filters nor chemically trapped. Thermoluminescent dosimeters are placed at 22 LLNL Livermore site perimeter locations and at 55 offsite locations to measure gamma radiation levels. These dosimeters are exchanged, analyzed, and the dose rates are calculated on a quarterly basis. Uranium-235 track-etch detectors are placed at eight onsite locations to measure environmental neutron dose levels (LLNL, 1991d).

Table C-5 Environmental Monitoring and Analysis Schedule

Sample	Location	Analysis	Collection Frequency	Number Collected	Analysis Frequency
Air	LLNL perimeter	gross alpha gross beta U-235, U238 and Pu-239 tritium (HTO) gamma beryllium	weekly " " biweekly weekly "	6 6 6 7 6 6	weekly " monthly composite biweekly monthly composite "
	Livermore Valley	gross alpha gross beta Pu-239 tritium (HTO)	weekly " " biweekly	11 11 6 6	weekly " monthly composite biweekly
	LLNL Site 300	gross alpha gross beta U-235, U-238 and Pu-239 gamma beryllium	weekly " " weekly "	10 10 10 10 10	weekly " monthly composite monthly composite "
Sewage	LLNL Livermore site and SNL, Livermore	pH gross alpha gross beta tritium (HTO) Pu-239 gamma heavy metals nutrients pesticides priority-pollutants BOD, COD, N, and others	continuous daily " " " " " quarterly " " "	N/A 1 1 1 1 1 1 1 1 1 1	continuous daily " " monthly composite " " quarterly " " "
Water	LLNL Livermore site Surface and domestic Storm Rain Ground water	rad, metals, organics alpha, beta, tritium tritium tritium	quarterly during storm after storm annual	12 9 17 13	quarterly during storm after storm annual
Water	LLNL Site 300 Surface Rain Water supply Water supply Ground water	alpha, beta tritium alpha, beta, tritium alpha, beta, tritium, metals, organics alpha, beta, tritium, metals, organics various*	quarterly quarterly annual quarterly quarterly	2 1 9 7 (4 of these also included in annual sampling network) 39	quarterly quarterly annual quarterly quarterly
Soil	LLNL Livermore site and SNL, Livermore	gamma scan, Pu-239	annually	16	annually
Soil	LLNL Site 300	gamma scan, U-235, U-238, and Pu-239	annually	14	annually
Arroyo sediments	Livermore Valley	gamma scan, Pu-239, tritium (HTO), PCBs/pesticides, metals, VOCs, semi-VOCs	annually	24	annually
Vegetation	Livermore Valley	tritium (HTO)	quarterly	8	quarterly
Vegetation	LLNL Site 300	tritium (HTO)	quarterly	6	quarterly
Wine	Livermore Valley, other areas of California, and Europe	tritium (HTO)	annually	30	annually
Honey	Livermore Valley	tritium (HTO)	annually	8	annually
Goat milk	Livermore Valley	tritium (HTO) K-40, Cs-137	monthly "	6 6	monthly "
Environmental radiation (TLD)	LLNL Livermore site, SNL, Livermore, and Livermore Valley	gamma neutron	quarterly "	77 8	quarterly "
Environmental radiation (TLD)	LLNL Site 300 and City of Tracy	gamma	quarterly	16	quarterly
Noise	LLNL Site 300 and City of Tracy	sound level	during testing	6 stations	during testing

HTO = Tritiated water.
N/A = Not applicable.
VOC = Volatile organic compound.
PCB = Polycholorinated biphenyl.
BOD = Biological oxygen demand.
COD = Chemical oxygen demand.
TLD = Thermoluminescent dosimeter.
* Depends on sampling location. Information from the 1990 Environmental Report.
Source: LLNL, 1991d.

C.4.1.2 Environmental Monitoring at LLNL Site 300

Environmental monitoring at LLNL Site 300 is conducted by the Environmental Surveillance Division of LLNL. See Table C-5 for an overview of the environmental monitoring and analysis schedule.

Air Monitoring

High-volume air particulate samplers are operated at LLNL Site 300 and in the City of Tracy to measure the concentration of various airborne radionuclides and beryllium. The samplers are located to ensure that any significant concentration of contaminants from Site 300 operations would be detected, regardless of local meteorological conditions at the time of release.

Water Monitoring

Routine analysis is conducted for the onsite surface and ground water and at nearby locations. Samples are collected annually from nine ground water sources (four from offsite active water supply wells, and five from offsite surveillance wells) from the area surrounding LLNL Site 300 to characterize local ground water quality and to assess the environmental impacts of LLNL Site 300. These samples are analyzed for gross alpha and beta, tritium, volatile organic compounds, pesticides, metals, minerals, and phenolic compounds (LLNL, 1990b).

Additional compliance monitoring is conducted around landfill and wastewater surface impoundment units, as required by the Regional Water Quality Control Board Central Valley Region, California Department of Health Services, and the EPA to determine whether these operations have impacted ground water.

Soil Monitoring

Soil sampling is conducted at LLNL Site 300 to document any changes in environmental radioactivity levels and to evaluate any increase in radioactivity that may be the result of LLNL operations. High explosives tests occasionally use depleted uranium (uranium-238). One of the purposes of the annual soil sampling is to determine how these tests affect the uranium content of the soil. The methods of soil sample collection and analyses at LLNL Site 300 are similar to those at LLNL Livermore site.

Vegetation Monitoring

The methods of vegetation sample collection and analyses at LLNL Site 300 are similar to those methods employed at the LLNL Livermore site.

External Radiation Monitoring

Thermoluminescent dosimeters are used to monitor the gamma radiation levels at strategic onsite and offsite locations at LLNL Site 300. Since there is no significant source of neutron radiation, only gamma radiation levels are measured.

Noise Monitoring

Six microbarograph recorders are maintained in or near the City of Tracy to determine if high explosives tests conducted at LLNL Site 300 have any impact on the local population. During 1990, 105 high explosives tests were conducted at LLNL Site 300. The peak noise limit of 127 dB was not exceeded during any of the tests, and there were no complaints of noise or overpressure from residents in the vicinity of LLNL Site 300 (LLNL, 1991d).

C.4.2 Radiation Exposures of the Public

This section discusses the radiological toxicity assessment, exposure assessment, and risk characterization with respect to the combined releases of radionuclides into the environment from normal operations of LLNL, Livermore site and SNL, Livermore.

C.4.2.1 Radiological Toxicity Assessment

This section describes the properties of the radionuclides that are released to the environment through stacks as a consequence of the operations at LLNL and SNL, Livermore and the properties that affect their radiotoxicities. As explained in section C.3.3, the most significant risk of exposure to low levels of radiation is cancer. The potential hazard (radiotoxicity) presented by these nuclides is based upon the physical radioactive decay characteristics and the biological distribution of these radionuclides and their radioactive decay products. Internal radiation exposures can occur as a result of inhalation, ingestion of water and contaminated food products, and absorption through intact skin or open wounds in the skin. External exposures can result from the presence of these materials in the air and water, and the deposition of these materials on ground and other surfaces.

Because each chemical element has its own characteristic biological distribution, the different radionuclides will selectively irradiate different organ systems of the body to varying degrees. The various organ systems differ in their sensitivity to radiation. In other words, if two different organ systems receive an identical quantity of radiation exposure, the probability of a deleterious effect occurring in the two organs may not be the same. Also, the severity of the detriment that occurs as a result of an effect (i.e., cancer) occurring in one organ may be different than that of another organ. For example, the thyroid gland is one of the more radiosensitive organs of the body; however, the chance of dying from thyroid cancer is smaller than the chance of dying from cancer of other organs such as the pancreas.

The International Commission on Radiological Protection has developed a system to normalize the potential for detriment which may occur as the result of exposure to many different radionuclides (ICRP, 1978). This system takes into account the physical and biological characteristics of the radionuclides and their decay products, the relative radiosensitivities of the organs irradiated, and the consequence of cancer occurring in the irradiated organs. These considerations are used to develop weighting factors that are used to convert radiation dose equivalents into effective dose equivalents.

The following paragraphs provide pertinent information on tritium, oxygen-15, and nitrogen-13. Table C-6 provides the dose conversion factors for these radionuclides, and Table C-7 provides information on their physical characteristics.

Hydrogen-3 (Tritium)

Tritium, a radioactive isotope of hydrogen, is produced naturally in the upper atmosphere by the action of cosmic rays (NCRP, 1979). Tritium is also man-made, and the tritium used in DOE weapons and fusion energy programs is primarily produced in reactors.

Tritium decays by b - emission (average energy 0.006 MeV) with a half-life of 12.3 years (see Table C-6 and Table C-7).

