Following the discovery of very high levels of indoor radon associated with homes in northeastern Pennsylvania in December of 1984, the New Jersey Department of Environmental Protection
Trang 1Following the discovery of very high levels of indoor
radon associated with homes in northeastern Pennsylvania
in December of 1984, the New Jersey Department of
Environmental Protection was designated as the lead state
agency to address the potential for radon problems in New
Jersey The Department was charged with characterizing the
problem as it might exist in New Jersey and developing a
coordinated state response to the problem
Due to the potentially serious public health implications
of exposure to high levels of radon, the characterization of
New Jersey’s radon problem proceeded simultaneously with
the development of a program to educate the public
regard-ing radon and respond to residents’ needs for reliable radon
testing and radon remediation services
The current data indicates that New Jersey’s indoor radon
levels are among the highest known and that as many as 1 6
million homes in New Jersey may be at risk for radon
prob-lems Approximately one-third of homes studied thus far
test at or above the 4 picocuries per liter guidance level
rec-ommended by the United States Environmental Protection
Agency as a feasible goal for remediation of high
concentra-tions of indoor radon New Jersey’s response to this problem
is characterized by an integrated multi-agency approach and
the growth of firms providing reliable, regulated radon
test-ing and remediation services in the private sector
BACKGROUND
Radon-222 is the single gaseous isotope among the fourteen
principal decay products composing the 4n + 2 natural decay
series beginning with uranium-238 and terminating in
lead-206 The principal decay products of this series, their half
lives and principal associated emissions are given in Table 1.1
The atmospheric concentration of radon varies with
loca-tion, but is typically on the order of 0.1 picocuries per liter
(0.1 pCi/1) over land masses. 2 The average radon
concentra-tion indoors in the United States in not well known, but has
been estimated 3 to be in the range of 1 to 2 pCi/1
In December of 1984, previously unheard of levels of
radon were found in the home of an engineer, Stanley Watras
who worked at the Limerick Nuclear Generating Station and
lived in the Boyertown, Pennsylvania area. 4 The engineer
had been tripping portal monitor radiation alarms
indicat-ing radioactive material on his clothindicat-ing when leavindicat-ing work
Investigations conducted by the utility and the Pennsylvania
Department of Environmental Resources demonstrated that the radioactive material on the engineer’s clothing consisted
of the short lived decay products of radon-222 (Po-218 through Po-214 in Table 1) which had originated in his home
The concentrations of radon in the home ranged as high as 2,600 pCi/1 Subsequent investigations of the area around the discovery home demonstrated that elevated levels of indoor radon were common to the area and that the probable source
of the radon was the underlying gramitec rock formation known as the Reading Prong. 5
In May of 1985, an article 6 by Phillip Shabecoff appeared
in the New York Times reporting the Watras incident and noting that the Reading Prong ran in a northeasterly direc-tion out of Pennsylvania, through northern New Jersey and into New York The article also identified an increased risk
of lung cancer as a possible outcome of exposure to elevated levels of radon and its decay products Immediately, state agencies in New jersey, particularly the Department of Environmental Protection, were deluged by telephone and written requests for information on radon and assistance in obtaining radon testing services
Numerous studies have demonstrated the link between exposure to radon and its decay products in mining situa-tions and an increased risk of lung cancer. 7 Research efforts directed at establishing a link between residential exposure
to radon and its decay products have been far more limited in scope than the mining studies and the data derived from them are, at best, equivocal. 8 Studies underway now in Sweden, New Jersey, Pennsylvania and New England may have suf-ficient power to elucidate the residential exposure risks
Based primarily on the results of the mining studies he United States Environmental Protection Agency (EPA) has estimated that from 5,000 to 20,000 of the 130,000 lung cancer deaths annually in the United States are attributable
to radon. 9 EPA has further estimated that 1 to 5 persons in
