Prepared in cooperation with the New Jersey Department of Environmental Protection Occurrence of Radium-224, Radium-226 and Radium-228 in Water from the Vincentown and Wenonah-Mount Laurel Aquifers, the Englishtown Aquifer System, and the Hornerstown and Red Bank Sands, Southwestern and South-Central New Jersey Scientific Investigations Report 2007-5064 U.S. Department of the Interior U.S. Geological Survey Version 1.1 Occurrence of Radium-224, Radium-226 and Radium-228 in Water from the Vincentown and Wenonah-Mount Laurel Aquifers, the Englishtown Aquifer System, and the Hornerstown and Red Bank Sands, Southwestern and South-Central New Jersey By Vincent T. dePaul and Zoltan Szabo Prepared in cooperation with the New Jersey Department of Environmental Protection Scientific Investigations Report 2007–5064 U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior DIRK KEMPTHORNE, Secretary U.S. Geological Survey Mark D. Myers, Director U.S. Geological Survey, Reston, Virginia: 2007 For product and ordering information: World Wide Web: http://www.usgs.gov/pubprod Telephone: 1-888-ASK-USGS For more information on the USGS--the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment: World Wide Web: http://www.usgs.gov Telephone: 1-888-ASK-USGS Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this report is in the public domain, permission must be secured from the individual copyright owners to reproduce any copyrighted materials contained within this report. Suggested citation: dePaul, V.T., and Szabo, Zoltan, 2007, Occurrence of Radium-224, Radium-226, and Radium-228 in Water from the Vincentown and Wenonah-Mount Laurel aquifers, the Englishtown aquifer system, and the Hornerstown and Red Bank Sands, southwestern and south-central New Jersey: U.S. Geological Survey Scientific Investigations Report 2007-5064, 62 p. iii Contents Abstract ...........................................................................................................................................................1 Introduction.....................................................................................................................................................2 Purpose and Scope ..............................................................................................................................3 Naturally Occurring Radionuclide Decay Series ............................................................................3 Description of Study Area ...................................................................................................................6 Geologic Setting ...........................................................................................................................6 Hydrogeologic Setting ................................................................................................................8 Vincentown Aquifer ..........................................................................................................11 Hornerstown and Red Bank Sands ................................................................................11 Wenonah-Mount Laurel Aquifer ....................................................................................12 Englishtown Aquifer System ...........................................................................................12 Land Use ......................................................................................................................................12 Previous Investigations of Radionuclide Occurrences in Water and Sediment in Southern and Central New Jersey .................................................................................13 Ground Water .............................................................................................................................13 Sediment......................................................................................................................................13 Methods.........................................................................................................................................................14 Design of Sampling Network ............................................................................................................14 Sampling Procedures .........................................................................................................................16 Quality-Assurance Program .............................................................................................................16 Analytical Methods.............................................................................................................................16 Radium-224 and Radium-226 ....................................................................................................17 Radium-228..................................................................................................................................17 Gross Alpha-Particle and Beta-Particle Activities and Radon-222 ...................................17 Reporting of Results of Analysis of Radionuclides ..............................................................17 Ancillary Inorganic and Organic Constituents ......................................................................18 Land-Use Classification .....................................................................................................................18 Statistical Analysis of Radionuclide Occurrence ..........................................................................18 Occurrence of Radium-224, Radium-226, Radium-228, and Gross Alpha-Particle Activity in the Ground Water ........................................................................................................18 Quality Assurance...............................................................................................................................18 Gross Alpha-Particle Activity ...........................................................................................................20 Radium-224...........................................................................................................................................24 Radium-226 and Radium-228 .............................................................................................................25 Significance of Radium-224 Concentrations for Gross Alpha-Particle Activity ................................25 Ratio of Radium-224 to Gross Alpha-Particle Activity ..................................................................25 Correlations Among Concentrations of Radium-224, Radium-226, and Radium-228, and Gross Alpha-Particle Activity ......................................................................................26 Factors That Affect Radium-224 Concentrations in the Ground Water ..............................................27 Geochemical Factors and Land Use ................................................................................................27 Relations Between Radium and pH ........................................................................................27 Relations Between Radium and Nitrate .................................................................................29 iv Chemical Classification of Ground Waters and Possible Effects on Radium Occurrence .....................................................................................................30 Unconfined Parts of the Aquifers ...................................................................................31 Confined Parts of the Aquifers .......................................................................................34 Radium Isotopes in, and Land Use Overlying, the Unconfined Parts of the Lesser Aquifers ......................................................................................................36 Hydrogeological Factors....................................................................................................................37 Occurrence of Radium Isotopes Among the Aquifers .........................................................37 Relations of Radium and pH to the Geologic Composition of Aquifer Materials ............38 Geographic Distribution of Radium Isotopes within the Lesser Aquifers ........................39 Regional Significance of Ra-224 Concentrations and Gross Alpha-Particle Activity ......................40 Comparison of the Occurrence of Ra-224, Ra-226, Ra-228 and Gross Alpha-Particle Activity in the Lesser Aquifers with that in the Kirkwood-Cohansey Aquifer System ......................................................................................................................40 Comparison of the Occurrence of Ra-224, Ra-226, Ra-228 and Gross Alpha-Particle Activity in the Lesser Aquifers with that in Other Aquifers in the Mid-Atlantic Coastal Plain ...................................................................................................41 Summary and Conclusions .........................................................................................................................42 Acknowledgments .......................................................................................................................................43 References Cited..........................................................................................................................................43