The major forms of tritium in the environment are tritiated hydrogen gas and tritiated water. Conditions in the upper atmosphere (the stratosphere) favor the conversion of tritium gas to tritiated water; naturally occurring tritiated water behaves much the same as normal water and follows the hydrologic cycle. In the lower atmosphere (the troposphere), tritiated hydrogen gas is only slowly oxidized to tritiated water at a rate of about 1 percent per day (NCRP, 1979). The form in which tritium exists is important because the committed effective dose equivalent per unit exposure of tritiated water is approximately 25,000 times greater than that of tritiated hydrogen gas (ICRP, 1978).

Tritiated water can enter the body by ingestion, inhalation, and absorption through intact skin and open wounds in the skin. Once inside the body, tritiated water mixes freely with body fluids and becomes nearly uniformly distributed throughout the soft tissues within a few hours. Small amounts of tritiated hydrogen gas can be oxidized to tritiated water or exchanged with organically bound hydrogen, but essentially all of the tritiated hydrogen gas is respired out of the body through the lungs. Thus, exposures from tritium are usually limited by the concentration of tritiated water rather than the total concentration of tritium.

The typical human body contains 7000 g of hydrogen, of which 4500 g is incorporated into water and 2500 g is organically bound. Since a person's daily water intake and output are equal, the turnover rate of water in the human body is relatively fast. The biological half-life of tritium is approximately 10 days, but this can be reduced by increasing the rate of body fluid turnover.

Nitrogen-13

Nitrogen-13 does not occur naturally in the environment. Table C-6 and Table C-7 present the pertinent radiological information for nitrogen-13. This radionuclide has a short half-life of 9.96 minutes and decays to stable (nonradioactive) carbon.

Oxygen-15

Oxygen-15 does not occur naturally in the environment. Table C-6 and Table C-7 present its decay characteristics. This radionuclide has a very short half-life of 2.05 minutes and decays to stable (nonradioactive) nitrogen.

Table C-6 Dose Conversion Factors of Radioactive Effluents Released

Radionuclide	Uptake Fraction	Effective Dose Equivalents
Radionuclide	Uptake Fraction	Inhalation (rem/µCi)	Ingestion (rem/µCi)	Submersion in Air (rem/yr per µCi/cubic m)	Immersion in Water (rem/yr per µCi/cubic m)	Ground Surface (rem/yr per µCi/square m)
Hydrogen-3	1	6.3×10^-5	6.3×10^-5	0	0	0
Nitrogen-13	N/A	1.6×10^-6	N/A	5.1	1.1×10^-2	1.1×10^-1
0xygen-15	N/A	1.6×10^-6	N/A	5.1	1.1×10^-2	1.1×10^-1

N/A = Not applicable.
Source: DOE, 1988a; ICRP, 1988.

Table C-7 Physical Characteristics of Radioactive Airborne Effluents Released

Radionuclide and Symbol	Half-Life	Type of Decay	Major Radiations, Energies (MeV), and Frequency Per Disintegration (%)	Decay Product
Hydrogen-3 (tritium)	12.3 years	b^-	b^-: 0.0186 (max), 0.006 (average)	3He (stable)
Nitrogen-13	9.96 minutes	b+	b⁺: 1.20 (max) y : 0.511 (200%)	13C (stable)
Oxygen-15	2.05 minutes	b+	b⁺: 1.74 (max) y : 0.511 (200%)	15N (stable)

Source: ICRP, 1978, 1988.

C.4.2.2 Exposure Analysis

An exposure analysis was conducted to evaluate the impact on environmental health due to releases of radionuclides through stacks from the combined normal operations of the LLNL Livermore site and SNL, Livermore. A separate analysis was conducted for LLNL Site 300. The analysis was conducted using AIRDOS-PC, 1990 releases of radionuclides reported by LLNL and SNL, Livermore, and local 5-year meteorological data collected at two onsite meteorological towers.

Sources

As a consequence of the operations at LLNL and SNL, Livermore, small amounts of radioactive materials are discharged into the surrounding atmosphere by the emissions from stacks. Table C-8 lists the releases into the atmosphere through stacks at LLNL and SNL, Livermore from 1986 through 1990. The 1990 releases were used as typical releases to provide the basis for calculating potential doses to members of the public from current operations. The information in Table C-8 can be used similarly to calculate exposures for any year or years listed.

During 1990, roughly 97 percent (1576 Ci) of the radioactivity released from LLNL and SNL, Livermore was tritium in the form of tritiated hydrogen gas or tritiated water vapor. The radiation dose from tritiated water vapor is 25,000 times that from tritiated hydrogen gas; thus tritiated water vapor is the form of most concern. The Hydrogen Research Facility (Building 331) at the LLNL Livermore site and the Tritium Research Laboratory (Building 968) at SNL, Livermore were responsible for essentially all of the tritium releases. Smaller amounts of tritium are, or may be, released from Buildings 292, 298, 381, 391, and other buildings.

During 1990, small amounts of oxygen-15 (24 Ci) and nitrogen-13 (24 Ci) were released to the atmosphere from Building 194, the Electron-Positron Accelerator Building, in the form of gases (LLNL, 1990b). The half-lives of oxygen-15 and nitrogen-13 are 2.05 minutes and 9.96 minutes, respectively. Oxygen-15 decays to stable (nonradioactive) nitrogen, and nitrogen-13 decays to stable (nonradioactive) carbon. As a result of their short half-lives, these radionuclides make only a very small contribution to radiation dose in the surrounding environment.

The potential environmental impact due to tritium is greater because more of it is released and it has a much longer half-life of 12.3 years. The radioactive plume disperses downwind and some of it is deposited onto ground surfaces by a combination of dry deposition and rainfall. Internal exposures can result from inhalation, absorption through the skin, and from the ingestion of food and water affected by the plume and its deposition. External exposures are of no consequence for tritium because the very low energy beta particle it emits does not penetrate the skin.

Building 331 is in the process of reducing the total tritium inventory present from 300 g (about 3 million Ci) to 5 g (about 50,000 Ci) as described in Appendix A. Though it is anticipated that this policy change will significantly reduce the tritium effluent, it is not certain how much the reduction will be.

Building 968 at SNL, Livermore released 295 Ci of tritium during 1990. This release was significantly less than previous years (834 Ci in 1989), and is the result of continuing efforts to decrease the release of airborne effluent. Furthermore, the administrative limit for tritium has been reduced from 300 g to 50 g. It is anticipated that the tritium inventory in Building 968 will go to zero in the near future.

There are no significant, routine airborne releases of uranium and plutonium at LLNL. This is because of the use of high-efficiency particulate air filters, exhaust air systems, and other control measures that prevent airborne releases of these radionuclides. Also, there are no major releases of radioactivity from SNL, Livermore other than the release of tritium from Building 968.

Federal regulations, the National Emission Standards for Hazardous Air Pollutants (40 C.F.R. part 61), require the determination of the effective dose equivalent to the maximally exposed individuals resulting from radionuclide emissions to the air. The annual doses for members of the public from this pathway must not exceed 0.010 rem per year. If an individual release point can result in a radiation dose to a member of the public of 0.0001 rem or greater, the release must be monitored.

DOE facilities are required to use approved computer modeling procedures, and/or environmental monitoring programs, to calculate the effective dose equivalents to the members of the public (DOE, 1990d). AIRDOS-PC is a computer code developed by the EPA to satisfy these requirements. AIRDOS-PC is a personal-computer implementation of the AIRDOS-EPA computer code developed for EPA by the Oak Ridge National Laboratory that was used in developing the National Emission Standards for Hazardous Air Pollutants. The program calculates the radionuclide concentrations in air and foodstuffs that are produced and consumed by people in the surrounding area using the U.S. Nuclear Regulatory Commission Regulatory Guide 1.109 terrestrial food chain models. The computer code estimates the effective dose equivalent to the whole body and the dose equivalent to selected organs of a hypothetical maximally exposed individual. The following exposure modes are considered:

Inhalation of radionuclides in the air;
Immersion in air containing the radionuclides;
Exposure from ground surfaces contaminated with radionuclides;
Immersion in water containing radionuclides;
Ingestion of food produced in the area that is contaminated with radionuclides; and
Ingestion of drinking water (for tritium it is assumed that the drinking water contains 1 percent of the concentration of tritiated water vapor in the air).

The calculated contribution to total dose from the ingestion pathway is about 86 percent compared with 14 percent from inhalation of tritiated water vapor and absorption through the skin. Thus, the effective doses will be overestimated to the extent that food consumed by the local population is grown elsewhere.

The Exposed Population

DOE requires that dose calculations be made for the population residing within a 50 mile radius of its operations. According to the 1990 census, there are approximately 6.3 million persons living within a 50 mile radius of LLNL Livermore site and SNL, Livermore. Information on the distribution of this population in each of 16 directional sectors and in various bands of distances out to 50 miles was used to calculate the radiation dose to members of the public residing at various locations.