100 exposed in their homes to radon at 4 pCi/1 over a 70 year lifetime, with 75% occupancy, will develop lung cancer. 10 As this risk is assumed to be linear, the risk at 200 pCi/1 under similar conditions of exposure is estimated to be from 44 to
77 in 100 These risks are two or more orders of magnitude greater than other environmental health risk levels which traditionally trigger actions to reduce them
It is important to note that radon itself is not believed
to be the major contributor to the possible development of lung cancer. 11 As radon is an inert gas there is not preference for deposition with the body When radon decays in ambient
Trang 2air, however, the decay products formed are metals which
initially associated with aggregates of water molecules in the
air These aggregates in turn adhere to airborne dust
parti-cles When inhaled, the dust particles, if of appropriate size,
will preferentially deposit in the tracheobronchial region of
the lung Radioactive decay of the short lived alpha emitting
progeny of radon will result in intense local irradiation of
the tissue underlying the deposited dust It has been
calcu-lated that the vast majority of the total radiation dose to the
lung tissue is due to the alpha decay of Po-218 and Po-214. 12
It is this localized irradiation which is believed to trigger the
development of lung cancer
In order to have a radon problem in a home, three
conditions are necessary First, the immediate parent of
radon-222, radium-226, must be present in the underlying
soil or rock to yield a radon source term Second, the home
must have penetrations in the basement or the ongrade slab
which provide entry points for the gas Third, the pressure
inside the home must be less than the surroundings so as to
provide a pressure differential to facilitate the entry of radon
into the home The first condition is geologic in origin and
is met in many locations in the United States The second
condition is a typical consequence of standard construction
techniques, particularly in homes where a peripheral channel
in the basement slab and an associated sump pump are used
to control wet basement problems Other points of entry for radon in a home include unsealed openings around piping,
at or below grade, cracks in the walls and floor, and porous concrete The third condition is met by a combination of fac-tors which include the normal stack effect associated with the house, combusting fuels for heating, and the use of appli-ances such as dryers which are vented to the outside These conditions are met in homes in much of the northern portion
of New Jersey, and to a lesser extent, in specific locations in southern New Jersey
THE NEW JERSEY RADON PROGRAM
Shortly after the Watras incident, Pennsylvania Department
of Environmental Resources personnel contacted their coun-terparts in the New Jersey Department of Environmental Protection (DEP) to advise them of the problem In the beginning months of 1985, DEP staff working with the New Jersey Department of Health began to assess New Jersey’s potential for a radon problem and develop a response to it
TABLE 1 The Uranium Decay Series
Nuclide Half Life
Alpha Energy (MeV)
Beta Energy (MeV)
Gamma Energy (MeV)
0.24 (7%) 0.30 (9%) 0.35 (37%)
0.77 (5%) 1.12 (15%) 1.24 (6%) 1.38 (5%) 1.76 (15%) 2.20 (5%)
Trang 3A review of available data demonstrated that New Jersey
had significant potential for a random problem and that it was
likely that the problem would not be confined solely to New
Jersey’s section of the Reading Prong The National Uranium
Resource Evaluation data 13 indicated that significantly
ele-vated levels of uranium, and hence radon, could exist both
north and south of the Reading Prong Outside the Reading
Prong elevated levels of uranium were associated with
lime-stone, shales and clays Additionally, a literature survey 14
pre-viously conducted by the New Jersey Geological Survey had
found reports of more than 100 locations of radioactive
min-erals in New Jersey, many well outside the Reading Prong
Early State planning activities focused on the need to
edu-cate the public with regard to radon and develop legislation
providing specific programmatic mandates and associated
funding
In January of 1986, Governor Kean signed a bill providing
$3.2 million to begin New Jersey’s radon program A second
bill, signed into law in August of 1986, provided an additional
$1 million, mandated the development of certification for
testing and remediation firms and also guaranteed the
confi-dentiality of random test results The major components of the
radon program developed using this funding include:
Radon Information Program
