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Agenda - 05-01-2001-10a
ORANGE COUNTY BOARD OF COMMISSIONERS ACTION AGENDA ITEM ABSTRACT Meeting Date: May 1, 2001 Action Agenda Item No... ,I~p-a SUBJECT: USGS Ground Water Resource Investigation / Report of the Water Resources Cammittee DEPARTMENT: ERCD PUBLIC HEARING: (Y/N) No ATTACHMENT(S): USGS Ground Water Resource Investigation (under separate cover) Report of the Water Resources Committee Radon Fact Sheet --.- INFORMATION CONTACT: David Stancil, 245-2590 Rosemary Summers, 245-2412 TELEPHONE NUMBERS: Hillsborough 732-8181 Chapel Hill 968-4501 Durham fi88-7331 Mebane 336-227-2031 PURPOSE: To receive a presentation of the U.S. Geological Survey (USGS) cooperative Ground Water Resource Investigation and consider the Report of the Water Resources Committee. BACKGROUND: The Water Resources Committee began work in late 1992 to evaluate the County's ground water quantity and quality. Over the last eight years, the Committee has produced an Interim Report, worked with the USGS on a report on ground water recharge rates, and over the last few years monitored and evaluated the progress of the recently completed, three-year Ground Water Resource Investigation. Both USGS projects were cooperative ventures with the County on a 50-50 cost-share arrangement. During this timeframe, the Committee also oversaw the initiation of a program to begin identifying all new well sites with Global Positioning System (GPS) receivers, for incorporation into the County's GIS system. . Over 1200 wells have now been located and entered into the Comprehensive Resource database. In addition, the County instituted a Ground Water Center in 1996 to provide assistance to citizens with questions or concerns about ground water. The attached USGS report, Investi ation of Ground-Water Availabili and uali in Oran e County. North Carolina has now been published. The report includes an evaluation of the County's hydrologic setting and ground water availability, including analyses and mapping that identifies "contours" of the County based on well yields, using the database of well records. The report also conducted a comprehensive well-sampling of 51 wells across the County, weighted by geographic distribution and underlying hydrogeology. Ground water quality in the County was generally quite good, with trace elements detected infrequently or at levels less than State drinking water standards. However, the level of water- borne radon in some portions of the County was worthy of note. Wells tested in a southern- central portion of the County generally west-southwest of Carrboro revealed higher than normal readings. ,This area conforms generally to an underlying granitic pluton, the likely source of the high radon readings. In all, sixty-seven percent of the radon activities measured in the County exceeded the USEPA proposed maximum contaminant level. However, the. evaluation of radon activity is complicated by the difficulty in measuring the aerated radon gas. While elevated and worthy of note, radon activity in Orange County was lower than that measured in Guilford County three years ago. Additional information on water-borne radon, how to test radon activity, and the potential issues are provided in the attached fact sheaf from the Environmental Health Department. Among the other water quality findings was the incidence of some wells with an elevated level of the naturally-occurring trace metals iron and manganese, which commonly cause staining of plumbing fixtures and other nuisance problems. The Report of the Water Resources Committee attempts to pull together the many findings of the last several years, and assess the implications of the recent USGS report. On pages 18-19 of the report are a list of 10 findings by the Committee, followed by six recommendations offered for further consideration by the Commission for the Environment and the Board of Commissioners. These recommendations include: • The need for further research into the radon results in south-central Orange, perhaps in conjunction with Chatham County. • An ongoing ground water monitoring program to evaluate changes over time in areas seeing new development • Consideration for a comprehensive water budget approach to link surface and ground water planning • Review of sustainable ground water yields and land use policies in some watersheds of the County, based on the available information about ground, water recharge rates • 'A requirement that new subdivisions locate not only septic sites but also well sites prior to subdivision approval • The importance of water conservation for ground ,water based systems - Note: Color v®rsions of maps in the Committee report maybe found in the accompanying USGS published report. The Board of Commissioners' adapted Water Resource Quantity and Quality goal would have the Commission for the Environment assume the mantle of the ground water project, in consultation with the Water Resources Committee. Using the work of the Water Resources Committee, the Commission for the Environment is to evaluate the implications of these findings and report to the Board of Commissioners early next year on suggested policy changes to address these issues. The Board of Health may be interested in examining radon findings. FINANCIAL IMPACT: There is no financial impact associated with receiving these reports. The Environmental Health Division is incumng costs far purchase of radon test kits (air test kits are $5 each and water test kits $10 each). RECOMMENDATION(S): The Manager recommends that the Board receive the report as information at this time, and schedule the ,items for discussion at a future worksession, before referring the reports to the Board of Health and the Commission for the Environment for further evaluation. Report of the Water Resources Committee County of Orange, NC Adopted March 27, 2001 4 Water Resources Committee Dan Cox, Chair Dr. Charles Daniel Stephen Dear Dr. Alice Gordon (BOCC Liaison) Tom Grizzle Terry Hackett Margaret Holton Diana Phillips Rick Fratt (Commission for the Environment liaison) John Rogers Bob Rubin Wes Scarlett Thanks to: Stephen Dear, Pat Davis, Nancy Mueller, Sharlene Pilkey, Phil Post, Larry Rogers, Ed Holland, Morris Shambley, Meg Scully, Lisa Carmichael, Gail Hughes, Ron Holdway, Milton Heath and Ray Sparrow for their assistance along the way. Staff: David Stancil, Environment and Resource Conservation Director; Paul Thames, County Engineer; Tom Konsler, Environmental Health Supervisor; Craven, Hudson, Cooperative Extension Service, Margaret Jones, Resource Conservation Technician 5 Table of Contents I. Project Activities .................................................................................. 1 TI. Charge to the WRC / BOCC Goal ....................................................... 4 TTT. What We Have Learned: Water Quality ............................................. 5 A. Field Parameters B. Major Ions C. Nutrients D. Total Dissolved Solids E. Metals & Trace Elements F. Organic Compounds G, Radon H. Susceptibility to Contamination IV. What We Have Learned: Water Quantity .......................................... 14 A. 1996- Recharge Rate Study B. 2001 Ground Water Resource Investigation C. Other Information Provided to the Committee V. Summary of Findings ......................................................................... 18 VI. Recommendations and Further Research Needs .............................. 