Input Parameters for AIRDOS-PC

The input parameters used for these AIRDOS-PC calculations are listed in Table C-9. The 1990 stack releases of tritiated water were used to represent the most recent typical releases from normal operations. Releases of tritiated hydrogen gas were not included because the dose conversion factor is 25,000 times lower than for tritiated water. The most recent 5-year average (1986–1990) joint frequency wind data (wind speed, wind direction, and stability classification), generated by two meteorological towers on site, were used as typical information for the meteorological dispersion calculations.

Calculational Procedures and Results for Inhalation and Ingestion

AIRDOS-PC was used to calculate a matrix of effective dose equivalents at the centroids of the area bounded by the 16 directional sectors and at various distances from the center of the LLNL Livermore site. Separate AIRDOS-PC calculations were made for Building 331 at LLNL Livermore site and Building 968 at SNL, Livermore, taking into account their actual locations with respect to the center of the LLNL Livermore site. The calculated doses ranged from 5×10^-6 to 2.5×10^-4 rem annual effective dose equivalent in 1990. The effective dose equivalent at each centroid was multiplied by the number of persons residing in the region bounded by that direction and distance and then summed for all of the regions in the 50-mile radius to obtain the collective dose. The summation of all of the doses, or the collective effective dose equivalent, totaled 31 person-rem; 14 percent, or about 4 person-rem, is due to inhalation with the remaining 27 person-rem attributed to ingestion of locally grown foods, assuming all food is produced locally. The annual collective effective dose equivalent to this same population from background levels (based on an estimated 0.3 rem per person annual background dose) is about 1,900,000 person-rem.

Figure C-10 is a graph showing the doses at the site boundary from the combined releases, starting at the northwest corner of the LLNL Livermore site and proceeding clockwise around the combined site boundary back to the starting point. The highest effective dose equivalent at the fenceline is 0.00025 rem per year in the east-northeast sector. This value can be compared with the EPA annual dose limit of 0.010 rem for atmospheric releases and background of 0.3 rem. The calculated dose is also well below the National Council on Radiation Protection and Measurements negligible individual risk level of 0.001 rem (NCRP, 1987).

Figure C-11 is a graph showing the potential radiation dose along East Avenue proceeding from its intersection with Vasco Road eastward to the intersection at Greenville Road. The calculated radiation doses are small compared with the National Council on Radiation Protection and Measurements negligible individual risk level and with regulatory annual dose limits (NCRP, 1987).

Estimates of Radiation Doses Based on Results from Environmental Monitoring

The doses calculated by AIRDOS-PC can be compared with estimates of radiation doses based on environmental monitoring measurements of tritium. Environmental monitoring for tritium in air indicates that the average concentration of tritiated water vapor in air in the Livermore Valley is about 0.5×10^-11 mCi/mL and that the highest level near the site perimeter is about 3.9×10^-11 mCi/mL (Brekke, 1990). Using the method of Till and Meyer (1983), and considering all pathways except drinking water, the concentrations measured during environmental monitoring translate into effective dose equivalents of 0.00005 and 0.00058 rem/yr. Thus, the measured contribution of the combined operations is about 0.0005 rem/yr compared with the value calculated by AIRDOS-PC of 0.00025 rem/yr.

AIRDOS-PC estimates the radiation dose from various environmental pathways and assumes that all food consumed is in equilibrium with the radionuclides in the atmosphere. However, there are some pathways of special interest in the Livermore Valley that are discussed below even though they represent subsets of the AIRDOS-PC estimates. Additional information on these and other pathways can be obtained from the 1990 environmental report (LLNL, 1991d).

Vegetation and Foodstuff

Retail wines are collected and analyzed for tritium; these include wines produced in the Livermore Valley, California wines from areas outside the Livermore Valley, and wines produced from European vineyards.

The average tritium concentration of wines produced in the Livermore Valley and purchased between 1986 and 1989 was 3.35×10^-7 mCi/mL. The observed values are greater than the average tritium concentrations of wines produced in other regions of California (1.05×10^-7 mCi/mL) and in Europe (2.43×10^-7 mCi/mL) which were purchased during this same period of time.

The potential dose from drinking wines produced in Livermore was calculated both by using a high consumption rate and by using a more realistic consumption rate. In the case of the high consumption rate, it is assumed that a person drinks one bottle (0.75 liter) of wine every day of the year. For an average tritium concentration in wine of 3.35×10^-7 mCi/mL, the effective dose equivalent is 6×10^-6 rem/yr. In the more realistic scenario, it is assumed that a person consumes one bottle of wine per week with a tritium concentration of 3.35×10^-7 mCi/mL. Under these conditions the effective dose equivalent would be 8×10^-7 rem/yr.

Tritium concentrations in vegetation are not statistically different at various locations in the Livermore Valley, indicating that there are no isolated areas of elevated concentrations (LLNL, 1991d). The 1990 Environmental Report (LLNL, 1991d) presented the results of a dose calculation assuming that an adult's diet includes vegetables with the highest observed average tritium concentrations and that all meat and milk were derived from livestock fed on grasses with the same concentration. For these assumptions the maximum potential dose is approximately 7×10^-5 rem/year.

The tritium content of the vegetation sampled around LLNL Site 300 was similar to those values observed in 1988 and 1989. Four sampling locations had average tritium concentrations ranging from 122-206 pCi/l. Two sampling locations have frequently shown elevated vegetation tritium values since 1971. These areas are adjacent to landfills that contain tritium-contaminated debris from firing tables. These landfill areas are under investigation by the Environmental Restoration Division for tritium contamination of the soil and ground water. The two areas of known contamination are well delineated and very localized.

In most cases, tritium in goat milk is not different from background levels. The highest measured level of 3.8×10^-7 mCi/mL (LLNL, 1991d) would result in an annual effective dose equivalent of 1.3×10^-5 rem/yr if 1 liter were consumed per day.

Rainwater

Tritium released into the atmosphere from LLNL and SNL, Livermore may become entrained in raindrops that pass through the plume. The washout coefficient is estimated to be on the order of 10^-4 sec-1 (NCRP, 1979). The incident rainfall may run off into surface drainageways, percolate into soil and ground water, or accumulate in standing pools of water at the ground surface. Potential exposures to tritium in surface water, ground water, and soil are considered in the environmental monitoring programs of the respective sites; however, the rainfall that accumulates in pools represents an additional potential source of exposure due to inhalation and absorption through the skin for the several days following a rain before the water evaporates or percolates into the ground. The contribution from exposures to standing pools of rainwater is implicitly considered in the AIRDOS-PC code, which assumes that all water taken up by an individual (i.e., that inhaled, absorbed through the skin, or ingested in food and 1 percent of the drinking water) is at equilibrium with the atmospheric water vapor.

A separate evaluation of this exposure pathway was conducted to determine the relative contribution to dose. Assuming exposure for 10 days per year to standing pools of rainwater with a concentration of 3.2×10^-6µCi/mL (maximum observed average concentration in rainwater at the site boundary during 1990), and a water intake rate through inhalation and absorption through the skin of 220 mL/day (NCRP, 1979), the resulting dose is estimated to be 4×10^-7 rem/year, compared to the annual dose limit of 0.01 rem for atmospheric releases.

Releases to the Sewer

The LLNL Livermore site and SNL, Livermore jointly discharge approximately 341,000 gal per day of wastewater to the City of Livermore sewer system. The treated sanitary wastewater is piped to San Francisco Bay for discharge, except for a small volume that is used for summer irrigation of the municipal golf course adjacent to the Livermore Water Reclamation Plant. Sludge from the treatment plant is disposed of in landfills (LLNL, 1991d).

The 1990 annual average radionuclide concentrations in wastewater discharged to the sewer (LLNL, 1991d) included 10^-10 mCi/mL of cesium-137, 1.3×10^-11 mCi/mL of plutonium-239, and 1.5×10^-6 µCi/mL of tritium, all well below DOE annual discharge limits for application of best available control technology to a public sewer system. See Table C-10 for a summary of the radioactive liquid effluents released by LLNL and SNL, Livermore from 1986 through 1990. During 1990, LLNL released 0.5 Ci of tritium to the sanitary wastewater system, and SNL, Livermore released 0.2 Ci, for a total of 0.7 Ci. The average of tritium concentration constitutes approximately 0.015 percent of the DOE limit for application of the best available control technology, 1×10^-2 mCi/mL, to sewer effluent releases (LLNL, 1991d). The discharges of plutonium-239 and cesium-137 were even further below DOE limits of 1×10^-5 mCi/mL and 1.5×10^-5 mCi/mL, respectively. The State of California limits the annual release of tritium to 1 Ci.

