Responses to Questions About Tritium

Responses to Questions Submitted to Berkeley Lab
at the November 12, 1996
Berkeley City Council Meeting

JANUARY 28, 1997

At the Berkeley City Council Meeting on November 12, 1996, Berkeley Lab received a list of 82 questions pertaining to tritium emissions from the National Tritium Labeling Facility (NTLF). This document provides a written response to the questions. Because many of the questions address similar topics, for example, the status of environmental monitoring for tritium, the questions have been sorted into 10 categories. No questions were omitted.

The following key points are the basis for the responses to these questions:

The NTLF has consistently operated safely and responsibly within regulatory limits for tritium emissions. The NTLF is under the oversight of the East Bay Municipal Utility District, the U.S. Environmental Protection Agency, and the U.S. Department of Energy.

Exposures to tritium, even on the Berkeley Lab site, are well below applicable exposure limits defined by the U.S. Environmental Protection Agency. The annual radiation dose to the public from NTLF emissions is small -- estimated to be around 0.001 mSv/year (0.1 mrem/year) -- in comparison to the typical annual dose received by the public from a variety of sources, including background radiation, about 2.6 mSv/year (260 mrem/year) in Berkeley.

The Lab is committed to environmental quality and to the health and safety of the public and of Lab employees. Even though the Lab meets all applicable environmental standards regarding tritium, it has continued to seek further reductions in emissions and exposures. Emissions from the NTLF have declined over time, as control systems have been improved and as additional protective features have been installed.

The Lab conducts extensive monitoring for tritium. Tritium is measured in air emissions, ambient air, sewer water discharges, nearby creeks and lakes, soil and soil water, rain water, groundwater, vegetation and milk of goats used to control vegetation as a fire control measure. The Lab’s measurement program includes many elements beyond those required for regulatory compliance.

Tritium Information

The Berkeley Lab has prepared this section to provide some basic scientific information about tritium and its radioactive nature so that readers can understand the laboratory's response to the community's questions about tritium. The following topics will be addressed in this section:

A. A definition of tritium.

B. How tritium is used at the National Tritium Labeling Facility.

C. What happens with the tritium that isn't used in experiments.

D. A definition of radioactivity and an explanation of how it is measured.

E. A description of global background levels of radioactivity and a comparison to background radiation exposure to residents in Berkeley. An estimate of global tritium background levels.

F. An explanation of the regulatory standards that protect the public from tritium exposure.

A. A definition of tritium.

Tritium is a radioactive form of hydrogen. Chemically, tritium behaves like hydrogen and is usually found attached to molecules in place of hydrogen. For example, a water molecule may exchange one of its hydrogen atoms for a tritium atom, resulting in "tritiated water" (HTO).

B. How tritium is used at the National Tritium Labeling Facility.

Tritium from the National Tritium Labeling Facility (NTLF) is used to help biomedical researchers study cell metabolism and test new products that can be useful in treating disease. For example, a potential cancer drug might be labeled (tagged) with tritium so that researchers can trace where the tritium-labeled drug is deposited in the body and evaluate its effectiveness. Tritium from the NTLF is not used for nuclear weapons research.

C. What happens with the tritium that isn't used in experiments.

The labeling facility uses approximately 3.7 x 10¹⁴ becquerels (Bq), equal to 10,000 curies (Ci) of tritium, per year. Through the labeling process, approximately 2% of the tritium goes into the labeled products, approximately 80% of the tritium is recycled, and approximately 17% is collected by an absorbent material, silica gel, which is disposed of as radioactive waste. Less than 1% escapes into the environment through the ventilation stack annually. 1995 tritium emissions totaled 1.85 x 10¹² Bq (50 Ci); 1996 emissions were less than 0.19 x 10¹² Bq (5 Ci). As a liquid, 1.85 x 10¹² Bq (50 Ci) of tritium is smaller than a drop of water. Whether in the form of gaseous hydrogen or as water vapor, 1.85 x 10¹² Bq (50 Ci) of tritium occupies a volume of about 1/6 of a cup.

D. A definition of radioactivity.

All things, whether natural or man-made, are made of atoms. Most atoms are stable, which means they retain their form and substance without change. Others, called radioactive atoms, are unstable and "transform" or decay to different forms. As atoms decay, they emit radioactivity in the form of particles (Alpha or Beta) or Gamma rays. Tritium is an unstable form of hydrogen atom. Tritium atoms emit weak Beta particles during the decay process. This illustration explains the different types of ionizing radiation and their potential effects on humans.

An explanation of how radioactivity is measured.

The curie is a traditionally used unit of measure of radioactivity. It represents the amount of radioactivity in one gram of radium, the source of radon. One curie equals 37 billion disintegrations per second. Becquerels are a measurement of radioactivity used in more recent publications to conform with international standards of measurement. One becquerel equals one disintegration per second. Therefore one curie equals 3.7 x 10¹⁰ Bq.

The dose due to exposure to radioactive materials is a measure of the energy absorbed by the body. A sievert (1 sievert equals 100 rem) is a basic unit of radiation dose. Sieverts express the rate that energy is deposited into tissue, weighted by a factor to account for differences in how different types of radioactivity exposures transfer energy. It is generally assumed that risk from radiation exposure is proportional to dose. That is, as radiation dose increases, the risk of cancer, genetic defects and reproductive effects increases proportionally. Tritium delivers a radiation dose to someone who inhales tritiated water vapor in the air or eats or drinks tritium-contaminated food or water.

E. A description of global background levels of radioactivity and a comparison to background radiation exposure to residents in Berkeley.

The purpose for discussing background exposure to radiation is to provide a frame of reference for readers who may be unfamiliar with radiation units.

The table below indicates the main sources of natural and man-made radiation. The average radiation exposure of individuals in the U.S. is approximately 3.6 millisieverts (mSv), or 360 millirem (mrem) per year (table 1). (1 rem = 1,000 mrem.) The background radiation exposure to residents of Berkeley is approximately 2.6 mSv/year (260 mrem/year). The background for Berkeley is lower than the U.S. average because radon levels are lower in Berkeley by approximately 100 mrem per year.

TABLE 1 SOURCES AND AVERAGE ANNUAL DOSE ESTIMATES FOR INDIVIDUALS IN THE U.S. POPULATION

Natural Radiation Sources	Dose (mrem/year)	Man-Made Radiation Sources	Dose (mrem/year)
Cosmic rays	28	Diagnostic x-rays	39
Terrestrial - natural radioactivity in rocks; uranium, thorium.	28	Nuclear medicine	14
Internal - natural sources of radioactivity in the body such as Potassium 40.	39	Consumer products	5-13
Radon - produced by the decay of radium as part of both uranium and thorium decay chains.	200	All other	<1
Subtotal	~300	Subtotal	60

Source: Based in part on National Council on Radiation Protection and Measurements Reports 1993, 1994, and 1995 and the National Academy of Sciences Technical Bases for Yucca Mountain Standards, 1995.

An estimate of global tritium background levels.

Global tritium background levels in 1982-89 were measured at 1.9 becquerels per liter (50 pCi/L) in surface water; they are lower today due to radioactive decay. In the atmosphere, the concentration of tritium depends on the humidity. A value reported for 1984-1990 atmospheric tritium concentrations was 0.07 mBq per cubic meter (0.0019 pCi/m³) (Okada and Momoshima, Health Physics, December 1993).