20 VIZ. Appendices ..........................................................................................24 6 Orange County Water Resources Project c% Environment and Resource Conservation Department 306 Revere Road PO Box 8181 Hillsborough, NC 27278-8181 Dr. Steve Halkiotis, Chair Board of County Commissioners PO Box 8181 Hillsborough, NC 27278 Dear Dr. Halkiotis: I wish to thank the Orange County Board of Commissioners for the creation of this Water Resources Committee, and for the opportunity to serve as chairman. It is the hope of the committee that the information obtained from the USGS investigations will be used in the comprehensive planning process to assist the citizens of Orange County in achieving a sustainable use of our groundwater resources. To focus on a few .key points that should be of general interest, I offer the following comments: 1. Let us put to rest the myths of an underground river or lake from which our groundwater resource is obtained. The ground water in Orange County is found surrounding the particles of sail and weathered rock and in cracks in the underlying rock formations. The water-saturated depth varies seasonally, and with multi-year wet or dry conditions. 2. Each well is surrounded by a "recharge area" that varies depending upon geology, topology, ~,nd surface ,use. Changes in land uses ,from forest and fields generally result in greater compaction of the soil and allow lower recharge rates of rain and snowfall to the groundwater. Storm water runoff retention structures can improve the recharge where it has •been changed by impervious surfaces and compaction caused by roads, driveways, and lawns. These recharge areas also need to be protected from contamination by petroleum products, chemicals, fertilizers and, septic tanks. Once contaminated, it may be impossible to clean up in one's lifetime - or more. 3. We need to be mindful about the use and the potential of over-use of groundwater. It is not only needed for the life and well being of people, but also sustains the flow of water in our streams, creeks, and rivers - so essential to the sustainability of all of our natural environment. 4. It is often observed that the rated "yield" of a well diminishes after a few years of use. One reason -for this is pumping the well level down, below the intercepted rock fracture that provides water to the well. Repeated exposure of the fracture or crack to air can allow mineral deposition or growth of naturally occurring bacteria or algae to seal up the area and reduce flow of water into the well. Pump burn-out may also be caused by pumping in excess of the in-flow rate long enough to lower the level of water below the pump. Pumping rates and pump depth in the well must be considered for long .term sustainable use. Some repair methods are available where reduction in yield due to fracture exposure has occurred. 5. Finally, the committee recommends that the county institute a long- term program of well measurements that can provide information as to the effects of land use changes and climatic changes on the availability of ground water. The USGS data gives us a base line of information that can be useful into the future with the addition of a good monitoring program. Sincerely, Donald N. Cox, Chairman Water Resources Committee S I. Project Activities Since its formation in 1992, the Water Resources Committee (or WRC for short) has worked steadily to learn more about the County's groundwater resources, with the eventual intention of helping the County coordinate and integrate planning for surface water and ground water. Because of the long-range, scientific nature of this project and the need far substantial research, much of the Committee's time and energy has been engaged in review and discussion of the major products of the report - a pair of published ground water studies from the U.S. Geological Survey (USGS) on the County's ground water, and a related map report also published by USGS: 1. Ground~Water Rechar a to the Re olith-Fractured C stalline Rock A uifer stem in Oranae County, North Carolina, by Dr. Charles C. Daniel III. This report was a pilot project recharge rate study performed by USGS in collaboration with the County, published in October 1996, 2. Susceptibility of Ground Water to_ .Surface and Shallow Sources of Contamination, Orange County. North Caroln_ar by Silvia Terziotti and Jo Leslie Fimers. Prepared in conjunction with #3 below, this 1999 map report ,illustrates the areas of the County that are most susceptible to ground water contamination. 3. Investi ation of Ground-Water Availabili and uali in Oran a Coun North Carolina, by William L. Cunningham and Dr. Charles C. Daniel III. This, ,the primary project of .the Water Resources effort, was athree-year ground ,water resource investigation, also conducted by USGS and the County on a cost-share basis. The review and discussion of the above reports commanded the majority of the Committee's time. However, over the seven years of the project a number of other activities were also performed. Several. key milestones in the Water Resources Project are outlined below: ~ au~e i -Key r~iies>cones r , Ma , 1992 First meetin of the Water Resources Committee March, 1993 Interim re ort to the Board of Commissioners November, 1993 Committee forms two subcommittees (Public • Information and Public Education, or PIPE, and Technical Advisory Subcommittee, or TAS) to meet between Committee meetin s March, 1994 Informational brochure ("Addressing Ground Water Concerns in Orange County") created and mailed to 1100 households on master mailin list A ril, 1994 en house held at Homestead Center May, 1994 Cooperative agreement signed with U.S. Geological Survey (C7SGS) for pilot project ground water anal sis of rechar a rates in Count by watershed September, 1995 Committee sponsors and helps conduct lead and nitrate water screenin in Hillsborou h. May, 1996 Senior essay thesis entitled "Statistical Analysis of Data from Water Supply Wells in Orange County" is produced by UNC graduate student, working with Coun and USGS. July 1996 Ground Water Center opens, housed in Soil and Water office. First meeting of Ground Water Inter- . departmental Team to coordinate efforts among Environmental Health, Soil and Water, Cooperative Extension, Count En ineer and Plannin . August 1996 _ Global Positioning System equipment purchased for the.location of all new wells. Part-time Water Resources Technician hired, works with Environmental Health to locate and map new wells. Work begins on a comprehensive Ground Water Database, to develop GIS coverages for all available ound water-related data November, 1996 USGS pilot project on Recharge Rates is published and presented to BOCC. Ground water model urchased for demonstration and ublic outreach. April, 1997 Committee sponsors and staffs ground water station at Earthwalk, an environmental event held annually at Eno River State park. Station includes electronic ground water quiz and demonstration of ground water model. Station continues annually next two ' ears. April, 1997 County applies for and is designated a Ground " Water Guardian Community, one of 54 nationwide, b The Groundwater Foundation Tune; 1997 County agrees to cooperative agreement for full Ground Water Resource Investi ation October, 1999 Review of Ground Water Susceptibility mapping ro"ect August, 2000 Commission for the Environment creates Water Committee to be in transition of Committee efforts October, 2000 Committee be ins discussion of final re ort February, 2001 Investigation of Ground Water Availability and uali re art com feted and ublished 1p Of~ these milestones, the following are of particular importance for additional elaboration: • 1993 Interim Report After nine months. of, assessing the available knowledge on ground water and the apparent needs, the Committee issued an Interim Report in March of 1993. The report called far research into ground water quantity and quality, and an examination of the impacts of human activity, and an increase in public awareness of the significance of ground water; This report set the stage for actions of the next seven years. • 1994 Info Brochure and Open House To help spread awareness of ground water issues and offer solutions to common