Potential health risks to workers at the Livermore Water Reclamation Plant were assessed on the basis of the radionuclides present in the sewage. Potential exposure pathways include incidental ingestion of sewage containing tritium, plutonium-239, and cesium-137 and dermal absorption of tritium (plutonium and cesium are not absorbed to any appreciable extent through intact skin). Exposures were assumed to occur 250 days per year for the Livermore Water Reclamation Plant workers. An incidental ingestion rate of 100 mg/day (EPA, 1989b) would result in an incremental effective dose equivalent of approximately 1.3×10^-7 rem. An assumed water intake rate of 220 mL/day for inhalation and absorption of tritium through the skin (NCRP, 1979) would result in an incremental effective dose equivalent of approximately 7×10^-6 rem per year.

Non-Tritium Contamination in the Air

Plutonium-239 was measured in air at a concentration of 2.15×10^-17 mCi/mL at the southeast perimeter of the LLNL Livermore site. This concentration is 0.11 percent of the Derived Concentration Guide for plutonium-239, 2×10^-14 mCi/mL (LLNL, 1991d). Derived Concentration Guides are concentrations of radionuclides in air (or water) that, if inhaled (or consumed) continuously for 365 days of the year would result in an effective dose equivalent of 0.050 rem per year. This is one-half of the DOE primary radiation protection standard to the public of 0.1 rem per year of effective dose equivalent. Continuous exposure to the observed plutonium-239 air concentration would result in an effective dose equivalent of 0.00004 rem/yr (ICRP, 1978).

The greatest uranium-238 activity in the air was observed at LLNL Site 300. This concentration (18.9×10^-5µg per cubic meter of air) is less than 0.05 percent of the Derived Concentration Guide for uranium-238, 2×10^-12 mCi/mL (LLNL, 1991d) and would result in an annual effective dose equivalent of 0.00005 rem/yr if it were continuously inhaled throughout the year.

The greatest average airborne uranium-235 activity was observed at LLNL Site 300. This concentration was 1.1×10^-6 µg per cubic meter of air and represents 0.002 percent of the Derived Concentration Guide for uranium-235, 2×10^-12 mCi/mL (LLNL, 1991d). Continuous exposure to this level would result in an annual effective dose equivalent of 0.00002 rem/yr.

Soil

The three highest levels of plutonium-239 in soil are at three locations at the Livermore Water Reclamation Plant (LLNL, 1991d). This is residual contamination from a plutonium release from LLNL in 1967. Continuous exposure to the average plutonium concentration observed at these sites (86×10^-9 mCi plutonium-239 per g of soil) would cause an annual effective dose equivalent of 0.000001 rem/yr assuming a combined incidental ingestion rate of 200 mg of soil per day through inhalation of dust and ingestion of soil from poorly washed crops grown in the contaminated soil (EPA, 1989b). This is 0.001 percent of DOE primary radiation protection standard for the public of 0.1 rem/yr effective dose equivalent.

Concentrations of uranium-238 greater than background were found in isolated areas near the firing tables at LLNL Site 300. The highest value of 62.2 mg uranium-238 per g of soil (roughly 20 times greater than background) was in the vicinity of an inactive firing table (LLNL, 1991d). In 1988, the uranium-238 contaminated gravel was removed from the firing tables and placed into onsite landfills. The observed uranium-238 contamination in these areas probably indicates small amounts of residual material in this area. Assuming a combined incidental ingestion rate of 200 mg of soil per day through inhalation of dust and ingestion of soil from poorly washed crops grown in the contaminated soil (EPA, 1989b), this value would correspond to an annual effective dose equivalent of 0.00017 rem/yr or 0.17 percent of DOE primary radiation protection standard for the public of 0.1 rem/yr effective dose equivalent.

External Radiation

The average annual external dose at the site boundary (0.065 rem) is not statistically different from the average value of 0.065 rem for the Livermore Valley. The 1990 average neutron radiation dose at the site perimeter was 4.6×10^-3 rem (0.0046 rem). The measured dose equivalents are typical of normal background radiation for the area, and indicate that there is no measurable dose due to direct radiation from LLNL operations at any point beyond the boundary of the LLNL Livermore site and SNL, Livermore (LLNL, 1991d).

Table C-8 Quantities of Radioactive Airborne Effluents Released by the LLNL Livermore Site, LLNL Site 300, and SNL, Livermore

Site and Type of Radioactive Airborne Effluent Released	Quantities Released Per Year (Ci)
Site and Type of Radioactive Airborne Effluent Released	1986	1987	1988	1989	1990
LLNL Livermore Site Tritium (³H) Contribution from Building 331 HTO HT Total from B-331:^a Total from LLNL:^b Nitrogen-13 (¹³N) Oxygen-15 (¹⁵O)	661	1246	1615	1555	700
	467	1388	2333	1395	581
	1128	2634	3948	2950	1281
	1254	2751	3983	2952	1282
	56.5	31	15	21	24
	56.5	31	15	21	24
LLNL Site 300^c Nitrogen-13 (¹³N) Oxygen-15 (¹⁵O)	22.5	7	5.7	0.57	0
LLNL Site 300^c Nitrogen-13 (¹³N) Oxygen-15 (¹⁵O)	22.5	7	5.7	0.57	0
SNL, Livermore Tritium (³H) HTO HT Total:	629	570	1047	656	244
	131	1257	543	178	51
	760	1828	1590	834	295

^a Includes tritiated water vapor (HTO) and tritium gas (HT).
^b The major source of 3H at the LLNL Livermore site is Building 331; other sources may include Buildings 292, 298, 381, 391, etc.
^c Some tritium may be released at Buildings 801, 850, 851, etc.
^d Building 968 is the only source of 3H at SNL, Livermore.
Source: LLNL, 1987, 1988, 1990b, 1991d; SNL, Livermore, 1991m, 1991a; Brekke, 1990.

Table C-9 Input Parameters Used for AIRDOS-PC Modeling

Characteristics	LLNL
Environmental: Average annual temperature	59^oF
Average annual rainfall	1 ft 3 in
Lid height	3281 ft
Stack: Stack height	100 ft
Exit velocity	29.9 ft/sec
Stack diameter	3 ft 11 in

Source: LLNL, 1990b, 1991c.

Table C-10 Quantities of Radioactive Liquid Effluents Released to Sanitary Sewer from the LLNL Livermore Site and SNL, Livermore

Site and Type of Radionuclide Released	Quantities Released Per Year (Ci)
Site and Type of Radionuclide Released	1986	1987	1988	1989	1990
LLNL Livermore Site Hydrogen-3	1.98	1.16	1.02	1.3	0.48
Plutonium-239	1.5×10^-5	6.9×10^-4	2.2×10^-5	4.8×10^-6	6.3×10^-6
SNL, Livermore Hydrogen-3	0.02	0.24	0.48	0.30	0.20

Source: LLNL, 1990b, 1991m; Brekke, 1990.

C.4.2.3 Radiation Risk Characterization

A discussion of the risk estimators of the EPA, the International Commission on Radiological Protection, and other authoritative bodies was presented in section C.3.3.

The maximally exposed member of the general public from routine operation of LLNL and SNL, Livermore is considered to be a hypothetical individual who resides at the point of maximum exposure at the fenceline and grows all of his food at that point. This hypothetical individual potentially receives an effective dose equivalent of 0.00025 rem from 1990 operations. The radiation doses from operations at LLNL Site 300 are small compared to those from LLNL Livermore site and SNL, Livermore. The environmental radiation doses from all operations are below the National Council on Radiation Protection recommended value for the negligible individual risk level of 0.001 rem and well below the regulatory standard for the airborne pathway of 0.010 rem. Using the risk estimators for fatal cancer induction and total health detriment, the highest potentially exposed individual would have an individual risk of 1 in 8 million of induction of a fatal cancer and 1 chance in 5 million of a detrimental health effect. As recommended by the ICRP, these numbers have been rounded to one significant figure.

Not all members of the public in the 50-mile radius surrounding LLNL and SNL, Livermore are exposed to the same level of risk. The calculated increment of radiation dose to members of

the public due to releases from LLNL and SNL, Livermore range from about 7×10^-6 at distances several tens of miles from the sites to 2.5×10^-4 rem per year at the fenceline in the east northeast direction depending on the location of the individual. Table C-11 summarizes the types and levels of radiation dose from selected exposure pathways involving tritium in 1990. This dose is in addition to background radiation of about 0.3 rem/yr. The individual risk for induction of fatal cancer is about 1 in 8 million and of total health detriment about 1 in 5 million. These increments of risk can be compared to the natural fatal cancer incidence of approximately 1 in 6.

The summation of all doses, or the collective effective dose equivalent, to the 6 million persons living within a 50-mile radius of LLNL and SNL, Livermore due to 1990 releases into the atmosphere was conservatively calculated to be 31 person-rem (a more realistic value is about 10 percent of this value). Using the value of 31 person-rem, the chance of inducing a single fatal cancer in the population of 6 million persons due to operations of LLNL and SNL, Livermore is about 1 in 60. The chance of any health detriment is also about 1 in 50.

