1047 RADON 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 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 clothing when leaving 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 C018_002_r03.indd 1047C018_002_r03.indd 1047 11/18/2005 11:04:57 AM11/18/2005 11:04:57 AM © 2006 by Taylor & Francis Group, LLC 1048 RADON air, 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) U-238 4.5 × 10 9 y 4.1−4.2 — — Th-234 24 d — 0.06−0.2 0.09 (6%) Pa-234 m 1.2 m — 2.3 — U-234 2.5 × 10 5 y 4.7−4.8 — — Th-230 8.0 × 10 4 y 4.6–4.7 — — Ra-226 1600 y 4.6−4.8 — — Rn-222 3.8 d 5.5 — Po-218 3.05 m 6.0 — — Pb-214 26.8m — 0.7–1.0 0.08 (17%) 0.24 (7%) 0.30 (9%) 0.35 (37%) Bi-214 19.7 m — 0.4−3.3 0.61 (45%) 0.77 (5%) 1.12 (15%) 1.24 (6%) 1.38 (5%) 1.76 (15%) 2.20 (5%) Po-214 1.5 × 10 −4 s 7.7 — — Pb-210 22 y — 0.1 — Bi-210 5.0 d — 1.2 — Po-210 138 d 5.3 — — Pb-210 Stable — — — C018_002_r03.indd 1048C018_002_r03.indd 1048 11/18/2005 11:04:57 AM11/18/2005 11:04:57 AM © 2006 by Taylor & Francis Group, LLC RADON 1049 A 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. d. Perform a risk assessment for New Jersey residents of the dangers posed by exposure to radon gas. e. Develop a computerized database for data 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 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 C018_002_r03.indd 1049C018_002_r03.indd 1049 11/18/2005 11:04:57 AM11/18/2005 11:04:57 AM © 2006 by Taylor & Francis Group, LLC 1050 RADON Valley & 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. C018_002_r03.indd 1050C018_002_r03.indd 1050 11/18/2005 11:04:57 AM11/18/2005 11:04:57 AM © 2006 by Taylor & Francis Group, LLC RADON 1051 Measurement 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 of samples Range (pCi/1) Atlantic 0.75 0.60 23 0.4−3 Bergen 1.85 1.14 234 0.3–43 Burlington 1.80 1.20 245 0.3–28 Camden 2.27 1.55 66 0.3–9 Cape May 1.43 0.50 18 0.4–8 Cumberland 1.79 1.10 29 03–12 Essex 1.23 0.90 116 0.4–5 Gloucester 3.12 1.10 27 0.4–34 Hudson 2.47 1.00 29 0.4–34 Hunterdon 6.88 3.40 732 0.1–112 Mercer 4.46 1.80 371 0.1–83 Middlesex 2.16 1.10 327 0.2–28 Monmouth 2.68 1.30 305 0.3–38 Morris 5.13 2.30 625 0.3–121 Ocean 0.95 0.70 35 0.3–2 Passaic 3.67 1.70 223 0.3–35 Salem 2.49 1.40 78 0.4–36 Somerset 5.20 2.30 469 0.3–91 Sussex 6.47 3.90 620 0.2–127 Union 2.32 1.30 183 0.3–22 Warren 11.83 6.20 603 0.4–246 Statewide 5.4 2.2 5288 0.1–246 C018_002_r03.indd 1051C018_002_r03.indd 1051 11/18/2005 11:04:58 AM11/18/2005 11:04:58 AM © 2006 by Taylor & Francis Group, LLC 1052 RADON TABLE 3 Summary of initial results for radon testing in non-residential buildings Province Type of building Number of buildings Average radon concentration (PCI/L) Range (PCI/L) Valley & Ridge School 8 1.5 1.4–2.9 Hospital 1 0.7 0.7 Municipal 10 2.4 0.7–5.8 Highlands School 12 2.3 0.3–6.9 Hospital 5 1.6 0.4–4.8 Municipal 10 4.4 0.3–36.2 Piedmont School 18 1.7 0.3–4.3 Hospital 20 1.4 0.3–5.7 Municipal 21 11.4* 0.4–192 Inner Coastal Plain School 14 1.6 0.3–4.7 Hospital 7 0.6 0.4–0.9 Municipal 10 1.9 0.3–6.1 Outer Coastal Plain School 11 1.4 0.3–5.6 Hospital 8 0.7 0.7–1.1 Municipal 10 0.6 0.3–1.1 Totals School 63 1.7 0.3–6.9 Hospital 41 1.1 0.3–5.7 Municipal 61 5.5 ** 0.3–192 All 165 2.9 0.3–192 * 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. C018_002_r03.indd 1052C018_002_r03.indd 1052 11/18/2005 11:04:58 AM11/18/2005 11:04:58 AM © 2006 by Taylor & Francis Group, LLC RADON 1053 Radon 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 2567.91.9 3.9 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. C018_002_r03.indd 1053C018_002_r03.indd 1053 11/18/2005 11:04:58 AM11/18/2005 11:04:58 AM © 2006 by Taylor & Francis Group, LLC 1054 RADON RADON CONCENTRATION (PCI/L) <.5 1–.5– .9 15.9 31.9 63.9 127.9 2567.91.9 3.9 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 8–4– 7 127 255 511 10236315 31 16– 32– 64– 128– 256– 512– >1024 13.6 26.4 27.3 17.8 9.1 3.7 1.5 0.1 0.4 0.1 0 10 20 30 40 50 FREQUENCY % TOTAL HOMES = 4, 107 FIGURE 4 Confirmatory monitoring data distribution. C018_002_r03.indd 1054C018_002_r03.indd 1054 11/18/2005 11:04:58 AM11/18/2005 11:04:58 AM © 2006 by Taylor & Francis Group, LLC RADON 1055 generally 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 concentration 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 <100 100– 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 Ͻ4 pCi/1 4–19pCi/1 20–199 pCi/1 200 pCi/1 N Clinton 4 20 54 41 119 Montgomery 5 6 3 1 15 Ewing 1 8 22 18 1 49 Ewing 2 10 8 10 3 31 Princeton 12 22 12 1 47 Bethlehem 16 26 16 7 65 Bernardsville 6 20 17 4 47 Mansfield 5 10 25 3 43 Hampton 0 5 7 2 14 TOTALS 66 138 162 63 429 % OF TOTALS 15.3 32.3 37.7 14.7 100 C018_002_r03.indd 1055C018_002_r03.indd 1055 11/18/2005 11:04:58 AM11/18/2005 11:04:58 AM © 2006 by Taylor & Francis Group, LLC 1056 RADON BERGEN 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 C018_002_r03.indd 1056C018_002_r03.indd 1056 11/18/2005 11:04:58 AM11/18/2005 11:04:58 AM © 2006 by Taylor & Francis Group, LLC [...]... 37–38 9 United States Environmental Protection Agency, A Citizen’s Guide to Radon, EPA document OPA-86–004, August 1984, p 1 10 Ibid., p 9 11 National Council on Radiation Protection and Measurements, Evaluation of Occupational and Environmental Exposure to Radon and Radon Daughters in the United States, NCRP Report No 78, Bethesda, MD, 1984, p 19 12 Ibid, pp 42–56 13 Popper G.H.P and T.S Martin, “National... Environmental Protection Agency, A Citizen’s Guide to Radon, EPA document OPA-86–004, August 1984, p 11 17 Andreas C George, “Passive, Integrated Measurement of Indoor Radon Using Activated Carbon”, Health Physics vol 46 no 4, pp 867–872, 1984 18 United States Environmental Protection Agency, Interim Indoor Radon and Radon Decay Protocols, EPA document EPA 520/1–86–04, April 1986 19 United States Environmental. .. Protection and Measurements, Exposures from the Uranium Series with Emphasis on Radon and Its Daughters, NCRP Report No 77, Bethesda, MD 1984, pp 2 and 9–11 2 Ibid p 25 3 Nero A.V., M.B Schwekr, W.W Nazaroff and K.L Revzan, “Distribution of Airborne Rn-222 Concentrations in U.A Homes” Science Vol 234, November 1986, pp 992–996 4 Margaret Reilley, untitled feature article, Newsletter, Conference of Radiation... Removal of Radon From Household Water, EPA document EPA-87–011, September 1987, pp 1–2 RICHARD T DEWLING Dewling Associates CONCLUSIONS Data obtained from the statewide study of radon, through the voluntary certification program for radon testing firms, and from the radon cluster identification program clearly DONALD A DEIESO Research Cottrell Co GERALD P NICHOLLS New Jersey Department of Environmental. .. Pennsylvania and New Jersey”, Berrdix Field Engineering Corporation Report PGTIF-1243 (83) for the U.S Department of Energy (1983) 14 Christy Bell, Radioactive Mineral Occurrences in New Jersey, New Jersey Geological Survey Open File Report No 83–5, Trenton, NJ, 1985 15 United States Environmental Protection Agency, Implementation Strategy for the Radon/ Radon Progeny Measurement Proficiency Evaluation and Quality... only source of risk as drinking water containing radon is not considered a health threat.19 Through the Radon Cluster Identification Program, a number of high level radon homes have been identified The data derived from the program is presented in Table 4 As indicated, approximately 85% of the homes tested as part of this program have radon levels at or above 4 pCi/1 Approximately 15% of the homes... above 4 pCi/1 Approximately 15% of the homes tested had a radon concentration of 200 pCi/1 or greater Thus, identification of a high level home and subsequent sampling of surrounding homes is a means of identifying radon problem prone areas Based on the available data, the DEP made recommendations to residents regarding radon testing in September of 1987 These recommendations are summarized in Figure.. .RADON problem prone areas, and the values somewhat overestimate the true population based averages A total of 35.0% of the homes in the study were found to have radon levels at or above the EPA’s 4pCi/1 guidance level This is in very good agreement with the 32.5% of the homes tested by commercial firms participating in the voluntary certification program This data, which is approximately log-normally... Shabecoff, “Radiation Gas in Soil Raises Concern in Three State Areas”, New York Times, 19 May 1986, p 1 7 Thomas D.C., K.G McNeill and C Dougherty “Estimates of Lifetime Lung Cancer Risks Resulting from Rn Progeny Exposure” Health Physics vol 45 no 5, November 1985, pp 825–846 8 Judith Klotz “Estimating Lung Cancer Risks of Indoor Radon: Applications for Prevention” Indoor Radon Proceedings of an... levels of homes are shown in Figure 3 Approximately 11.7% of these results are equal to or exceed 4 pCi/1 Data collected as part of the confirmatory monitoring program are shown in Figures 4 and 5 Figure 4 shows that, in 86.4% of the homes tested, the DEP measurements corroborated the commercial testing result to the extent that both indicated a radon concentration at 4 pCi/1 or greater In the 13.6% of . 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. 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. 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