ground water questions, an information brochure was developed and mailed to over 1100 households on a master mailing list. An open house also was held, which offered a slideshow about ground water, a question and answer session and a ground water model demonstration. • 1996 Recharge Rate Study One of the, pressing issues driving, the ground water project, a scope of work for a joint venture between the County and USGS was developed and pursued in May 1994 to examine the recharge rate for ground water supplies in different basins and sub-basins in the County. The resulting report was published by USGS in, November 1996 and presented to the Board of Commissioners. • The Ground Water Center With increasing public awareness a project priority, the Committee suggested the creation of a one-stop resource for County citizens, called the Ground Water Center. Upon approval by the Board in 1996, the Center is housed in the Soil and Water District offices in Hillsborough, and features a dedicated phone line for citizens to call with ground water questions (644-3333 -calls are referred to the appropriate agency). Brochures and other materials are available on site. • Groundwater Guardian A national program dedicated to informing the public about the protection of groundwater resources, the County applied and was awarded membership in the organization in April 1997. The County is one of only 156 local governments in North America (and four in NC) to receive the designation. The Groundwater Guardian offers public information assistance and materials and networking on ground water problems. • 1997-2000 Ground Water Resource Investigation To analyze the County's ground water resource more thoroughly, the Committee developed a .scope of work for a -full Ground Water Resource Investigation. The .USGS was selected to conduct the project, again as a cooperative venture with the County. The Resource Investigation featured scientific sampling of wells across the County, further analysis of ground water availability and susceptibility, and distribution analysis of well yield. The report was completed and published in February 2001. 1' II. Charge to the WRC / BOCC Goal When the Water Resources Committee was formed, the Committee was charged with the following task: Develop along-range study .and placnning process to identify and address the i waste treatrrient options on .the mpacts of various land uses and :; q ntLty and ual o round and sur es of .gran ua q ` ity f g farce water resourc ge County, ,so that'these impacts .can. be factored into long~range planning. All of the subsequent activities of the Committee and the project have been oriented .around this dual purpose . of assessing quantity and quality of groundwater. This includes the substantial research and three reports produced by USGS, the research of graduate students, the activities of the Committee (such as the creation of the Ground Water Center, joining the Groundwater Guardian program, and conducting open houses and other informational brochures). The final stages of the project, the integration of surtace water and ground water planning, is scheduled to occur in the next two years, using this Committee's report as a guide, Finally, as per the Board of Commissioners goal, the WRC is also asked to conduct the following tasks; • Estimate the activities and costs that will be needed to have complete data and information (i.e., further research needs) • Examine the implications of the USGS reports •. Offer ideas on directions the Commission for the Environment and the BOCC. might take for ground water protection, and in linking surface and ground water planning into the Water Resources Element of the Comprehensive Plan 12 III. What We Have Learned: Water Quality Grvund water quality issues .may range from very localized quality concerns (whether naturally occurring or synthetic contaminants) to larger, wide-ranging water quality problems. There are many locations in North Carolina and other states that have serious water quality concerns, whether from naturally occurring substances or from municipal, agricultural or industrial contamination. Fortunately, in this County, we have relatively good wader quality. While there are some portions of the County that are more susceptible to contamination, the County's land use policies limiting high-water use or polluting industrial operations has resulted in few episodes of contamination, and all of the known areas of contamination have been identified and mapped. While there are occasional dialogues about potential water quality (such as at the landfill); there are few water quality problem areas in the County, and those that do exist are very localized. This is due primarily to generally good ambient ground water quality, and good well-siting and construction practices (the County's Health rules for well siting and construction exceed the State standards). The primary water quality- concern in the County is from naturally-occurring contaminants, such as iron and manganese. These metals, naturally found in the County's soil and bedrock, produce rust-colored stains and other nuisance-type water problems. Another potential concern identified is from water-born radon, as noted below. As a part of the USGS Ground Water Resource Investigation (GWRI), extensive well-sampling was conducted at 51 wells across the County. These wells were selected to maximize geographic and hydrogeolagic distribution, NOTE: A statistPca/ summary of resu/fs is presented in Table B on page Z6. Results of the well-testing confirm the County's generally good ground water quality. The following sub-sections address the different types of well-testing conducted, with a brief summary of the findings of those samples. The average well in the sample was X05 feet deep, and about three years old. A. Field Parameters (pH, conductance, temperature, dissolved oxygen, alkalinity) Measuring field parameters such as pH and dissolved oxygen offers a broad characterization of water quality, when taken together. The parameter pH measures the acidity or lack thereof in water. Water that has a pH measurement of 7 is considered neutral, while waterwith pH less than pH 7 is considered acidic, and water with a pH greater than 7 is considered ,basic. Acidic water contributes to corrsiveness and can damage plumbing systems. The 1: median pH level for County ground water was 6.93, very close to neutral. There was a wide range of values, with a high of $.3 at a well northeast of Hillsborough, and a low of 4.72 in Bingham Township. Conductance measures the ability of water to conduct electricity, which is of significance because ionized particles in ground water may be indicative of total dissolved solids in the .water. The median value in the County is 180 microsiemens per centimeter. A considerable range of conductance exists in the County, with values ranging from a high of523 and a low of 26. Although the range is broad ,mast values were typical for ground water in the Piedmont. Dissolved oxygen is a product of precipitation and ground water recharge. Increased dissolved oxygen can indicate loss of precipitates, while low levels of dissolved oxygen are associated with high levels of iron, manganese, sulfate and dissolved organic matter. The median value for County ground water was 2.5 milligrams per liter (mg/L), with highest variance again found in felsic metavolcanic rocks. The range of Endings for dissolved oxygen runs from 9.4 mg/L to 0.03 mg/L. Again, these measurements are within the expected range of ground water quality for the Piedmont. Alkalinity measures the capacity to neutralize acid in the water, usually produced by carbon dioxide and bicarbonate, The median alkalinity found in Orange is 103 mg/L of calcium carbonate, with a high of 194 and a low of 24. B. Major Ions Major ions dissolved from soil and bedrock into