If the risk estimators are applied to the effective dose equivalent from background of 0.3 rem, the individual lifetime chance for fatal cancer from one year of exposure to background radiation would be about 150 in a million and about 200 in a million for total health detriment. The calculated number of fatal cancers attributable to the annual collective background dose of 1.9 million person-rem effective dose equivalent would be about 950, and the number of detrimental health effects is calculated to be 1400.

Table C-11 Radiation Doses and Health Effects to Members of the Public from Exposures in 1990

Individual Exposures	Radiation Dose (rem)	Chance in a Million of Fatal Cancer	Chance in a Million of Total Detriment
Inhalation of tritium Rainwatera Ingestion of tritium Wine(1 bottle/day)^{a Honey (100 grams/ day) Goat milk (1 liter/day) Background Radiation}	0.0000010 to 0.0000350 0.0000004 0.0000060 to 0.00022000 0.0000060 0.0000007 0.0000150 0.3	0.0005 to 0.0180 0.0002 0.0030 to 0.1100 0.0030 0.00035 0.0075 150	0.00073 to 0.26000 0.00029 0.0044 to 0.1600 0.0044 0.00051 0.0011 220
Collective Exposures	Radiation Dose (person-rem)	Chance of Fatal Cancer	Chance of Total Detriment
Inhalation of tritium Ingestion of tritium Total: (collective dose) Background Radiation^b	4.3 26.7 31 1,900,000	0.0021 0.0130 0.0160 950	0.0031 0.019 0.023 1400

^a AIRDOS-PC calculations assume that all food consumed by an individual, all water vapor absorbed through the skin, and 1 percent of the drinking water is in equilibrium with the tritiated water vapor in the air. Thus, these doses are included in the AIRDOS-PC calculations and are not additive.
^b Based on an annual background radiation dose of 0.3 rem per person to a population of 6.3 million.

C.4.3 Exposures to Toxic Materials

As described in Appendix A, there are numerous chemicals present at LLNL and SNL, Livermore.

C.4.3.1 Exposure Analysis

There are three potential pathways through which members of the public could be exposed to toxic materials: exposure to airborne chemicals released from LLNL and SNL, Livermore; exposure to contaminated ground water; and exposure to chemicals released to the sewer. Exposure to airborne chemicals could result from emissions from current operations including emissions from hazardous waste storage and treatment facilities at LLNL and SNL, Livermore. Contaminated ground water is not a result of current operations, but it may be a potential source of exposure, though currently no public wells are affected by the contamination. The third pathway, exposure to chemicals released to the sewer, is applicable only to treatment plant workers. The sewer release pathway, as described in detail here, illustrates analytical methods used to conduct risk assessments for air and ground water. The standard approach to risk assessment includes estimation of exposure point contaminants and concentrations, estimation of daily intake of contaminants, toxicity assessment, and risk characterization using standard EPA and California Air Pollution Control Officers Association (CAPCOA) methodology and toxicologic criteria (EPA, 1989b; CAPCOA, 1991). The sewer release risk assessment process is described in detail below; more brief descriptions are presented for air and other pathways. The risk probability numbers are presented for all potential exposure pathways in this appendix and in the text.

C.4.3.2 Risk Characterization

Releases to the Sewer

LLNL and SNL, Livermore release wastewater into the City of Livermore sewer system. Wastewater potentially contaminated with hazardous material is not released into the sewer system until it is analyzed and determined acceptable for release. Wastewater with contamination levels above those acceptable for discharge into the sewer is collected in tanks (see Appendix B). LLNL and SNL, Livermore sewage is mixed with municipal sewage and is piped to the Livermore Water Reclamation Plant for treatment. Workers at the treatment facility may be routinely exposed to sewage and sludge that results from treatment. Data regarding concentrations of chemicals in the sanitary sewer effluent, presented in Table C-12, were obtained from the 1990 LLNL Environmental Report (LLNL, 1991d).

An assessment was conducted to estimate the potential health risks resulting from exposure of workers to the sewage. It was assumed that workers would be exposed to the effluent via incidental ingestion and dermal absorption. Many of the constituents assessed are metals. With few exceptions (e.g., organic mercury), metals are not believed to be absorbed through the skin. For the purpose of this assessment, it was conservatively assumed that 10 percent of the organics, 0.2 percent of cadmium and nickel, 1 percent of mercury, and 0.1 percent of other inorganics would be absorbed through the skin (CAPCOA, 1991). Daily intakes were estimated for an 8-hour day, 5-day work week, over a period of 7 years. The estimated daily intakes are presented in Table C-12.

Dermal absorption was calculated using the following algorithm:

	       		CSxCFxSAxAFxABSxET
	E^d=	     -------------------------- 
				BWxAT

Where,
E^d = Estimated daily intake through dermal absorption (mg/kg-day).
CS = Concentration of constituent in sewage (mg/kg).
CF = Conversion factor (1.0×10^-6 kg/mg).
SA = Surface area exposed [4.66×10+3 cm2/day, (CAPCOA, 1991)]. AF = Adherence factor [0.5 mg/cm2 (CAPCOA, 1991).
ABS =Percent absorption [cadmium and nickel (0.2%), mercury (1%), other inorganics (0.1%), organics (10%) (CAPCOA, 1991)].
ET =Exposure time (7 years×5 days/week) (i.e., 1820 days).
BW = Body weight [70 kg (EPA, 1989a)].
AT =Averaging time (2550 days for noncarcinogens and 25,500 days for carcinogens).
Exposure via incidental sludge ingestion was calculated using the following algorithm:

                       CSxIRxCFxFIxET
        E^si=   -----------------------     
                            BWxAT

Where,
E^si = Estimated daily intake through incidental sludge ingestion (mg/kg-day).
CS = Concentration of constituent in sewage (mg/kg).
IR = Ingestion rate [150 mg/day (CAPCOA, 1991)].
CF = Conversion factor (1.0×10^-6 kg/mg).
FI = Fraction ingested from source (100 percent).
ET =Exposure time (7 years×5 days/week) (i.e., 1820 days).
BW = Body weight [(70 kg) (CAPCOA, 1991)].
AT =Averaging time (2550 days for noncarcinogens and 25,500 days for arcinogens).
(EPA, 1989b), the Exposure Factors Handbook (EPA, 1989a), and CAPCOA guidance (CAPCOA, 1991).

The estimated daily intakes were then assessed for potential noncarcinogenic and carcinogenic risk using toxicological criteria. Toxicological data stating acceptable daily intake (RfDs) and carcinogenic slope factors were obtained from the EPA and CAPCOA. The toxicological data obtained from CAPCOA are more conservative than the EPA's. The toxicity criteria used in the assessment are presented in Table C-13. The estimated daily intakes were then assessed for potential noncarcinogenic and carcinogenic risk using toxicological criteria. Potential noncarcinogenic risks are assessed by comparing projected daily intakes of substances to substance-specific acceptable daily intake values as presented below.

				  Eⁱ
             HI =  	----------------
				  RfD

Where,
HI = Hazard Index.
Ei =Estimated daily intake (mg/kg-day) using an averaging time of 7 years×365 days/year (2555 days).
RfD = Reference dose (mg/kg-day).
The result of the comparison is a hazard index. A hazard index greater then 1 indicates that noncarcinogenic health effects may occur.
For potential carcinogenic risks, the probability that an individual will develop cancer over a lifetime is estimated from daily intakes and dose-response information (carcinogenic slope factors) as presented below.
Risk = Ei x CSF
Where,
Risk = Probability that an individual will develop cancer over a lifetime.
Ei =Estimated daily intake (mg/kg-day) using an averaging time of 70 years × 365 days/year (25,550 days).
CSF = Carcinogenic slope factor (kg-day/mg).
The noncarcinogenic and carcinogenic risk estimates are presented in Table C-14.

In the absence of dermal health criteria, dermal values were derived for each chemical in accordance with EPA and CAPCOA guidance by adjusting the oral value based on the gastrointestinal absorption of each of the chemicals. Gastrointestinal absorption factors were obtained from CAPCOA (1991).

Results of the risk analysis indicate that the noncarcinogenic and carcinogenic risks posed by inorganic constituents present in the effluent are very low. The total noncarcinogenic hazard index (determined by summing all of the individual hazard indices) was estimated to be 0.00007. A hazard index of less than 1.0 indicates that no noncarcinogenic health effects would be expected based on this exposure scenario. The total lifetime carcinogenic risk was estimated to be 0.0017 in a million. A common benchmark often used to determine if a carcinogenic risk is significant is a probability of one in a million that there would be one excess cancer. The carcinogenic risk associated with exposure to sewage effluent is well below this level.

