AWWA WQTC58966

The US Geological Survey currently is conducting a study in cooperation with the New Jersey Department of Environmental Protection (NJDEP) to evaluate the fate of the radium (Ra) passing through individual ion-exchange treatment units (treating water from private wells) in areas of the State underlain by the Kirkwood-Cohansey and the Potomac- Raritan-Magothy aquifer systems. Water from the Potomac-Raritan-Magothy aquifer system is chemically complex (high dissolved-solids content) and contains abundant iron (up to 32 milligrams per liter), whereas low-ionic-strength, iron-poor water is typical of the Kirkwood- Cohansey aquifer system. The study was undertaken to determine: the proportion of Ra that eventually returns to shallow groundwater from the septic leach field; the mass proportion of Ra that ultimately is retained in septic sludge and hauled to publicly owned treatment works (POTWs); and, whether these proportions differ depending on water quality type or which aquifer is the source of the drinking water. Differences between Ra concentrations in treated water or in backwash brine in iron-rich areas and those in areas where water contains less iron are not known. At each domestic-well test site, water samples are being collected at five locations: the water-supply well (untreated groundwater); the treatment system (treated drinking water and backwash brine); the septic system (septage); and a downgradient shallow observation well (untreated groundwater). Samples are analyzed for gross alpha-particle activity (within the 48-hour holding time) and for concentrations of Ra-226, Ra-228, calcium, iron, chloride, and nitrate. Includes extended abstract only.