ground water also help describe the chemical makeup of the water -whether cations (ions with a positive electrical charge) or anions (negative electrical charge). Common cations are calcium, magnesium, sodium and potassium. Common anions include bicarbonate, sulfate, chloride, fluoride and nitrate. Calcium and magnesium, as previously noted, are among the chemicals that, cause many problems in ground water, including hardness of water -which can potentially cause scale in pipes and precipitates in hot water heaters. In certain areas of the .County, high levels of these chemicals pose nuisance problems for many citizens. Generally-speaking, however, the incidence of these ions in the County's ground water is not out of line with expected levels in the Piedmont region. The median concentration of calcium in samples was 23 mg/L, and the median for magnesium was 4.4 mg/L. Other ions analyzed include sodium, potassium, bicarbonate, sulfate chloride and flouride. No unusual levels of these compounds were found in the sample. G 14 C. ' Nutrients Nutrients such as nitrogen and phosphorus are important to plant and animal life, but higher concentrations of these nutrients can often threaten surface and ground water supplies. Usually; increased levels of nutrients are the result of human activity -the use of fertilizer ar manure, septic systems, or combustion of fossil fuels. Nutrients in ground water usually take the form of nitrate, nitrite and ammonia. In particular, a drinking water standard far nitrate (10 mg/L) is set to protect against high levels, which are dangerous and can pose health risks of anemia and other conditions for small children and the. infirm. High concentrations of nutrients in County ground water may reflect excessive human activity as mentioned above, or poor well construction. of the 51 wells studied in the County, 82% of the samples contained nitrate. While there were widespread findings of nitrate, most were of low concentration. The median value of all wells sampled was 0.49. mg/L, although one well had a high reading of ~.2 mg/L. All other wells sampled were below 3 mg/L. Ammonia and orthophosphate were only detected at low concentrations. D. Total Dissolved Solids Dissolved solids measures the mass of solutes in a water sample after evaporation. Higher or lower than average dissolved solids are indications of the potential for scaling or clogging of plumbing from precipitate minerals. Dissolved solids are generally lower in the Piedmont's crystalline rocks ,than in other regions of the state and nation, and the median dissolved solids concentration in the, County from the analysis is 125 mg/L. This level is typical of the Piedmont .area of the southeastern U.S. E. Metals and Trace Elements Metals and trace elements were ~ detected infrequently in the County's well sampling. Na trace elements exceeded the U.S. EPA's MCL's (maximum contaminant levels), although some metals were found at levels worthy of note. Zinc, manganese, iron and copper were the most frequently detected metals. In three samples, the level of iron exceeded the level of N.C. drinking water standards. Manganese exceeded drinking water standards in 12 of the 51 wells sampled - and' in three cases both iron and manganese were exceeded. As has been known for years, iron and manganese are sometimes a primary concern with ground water supplies in the County, and cause significant water quality nuisances in both the County and state. In excessive amounts, iron and manganese can stain teeth, plumbing fixtures, skin or laundered products, and also may cause odor or taste concerns. Lead was detected in 8 of the 51 samples, although at levels below State and Federal MCL. The levels were, however, greater than the zero-level goal that has 1 been established by the EPA. The incidence of lead is usually tied to corrosion of solder joints in metal household pipes and alloys in pumps and faucets. Elevated lead exposure is known to cause delayed physical and mental development in babies and young children and also has been linked to kidney disease. F. Organic Compounds The ground water samples collected in the County were also examined for certain organic compounds that may indicate the presence of herbicides or petroleum products. Specifically, the water testing checked for atrazine-type compounds and total petroleum-hydrocarbon compounds, including BTEX ( a common measurement of benzine, toluene, ethylene and xylene). Atrazine is a frequently used herbicide. None of the compounds were detected in the samples, and this result in the geographically and statistically sampled wells may indicate that contamination by organic compounds is not a widespread problem in the County. Further work would be needed to more comprehensively determine this, however. G. Radon Water-borne radon is anaturally-occurring substance from the decay of uranium bearing rocks. It is the dissolved state of radon (or radium-222) that poses potential health risks. As ground water is exposed to air through showers and running faucets, radon present in the water may diffuse into the air. Thus, there are two potential means of exposure to radon -ingestion and inhaling. Because radon exposure can occur in two ways, EPA has had difficulty addressing regulations, eventually deciding on a "multi-media" approach. If no State or EPA- approved mitigation program exists, the MCL for radon is 300 picoCuries per liter (pCi/L). If there is an approved mitigation program, then 4000 pCi/L is proposed. Results from the wells sampled in this study used these standards for comparison. The results of this sampling are the most significant of all the water quality findings, as some limited incidence of high radon readings were found in the County. These high readings are not completely unexpected. In 1998, findings of high radon levels in nearby Guilford County (in similar geologic formations) led to some expectation by the Committee that higher than average radon findings would also be observed in Orange. The range of radon activity in Orange was quite dramatic, from a low of 38 pCi/L (picocuries per liter) to 4462 pCi/L (please see Map 2) .The median finding of all samples was 405 pCi/L, above the 300 pCi/L standard suggested by EPA. Generally, the radon activity was highest in felsic (silica and feldspar) rocks and lowest in mafic rocks (iron and manganese base). 16 36°15' 36°!37'30' 36' 35°52'8G' EXPLANATION Q•iYl)RGGEGLOGIC UNITS IARG)A3iG10.WTE [~ IMIFJ METAIGNEOUS,F"EL51C a:~ IMIIIMEFAIGNEOUS,INTERMEaIATE ® {MlM)METAIGNEGUS,MAFIG (MM1(E) METAVGLCANIC, EPICLA5T3~C IM1JF) METAVGLCANIC, FEL51C 'IMVIV META40LCANIC, INTERMEDIATE "~ IPHI~ PHYLLIT£ ITRI) 7RIAS51+r 5EDIMENTARY ROCK5 RA08N,13b PICOCURIES PEI1 LlrElt ~~"~~ ~ 38.299 ANl7 WE0.L NUMBER ~R-1~~® 91Dn • 999AN0 WELL NUMBER OR-104 1,n00-2d99AN0WEL0.NUMBER OEC-1~6® G1~EATER THAN DR EGUAL TD 2,500 pNG WELL NUMBER 0 5 ~a r+~iL~s ~ -- ' r- 0 5 InKILOMETERs Source :Investigation of Ground Water Availability and Quality in Orange County, NC, USGS, 2001 If there is .a geographic area of concern for radon, it is in the south central portion of the County. The wells sampled in the areas west and southwest of Chapel Hill and Carrboro had radon levels in excess of X500 pCi/L. The underlying geology in this area contains several granitic plutans that are relatively "newer" in geologic terms - with a high percentage of feldspar and mica. The largest of these plutons, known as the Farrington pluton, extends south into Chatham County at least as far as the Haw River. This same type of geology was associated with the highest radon readings in Guilford County. Overall, 67% of the wells sampled exceeded the US~PA proposed MCL of 300 pCi/L. 7$°15' 79°07'3$' 79° 17 It is significant that the radon activity overall in Orange is lower than observed in Guilford -but still worthy of note and further