Stack and Fugitive Emission

The general public living in the area surrounding LLNL Livermore site and SNL, Livermore may be exposed to chemicals released from various processes. In order to determine if any detrimental health effects are likely, it is first necessary to determine which constituents are being released and in what quantities, and then to determine how individuals are likely to be exposed to the materials that are released. The materials are released primarily as vapors. At present there are no adequate models to predict vapor deposition. As a result, indirect pathways of exposure, such as uptake via vegetables, cannot be adequately modeled.

LLNL and SNL, Livermore are required by California law (AB2588) to estimate the amount of certain toxic substances that may be emitted during routine operations. If the quantities exceed a specified threshold, a risk assessment is required to estimate the potential health effects. Based on the information submitted by SNL, Livermore, the Bay Area Air Quality Management District determined that projected emissions were lower than the threshold requiring a risk assessment (DOE, 1989b). LLNL, however, was required to perform a screening risk assessment. The AB2588 report for LLNL Site 300 is currently being completed pending approval of source emission test procedures to determine toxic emission rates by the San Joaquin Valley Unified Air Pollution Control District and California Air Resources Board.

LLNL has completed a "Screening Risk Assessment" as required by the California Toxic Information and Assessment Act (AB2588). The specific input parameters for the assessment are presented and discussed in the "Air Toxics Risk Screening Document" (LLNL, 1991a). A screening residential risk assessment was conducted to estimate human health impacts to a resident living near the boundary (i.e., at the fenceline) of LLNL Livermore site. The chemicals evaluated in the assessment were identified by comparison with the list of chemicals that are presented in the AB2588 guidelines. Emissions of chemicals considered to be carcinogenic (8 chemicals) and noncarcinogenic (19 chemicals) were estimated for each building at LLNL. Ambient air modeling was conducted, using site specific information on stack heights and meteorological data. The modeling output and the emission factors were used to predict airborne concentrations of chemicals.

The risk analysis assumed a continuous lifetime exposure of 70 years for an individual located at the fenceline where the maximum airborne concentrations are predicted to occur. The daily intakes of pollutants were estimated and compared to CAPCOA toxicological criteria to calculate the potential health risks. The maximum cumulative carcinogenic risk is three in a million. This is below the benchmark of 10 in a million, which the Bay Area Air Quality Management District designates as the level of concern (LLNL, 1991a). The maximum value for noncarcinogenic hazard indices are 0.089 for chronic exposures (i.e., exposure durations greater than seven years) and 0.42 for acute exposures (i.e., brief exposures). Both of the noncarcinogenic hazard indices are below the benchmark of 1.0 established by CAPCOA (1991) (LLNL, 1991a). There is greater uncertainty associated with the acute hazard index because there is a lack of acute health criteria for the majority of chemicals. Table C-15 tabulates the results of the risk assessment. Although included in the LLNL emissions inventory, risks associated with fluorocarbon emissions were not calculated as there were no noncarcinogenic and noncancer acceptable exposure limits at the time the document was prepared. The Bay Area Air Quality Management District is currently reviewing this assessment.

Hazardous Waste Storage and Treatment Emissions

LLNL operates several hazardous waste storage and treatment units for managing the wastes generated by research programs. The storage and treatment units are currently operated under interim status in accordance with federal (EPA) and state (California Department of Health Services) requirements (Radian Corporation, 1990).

LLNL has applied for a Part B permit to continue operating its waste and storage treatment facilities, as required by the California Hazardous Waste Control Act and the Resource Conservation and Recovery Act (RCRA). As part of the permitting process, a human health risk assessment (Phase II) was performed to examine the potential health impacts to the surrounding community from continued storage and treatment of hazardous and mixed radioactive wastes. The risk assessment was prepared in accordance with CAPCOA "Air Toxics Assessment Manual," and specific requirements of the California Department of Health Services (Radian Corporation, 1990).

The types of wastes generated at LLNL and the potential emissions of toxic substances from different treatment technologies were determined. Once the hazardous wastes were identified, their concentration in air and deposition rates were estimated based on weather and wind patterns. The assessment evaluated a hypothetical, maximally exposed individual in order to estimate human exposure to nonradioactive emissions from LLNL. This hypothetical individual was conservatively assumed to be born, reside, and work for a 70-year lifetime at the point where the highest concentration of emissions occur from the hazardous waste and storage and treatment units (Radian Corporation, 1990).

The location of the hypothetical, maximally exposed individual was identified as 600 meters north of East Avenue along Greenville Road. The following primary routes of human exposure were considered:

Inhalation;
Ingestion (including soil, vegetation, wine, and water); and
Skin contact with soil.

The lifetime risk of developing cancer and the potential for acute and chronic noncarcinogenic effects were evaluated for worst- and plausible-case scenarios. The lifetime risk of developing cancer for the maximally exposed individual from exposure to nonradiological substances was determined to be 0.083 in a million for acute effects and 0.076 in a million for chronic effects, using the California Department of Health Services and EPA potency factors. The risk to the maximally exposed individual in the plausible case was found to be 0.02 in a million. A hazard index of less than 1.0 indicates that deleterious noncarcinogenic effects are unlikely. The highest chronic and acute noncarcinogenic hazard indices were found to be 0.00027 and 0.17, respectively (Radian Corporation, 1990).

The evaluations of the potential exposures and the associated risks presented in section 4.3.3 are very conservative (i.e., the risks are likely overestimated). Conservative assumptions have been made for each scenario concerning how long an individual lives at one location, where the individual obtains drinking water, and where an individual works. Therefore, it is inappropriate to attempt to estimate the total or overall cumulative risk because these exposure scenarios are for the most part exclusive.

Table C-12 Concentrations of Constituents in Sewage and Sludge and Estimated Daily Intakes

Compound	Concentration* (mg/kg)	Exposure Through Dermal Absorption (mg/kg-day)	Exposure Through Incidental Ingestion (mg/kg-day)
Inorganics Arsenic Beryllium Boron Cadmium Chromium (total) Copper Iron Lead Mercury Nickel Silver Zinc	4.0×10^-3 3.0×10^-4 3.0×10^-1 4.0×10^-3 6×10^-1 2×10^-1 8.7×10^-1 2.6×10^-2 2.5×10^-3 3.1×10^-2 6.0×10^-3 4.1×10^-1	9.5×10^-11 7.1×10^-12 7.1×10^-9 1.9×10^-10 3.8×10^-9 5.2×10^-9 2.1×10^-8 6.2×10^-10 5.9×10^-10 1.5×10^-9 1.4×10^-10 9.7×10^-9	6.1×10^-9 4.6×10^-10 4.6×10^-7 6.1×10^-9 2.4×10^-7 3.4×10^-7 1.3×10^-6 4.0×10^-8 3.8×10^-9 4.7×10^-8 9.2×10^-9 6.3×10^-7
Volatile Organics Acetone Bromodichloromethane Bromoform Chloroform Dibromochloromethane Dimethyl disulfide Ethylbenzene Freon 113 Tetrachloroethylene Toluene Xylene (total) 1,1,1-Trichloroethane	4.7×10^-2 5×10^-3 9×10^-3 1.0×10^-2 2.4×10^-3 8.0×10^-3 7.5×10^-4 1.3×10^-3 8.0×10^-4 1.2×10^-3 1.3×10^-3 1.2×10^-3	1.1×10^-7 3.6×10^-9 6.9×10^-9 2.4×10^-8 5.7×10^-9 1.9×10^-8 1.8×10^-9 3.0×10^-9 9×10^-9 9×10^-9 0×10^-9 2.9×10^-9	7.2×10^-8 2.3×10^-9 4.4×10^-9 1.5×10^-8 3.7×10^-9 1.2×10^-8 1.1×10^-9 1.9×10^-9 1.2×10^-9 1.8×10^-9 1.9×10^-9 1.8×10^-9
Semivolatile Organics Benzyl alcohol Bis(2-ethylhexyl)phthalate Butoxy ethanol phosphate 1,3-Dichlorobenzene 1,4-Dichlorobenzene	0×10^-2 0×10^-2 1.5×10^-1 2.0×10^-3 5.0×10^-3	2.4×10^-8 4.8×10^-8 3.6×10^-7 4.8×10^-9 1.2×10^-8	1.5×10^-8 3.1×10^-8 2.3×10^-7 3.1×10^-9 7.7×10^-9

* Based on 1990 Environmental Monitoring Report (LLNL, 1991d). Note that the concentrations were reported in mg/L, which is equivalent to mg/kg. Metals are average concentrations. Organics are median concentrations. Percent absorption was obtained from CAPCOA, 1991. Cadmium and nickel (0.2%), mercury (1%), other inorganics (0.1%), and organics (10%).