F. An explanation of the regulatory standards that protect the public from tritium exposure.

There are three regulatory standards that apply to tritium specifically. These are: 1) U.S. Environmental Protection Agency air emission standard (National Emission Standards for Hazardous Air Pollutants), NESHAPs) at 0.1 mSv/year (10 mrem/year); 2) East Bay Municipal Utility District sewer discharge guideline at 1.85 x 10¹¹ Bq/year (5 Ci/year) and 3) U.S. Environmental Protection Agency drinking water standard at 740 Bq/L (20,000 pCi/L). The drinking water standard is a conservative benchmark for the Berkeley Laboratory since the site does not provide drinking water to any communities.

TABLE OF CONTENTS

Page

Numbers

I. NTLF Operational Issues I-1, I-2

Questions 1, 2, 58, 66 and 79.

II. Monitoring and Local Environmental Conditions/

Access to Site Environmental Data/EIR Issues II-1 thru II-14

Questions 3, 4, 5, 6, 7, 22, 24, 29, 32, 39, 41, 57, 59, 60,

62, 63, 64, 65, 68, 71, 72, part of 73, 74, 78, 81, and 82.

These questions are further divided into groups addressing

monitoring of creek water, groundwater, soil and vegetation,

air, corrective actions, the 1995 Site Environmental Report,

and Environmental Impact Report issues.

III. UC Berkeley Questions III-1, III-2

Questions 8, 9, 10, and 15.

IV. Tritium and Radiation Issues, Including

Comparisons with Other Releases IV-1 thru IV-4

Questions 11, 12, 13, 14, 25, 26, 37, and part of 73.

V. NTLF Emissions V-1, V-2

Questions 16, 17, 43, 61, 67, 75, and 80.

VI. Tritium Risk Assessment VI-1, VI-2

Questions 18, 19, 20, 21, and 23.

VII. Transpired Vapor from Plants VII-1, VII-2

Questions 27, 28, 30, 56, and part of 74.

VIII. HWHF/HWHF Permits/Other Waste Management Issues VIII-1, VIII-2

Questions 31, 33, 34, 40, 76, and 77.

IX. Use of Goats to Clear Vegetation IX-1

Questions 35, 36, and 38.

X. Lawrence Hall of Science/Children Visitors/ X-1 thru X-4

Summit Road

Questions 42, 44, 45, 46, 47, 48, 49, 50, 51, 52,

53, 54, 55, 69, and 70.

I. NTLF Operational Issues

1. What were the reasons for the closure of the Lab’s National Tritium Labeling Facility from March 20 through October 1, 1996?

2. What caused the lab to reopen the NTLF?

58. How often and in what quantities are radioactive substances from outside generators shipped through Berkeley streets for delivery to the NTLF or other LBNL facilities without notice?

66. What is the projected working life of the NTLF?

79. Has LBNL considered relocating the NTLF to another DOE facility with a smaller concentration of civilian population? If so, how many jobs would be transferred?

Responses

Questions 1 and 2	Berkeley Lab temporarily suspended tritium operations of the National Tritium Labeling Facility (NTLF) to address three objectives: to review Environmental Health and Safety (EH&S) documentation and procedures at the NTLF, especially with respect to waste generation and characterization [determining if the waste is hazardous, radioactive, or mixed (hazardous and radioactive)], to review NTLF processes that generate mixed waste to assess how generating this type of waste can be reduced or eliminated, and to review the Berkeley Lab's options for managing and disposing of the existing tritium waste inventory, including tritium mixed waste. The NTLF staff continued all other research operations other than tritium experiments during the stand down period. Operations resumed once these three objectives were met.

Question 58	Typically, millicurie to microcurie quantities of Beta emitters such as phosphorus-32, carbon-14, and sulfur-35 are received at the lab on a daily basis. All radioactive materials meet U.S. Department of Transportation packaging, labeling, and shipping standards for radioactive materials. The NTLF receives tritium in kilocurie quantities, usually, once a year or less. Tritium is transported in packages made of stainless steel. The tritium source used at the NTLF occupies approximately the size and shape of a 35 mm film canister, and holds about 3.7 x 10¹⁴ Bq (10,000 curies).

Questions 66 and 79	The projected working life of the NTLF is determined by funding from the National Institutes of Health. The current grant is a five-year term, concluding late in 1999. Scientists at the NTLF may enter a competitive renewal process to obtain funding for an additional five-year term. The NTLF is a research facility that requires biochemical expertise not available at other DOE facilities. Currently, four full-time scientists and four part-time employees work at the NTLF.

II. Monitoring and Local Environmental Conditions, Access to Site Environmental Data

Many of the 82 questions address monitoring for tritium and the concentrations of tritium measured in surface water, ground water, soil, vegetation, and air. This section also addresses the questions concerning corrective actions, the 1995 Site Environmental Report, and Environmental Impact Reports.

The sections below are organized into groups reflecting the different types of monitoring that have been conducted by the Berkeley Lab. As an overview, the Berkeley Lab currently is required to monitor tritium emissions in the air leaving the stack near the NTLF, tritium in sewage waste water as it leaves the site, and tritium from surface water runoff from nearby creeks as they leave the lab during storm events.

In addition to this required monitoring, the Lab has voluntarily conducted additional tritium monitoring. The additional monitoring includes ambient air monitoring stations, that measure monthly average concentrations of tritiated water vapor in air. This air monitoring has been conducted for over 20 years, and is included in the annual Site Environmental Report. The Berkeley Lab has designed a real-time monitoring system for emissions from the NTLF. This allows the lab to determine when peak emissions occur and correlate these with NTLF research activities. With this information, NTLF staff can more effectively study options for reducing stack emissions. The Berkeley Lab conducts routine monitoring of surface water in the Lab’s vicinity and has measured tritium concentrations in extracted water from on-site vegetation (1995, 1996). Since 1995, the Berkeley Lab has measured tritium concentrations in goat’s milk from grazing goats used for on-site fire prevention activities.

As of January 1997, the Berkeley Lab will fund an independent monitoring program to be developed by a group composed of representatives from the State Department of Health Services, the U.S. Environmental Protection Agency (EPA), the City of Berkeley's Toxics Management Department, and the State Department of Toxic Substances Control. The group intends to receive suggestions from the broader Berkeley community in developing protocols for the independent sampling program. The program will monitor tritium levels in the air, soil, water and plants in the vicinity of the NTLF.

Creek (Surface) Water, Runoff

3. Is it true that radioactive tritium has been found in Wildcat Creek in Tilden Park, miles away from the National Tritium Labeling Facility (NTLF)? How did it get there?

4. Is it true that radioactive tritium has been found in the north fork of Strawberry Creek also known as Blackberry Creek, as it flows into the neighborhoods of North Berkeley around the residential streets La Vereda, La Loma, Highland, Hilgard, Le Roy, Virginia, Le Conte, Ridge, and Hearst? How did it get there?

5. Is it true that radioactive tritium has been found in Chicken Creek, which is part of the Strawberry Canyon watershed? How did it get there?

6. Is it true that radioactive tritium has been found in the south fork of Strawberry Creek as it flows through the UC Berkeley campus? How did it get there?

22. Why is radioactive tritium found in Tilden Regional Park, a popular local recreation and biological study area?

57. Why has the Lab refused to provide measurements of tritium in the surface runoff directly below the NTLF?

64. Which surface waters does the Lab monitor for H3O?

68. These are the results from LBNL’s lack of action: 80,000 pCi/L of tritium in shallow groundwater, 30,000 pCi/L of tritium in deep groundwater, 2,000 pCi/L of tritium in rain water. We do not know how much tritium is entering the creeks. Why has LBNL refused to provide measurements for surface water runoff as it enters the creeks?