analysis. This difFerence may be explained in part by the older age of the granitic plutons underlying south central Orange, as compared to younger formations in Guilford. The County's Environmental Health office is aware of the radon findings and is prepared to assist property owners who may have concerns about potential radon levels. Radon test kits are available from Environmental Health to help test for high radon readings in air and water. NOTE; The Committee's recommendations regarding the radon findings may be found in Section VI, beginning on page ~0. For more, information on these water quality samples and results, please see the USGS Ground Water Resource Investigation report. H. Susceptibility to Contamination To address the question of the likelihood of contamination of ground water supplies, the USGS developed a parallel GIS analysis to indicate susceptibility to contamination. The map results of this analysis were eventually published as a map report "Susceptibility of Ground Water to Surface and Shallow Sources of Contamination, Orange County, NC." These data are available from USGS as part of their digital mapping product for the County, and will be incorporated into the Comprehensive Resource GIS Database. Generally, three contributing factors to indicate susceptibility were used to compute this index: 1. Soil permeability 2. Land use/land cover, and 3. Slope Each of these factors was evaluated through data in the GIS database and mapped (please see Map 2). The range of values were assigned a "contamination potential" rating, which was then used to calculate an overall relative susceptibility value. Generally, land with high ground, less permeable soils and forested land use have the lowest susceptibility to contamination. Conversely, low-lying areas that have permeable soils and higher risk land use (underground storage tanks) have the highest potential for contamination. 1n 18 Map 2 -Susceptibility to Contamination R',, ` _ ~: ,~,~ ~ ^ K i n ~~ ~ _.:..` ~,,'j ~ e~:~,~„~- ..v '~~~• fir.. ". ~~. v+ '•~ ~" ~: ;~•" Yy !•(~ •-" . ~ `~ • L C" ~~ r~~x- ~•~Sh.; -,t +w'. l'bw'. 6?~ Y . "'~ ~ , ; sue' ~,•.3~'3~` . eE" " .: .v;:.~ ..e . ~+i~~ a ~"r mar. /J V' ,~~wl ~ C',~~~ ..W ,/ , ' ~ !"~ Y y ~ .-f W :~~ 1 ~'rl.~ . ,2! ~ rte. '°"~e~„t~'{'/ ~ ~ ; a+ ~ ~, ' . i ,i yam` f ~,"~ f ~ ~4 ~~ •. (1 , ~%.~ r' •,' ihl'` •~ •dV~ ~, ,Y a... - w~yTc,r f ~}( ~. EXPLANATIUN - RELATIVE SUSCEPTIDIUTV CATEGDRIES ~ LOWEST LOW [] MODERATE [] HIGH ~ HIGHEST , FPgure 13. Relative susceptibility to ground-water contamination from surFace or shallow subsurface sources, Orange County, N.C. (from Terziotti and Eimers, 1999). Source : Investigation of Ground Water Availability and Quality in Orange County, NC, USGS, 2001 41 19 As shown on the attached map, about 12% of the County's land area can be categorized as having high susceptibility to contamination. About 21% of the County ranks as low potential for contamination. Water Quality Summary Table ~ Com orison o f Selected Resu lts and Drinkin g Water Stand ards ., .~ .~ PH (units) 8.3 4.72 6.93 Not less than 6.5 units Conductivity 523 ms/cm 26 ms/cm 180 ms/cm No established (microsiemens limits er centimeter Dissolved 9.4 mg/L 0.03 mg/L 2.5 mg/L No established Oxygen limits (milligrams per Litre Alkalinity 194 mg/L 24 mg/L 103 mg/L No established limits Nitrate 7.2 m /L 0.02 m /L 0.49 m /L 10 m L Tron 1100 1 N/A ~ 0.30 m /L Manganese 890 0.4 N/A 0.05 mg/L (micrograms per Litre Calcium 64 mg/L 0.8 mg/L 23 mg/L No established limits Magnesium 21 mg/L 1 mg/L 4.4 mg/L No established limits Fluoride 0.6 m /L 0.1 m /L 0.12 4 m /L Lead 3.7 1.1 N/A 0.015 m /L Zinc ~ 4900 4.5 N/A 5.0 mg/L (micrograms per Litre Copper 24 1.1 N/A 1.3 mg/L (micrograms/ Litre Radon 4462 pCi/L 38 pCi/L 405 pCi/L 300 pCi/L or (picocuries/Litre) 4 000 CI/L 17 ~~ 1n summary, the County's ground water quality is relatively goad. A major benefit on the new data is that a baseline of information about the status of ,ground water in 2000 is now available. This baseline could be of great importance in evaluating change in the future. As land use .patterns change and new plans are developed, the, baseline of information and Susceptibility to Contamination mapwill help illustrate the ramifications of change and steer growth to areas where ground water quality will be less compromised. While naturally-occurring contaminants (i some County residents in the color, od sporadic cases of contamination have bee readings (particularly in the southeastern note and further research may be needed the potential problem. 'on, manganese) cause problems for ~r and taste of ground water, only ~ identified. However, the high radon portion of the County) are worthy of to determine the extent and scope of Additionally, a program of periodic sampling in this area and Countywide may be worthwhile to examine future water quality in developing areas to see if there. are any trends of note. These wells could be compared to "control" wells in areas of the County not seeing development pressures, for comparison and test purposes. ~~ 21 IV. What We Have Learned: Water Quantity The availability of ground water supplies -now and into the future -was the initial impetus for the investigation of ground water resources and the Water Resources project. As such, substantial time and energy has been spent in determining the following components: 1. What is the sustainable yield of the ground water system in the County (i.e., the amount of ground. water that can be removed from the ground water system without exceeding recharge and/or depleting long-term storage)? 2. What type of ground water yield can be expected in the County, and where might the highest-yielding wells be located? 3. Using the well data and statistical analysis,. develop a general prediction of areas in the County that are more likely to produce higher-yield wells. The two reports on ground water produced by USGS (in conjunction with the County) offer the first major research into this resource in the County, and will provide useful information for many years to come. While we may. never be able to predict on asite-specific basis the ground water yield for a piece of land, we can now begin to speak knowledgeably about groundwater availability at sub- watershed level in the County. A. 1996 Recharge Rate Study Published in 1996 (please see page 4), this study looked at the rate of recharge to the County's ground water supplies through investigating data for 12 watershed basins in the County. Ground water is taken out of storage -into springs, streams and lakes, or is pumped from wells. Recharge may be defined as the replenishment of that ground water. A technique known as "hydrograph separation" allowed USGS to use computer models to isolate the ground water component of stream flow at each of, the USGS gaging stations in these basins. Fram this information, seasonal and long- term recharge to the ground water system was estimated far each basin. Mean annual recharge to the system ranges from 4.15 to 6.4 inches per year, with a mean of 4.9 inches per year for the 12 basins. The inches per year rates can be converted to gallons per day per acre to assist in water supply planning purposes. The higher the recharge rate, the more available ground water for use -- the lower the recharge, the less available ground water. i it 22 Recharge for the Morgan Creek basin (upstream from White Cross and Chapel Hill) is higher than any other basin, explained in part by the soil properties in this area that allow high infiltration rates (sometimes known as "Chapel Hill gravel"). The Haw River basin (Bingham. Township and the northwestern edge of the County) and New Hope River sub-basin (northern and eastern Chapel Hill) has the lowest recharge, the latter largely due to the presence of Triassic sedimentary rocks and soils with low infiltration capacities. Finally, the