Table C-13 Carcinogenic and Noncarcinogenic Toxicity Criteria

Compound	Incidental Ingestion				Dermal Absorption*
Compound	Carcinogenic Potency Factor (day-kg/mg)	Source	Chronic Noncarcino-genic Health Criteria (mg/kg-day)	Source	Percentage Gastro-intestinal Absorption	Source	Carcino-genic Potency Factor (day-kg/mg)	Source	Chronic Noncarcino-genic Health Criteria (mg/kg-day)	Source
Inorganics Arsenic Beryllium Boron Cadmium Chromium (total) Copper Iron Lead Mercury Nickel Silver Zinc	1.75×10⁺⁰ 4.30×10⁺⁰	IRIS, 1991 IRIS, 1991	5.00×10^-3 9.00×10^-2 1.00×10^-3 1.00×10⁺⁰ 3.70×10^-2 40×10^-3 00×10^-3 1.00×10^-2 3.30×10^-3 2.10×10^-1	CAPCOA, 1991 IRIS, 1991 CAPCOA, 1991 IRIS, 1991 CAPCOA, 1991 CAPCOA, 1991 CAPCOA, 1991 CAPCOA, 1991 IRIS, 1991 CAPCOA, 1991	1.00×10⁺⁰ 1.00×10⁺⁰ 5.00×10^-2 1.00×10⁺⁰ 1.00×10^-1 1.00×10⁺⁰ 1.00×10⁺² 1.00×10⁺² 1.00×10⁺² 1.00×10⁺⁰ 1.00×10⁺⁰	CAPCOA, 1991 CAPCOA, 1991 Assumed CAPCOA, 1991 CAPCOA, 1991 Assumed CAPCOA, 1991 CAPCOA, 1991 CAPCOA, 1991 Assumed Assumed	1.75×10⁺⁰ 4.30×10⁺⁰	Oral CPF Oral CPF	5.00×00^-3 4.50×10^-3 1.00×10^-3 1.00×10^-1 3.70×10^-2 40×10^-1 00×10^-1 1.00×10⁺⁰ 3.30×10^-3 2.10×10^-1	Oral RfD Oral RfD Oral RfD Oral RfD Oral RfD Oral RfD Oral RfD Oral RfD Oral RfD
Volatile Organics Acetone Bromodichloromethane Bromoform Chloroform Dibromochloromethane Dimethyl disulfide Ethylbenzene Freon 113 Tetrachloroethylene Toluene Xylene (total) 1,1,1-Trichloroethane	1.30×10^-1 7.90×10^-3 6.10×10^-3 8.40×10^-2	IRIS, 1991 IRIS, 1991 IRIS, 1991 IRIS, 1991	00×10^-1 00×10^-2 2.00×10^-2 00×10^-2 00×10^-2 1.00×10^-1 3.00×10⁺¹ 00×10^-2 00×10^-1 2.00×10⁺⁰ 9.00×10^-2	IRIS, 1991 IRIS, 1991 IRIS, 1991 IRIS, 1991 CAPCOA, 1991 IRIS, 1991 IRIS, 1991 IRIS, 1991 IRIS, 1991 CAPCOA, 1991 IRIS, 1991	1.00×10⁺⁰ 1.00×10⁺⁰ 1.00×10⁺⁰ 1.00×10⁺² 1.00×10⁺⁰ 1.00×10⁺⁰ 1.00×10⁺⁰ 1.00×10⁺² 1.00×10⁺⁰ 1.00×10⁺⁰ 1.00×10⁺²	Assumed Assumed Assumed CAPCOA, 1991 Assumed Assumed Assumed CAPCOA, 1991 Assumed Assumed CAPCOA, 1991	1.30×10^-1 7.90×10^-3 6.10×10^-5 8.40×10^-2	Oral CPF Oral CPF Oral CPF Oral CPF	00×10^-1 00×10^-2 2.00×10^-2 00×10⁺⁰ 00×10^-2 1.00×10^-1 3.00×10⁺¹ 00×10⁺⁰ 00×10^-1 2.00×10⁺⁰ 9.00×10⁺⁰	Oral RfD Oral RfD Oral RfD Oral RfD Oral RfD Oral RfD Oral RfD Oral RfD Oral RfD Oral RfD Oral RfD
Semivolatile Organics Benzyl alcohol Bis(2-ethylhexyl) phthalate Butoxy ethanol phosphate 1,3-Dichlorobenzene 1,4-Dichlorobenzene	1.40×10^-2	IRIS, 1991	3.00×10^-2 2.00×10^-2 2.00×10⁺¹	IRIS, 1991 CAPCOA, 1991 CAPCOA, 1991	1.00×10⁺⁰ 1.00×10⁺⁰ 1.00×10⁺⁰ 1.00×10⁺⁰ 1.00×10⁺⁰	Assumed Assumed Assumed Assumed Assumed	1.40×10^-2	Oral CPF	3.00×10^-2 2.00×10^-2 2.00×10⁺¹	Oral RfD Oral RfD Oral RfD

* Dermal slope factors and RfDs are based on the oral value and adjusted for oral absorptions. CAPCOA states that in the absence of specific information to assume 100 percent gastrointestinal absorption.

Table C-14 Noncarcinogenic Hazard Indices and Carcinogenic Risks from Sewage and Sludge

Compound	Incidental Ingestion Hazard Index	Dermal Absorption Hazard Index	Total Hazard Index	Incidental Ingestion Carcinogenic Risk	Dermal Absorption Carcinogenic Risk	Total Carcinogenic Risk
Inorganics Arsenic Beryllium Boron Cadmium Chromium (total) Copper Iron Lead Mercury Nickel Silver Zinc	9.2×10^-8 6.1×10^-6 9.1×10^-6 2.8×10^-5 1.9×10^-6 4.7×10^-6 2.8×10^-6 3.0×10^-6	1.4×10^-9 7.9×10^-8 1.9×10^-7 3.8×10^-9 1.4×10^-7 4.4×10^-7 1.5×10^-7 4.3×10^-8 4.6×10^-8	9.3×10^-8 7.9×10^-8 6.3×10^-6 3.8×10^-9 9.2×10^-6 2.9×10^-5 1.9×10^-6 4.9×10^-6 2.8×10^-6 3.0×10^-6	1.1×10^-9 2.0×10^-10	1.7×10^-11 3.1×10^-12	1×10^-9 0×10^-10
Volatile Organics Acetone Bromodichloromethane Bromoform Chloroform Dibromochloromethane Dimethyl disulfide Ethylbenzene Freon 113 Tetrachloroethylene Toluene Xylene (total) 1,1,1-Trichloroethane	7.2×10^-7 1×10^-7 2×10^-7 1.5×10^-6 1.8×10^-7 1.1×10^-8 6.4×10^-11 1.2×10^-7 9.2×10^-9 9.6×10^-10 2.0×10^-8	1.1×10^-6 1.8×10^-7 3.4×10^-7 2.4×10^-6 2.8×10^-7 1.8×10^-8 9.9×10^-11 1.9×10^-7 1.4×10^-8 1.5×10^-9 3.2×10^-8	8×10^-6 9×10^-7 5.7×10^-7 3.9×10^-6 4.7×10^-7 2.9×10^-8 1.6×10^-10 3.1×10^-7 2.3×10^-8 2.4×10^-9 5.2×10^-8	3.0×10^-11 3.5×10^-12 9.3×10^-12 3.1×10^-11	4.6×10^-11 5.4×10^-12 1.4×10^-11 4.8×10^-11	7.6×10^-11 8.9×10^-12 2.4×10^-11 7.9×10^-11
Semivolatile Organics Benzyl alcohol Bis(2-ethyhexyl)phthalate Butoxy ethanol phosphate 1,3-Dichlorobenzene 1,4-Dichlorobenzene	5.1×10^-7 1.5×10^-6 3.8×10^-10	7.9×10^-7 2.4×10^-6 5.9×10^-10	1.3×10^-6 3.9×10^-6 9.8×10^-10	4.3×10^-11	6.7×10^-11	7.8×10^-11
Total:	6.1×10^-5	8.8×10^-6	7.0×10^-5	1.4×10^-9	1.8×10^-10	1.6×10^-9

Table C-15 Carcinogenic Risks and Noncarcinogenic Hazard Indices from Air Emissions

Constituent	Maximum Individual Cancer Risk	Chronic Noncancer Health Risks	Acute Noncancer Health Risks
Benzene	3.3×10^-7	5.0×10^-5	N/A
Carbon Tetrachloride	2.4×10^-6	2.9×10^-3	8.6×10^-2
Chlorine	N/C	8.4×10^-2	3.3×10^-1
Chloroform	4.7×10^-7	2.8×10^-4	N/A
Dioxane (1,4-)	1.3×10^-8	N/A	N/A
Ethylene dichloride	1.6×10^-10	1.7×10^-7	N/A
Ethylene glycol ethyl ether acetate	N/C	5.7×10^-5	N/A
Fluorocarbons	N/C	N/A	N/A
Formaldehyde	8.0×10^-9	4.2×10^-5	9.6×10^-5
Glycol ethers (other)	N/C	4.6×10^-6	N/A
Hydrogen fluoride	N/C	9.3×10^-6	7.8×10^-7
Methanol	N/C	1.1×10^-4	N/A
Methylene chloride	2.6×10^-8	1.9×10^-6	1.8×10^-3
Toluene	N/C	1.9×10^-6	N/A
Trichloroethane (1,1,1-)	N/C	1.2×10^-3	N/A
Trichloroethylene	3.8×10^-8	5.9×10^-5	N/A
Xylenes	N/C	5.9×10--6	N/A
Total:	3.25×10^-6	8.9×10^-2	4.2×10--1

N/A = Noncarcinogen or noncancer acceptable exposure levels (NAELs) not available.
N/C = Chemical is not carcinogenic.
Source: LLNL, 1991a.