Responses

Questions 3, 4, 5, 6, 22, and 64

Tritium does not normally exist as H₃O, therefore it is not monitored in this form. This response assumes that Question 64 refers to tritiated water, HTO.

Tritium is present in the atmosphere due to global background tritium levels and to tritium emissions from the NTLF. In the form of tritiated water, some of the tritium will combine with moisture in the air and fall to ground, especially during storm events or on foggy days. Rain water, which may contain some tritiated water, will enter storm water drains on site which lead to nearby creeks.

The surface water monitoring program conducted by the Berkeley Lab includes rain water, creeks, lakes, hydraugers (horizontal drainage pipes), and storm water. All are routinely monitored and results are available in the annual Site Environmental Reports at the Berkeley Public Library, the Berkeley Lab Main Library, or by request from the Berkeley Lab. The 1994 and 1995 reports are also available from the Berkeley Lab home page (www.lbl.gov).

Berkeley Lab monitors several creeks in the Berkeley Lab's vicinity for Alpha, Beta and tritium activity. In 1995, small amounts of tritium were sometimes detected in the following creeks: Chicken, Claremont, Lower Strawberry, North Fork Strawberry, Upper Strawberry (on campus) and Wildcat. Chicken Creek exhibited the highest level of tritium seen in the creeks during 1995; 179 Bq/L (4,840 pCi/L). The levels did not exceed one-quarter of the EPA drinking water standard of 740 Bq/L (20,000 pCi/L) and in most cases did not exceed 37 Bq/L (1,000 pCi/L). The EPA drinking water standard is considered a conservative benchmark for assessing creek levels of tritium since water from these creeks is not used as a public drinking water supply. Tritium was not detected at the smaller creeks (Botanical Garden, Cafeteria, Ten-Inch, No-Name, Ravine.

1996 results indicate that tritium levels in creeks are lower than 1995 levels. The highest level of tritium was found at Chicken Creek; 94 Bq/L (2,540 pCi/L) during a February storm event. North Fork of Strawberry, and Strawberry (on campus) all were below 19 Bq/L (500 pCi/L). Claremont and Wildcat Creeks were all below detection limits. In addition, the Berkeley Lab expanded its surface water sampling program in 1996 to include lake samples. Samples taken at Lake Anza and Lake Temescal were both below the detection limit for tritium. All 1996 surface water samples will be reported in the 1996 Site Environmental Report.

Question 57 and 68 [The groundwater aspects of Question 68, including the 80,000 pCi/L and 30,000 pCi/L measurements are addressed in the following section.]

Under the monitoring program required by the state storm water permit, the Berkeley Lab monitors surface runoff where it leaves the Lab and joins the North Fork of Strawberry Creek and Chicken Creek. Surface runoff is not measured in the immediate vicinity of the NTLF since this location will be very dependent on wind conditions during a particular storm event and, as a result, much of the runoff to the watershed may be missed . The Chicken Creek location provides the most accurate information regarding potential impacts to the watershed from surface runoff due to NTLF activities. The tritium levels measured at this location are far below the EPA drinking water standard.

In addition to surface water runoff, rainwater is monitored in the vicinity of the NTLF during storm events. In 1996, the maximum level measured was 16 Bq/L (432 pCi/L) during February; all other samples were at about 7 Bq/L (200 pCi/L) or less.

Groundwater Monitoring

7. Is it true that groundwater at LBNL is contaminated with radioactive tritium?

73. Exposure to tritium is not a chemical exposure. It is an ionizing radiation exposure, and there is no threshold, no safe dose level for an ionizing radiation carcinogen. [See section IV]. How much of the hillside between LBNL and the Lawrence Hall of Science is contaminated? What is the level of contamination? Is the groundwater contaminated? What is the level of the groundwater contamination?

Responses

Questions 7 and 68	Groundwater is defined as underground water that fills pores in soil or openings in rocks to the point of saturation. Where groundwater occurs in significant quantities, it can be used as a water supply. Any chemicals, or radioactivity, such as tritium, detected in groundwater at the Berkeley Lab do not come into contact with the community's drinking water; East Bay Municipal Utility District provides the water supply to the area. Therefore, EPA drinking water limits do not apply and are used as a conservative benchmark.

	Groundwater monitoring wells installed in the vicinity of the NTLF have detected tritium at levels below the EPA drinking water standard. No tritium has been detected in ten monitoring wells on LBNL property between the southern border of the Lawrence Hall of Science and UCB campus. However, water samples collected from a slope stability well (hydrauger) located near the NTLF showed tritium levels above the drinking water standard. Samples have been collected from this slope stability well since 1990 and tritium results have fluctuated from 700 to 1,330 Bq/L (19,000 to 35,800 pCi/L). The basis for these results is not understood; however, the slope stability well was not constructed for groundwater sampling, and does not include a seal to avoid surface water contamination. A groundwater monitoring well located within 5 feet of the slope stability well has shown a maximum tritium level of about 200 Bq/L (5,400 pCi/L).

	Soil water is water contained in soil above the level of the groundwater table and is typically extracted using mechanical suction equipment. This water is not available for public consumption. The Berkeley Lab monitors soil water as part of its effort to better understand the contamination profile of the site and to track changes over time. Typical sample volumes for soil water are 20 milliliters (less than 1 fluid ounce). The highest level observed was a concentration of 3,200 Bq/L (86,000 pCi/L) in a soil water monitoring instrument (lysimeter) closest to the NTLF. Also, a lysimeter 55 feet away from the NTLF stack showed tritium with a concentration of about 370 Bq/L (10,000 pCi/L). These soil water samples do not represent the source of the community's drinking water; therefore, drinking water standards do not apply to these samples. More detailed information on the locations and analytical measurements from all groundwater and soil water samples near the NTLF and throughout the Berkeley Lab is available in the annual Site Environmental Reports and Environmental Restoration Program Reports, available in the Berkeley Main Library.

Question 73	Soil water samples extracted in the vicinity of the Lawrence Hall of Science in May, 1996 showed tritium concentrations ranging from below detection limits to 130 Bq/L (3,500 pCi/L). Ten monitoring wells are available on the southern border of the Berkeley Lab and UCB property; no tritium contamination has been detected in these wells.

Soil/Vegetation Monitoring

24. Why were all data regarding organically bound tritium (OBT) omitted from the 1995 Site Environmental Report?

29. Is it true that soil, creeks, and plants and trees in a large area both within and beyond the perimeter of LBNL are contaminated with radioactive tritium at levels far exceeding permissible EPA standards?

63. What soil and plant monitoring has the lab performed? What are the accumulated levels of H₃O in plants and soil?

74. What is the status of the ongoing investigation regarding OBT, and what are the radioactive levels, both inside and outside the Lab’s perimeter?

Responses

Questions 29 and 63

Tritium does not normally exist as H₃O, therefore it is not monitored in this form. This response assumes that the question refers to tritiated water, HTO.

The Environmental Restoration Program has been collecting soil samples in the area of the NTLF since 1991. The maximum tritium level detected in soil samples was about 0.4 Bq/gram (12 pCi/gram).

In 1995, the Berkeley Lab conducted a special study to measure tritium concentrations in extracted water from vegetation in the area where the new Hazardous Waste Handling Facility will be located. The highest average tritium concentration was found in laurel leaves at 671 Bq/L (18,000 pCi/L). These results are published in the 1995 Site Environmental Report, page 10-16.