report offers a method of using the recharge rate data for ground water management planning. The ultimate limit on ground water availability is the rate of recharge, i.e., the amount that can be sustainably withdrawn without averdrafting the supply. Twa examples are provided that offer ways to translate the recharge rate data on a basin-by-basin approach to determine the recharge area needed and~the sustainable lot size, given a known water demand. In summary, the report found that there are significant reserves of ground water in the County, but that the rate of recharge varies from one geographic area, to another. Although ground water supplies are currently sufficient, the report notes the critical importance of proper management, conservation and planning for, use of ground water supplies for the future. B. 2001 Ground Water Resource Investigation Where the ].996 Recharge Rate report looked at the County's ground water availability using, streamflaw records by basin, the 2001 Resource Investigation augments this report with actual well data. The new report provides a baseline on well yield in the County, from data gathered from 649 wells. These data include yield, depth, diameter, location, casing depth, and water level. Table 3 on page 11 of the USGS report offers a synapsis of the water availability findings. Well yield (in gallons per minute) ranged dramatically, as has been known for many years by those involved in well drilling and. inspection. The lowest yield well in the,600-plus sample produced only 0.1 gallons per minute (gpm), while the high yield well produced 240 gpm. The average well in the sample was much lower, however, averaging 17.6 gpm. The depth for wells in the sample likewise varied signifcantly, from a minimum of 24 feet to a maximum of 805 feet. The average well depth was 208 feet. The well ,yield and well depth findings allowed USGS to perForm sensitivity analysis to see what type of correlation well yield had to construction practices and siting of wells -and to well yield per foot of depth. 15 23 This analysis was then used to develop a map of well yield distribution based on yield alone, and yield by depth. These maps show that there are quantity "contours" -portions of the County where well yield was likely to fall within a certain range. From these data, the highest-yielding contours in the County are an area near the intersection of Dodson's Crossroads and Dairyland Road in Bingham Township, and in south-central Cedar Grove Township. zn these areas, well yields were from 25 gpm to over 100 gpm. Nearly everywhere else in the County, well yield was less than 25 gpm (please see Map 4 below). When adjusted for the difference in well yields by depth of well (Map 5), the highest contours expand in Bingham to the east and southwest, and in Cedar Grove to the west and north. Maps 3 and 4 36° 35°97' 95°52 T9°15' 79°D'79P 79° 15' I r ~ Sk. yy't~ i Lif i'°.:~~1~~ yic5ei' - ::.!f!.Y:~`:~7~.k'~I3.` i~: ._[... .: +.:•4::~=~ '+4:iw•14'y'J: X ~ Tti'" ~ -•.1~~ urUl $ ry '+: xv7;•i (~ _-•^~~}~~~e e'9r1~[~.~~a~ 3 ai~.~; '17,r~r~-r~ rrW . ^ •j5;t'Ty.-i.}1. `V ' A~r.r„~~5,'~:y^~ro=,;`3' u~., y 36° 1.'%id elii.~y~'P~`..~y+~r?I;,~Y;e;.~}.. -- -y p.,i~S 1 ~ti: nM1 4~yY.1D.~~i~i~~~~~l~~~j4 y~~qi. ~ -_ - ~/ r: i'iP~: EIS '7;~1. - •~~*rp~ -q` - r ~ r ; Yd t:,~ 11 t 1 i 1f~ ~~i ` d ~ ®(' R Tye P :-~.o-~~"~ y.~~i~i~a :~ii .~~~'",^~~. N.S.-•Y.....'.e~, `_c !'°•~i r ij~w `_ - M1~iA ~.7'' dp c'.. ;~.1' `N 0 6 le IALFS 0 5 - to 10UJME1FA5 15cruwanaw . MAXIMUM wELL YlEU7 M 9~~ per minlAel 9.25 . Q 29.50 51-76 76 - lOp ® a 199 Distribution pf maximum well yields in Orange County, N.C. 35°1 79°15' 79°P79P ~° _ {~. . I ©• ~'~ ~9: .. ~ ,y j,. °{I ~ I "~~ ~% ~ a1 '+il v i H try! .. ' 1. ~k 1} J t ' '.M' ' 5 ~~ p ~ le M9E5 o s 1o131aerEl~As pcPwrlAnaa MAxlMUUVUEU.nan pn pe9oa per mulure per kW of mmlwe9 depdd 0-N6 OAB-419 ~] 411-0.29 Q 421-499 491.6:10 ®> 410 Distribution of maximum values of yield par foot of total well depth in Orange County, N.C. Source :Investigation of Ground Water Availability and Quality in Orange County, NC, USGS, 2001 a~ 24 One finding of the study did not support. an expected hypothesis. Previous studies have shown that, in other areas of the Piedmont of North Carolina, there was a relationship between the topography of the land and the well yield, such that the average yield in valleys, and draws was nearly three times greater than wells on hills and rides. However, the Orange data shows well yields have little or no relationship to topographic setting. This pattern is more similar to the Piedmont of Georgia and Alabama than to the rest of the Carolinas. This may be due in parr to the fact that there is a difference in the way the County's underlying bedrock relates to surface drainage patterns. These data are then combined with the findings of the 1996 report to address ground water availability. C. Other Ynformatioin Provided to the Committee i. Discussion of Optimizing existing Wells Ray Sparrow, a local well contractor, presented information to the committee regarding the use of "down-hole" cameras in wells to diagnose well problems and possible remedies, such as appropriate installation of liners. Sparrow found that the cameras prove to be a useful tool in remediation of wells that have . become susceptible to contamination and yet, can be successfully repaired by the installation of a properly placed liner and packer. Cameras are also a useful tool in assuring that new wells are constructed properly. The discussion also entailed the need for proper set-up of the well pump in order to optimize each well. This approach matches the pump size, pump depth, and storage and pressure system to the characteristics of that particular well. A common practice contrary to this has been to oversize pumps and set them too deep. This results in excessive drawdown of the water column which aerates the well wall and fracture zones. This leads to formation of slime bacteria, iron bacteria and a buildup of minerals in the fracture zones which reduces the well yield over time and causes water quality problems for the user. Generally, these wells do not have to be replaced, they can be rejuvenated and the original yield can be restored by appropriately treating the well with the application of acids or special cleaning agents, or by methods using hydrostatic pressure to physically clean the well out the well. Zn receiving this information, the .Committee noted that this draws attention to the need far conservative pump sizing for new wells (please see Pinding 9 on page 24). 17 25 V. Summalry of Findings To summarize, the work of the last seven years has led the Committee to draw the following conclusions and findings: Finding #1 Potable water is a finite resource in the County. The availability of potable wafer is an issue that has public health, economic development and environmental ramifications. A decline in quantity or quality would represent a potential serious environmental and/or public health problem, and scarcity of potable water would hinder the economic development potential of the County. Finding #2 Ground water quality in the County is generally good and may be considered a reliable source of potable water. Although there have been isolated or localized incidents of ground water quality problems, the results of the last eight years have not turned up any widespread problems of ground water contamination. The primary ground water quality concern in the County appears to be from naturally-occurring sources, such as iron and manganese. Finding #3 However, while quality is generally good, elevated water-borne radon levels in certain geologic formations of the County (more often found in the south-central part of the County) may pose health risks, and should be evaluated further. Finding #4 Ground water quantity in the County can