C.4.3.3 Cumulative Impacts from Historical Contamination

Assessments have been performed to estimate the potential human health risks associated with environmental contamination as part of remedial investigations. These risk assessments integrate chemical-specific media concentrations and potential routes of exposure to estimate potential health risks. The results of the risk assessments are summarized in the following section. A more detailed discussion of the investigations that are being performed or have been performed as part of the Environmental Restoration Program is presented in section 4.17.

In 1987, the EPA added the LLNL Livermore site to the National Priorities List due to volatile organic compounds found by LLNL in ground water on and offsite. A Baseline Public Health Assessment was performed to address the future public health risk that could exist in the future if no cleanup were attempted (Thorpe et al., 1990).

In order to assess possible human exposure to volatile organic compounds in ground water, the maximum concentrations to which a person could be exposed over a 70-year lifespan at both existing and potential offsite wells was estimated. The estimates were made using an analytic computer model to simulate contaminant transport and fate in ground water. Two exposure scenarios were developed to account for the uncertainties in potential exposures. These two scenarios included:

A "best-estimate" case, consisting of existing private and municipal supply wells as receptor wells and the most probable hydrogeologic, chemical, and source parameters; and
A "health-conservative" case, including hypothetical wells (i.e., potential monitor wells), the highest possible source contamination, transport, and fate parameters that would produce the highest offsite concentrations.

Potential exposures to volatile organic compounds were estimated for tap water used in the home through ingestion of water, inhalation of organic compounds volatilized during showers, and uptake through the skin of organic compounds in bath water. Potential irrigation-related exposures consisted of the ingestion of fruits and vegetables from home gardens watered with contaminated well water and the inhalation of organic compounds that volatilize during sprinkler irrigation (Thorpe et al., 1990).

The incremental risk of developing cancer (i.e., the risk added to the background risk of developing cancer) was predicted on the basis of a 70-year (lifetime) exposure to volatile organic compounds in well water. The maximum "best-estimate" cancer risk for the combined 70-year maximum exposure to volatile organic compounds associated with the domestic use of the municipal supply well in downtown Livermore is calculated to be 0.3 in a million. Under the health-conservative transport scenario, the highest predicted risk is 6 in 10,000 for exposure to contaminated well waters from a potential monitor well drilled 200 meters west of the LLNL Livermore site. Under the health-conservative transport scenario, the highest predicted risk is 5 in 10,000 for exposure to contaminated well waters based on receptor wells in downtown Livermore. The arrival time of the maximum concentration was estimated to be 270, 110, and 35 years, respectively, for the best estimate, the health conservative estimate receptor wells in downtown Livermore, and the health conservative estimate based on a potential monitoring well located 200 meters west of LLNL (Thorpe et al., 1990).

No members of the public are currently exposed to volatile organic compounds derived from the use of wells near the LLNL Livermore site. The estimated risks are based on the premise that no remediation will occur. LLNL will remediate the contamination in the near future following the schedule determined in the Feasibility Study (Thorpe et al., 1990).

LLNL Site 300

At LLNL Site 300 there are a number of dry wells that have been used for disposal of rinse, process, and wash waters. None of these dry wells have been used since 1984. An investigation was undertaken to determine if any of the dry wells are a source of soil or ground water contamination. The dry wells investigated included those near Buildings 807, 810A, 812, 815, 827(5), 834(2), 835, and 836 (Lamarre, 1989). In only one sample did any of the analyte concentrations exceed regulatory criteria; the concentration of barium was slightly higher than the soluble threshold limit concentration as specified by the California Code of Regulations (Lamarre, 1989).

LLNL is currently investigating and defining the characteristics of the ground water contamination at LLNL Site 300. The ongoing investigations are discussed in section 5.2.4.2. There are currently two different areas where contaminant plumes have migrated offsite. Trichloroethylene (TCE) and tetrachloroethylene (PCE) are the chemicals of concern. One plume is in the vicinity of the General Services Area (GSA) near the southeast portion of LLNL Site 300 (Lamarre, 1989). One contaminant plume is located near Pit 6 near the southern portion of LLNL Site 300 (Taffet et al., 1991).

Evaluations were performed to estimate the potential health risks associated with these plumes. The potential routes of exposure were examined and it was determined that the only way that people could be exposed to the chemicals in the ground water was through ingestion of ground water. Therefore, the only potential exposure points are water supply wells. Three private water supply wells (two inactive and one active) and one active well used by the Caste Rock Department of Forestry are located near the GSA plume area. The only active water supply well in the Pit 6 area is the offsite Ranger well. No TCE or PCE have been detected in the wells to date (Lamarre, 1989; Taffet et al., 1991).

The exposure point concentrations in these offsite wells were estimated to be 15 mg/L for TCE and 2.5 mg/L for PCE. These values represent a 50 percent reduction in the predicted maximum concentration because most of the ground water that would be pumped from the wells is derived from a bedrock aquifer that is deeper than the contaminated aquifer (Lamarre, 1989; Taffet et al., 1991).

The estimated concentration of TCE exceeds the California Department of Health Services Maximum Contaminant Level of 5 mg/L. The estimated concentration of PCE is one-half of the California Department of Health Services Applied action level of 5 mg/L for PCE. The noncarcinogenic and the carcinogenic risks were also estimated. The noncarcinogenic hazard index was 0.004 although the noncarcinogenic health criterion was not available for TCE. The carcinogenic risk was estimated to be between 6.1 in a million and 1.4 in 100,000. (Lamarre, 1989; Taffet et al., 1991).

SNL, Livermore

SNL, Livermore has two sites requiring environmental remediation: the diesel fuel oil spill site and the Navy landfill (Brekke, 1990). The Trudell Auto Repair Site has been remediated and officially closed by the Regional Water Quality Control Board. The following section summarizes the potential human health impacts.

In February 1975, a 59,500-gal spill of No. 2 diesel fuel oil resulted from the accidental puncture of an underground transfer line buried 4 ft deep. A qualitative risk assessment was performed to evaluate the potential threat to human health and the environment. Benzene, a component of diesel fuel, was chosen as the sole indicator chemical based upon toxicity and its documented presence in ground water. The total lifetime carcinogenic risk for benzene is 5.7 in a million. This figure has been adjusted for the duration of exposure for each of the childhood and adult segments of the lifetime of an individual using the ground water. The aquifer is currently not used for residential or agricultural purposes. SNL, Livermore is preparing to use in situ bioremediation as the most effective means of achieving appropriate cleanup levels (Brekke, 1990).

An inactive landfill used by the Navy during and after World War II and by LLNL in the 1950s and early 1960s is located at SNL, Livermore. Historical records and an earlier investigation determined that it contains mainly construction debris and machine turnings. The site consists of debris fill placed in and around a natural ravine that extends approximately 200 ft by 400 ft. There does not appear to be contamination of the soil or ground water from the Navy landfill, and no contaminants have been shown to have migrated from the site to the ground water (DOE, 1990b). The ground waters in the vicinity of the inactive landfill are sampled quarterly. In 1990 the levels of organic chemicals have not exceeded any maximum contaminant levels (MCLs) for federal drinking water standards. Manganese and zinc have been detected at levels which exceed the secondary MCLs, which are for aesthetic standards (i.e., taste and smell) (SNL, Livermore, 1990b, 1990c, 1990d, 1991e).

C.4.4 Environmental Exposures from Potential Accidents

Environmental exposures from previous incidents in which radioactive and nonradioactive materials were released into the environment are considered to be part of the actual releases as discussed above. Potential exposures from postulated releases and the resulting impacts are discussed in Appendix D. The chemicals selected for examination in the accident analyses are different than the chemicals examined in section C.4.3. The chemicals examined in Appendix D were selected based on quantities of chemicals in single locations, likelihood of an accident occurring, and the potential health effects associated with short-term (i.e., acute) exposures, whereas those evaluated in section C.4.3 have been or are being released to environmental media.

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