By December 1, 1987 the DEP’s toll free information line
had received and responded to more than 52,000 telephone
inquiries As a result of these inquiries more than 20,000
informational packages have been mailed out to New Jersey
residents As the knowledge of radon has grown among New
Jersey residents so has the sophistication and complexity of
the telephone inquires Currently, a great deal of staff time is
spent providing telephone consultation to residents who wish
to discuss the interpretation of their radon test results or who
wish an in depth discussion of the relative effectiveness of
alternative remediation methods The Department of Health
also provides telephone consultation on specific health issues
related to radon The Department of Environmental Protection
and the Department of Health provide speakers for groups
interested in learning about radon By December 1, 1987,
more than 250 presentations have been made to interested
groups Also, a slide presentation on radon was developed for
use with general audiences throughout the state This slide
presentation is currently being expanded and re-packaged in
a video tape format for distribution to local libraries
Statewide Study of Radon
In 1986 the DEP contracted with the environmental
engi-neering firm of Camp, Dresser and McKee, Inc (CDM) to
perform a $1.3 million statewide study of radon The
spe-cific tasks within this study are to:
a Map areas of potential radon problems using all available geographic, geologic, radiometric and demographic data
b Develop a model to predict indoor radon exposure statewide
c Test the model developed in Task b using a sampling program including approximately 6,000 structures statewide
residents of the dangers posed by exposure to radon gas
collected in the study
f Propose and prioritize further research suggested
by the statewide study
g Provide a summary report containing the most salient findings of the study for presentation to the legislature and the public
Epidemiologic Study
The New Jersey Department of Health is conducting a case-control study of female lung cancer victims and case-controls
in New Jersey The primary aim of this study is to deter-mine whether or not the lung cancer risk estimates derived from studies of uranium and other miners are applicable to individuals exposed to radon in their homes The DEP has supported this effort by performing radon tests in more than
800 homes of cases and controls
Confirmatory Monitoring
As the radon program was being planned the spring of
1985, it was recognized that as many as 1.6 million New Jersey homes might be at risk for elevated levels of indoor radon It was clearly outside the resources of state govern-ment to offer free testing to each potentially affected house-hold Preliminary cost analyses of no-charge testing for 1.6 million homes indicated a cost ranging from $40 million
to $200 million A conscious decision was therefore made
to allow, and even assist in, the development of a radon test-ing industry in the private sector It was also recognized however, that the unregulated growth of such a new industry carried with it a significant potential for error and for con-sumer fraud Therefore, to protect New Jersey citizens, it was decided to offer confirmatory testing to those residents who had commercial radon tests performed in their homes and obtained radon concentrations equal to or greater than the 4 pCi/1 guidance level at which the EPA recommends consideration of remedial action
Certification of Radon Testing and Mitigation Firms
The DEP is in the process of promulgating regulations for the mandatory certification of radon testing and mitigation firms In the interim, a voluntary certification program has been implemented This program currently enrolls 58 radon testing firms and 24 radon mitigation firms Respectively, these total represent about one-half the number of firms applying for enrollment in the two programs The firms are required to document specific expertise, refrain from scare-tactic advertising, participate in the EPA Radon Proficiency
Trang 4Valley & Ridge
Average = 8.2 pCi/l
N = 634
Reading Prong
Average = 8.1 pCi/l
N = 1443
Pledmont
Average = 4.2 pCi/l
N = 2169
Inner Coastal Plain
Average = 2.5 pCi/l
N = 745
Outer Coastal Plain
Average = 1.8 pCi/l
N = 297
State
Average = 5.4 pCi/l
N = 5288
N = Number of Homes Tested
BERGEN
HUDSON ESSEX
UNION
MERCER
HUNTERDON
MIDDLESEX SOMERSET
MONMOUTH
GLOUCESTER
SALEM
BURLINGTON
CAMDEN
ATLANTIC
CUMBERLAND
CAPE MAY
WARREN
SUSSEX
PASSAIC
MORRIS
OCEAN
FIGURE 1 New Jersey Department of Environmental Protection, preliminary report on statewide radon study.
Trang 5Measurement Program 15 and meet other quality assurance
objectives
Follow-Up Testing
As residents tested for radon and remediated their radon
prob-lems, they requested access to reliable, unbiased radon
test-ing which would enable them to determine whether or not the
remediation methods employed were effective In response
to these requests, DEP began a program of testing
remedi-ated homes at no charge to the owner As of December 1,
1987, a total of 774 homeowners had availed themselves of
this service In general, these follow up tests document the
effectiveness of the remedial actions employed When they
do not, DEP staff advise both the homeowner and the
con-tractor and then assist in working out a mutually acceptable
solution
Radon Cluster Identification
In March of 1986, through the Confirmatory Monitoring
program, the DEP became aware of several homes in Clinton,
New Jersey which had unusually high concentrations of
indoor radon The DEP and Department of Health worked
closely with municipal and county officials to identify other homes in the area which also had very high radon levels
In one neighborhood in Clinton, 105 homes were found to
be above 4 pCi/1 Forty of the 105 homes were found to be above 200 pCi/1 and five of the forty homes were found to
be above 1000 pCi/1
Through the cooperation of government at all levels, what could have been a disaster for the community became
a solvable problem The DEP, the Department of Health and local officials provided information on radon and access to testing for those judged to be at significant risk The munici-pal government participated fully in all the decision making with regard to the State activities in Clinton and offered access to random testing at reduced cost to all residents
The EPA was invited to extend their radon remediation research program begun in Boyertown, Pennsylvania into New Jersey EPA remediated ten of the highest radon level homes at no cost to the occupants and provided detailed specifications for the remediation of twenty more homes
The successful remedial techniques developed in Clinton have been adapted to hundreds of other homes in northern New Jersey
Due to the experience of finding a clustering of high radon level homes in Clinton, the DEP and Department of Health
TABLE 2 Initial results statewide scientific study of radon, home radon testing results by county
County
Average Radon concentration (pCi/1)
Median radon concentration (pCi/1) Number ofsamples (pCi/1)Range
Trang 6TABLE 3 Summary of initial results for radon testing in non-residential buildings
Province buildingType of of buildingsNumber
Average radon concentration (PCI/L) (PCI/L)Range
* Becomes 2.4 if the single 192 pCi/1 value is excluded
** Becomes 2.3 if the single 192 pCi/1 value is excluded
developed a program of responding to reports of high radon
level homes (i.e., homes which are confirmed to have radon
concentrations at or above 200 pCi/1) A report of such a
home triggers the Radon Cluster Identification Protocol under
which the local governing body is advised of the confirmation
of such a home in their community and their cooperation in
sponsoring a public information meeting solicited Following
the public meeting, DEP staff test for radon in homes in the
area around the “discovery” home If this survey yields one or
more additional homes with radon concentrations at or above
200 pCi/1, the survey is repeated in the area around these
homes This process is repeated until all homes in the area
with radon levels at or above 200 pCi/1 have been identified
The specific concern with homes having this level of exposure
to radon is that the lung cancer risk associated with a lifetime
of such exposure at 75% occupancy is estimated by EPA to be
in the range of 44 to 77 in 100 EPA has recommended that
individuals finding such levels in their homes remediate them
within several weeks or temporarily relocate until such
reme-diation can be accomplished. 16
Radon Remediation Research
In addition to supporting EPA’s remediation research in
Clinton, DEP is also cooperating with the EPA on its House
Evaluation Program under which fifteen New Jersey homes,
predominantly in the Piedmont region, are undergoing
in-depth evaluation of their radon problems at no charge to the homeowner This program is expected to yield important information on how specific house characteristics and weather patterns influence the radon levels in homes Additionally, the DEP has contributed $185,000 in funding to a radon reme-diation research program being undertaken cooperatively by EPA, DEP, Lawrence Berkeley Laboratory of the University of California, Oak Ridge Associated Universities and Princeton University The primary aim of this research is to fine tune existing remediation methods so as to make them easier to implement and more cost effective
Radon Database Development
Radon testing firms participating in the voluntary certifica-tion program submit radon testing data they have collected summarized by municipality name and zip code This data is entered into a computerized database by DEP and used as an aid to decision making
Radon in Non-Residential Structures
The DEP issued interim guidance for the testing of non-residential structures such as schools, hospitals, government buildings and businesses in 1986 The Department of Health issued health related guidance for such structures in November
of 1987
Trang 7Radon Registry
In order to maintain an open channel of communication
with individuals who have already been exposed to elevated
levels of radon, the Department of Health developed a
Radon Registry for New Jersey residents Participants in the
survey are advised of the most current information regarding
radon and lung cancer via a newsletter Over 200 New Jersey
residents are participating in the registry
Low Interest Loans
In comparison to the equity value of most New Jersey homes,
the cost of remediating a significant radon problem (i.e., initial
test results in excess of 20 pCi/1) is relatively small, currently
averaging about $1,200 There are, however, some New Jersey
resident would find a single expenditure of this amount quite
burdensome In response to this potential problem, the New
Jersey Housing and Mortgage Finance Agency developed a
low interest loan program for affected residents There are no
income requirements associated with the program and the rate
is at or below the best available loan rates, currently 7.875%
For residents with severe radon problems (e.g., radon levels at
or above 200 pCi/1) an expedited loan application processing
procedure is available within three working days
Additional Research
External to the funding provided in the radon legislation, the DEP’s office of Science and Research and the New Jersey Geological Survey are conducting research to deter-mine radon in water levels in selected northern New Jersey aquifers
ASSESSMENT
The various state radon efforts provide a significant body
of data from which an assessment of New Jersey’s radon problem can be drawn
Preliminary radon concentration data from homes tested as part of the statewide study are listed by country in Table 2 The same data is organized by physiographic province in Figure 1 These data are almost exclusively for single family homes
Data on the testing on non-residential structures obtained
as part of the statewide study is summarized in Table 3 All the radon test data presented here were obtained using charcoal canisters 17 exposed for a period of four days under the EPA recommended protocols. 18 All testing was conducted during the period from November 15, 1986 through March 15, 1987 when closed house conditions
RADON CONCENTRATION (PCI/L)
<.5 1–.5–
.9 15.9 31.9 63.9 127.9 2561.9 3.9 7.9
2– 4– 8– 16– 32– 64– 128– >256
7.4
17.2 21.9 21
13.9 13.1
3.5 1.3 0.4 0.2 0.1 0
10 20 30 40
50
FREQUENCY %
TOTAL MEASUREMENTS = 13, 287
FIGURE 2 Commercial firm radon test data distribution, basement measurements.
Trang 8RADON CONCENTRATION (PCI/L)
<.5 5– 1–
.9 1.9 3.9 7.9 15.9 31.9 63.9 127.9 256
2– 4– 8– 16– 32– 64– 128– >256
16.33
32.91 23.93
14.65
6.92 3.49 1.00 0.02 0.21 0.02 0.02 0
10 20 30 40
50
FREQUENCY %
TOTAL MEASUREMENTS = 6, 101
FIGURE 3 Commercial firm radon test distribution, ground level measurements.
RADON CONCENTRATION (PCI/L)
<4 4– 8–
7 15 31 63 127 255 511 1023
16– 32– 64– 128– 256– 512– >1024
13.6
26.4 27.3
17.8 9.1 3.7 1.5 0.4 0.1 0.1 0
10 20 30 40
50
FREQUENCY %
TOTAL HOMES = 4, 107
FIGURE 4 Confirmatory monitoring data distribution.
Trang 9generally prevail in New Jersey homes In accordance with
the EPA protocols, the canisters were placed in the level of
the home closed to the underlying soil Unless individuals
live at the same level as the tests were made, this testing
method tends to overestimate the average concentrations
actually breathed by residents by a factor of about two
Most participants in the study lived one floor in the home above the testing level An exception to the two fold reduc-tion in radon concentrareduc-tion with a one floor increase in dis-tance from the underlying soil occurs in homes with forced air heat Openings in duct work in the basement make pos-sible the circulation of basement air throughout the home
RADON LEVELS IN WATER
(PCI/L)
0 10 20 30 40
50
FREQUENCY %
TOTAL WELLS = 872
1,000
1,000-5,000
5,000-10,000
10,000-50,000
50,000-100,000
>100,000
0.3 1.6
11.5 9.2
47.6
27.0
2.9
FIGURE 5 Radon in domestic well water obtained in the confirmatory monitoring program.
TABLE 4 Radon cluster identification program data distribution Location ⬍4 pCi/1 4–19pCi/1 20–199 pCi/1 200 pCi/1 N
Trang 10BERGEN PASSAIC
MORRIS
UNION ESSEX
MONMOUTH
SALEM GLOUCESTER
CAMDEN BURLINGTON
Tier 1-Test as soon as practical Tier 2- Test within one year Tier 3 - Test if concerned
New Jersey Department of Environmental Protection Testing Recommendation
WARREN
HUNTERDON
MIDDLESEX
MERCER
ATLANTIC
CAPE MAY CUMBERLAND
SUSSEX
SOMERSET
OCEAN
HUDSON
FIGURE 6 New Jersey Department for Environmental Protection, preliminary
recommenda-tions for radon testing.
Under these conditions, radon levels on upper floors have
been observed to equal or, in a few cases, even surpass
basement level radon concentrations
It should be noted that the statewide study was designed
to locate areas of potential radon problems and hence the
area sampling density was varied depending on anticipated results Approximately 20% of the total number of samples were set aside for use later in the sampling period to better define potential problem areas identified in the initial sam-pling Hence, the sampling is somewhat biased in terms of