vary dramatically, due to the type of fractured rock geology that underlies the surface. While ground water availability is adequate to meet current needs, the density of development permitted by zoning in some watershed basins may exceed the ability for ground water to be recharged to meet demand. Finding #5 Protection of water supplies needs a conservative approach to maintain our resource in a sustainable way and ensure that adequate ground water remains for future generations. Finding #6 The results of the cooperative research with USGS has provided a solid baseline of ground water quality and quantity, that may be used to measure trends and changes in well yield and quality over time. iR zb Finding #7 The results of the two studies with the USGS provide sufficient data for plans and policy recommendations to be developed to ensure sustainable use of the resource., Findi~ na #8 While well construction standards in the County exceed State standards, diligence is needed to ensure that new wells are appropriately sited and constructed to the degree that wastewater systems are addressed. In ,particular, new development proposals currently are required to address' the availability of acceptable soils for wastewater (septic) systems, but no such. set of requirements exist to addressing water availability for wells prior to development. . Finding #8 The X99b USGS study provides data and examples that can be used to evaluate the available ground water supply by watershed, and site new wells appropriately. The effect of dense develapment could cause a net reduction in ground water recharge rates and in baseflow to streams, thus reducing supplies and storages. Finding #9 Well plumbing design and maintenance are important components of well construction. Good pump system installation, the appropriate sizing of well pumps and balancing the pumping rate to in flow can help to address these issues. Finding #10 Ground water and surface water quantity and quality are inextricably inter-related. Ground water represents the source of up to 50% of stream flaw. In order to ensure that the use of available ground water does not exceed availability (i.e., demand not exceeds supply), future planning for water resources must recognize the inter-relationship and address ground water and surface water protection as two parts of the same whole. 19 z~ VI. Recommendations and Furthell• Research Needs Over the last seven years, the Water Resources Committee had the opportunity to receive many presentations and examine much newfound data about the County's ground water resources. Prior to this work, very little was known about this resource that is often "out of sight, out of mind" until problems arise. The pursuit of these data itself is one of the Commitkee's proudest legacies, and the Committee commends the Board of Commissioners for having the foresight to be proactive in investigating ground water issues in the County. On several occasions, representatives from other jurisdictions and agencies in North Carolina and around the nation have expressed admiration and ~at times, surprise, that a local government with no known ground water problems would undertake such a proactive review. In almost every case, it has been reaction to ground water contamination or overuse of supplies that has generated the type of resource analysis undertaken here. The County can be proud of its proactive stance in evaluating ground water quantity and quality before problems arise. The money spent to study our resource and obtain these data will undoubtedly yield many benefits in years to come -benefits that will greatly outweigh the cost of research. As a result of this. work, the County has gone from little or no knowledge about ground water resources to a substantial database on the resource, one that grows every day as new well data is compiled and added to the database. The three USGS cooperative reports provide a wealth of information about ground water -information that may not make for exciting reading, but will be of great value in years to come, as increased demand mounts pressure on 'our ground water supplies. The value of having performed this analysis now, without the pressure of a crisis, may be tenfold in the future. As the Board of Commissioners consider this report, and the Commission for the Environment takes up the mantle of considering policy recommendations for ground water (and eventually integration of surface water and ground water protection into a comprehensive Water Resources Element of the Comprehensive Plan), the Water Resources Committee offers the following recommendations: 20 28 Recommendation 1 Conduct further research into water-borne radon results in south- central Orange, to see if there is a health concern present. Since the geologic formation where the highest radon levels are found extends south into Chatham County, the Board may wish to engage Chatham County in discussing possible additional research that should be of mutual interest. Recommendation 2 Create an ongoing ground water monitoring program using wells to evaluate changes in yield and water quality changes over time in areas of the County that are seeing significant new development. This monitoring system would provide an "early-warning system" to provide . advance notice of impending ground water problems. It would also help detect potential depletion of ground water storage in developments using wells, as well as trends in availability, yield and quality over time. This data could be compared against control well data in undeveloped areas measured against piezometers (test wells) in new subdivisions. Recommendation 3 As the Commission for the Environment reviews ground water and surface water resource management options, the Committee recommends that a "water budget" approach be studied for use as a means to tie together planning and use of these inextricably related components- of our water resources. Changes in land use can change the overall water budget -- urbanization and development tends to decrease recharge and increase surface runoff This reduces ground water in storage and increases the chance of flooding. The cumulative effects of development within a basin can reduce baseflow to streams, which can adversely affect instream flow needs for aquatic life and riparian vegetation habitat. More information on water budgets may be found in Appendix H. Recommendation 4 Based. on the conservative approach to estimating sustainable ground water yield in the 1996 USGS report, there are five watersheds in the County that may not be able to sustain the density of development that current zoning will permit. The Committee recommends that potential changes to the zoning in these watersheds be revisited as part of the ongoing update to the Land Use Element of .the Comprehensive Plan, and that sustainable round water field be incorporated into the decision- 21 29 making process for zoning. These watersheds are the Back Creek, .Haw Creek, Haw River and Hyco Creek watersheds, along with portions of the Upper and Lower Eno2. Recommendation 5 Currently, as new development proposals in the rural areas receive approval, there are requirements that wastewater disposal be addressed up front before development is approved. However, there is no such assessment of water availability required, and thus many eventual homeowners and business-owners expend significant resources to find adequate ground water. While it may never be possible to predict where the best ground water yield is on a site-specifac basis, the County should consider requiring thact new subdivision lots locate a well site (as well as ac septic/wastewater site) prior to subdivision approval. Furthermore, the Committee recommends that, as is done with septic systems, consideration be given to requiring a "well reserve" (or a 100-foot wellhead protection area instead of a reserve) area on new lots, so that future well sites that are needed will be accounted for in site design. It is recognized that this last provision may mean that an increased minimum lot size will be needed in zoning districts where the minimum lot if less than two acres. Areas zoned far lots larger than two acres should generally be able to meet this provision without an effect on lot size. It is recognized that, as a growth management issue, the potential of low-density sprawl must also be weighted against this need. Recommendation 6 Water conservation is not just for surface water. The use of lower-flow appliances and reductions in water use for private wells should also be pursued. The County should consider a public education campaign to this end. As an added benefit, water conservation will reduce the likelihood of overuse of wells, which can result in overloaded septic systems. 