Beginning in 1996, the Berkeley Lab measured tritium in water extracted from eucalyptus leaves. The maximum concentration of tritium in this water was approximately 4,700 Bq/L (128,000 pCi/L) in the immediate area of the NTLF stack, and decreased to approximately 670 Bq/L (18,000 pCi/L) at 50 meters from the stack. Five vegetation samples were collected north of the NTLF beyond the site perimeter in 1996 and will be included in the 1996 Site Environmental Report. Preliminary results for plant water tritium concentrations are: at 100 m, 133 Bq/L (3,600 pCi/L); at 200 m, 78 Bq/L (2,100 pCi/L); and at 300 m, 52 Bq/L (1,400 pCi/L).

EPA has not established concentration limits for tritium in soil or vegetation. Potential exposures to tritium are regulated under EPA’s 0.1 mSv annual dose limit for air emissions. This limit is enforced based on measured stack emissions and EPA’s CAP88-PC model.

Questions 24 and 74

The Berkeley Lab measured organically bound tritium (OBT), tritium chemically combined with carbon, in eucalyptus trees in 1996. Results ranged from non-detectable (off-site) to 20 Bq/gram (524 pCi/gram) at the NTLF stack. These results will be reported in the 1996 Site Environmental Report. Prior to 1996, OBT was not measured.

NTLF Air Monitoring

59. Does LBNL conduct H₃O monitoring at the NTLF stack? If so, is that monitoring performed on a continuous basis?

60. What is the level of radioactive H₃O leaving the stack?

62. How many fixed monitoring devices for H₃O are there? Where are they located? What methods and monitoring equipment are used?

65. Does the Lab currently conduct monitoring at points off site? If so, at how many locations, and where are they?

78. Has the stack monitoring unit been updated to a continuous real time monitor of radioactive emissions? If so, when? If not, why not, and when will it be updated?

Responses

Questions 59, 60, and 78	Tritium does not normally exist as H₃O, therefore it is not monitored in this form. This response assumes that the question refers to tritiated water, HTO. The Berkeley Lab monitors tritium releases and concentrations in air in three ways: 1) continuous, real-time monitoring of NTLF stack emissions, 2) weekly silica gel sampling from the stack, and 3) monthly silica gel sampling of ambient air at four locations. At the NTLF, a side stream of exhaust air is continually passed through a tritium monitor, which measures and records the tritium concentrations. The data are displayed, real-time, in Building 75, and recorded every 100 seconds on a computer file.

	The amount of tritium leaving the stack varies, depending on the nature of the activity conducted at the NTLF. The total amount of tritium released in 1995 was approximately 1.85 x 10¹² Bq (50 Ci); the total amount in 1996, less than 0.19 x 10¹² Bq (5 Ci). In 1996, the NTLF was in operation for approximately one-half of the year.

Questions 62 and 65	There are four ambient air monitoring stations for tritiated water vapor (HTO):
	north of the NTLF stack, at the Lawrence Hall of Science,
	east of the stack, on the roof of Berkeley Lab Building 69,
	west of the stack, near Berkeley Lab's Building 88,
off-site	south of the stack, on the south ridge of Strawberry Canyon (Panoramic Hill).

	The monitoring stations operate by continuously pumping ambient air through a column containing silica gel, which traps the HTO. The column is gathered from the field once each month and is exchanged for a clean silica gel column. An EPA-approved method of analysis is used to determine the amount of tritium for each sample from the silica gel column. The sample is counted by a liquid scintillation instrument and the concentration of HTO in air is then calculated. The monitoring method is described in detail in chapter 4 of the 1995 Site Environmental Report.

Corrective Action

32. Is it true that there is so much �hot� solid and �hot� organic matter around the NTLF that it warrants immediate removal of all soil and plant matter and the capping of the hillside with concrete?

71. What is LBNL planning to do with regard to:

- Near surface and surface tritium contamination

- Containing airborne tritium

- Tritium in the soil surface and in vegetation so that tritium cannot and will not be available for human inhalation?

72. LBNL must remove all tritium-contaminated soil and groundwater from the community. What are the costs? When and how will LBNL dispose of these contaminated materials? Is LBNL planning to follow through on this obligation?

Responses

Questions 32, 71, and 72	Environmental monitoring results demonstrate that the Berkeley Lab complies with tritium emission standards. Corrective measures such as removing soil, or plant matter, or capping the hillside are not necessary based on this information.

	In addition, as part of its federally mandated corrective action process, the Berkeley Lab has been gathering data to determine the extent of contamination for multiple substances in addition to tritium, conducting a risk assessment and evaluating, selecting, and implementing corrective measures if warranted. This process involves quarterly meetings with regulatory agencies including the California Department of Toxic Substances Control, the Regional Water Quality Control Board, and the City of Berkeley. Site characterization will be completed in approximately two years and the report will be made available to regulators and the public at that time.

1995 Site Environmental Report

81. Why did LBNL delay publication of the 1995 Site Environmental Report for seven months?

82. How was that Report revised before it was finally released to the public on November 7, 1996? Please provide the full texts of those segments that were changed:

a. as they were in the original Report: and

b. as they appear in the revised version released to the public.

Responses

Questions 81 and 82	The seven month figure is incorrect. The DOE order requiring the Site Environmental Report gives a distribution deadline of October 1. The revised report was issued on November 5, 1996, a delay of approximately one month.

	The Berkeley Lab was on schedule to release the Report by the October 1 date, but it became aware of an analytical error affecting a few sampling results just prior to issuing the report. The following pages were revised in the final document: Page 2-15, Fig 2-11, Page 5-5, Tab 5-2, Page 10-7, Tab 10-5, Page 11-9, Tab 11-5, Page 11-10, Tab 11-6, Appendix A-12, A-21, A-23, A-24, and A-28. The primary cause of the revision was attributable to �overlap� or double-counting by laboratory analytical equipment. When the Berkeley Lab was measuring Beta activity for various lab samples, some of the positive Beta counts also resulted in positive Alpha counts. This resulted in a set of false positive results and an overestimate of the predicted dose distribution for Alpha emitters that Berkeley Lab includes in the Report. These changes did not affect the reported dose at the Lawrence Hall of Science since this value is based on tritium, a Beta emitter. Correction of the error lowered the calculated population dose in the 80-kilometer region surrounding the Laboratory since this value is based on both Beta and Alpha emitters. The laboratory analytical equipment has since been recalibrated so that the double-counting will not occur.

	In addition, the Berkeley Lab also used this delay to correct some typographical errors in the report, such as an axis labeling error on a chart, a minimum value reported as greater than a maximum value, and a discussion where the total exceeded 100%.

Environmental Impact Report Issues

39. Why did LBNL fail to prepare a comprehensive EIR to evaluate the extent and degree of seriousness of the tritium contamination of the water, soil, organic matter, plants, etc. in and around the NTLF?

41. The Berkeley community feels that the only morally and legally appropriate action for LBNL is to shut down the NTLF immediately and permanently. Why is the Lab, having failed to collect and evaluate the requisite environmental contamination data and to produce an EIR based on those findings, of the opposite opinion?

Responses

Questions 39 and 41	The Berkeley Lab does not agree that it is appropriate to terminate NTLF operations. The NTLF is conducting research in the national interest and is performing well within applicable limits to maintain environmental quality and public health. For example, tritium-labeled compounds produced at the NTLF have been used to better understand the cause of Alzheimer's disease and viral infections.

	The NTLF is committed to safe operating practices and continues to reduce its emissions even though the NTLF is in compliance with all federal and state regulations. A significant operational improvement was the development of a tritium gas recovery loop that captures and recycles 80% to 90% of the unconsumed tritium used in experiments. From 1991 to 1994, the amount of tritium emitted from the labeling facility has averaged 3.7 x 10¹² Bq/year (100 Ci/year). This is a three-fold reduction compared to average emissions from 1982-1990. In 1995 and 1996, tritium emissions have been further reduced to 1.85 x 10¹² Bq/year (50 Ci/year) and to less than 0.19 x 10¹² Bq/year (5 Ci/year), respectively. In 1996, the NTLF was in operation for approximately one-half of the year.

	The Berkeley Lab has collected and evaluated requisite data in an EIR and other reports. The Berkeley Lab takes samples of NTLF stack emissions, air, local rainfall, groundwater, creeks, and sewers to check for tritium. The Laboratory publishes these monitoring results annually in a Site Environmental Report that is provided to all regulatory agencies. The report is available to the public at the Berkeley Public Library or at the Lawrence Berkeley Building 50 Main Library. The Berkeley Lab has mailed copies of the report to individuals by request.

	The September 1992 Supplemental Environmental Impact Report (SEIR) was prepared to update LBNL's 1987 Long Range Development Plan EIR to cover operations over the period 1992-1997 and beyond. There have been no changes at the NTLF since 1992 that required preparation of an EIR. Tritium emission has been reduced from approximately 3.0 x 10¹² Bq/year (80 Ci/year) to less than 0.2 x 10¹²Bq/year (5 Ci/year) in 1996. Since the NTLF was in operation for approximately one-half of the year in 1996, this amount would be equivalent to approximately 0.4 x 10¹² Bq/year (10 Ci/year) for a full year of operation The presence of tritium in the air, soil, sediment, and biota at the Berkeley Lab site was documented and evaluated in the 1992 SEIR. Please refer to sections: III-J: Air Quality, IV-I: Remediation Activities, and IV-J: Environmental Monitoring. Section IV-K of the SEIR provides mitigation measures to reduce any potentially significant impacts from the use of radioactive materials including tritium from the NTLF to less than significant levels.

III. UC Berkeley Questions

8. Is it true that for over twelve years, from 1969 until 1981, the NTLF was located at Melvin Calvin Laboratory on UCB’s central campus?

9. Is it true that hundreds of Curies of tritium were released among the UC Berkeley student population during the period from 1969 through 1981?

10. Is it true that over 300 Curies of tritium were released over the UCB student population on campus in 1978 alone?

15. Is it true that the authors of the October 1995 Draft Health Risk Assessment for Tritium Releases omitted all references to the Tritium facility’s operations while on the UC Berkeley campus? Why?

Responses

Questions 8 and 15	The NTLF has never been located on the UC Berkeley campus, including the Melvin Calvin Laboratory. The Berkeley Lab tritium labeling activities, that preceeded the NTLF, were all conducted in Building 75, on the main Berkeley Lab site, i.e., at the same location as the current NTLF laboratory. Because the tritium facility never operated on the UC Berkeley main campus, no such emissions were considered in the October 1995 Draft Health Risk Assessment for Tritium Releases. The purpose of the risk assessment was to estimate risks from current release rates from the NTLF. In addition, the doses and risks from earlier periods with higher releases were also addressed.

Questions 9 and 10	It is true that hundreds of curies of tritium were released during the period from 1969 through 1981, and that over 300 curies of tritium were released in 1978. It is not correct to characterize them as �releases to the UC Berkeley student population� because the releases were to the air at the NTLF site. The physical separation between the NTLF and the UC Berkeley campus results in significant dilution of the emissions.

	The risk assessment and calculations with the EPA CAP88-PC computer model (used to determine whether releases are within regulatory limits) both indicate that annual exposures on the UC campus to tritium are around 0.0004 mSv (0.04 mrem), based on an annual release of 3.7 x 10¹² Bq (100 Ci) from the NTLF. In earlier years with higher releases, exposures would be proportionately higher. In all years of operation, exposures have been well below the annual limit of 0.1 mSv (10 mrem).

IV. Tritium and Radiation Issues, Including Comparisons with Other Releases

11. Is it true that the accident at Three Mile Island discharged about 50 curies?

12. Is it true that tritium has a hazardous life of 125 years, meaning it will take 125 years for radioactive tritium to fully decay?

13. Is it true that, rad for rad, tritium Beta rays do more biological damage than the high energy Gamma rays of the Hiroshima/ Nagasaki atomic bombs?

14. How harmful is �low level� radiation from tritium Beta rays? Is such low level radiation more harmful than high level radiation from Gamma rays?

25. Is it true that tritiated water is 25,000 times more toxic than tritium gas?

26. Is it true that OBT is 250,000 times more toxic than tritium gas?

37. Is it true that the tritium in the milk from these goat herds feeding on OBT matter is potentially 250,000 more toxic than tritium gas?

73. Exposure to tritium is not a chemical exposure. It is an ionizing radiation exposure, and there is no threshold, no safe dose level for an ionizing radiation carcinogen. How much of the hillside between LBNL and the Lawrence Hall of Science is contaminated? What is the level of contamination? Is the groundwater contaminated? What is the level of the groundwater contamination?

Responses


Question 12
Questions 13 and 14	For tritium to be harmful, it must be ingested or inhaled by the human body. Radioactive decay of tritium produces a Beta particle, which is not sufficiently penetrating to pose a hazard when outside the body. In contrast, materials that release Gamma radiation not only produce a radiation dose if ingested or inhaled, but also produce a radiation dose from outside the body. This is because Gamma radiation is far more penetrating than Beta radiation.

	The �rad,� a radiation unit referred to in Question 13, applies to the absorbed radiation dose which is the amount of energy absorbed in tissue. To estimate risk, the absorbed dose is multiplied by a quality factor to convert it to a measure of dose equivalent. Rads are multiplied by a quality factor to get rems, a measure of dose equivalent. In most recent scientific papers, the �rad� and �rem� have been replaced by the �gray� and �sievert,� where 100 rads equal 1 gray and 100 rems equal 1 sievert.

	Estimates of the quality factor for Beta radiation from tritium range from 1 to 3, according to a 1993 article by Straume in the journal Health Physics. A quality factor of 1 is used for Gamma radiation, so that, rad for rad, the estimated dose equivalent for tritium Beta radiation is 1 to 3 times that of an equal amount of energy deposited in the body by Gamma radiation. The National Academy of Sciences (Health Effects of Exposures to Low Levels of Ionizing Radiation, BEIR V, 1990) recommends a quality factor of 1 for both Beta and Gamma radiation. In the risk assessment of the NTLF by Tom McKone and Kevin Brand, a risk factor consistent with a quality factor of 1.8 was used, based on Straume’s work.

Questions 25, 26, and 27	An important consideration in determining the dose that tritium produces is the amount of time that tritium remains in the body, a period referred to as the biological half-life of tritium. Most tritium taken into the body as tritiated water (HTO) is reduced by about half in around 6 to 12 days. Tritium converted or consumed in an organically bound form (OBT), a chemical combination with carbon, remains in the body for a longer period, with a biological half-life of around 10 to 34 days. A smaller fraction of OBT that combines with fatty tissues has a biological half-life estimated to be 130 to 550 days.

	The chemical form of tritium, either as a tritium-hydrogen molecule (HT) or tritiated water (HTO), affects the degree to which tritium is taken into the body and how long it stays if taken in. Ingestion of HTO produces about 10,000 to 25,000 times the exposure as inhalation of the same amount of tritium as gaseous HT, because the tritiated water is taken up and retained by the body more effectively than is HT.

	The risk from consumption of OBT is probably higher than that of HTO by a factor of 2 or 3 because tritium consumed in an organically bound form may reside in the body somewhat longer on average than tritiated water. The relative risk is not directly proportional to the biological half-lives of HTO and OBT because some HTO is converted into an organically bound form in the body and some ingested OBT is converted to HTO during digestion. In addition, OBT that resides in the indigestible portion of a plant, i.e., as roughage, will not be absorbed by the human body.

	The quoted difference in toxicity between OBT and HTO, with OBT more hazardous than HTO by a factor of 10 and more hazardous than HT by a factor of 250,000, is based on experiments concerning the uptake of OBT and HTO in cattle. These results are not applicable to humans, because cattle and other ruminants take up 10 times the amount of ingested organically bound tritium that humans do. This difference in uptake occurs because ruminants have the ability to digest cellulose (plant fiber) whereas humans do not. Most of the OBT in plants is in the form of this non-digestible fiber.

Question 73 [The second half of this question is addressed in Section II, above.]	The first part of Question 73 makes the statement that �Exposure to tritium is not a chemical exposure. It is an ionizing radiation exposure, and there is no threshold, no safe dose level for an ionizing radiation carcinogen.� The issue of the risk of low-level exposures to agents known to cause cancer at high exposure levels has been and remains a subject of some debate within the scientific community, and the absence of a threshold (i.e., a level below which there is no risk) for ionizing radiation is not an established scientific fact. The controversy over thresholds includes risks from both ionizing radiation and chemical carcinogens. Key issues in this controversy are whether there is a dose rate below which there is no risk, and whether the risk per unit of exposure is lower at low doses. In the risk analysis for the NTLF releases, it was assumed that there is no radiation risk threshold. Radiation risks calculated in the risk assessment used methods generally accepted by the scientific community.

Question 11	Risk from radiation exposure is determined by both the risk per rad and the amount of rads to which a person is exposed. The Hiroshima/Nagasaki atomic bombs resulted in very large radiation exposures, in no way comparable with those due to the tritium released from the NTLF. The Three Mile Island accident discharged about 9 x 10¹⁶ Bq (2.5 million curies) of radioactive gases -- xenon, iodine, krypton -- into the reactor containment building. About 5 x 10¹⁵ Bq (140,000 curies) of xenon-133 and smaller amounts of krypton and iodine were released to the atmosphere. (Ref.: U.S. Nuclear Regulatory Commission, Special Inquiry Group Report, Mitchell Rogovin, 1980).

V. NTLF Emissions

16. Is it true that the Lab’s NTLF has emitted thousands of full Curies of radioactive tritium since 1982?

17. Is it true that close to 1,500 full Curies of tritium were emitted into the air in 1987 - 1989 alone?

43. Are the NTLF stack’s blowers on continuously in order to keep the air clean inside the Facility? Is this why there are constant tritium emissions from the stack?

61. What would need to be done to reduce emissions to at or near zero?

67. About two years ago David McGraw in a television interview stated that LBNL would like to adopt a zero emission policy regarding tritium releases. What has the Lab done other than increasing the diameter of the silica gel filter to achieve this? What costs would be involved in achieving a true zero emission operation for the NTLF?

75. Since the Lab has publicly committed itself to a zero emissions policy, what kinds of technologies have been researched to accomplish capture of all tritium emissions?

80. According to a letter from Ron Pauer dated July 19, 1996: �...In addition to airborne releases, small amounts of tritium are also released to the sanitary sewer.� If this is a standard method of disposal, how are these releases monitored? Please provide dates and quantities of all releases for the past five years (1991 to present).

Responses


Questions 61, 67, and 75
Questions 16 and 17	For 1983-1995, airborne releases from the NTLF stack totaled 9.7 x 10¹³ Bq (2,617 curies), an average of about 7.5 x 10¹² Bq (200 curies) per year. For 1987-1989, emissions totaled 5 x 10¹³ Bq (1,385 curies), an average of about 1.7 x 10¹³ (460 curies) per year. In 1995, 1.85 x 10¹² Bq (50 curies) were emitted; in 1996, less than 0.19 x 10¹² Bq (5 Ci) were emitted. Since the NTLF was in operation for approximately half of the year in 1996, this amount would be equivalent to approximately 0.38 x 10¹² Bq (10 Ci) for a full year of operation.

Question 43	The blowers at the NTLF are on continuously to ventilate and provide fresh air to the building. Although air continuously exits the stack, tritium emissions are not constant, but vary with activities inside the facility.

Question 80	Mop water that has been used by the janitors to clean the NTLF is released to the sanitary sewer if, after analysis for potential radioactivity, it meets discharge criteria of 74 million Bq (2 mCi) per day. For 250 working days per year, this is one tenth of the state and federal limit of 5 curies per year. The actual releases of tritium in mop water were 2.3 x 10⁸ Bq (6.3 mCi) in 1995. The NTLF discharges its wastewater to the Strawberry sewer outfall. The Strawberry sewer water is monitored, with samples automatically collected at 20-minute intervals. In 1995, the average concentration of tritium in the Strawberry Station sewer water was 83.7 Bq/L (2,262 pCi/L); the maximum concentration measured was 809 Bq/L (21,865 pCi/L). These monitoring results are reported annually in the Site Environmental Report.

VI. Tritium Risk Assessment

18. Why was Real Source Data not used in the Tritium Health Risk Assessment?

19. Why were all accidental releases (and there were quite a number of them!) entirely omitted from the calculations in the Tritium Health Risk Assessment?

20. Why did the Tritium Health Risk Assessment use wind speed data from the airports of Oakland and San Francisco and from Livermore, all at a great distance from LBNL, instead of the real data available from the Lab’s own 24-hour SODAR meteorological monitoring system?

21. Why was all data regarding wind direction ignored and completely omitted from the Tritium Health Risk Assessment regarding tritium releases from LBNL?

23. Why were all source data regarding Organically Bound Tritium (OBT) omitted from the Tritium Health Risk Assessment?

Responses

Question 18	Actual (real) source data were used as the basis for the emissions rate used in the risk assessment. The average release from the NTLF from 1970 to the present is 5.1 x 10¹² Bq/year (138 Ci/year). A 3.7 x 10¹² Bq/year (100 Ci/year) release rate was used to represent the level of release following implementation of the 1990 emissions reduction plan. Monitored releases have been approximately 3.7 x 10¹² Bq/year (100 Ci/year) during recent years, dropped to half that amount in 1995, and were further reduced in 1996. The final version of the NTLF Risk Assessment will include a discussion and a figure illustrating the actual annual releases for the period 1970 to 1995. An appendix of the assessment addresses the impact of higher releases in earlier years and their risk implications.

Question 19	The accidental releases were not omitted from the risk assessment, because the annual emission rate estimate on which the risk assessment is based includes both routine (normal) releases and accidental (off-normal) events. All tritium releases, including accidental releases, have been monitored and assessed.

Question 20	Until 1994, on-site meteorological information was not available that was acceptable for use in the EPA’s CAP88-PC compliance model. Thus, it was necessary to make use of other sources of meteorological data, such as Oakland airport data. This practice was accepted by the EPA. Now that actual on-site data suitable for use in CAP88-PC are available, they have been used in the most recent compliance analysis for EPA.

Question 21	Wind direction was not completely omitted from the Tritium Health Risk Assessment. There were two calculations provided in the risk assessment report. In the main body of the text, risk calculations are made using what is called a box model to calculate atmospheric mixing. Such methods are often used for air concentration calculations within a small area. A box model does not consider wind direction as a variable. However, in the appendix, the results from a risk assessment carried out using the EPA CAP88-PC model are provided. The risk assessment based on the EPA model uses meteorological data, including data on wind direction, based on measurements on the LBNL site. The model provides dose and risk estimates in all directions and for a number of distances from the stack. The box model and the CAP88-PC dispersion model produced very similar results.

Question 23	In the risk assessment, the residents consuming home grown food are assumed to be eating a mix of tritiated water and organically bound tritium. This is a very conservative assumption since home grown fruit samples were obtained from three homes north of the Lawrence Hall of Science, and no tritiated water or organically bound tritium were detected in any of these samples. In addition, all tritium released from the NTLF is assumed to be released as tritiated water (HTO), even though measurements indicate a portion of the releases are as tritium gas (HT). This is a conservative assumption from the viewpoint of health risk, because HTO is much more hazardous than HT.

VII. Transpired Vapor from Plants

27. According to the Department of Health Services Agreement in Principle 1995 Annual Report: �...There may be significant amounts of tritium in the upper, non-saturated soil strata. It appears that there may be sufficient evidence to suggest that there may be more tritium in the environment than previously suspected. There are apparently no validated explanations for the appearance of tritium in streams not obviously associated with NTLF.� [Emphasis Added.] Why has this information been kept from the public for the past two years?

28. Is it true that tritium measurements in the transpired vapor from plants outside the LBNL perimeter far exceed any levels that the Environmental Protection Agency (EPA) considers safe [protective of public health] in drinking water?

30. Is it true that the significant new information contained in Question No. 27 above has been kept from the public?

56. Despite the fact that LBNL’s upper management had information that the tritium contamination in water vapor far exceed levels set by the EPA, why was the re-opening of the NTLF ordered for October 1, 1996?

Responses


Questions 28 and 56
Questions 27 and 30	The Department of Health Services (DHS) Agreement in Principle 1995 Annual Report comments quoted above are apparently based on an informal presentation to DHS by the researchers who conducted the transpired water vapor measurements. These results were not collected by LBNL personnel involved with compliance monitoring. To date, no peer-reviewed publication or formal report of this research has been provided to the Berkeley Lab by the researchers. Because the Berkeley Lab was requested to provide this raw data during a Berkeley City Council meeting on November 11, 1996, the Berkeley Lab looked for the data from the transpired water vapor measurements, and upon finding that the data had been analyzed using Lab analytical facilities, sent it to the City Council.

VIII. HWHF/HWHF Permits/Other Waste Management Issues

31. Is it true that this significant new information would trigger the need for an EIR for the permit modification for the Lab’s new, expanded Hazardous Waste Handling Facility (HWHF)?

34. Is it true that LBNL, due to the excessive amounts of waste stored at its HWHF, is in violation of its original permit for that facility?

33. Is it true that LBNL’s HWHF is already full of pure radioactive waste, and mixed radioactive waste, tritium being the major component of the latter?

40. The Berkeley community believes that no permit modification decisions regarding the Lab’s HWHF can be made until completion of a full investigation of OBT and tritium in transpired vapor from plants in and around the NTLF. Why does LBNL believe such investigation to be unnecessary?

76. How can LBNL justify the incineration of radioactive and mixed waste? Is it not morally objectionable to manage and handle disposal of such wastes in this manner? Is it because liability for incineration is lower than if the waste were sent to a landfill?

77. Is the silica gel used in tritium monitoring recyclable, or does it become mixed or radioactive waste?

Responses

Questions 33 and 34	The HWHF is in compliance with its waste storage capacity requirements. The California Department of Toxic Substances Control has issued a Consent Order to the Laboratory that includes a 5,060 gallon storage capacity increase for mixed waste (i.e., waste that is both hazardous and radioactive) at the existing HWHF while a permit modification is being considered. As a result, the current mixed waste storage capacity of the existing HWHF is 8,305 gallons, based on outer container capacity. Because the increase in the existing HWHF's capacity to store mixed waste is wholly offset by a decrease in its capacity to store solely radioactive and solely hazardous waste, the total volume of hazardous, mixed, and radioactive waste that can be stored at the existing HWHF is unchanged. As of January 28, 1997, the HWHF contains 3,960 gallons of mixed waste based on outer container capacity (the actual amount of mixed waste is smaller), and hazardous and radioactive wastes are also within their current capacity limits. The permit modification would authorize an increase in mixed waste capacity at the existing HWHF from 3,245 gallons to 8,305 gallons, which would be wholly offset by a combined reduction in the capacities for solely hazardous and solely radioactive waste of 5,060 gallons. The replacement HWHF would be authorized for a mixed waste capacity increase of 1,925 gallons from 6,490 gallons to 8,415 gallons. Of this increase, 1,880 gallons would be offset by a reduction in storage capacity for hazardous waste.

	Tritium is the predominant radioactive component in radioactive waste and mixed waste inventories. Currently, there are 2.1 x 10¹⁴ Bq (5730 Ci) of tritium in radioactive waste and 8 x 10¹³ Bq (2160 Ci) of tritium in mixed waste. The total of all other radioactive materials in both radioactive and mixed waste is less than 3.7 x 10¹⁰ Bq (1 Ci). The waste containing tritium, however, represents a small portion of the total inventory as measured by volume. In mixed waste, it represents approximately 3% of total volume; in radioactive waste, it represents approximately 11%.

Question 31 and 40	Based on the Berkeley Lab's tritium environmental monitoring, the Lab has a sound technical basis for stating that any tritium exposures to members of the Berkeley community are far below the limits established by the EPA. These exposure estimates assume that people living and working on or near the Berkeley Lab eat tritium-contaminated garden produce on a regular basis. Actual organically bound tritium (OBT) and transpired measurements are not necessary for calculating risk; however, home grown fruit samples were recently obtained from three homes north of the Lawrence Hall of Science. No free water tritium or OBT were detected in any of these samples.

Question 76	Berkeley Lab does not have an incinerator on-site. Any incineration of Lab waste occurs at off-site commercial facilities permitted for this authorized form of treatment. Incineration is an accepted means, and often the only available means, of treating mixed waste. EPA and other agencies have addressed the comparative merits and disadvantages of incineration versus disposal in landfills without prior treatment to formulate federal and state laws on waste disposal.

	Waste disposal options must meet health protection criteria to be accepted by EPA. The Berkeley Lab follows the law and seeks out the few facilities available to treat mixed waste as the law requires.

Question 77	The silica gel is not recycled. After analysis, it is managed either as low-level radioactive waste or as nonradioactive waste, based on the analytical results.

IX. USE OF GOATS TO CLEAR VEGETATION

35. Is it true that as part of the Lab’s fire prevention measures, herds of goats are used on the hillside which eat vegetation, and that the goats are thus potentially ingesting OBT?

36. Is it true that the milk from these goats is sold commercially?

38. How does LBNL justify this practice?

Responses

Questions 35, 36 and 38

Goat grazing is used to help prevent wild land fires as a preferred alternative to the use of herbicides. The first measurements for goat milk were taken in August 1995. During March 9, 1996 to April 22, 1996, tritium was measured in samples of goat milk, excreta, and grasses, shrubs, and trees consumed by the herd. Preliminary results indicated that tritium levels in goat’s milk were approximately 85 Bq/L (2,300 pCi/L), below the EPA drinking water standard. The goats are provided by a private contractor, who has stated that milk from these goats is not consumed or sold commercially.

X. Lawrence Hall of Science/Children Visitors/Summit Road

42. Is it true that over a hundred thousand school children per year visit and play at the Lawrence Hall of Science in the area immediately adjacent to the NTLF stack, and that that area is contaminated with radioactive tritium in quantities far exceeding EPA allowable standards?

44. Is it true that during the last 15 years over 1.5 million school children have visited and played in the area where tritium in water vapor from plants far exceeds levels considered acceptable by the EPA?

45. Is it true that these same millions of children have been directly exposed to emissions from the huge tritium stack located on the hillside just a few hundred feet from the Lawrence Hall of Science?

46. What might be the health effects on a child at the Lawrence hall of Science who inhales tritium emissions blown in an easterly direction from the NTLF stack, which is at nose level less than 100 yards west of the Lawrence Hall of Science?

47. Is it true that the mouth of that stack is below the eye level of children visiting the Lawrence Hall of Science and standing next to the Space Shuttle Challenger Memorial?

48. Is it true that the �unplanned release� of 30 full Curies of radioactive tritium from the NTLF stack that occurred during the week of September 23 to 30, 1994 during business hours fully exposed all children playing outside in the yard of the Lawrence Hall of Science?

49. Is it true that there are no signs posted at the Lawrence Hall of Science, at the Challenger Memorial, or at the LBNL fence a few yards away warning teachers, parents, children, and casual visitors of the potential dangers of radioactive exposure from tritium releases from the NTLF stack?

50. Why are there no warnings posted?

51. Why are children and adults being exposed to radioactive tritium in this manner without warning?

52. Why are the residents on Summit Road, as well as those of Wilson Circle, Olympus Avenue, and Campus Drive, being exposed to radioactive tritium without their knowledge?

54. Is it true that the maximally exposed individual outside LBNL as described in the Tritium Health Risk assessment is a child visiting the Lawrence Hall of Science?

55. There are laws and regulations governing the height of industrial stacks. Why is the mouth of the NTLF stack below the eye level of the maximally exposed individual?

69. The wind around the NTLF is westerly. Why is the Lab allowing over 100,000 children per year to visit Lawrence Hall of Science and play outside to be exposed to tritium?

70. Why are children, their parents, and the schools that send them not notified of the real tritium exposure risks? Tritium’s biological harm starts from the inside out. It is a long-lived radiation source and can enter the lungs, and accumulate in the skin and brain and do considerable biological damage.

Responses

Questions 42, 44, and 45	Tritiated water concentrations in air are monitored near the Lawrence Hall of Science. Given these measurements, doses can be assessed with reasonable certainty. These measurements are independent of the tritiated water source, i.e., the concentration includes emissions from the stack, from transpired water vapor, and from any other sources. In 1995, the average tritium level measured in air at this location was 5.3 Bq/m³ (143 pCi/m³). Based on the Lab’s risk assessment, someone living at this location for 70 years would receive an exposure of about 0.001 mSv/year (0.1 mrem/year), including exposures from inhalation and from home-grown garden produce. This exposure is about 1% of the EPA standard of 0.1 mSv/year (10 mrem/year) established under the Clean Air Act. A similar result was obtained using EPA’s CAP88-PC computer model. The estimated dose to someone 125 meters northwest of the NTLF (the direction of the Lawrence Hall of Science) was estimated to be about 0.001 mSv/year (0.1 mrem/year). This agrees with the risk assessment and with the measured air concentration at the Lawrence Hall of Science. This calculation was based on meteorological data collected at LBNL, and average emissions of 3.7 x 10¹² Bq/year (100 Ci/year).

	In addition to the air sampling, soil water samples collected from two locations in the vicinity of the Lawrence Hall of Science showed tritium ranging from below detection limits to 130 Bq/L (3,500 pCi/L). There are also 10 groundwater monitoring wells on the LBNL site between the southern border of the Lawrence Hall of Science and the UCB campus. No tritium contamination has been detected in these wells.

Question 47	The Lawrence Hall of Science is at a higher elevation than the NTLF. In contrast, the EPA model assumes that the terrain is flat. It may be the case that the EPA model under predicts exposures at the Lawrence Hall of Science somewhat, due primarily to change in elevation. The good agreement between the modeled result and measured concentrations at the Lawrence Hall of Science may reflect the fact that the modeling was based on a 3.7 x 10¹² Bq/year (100 Ci/year) emission rate, while actual 1995 emissions were only half that amount. Whatever uncertainties are associated with the complex terrain calculations at the site and at the Lawrence Hall of Science, the tritium concentrations in the air monitored at the Lawrence Hall of Science are well below EPA standards. The NTLF stack meets all applicable regulations.

	All of these data and analyses taken together indicate that the exposures at the Lawrence Hall of Science, even to a full-time resident at that location, or at other locations near the Berkeley Lab such as Summit Road, Wilson Circle, Olympus Avenue, and Campus Drive, are very much below allowable standards. Nearby residents and visitors to the Lawrence Hall of Science are not exposed to tritium levels in excess of EPA standards.

Questions 42, 44, 45, 46 and 54	Several of the questions above concern exposures to children visiting the Lawrence Hall of Science. To estimate exposures to children visiting the Lawrence Hall of Science, the exposure estimates reported in the first paragraph of this section would need to be adjusted downward to account for the amount of time that the children spend at that location. The maximally exposed individual that was considered in the risk assessment is someone assumed to live at the Lawrence Hall of Science for 365 days a year, not a visitor. In addition, children would be unlikely to eat home-grown produce from the site, especially on a full-time basis. For these reasons, it is reasonable to estimate that the exposure to a child who visits the facility for several hours a visit, several times a year, would be less than 1% of the exposure estimates reported above. That is, the exposures would be less than 0.00001 mSv/year (0.001 mrem/year). In contrast, background radiation exposures in Berkeley are around 2.6 mSv/year (260 mrem/year). Based on a risk factor of 0.05 fatal cancers per sievert and 70 years exposures at 0.00001 mSv/year, the risk would be 5 x 10^-10.

Question 48	The accidental release of September 1994, and other accidental releases, were measured and included in the emissions data for the year in which the release occurred. The release in September 1994 was estimated to have produced a dose of 4.4 x 10^-4 mSv (0.044 mrem) to an individual 110 meters northwest of the NTLF.

Questions 49, 50, 51, 52 and 70	Regarding the issue of notification and warnings, the exposures and risks from the tritium released from the NTLF are so low, both in comparison to regulatory standards and to background exposures and other everyday risks, that there is no need to issue warnings. The annual exposure rate from tritium to someone who spends 24 hours a day, 365 days a year at the Lawrence Hall of Science, is about 1% of the public dose limit. Visitors and employees receive a fraction of that exposure. An hour at the Lawrence Hall of Science yields an exposure of 0.000015 millirem. By comparison, the natural background exposure rate in Berkeley is typically 0.03 millirem per hour -- 2,000 times greater than the average tritium exposure rate at the Lawrence Hall of Science. Also, one typically gets an added radiation dose of 0.1 millirem per hour spent in an airplane.

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