77 30 Further Research Needs In addition to these recommendations, the Committee suggests that the County consider additional research in the following areas: 1. The areas of the .County that contain the highest radon 1=lndings are ,associated with geologic conditions that extend into Chatham County. Additional research in conjunction with Chatham to explore these' radon levels may be warranted. ' 2. For those areas of Orange County with higher water-borne radon, the potential exists for the gas to collect in houses, basements and other poorly ventilated areas. A program for testing of air and water radon levels should be encouraged in these areas. .End Notes 1- Additional information on the efFects of land use change, the use of on-site wastewater systems (septic systems), swales, and retention ponds on groundwater recharge is captained in a similar report for Guilford County written in 1997 2- Please see table from 1996 entitled "Calculation of Recharge Area Required for Single-Family Residential Dwellings.:,", included in Appendix E. z~ 31 VII. Appendices N~TE.• Many of appendices to this report are lengthy, and as such are availab/e upon request A. Interim Report of the WRC, March 1993 B. 1994 WRC Progress Report C. Ground Water Center D. Ground Water Databse Inventory C. 1996 USGS Recharge Rate report (Ground Water_Recharge to the Regolith Fractured C stalline Rock A uifer S stem Oran a Coun NC) _ available upon request F. Ground Water Guardian Program G. 1999 USGS Open File Map Report, "Susceptibility of Ground Water to Surface and Shallow Sources of Contaimination, Orange County NC" H. 2001 USGS Ground Water Resource Investigation (Tnvestigation of Ground Water Availability and Quality_ in Oranae County. NC) -available upon request) I. The Concept of a Water Budget Z4 ~~ ~ a~ ~ ~ ~ ~ ~ ~ ~G t, .Y 'I What is radon? Radon is a naturally occurring, invisible, odorless gas that comes from deposits of uranium in soil, rock, and water. It is harmlessly dispersed in outdoor air, but when trapped in buildings, can be harmful, especially at elevated levels. Radon is a radioactive decay product of radium, which is a decay product of uranium. Both uranium and radium are common elements in soil. Where is radon found? - The primary source of high levels of radon in homes is the surrounding soil and underlying rock. Radon in water is found in nearly all sources of surtace water and groundwater. ,Water that flows through or over radium rich rock formations chiefly found in the piedmont and mountain regions of the state, accumulate radium and-thus radon from the decay process.. Groundwater usually has much higher levels than surtace water because radon in groundwater is "trapped" by being submerged underground and cannot easily escape. How does radon get into my house? Air pressure inside your home is usually lower than pressure in the soil around your home's foundation.. Because of this difFerence in pressure, your house acts like a vacuum, drawing radon in through foundation cracks and other openings like floor drains, ductwork, and pipes. Radon may also be present in well water and can be released in the air in your home when water is used for showering and other household . uses. In most cases, radon entering your home through water is a small risk compared with radon entering your home from the soil. What are the health efFects of radon? Exposure to radon is the second leading cause of lung cancer in the United States. Radon can be inhaled into the lungs, where it undergoes radioactive decay. As it decays, radon releases tiny bursts of energy called alpha particles, which can harm sensitive lung tissue by damaging the DNA. This damaged DNA can lead to lung cancer. The main type of cancer caused by radon in water is also lung cancer. This is because a large, fraction of radon in water is released to the air when water is used in common household tasks such as showering, washing clothes, and other uses where water can become vaporized. How is radon measured? Radon is measured in picocuries per liter of air (pCi/L). The US Environmental Protection Agency and the Centers for Disease Control and Prevention recommend that homes with radon levels at or about 4 pCi/L be fixed. The "action" levels in water are set much higher at 300 pCi/L. The water levels are considerably higher because it takes high. levels of radon in water to produce significant levels of radon in air. The rule of thumb is that it takes 10,000 pCi/L of radon in water to raise the level of radon in air 1 pCi/L. Using this rule, it would take 40,000 pCi/L in water to raise the indoor air radon level to 4 pCi/L. 33 How do I find out if my house has elevated levels of radon? -Even if the radon level in your water appears high (above 300 pCi/L), the Division of Radiation Protection of the Department of Environment and Natural Resources recommends that you begin with testing the air in your home fast. This will help determine whether the radon is being released in sufficient levels to be of concern. If the air tests are high (over 4 pCi/L), then additional water sampling and testing can be undertaken. The air sampling kits are simple for homeowners to do on their awn. Where can I get the air and water testing kits? The Division of Environmental Health Services at the Orange County Health Department has radon air sampling canisters available at no charge for residents in areas where there may be concern about high levels of indoor radon. A limited number of water sample kits are also available through Environmental. Health. Staff will either collect the water samples or help homeowners to self-collect water samples. You may also get air testing and water testing kits through a list of distributors on the website at the bottom of the page or by calling Orange County Health Department if you. do not have Internet access. What can be done if my home has elevated levels of radon? Radon problems can sometimes be fixed by caulking cracks along basement foundations, sealing leaks around pipes, or installing a pipe and fan system to vent the radon away from beneath the house. If water is releasing a significant amount into the indoor air space, water aeration or carbon filters that absorb the radon may help the situation. There is a list of North Carolina organizations that specialize in radon mitigation (radon reduction systems) on the website at the bottom of the page or by calling Orange County Health Department if you do not have Internet access. Where can I get more information? There are several helpful websites on the Internet. The first one has specific information for North Carolina. • www.drp,enr,state.nc.us/nf&ers/radoninwater,htm • www.ces.ncsu.edu de is fcs radon radonweek.htm • www.epa.govLaa/radon/pubs/consguid.html • www.epa.gov/safewater~radolnasdw.html Call Ron Holdway or Tom Konsler with the Division of Environmental Health at the Orange County Health Department for more information. 245-2360 t~ ,~, ~ ~: