Municipal biosolids land application and ground-water pollution, Piedmont Province, Southeastern United States

A five-year study of two fields located near Raleigh, North Carolina, USA to which sewage sludge (biosolids) is applied and on which crops are raised demonstrated that a small percentage of the total applied nitrogen reaches the saturated zone. In as short a time as two years following initial application of the biosolids the nitrate-nitrogen began to exceed drinking water standards of 10 mg/l. Soil moisture studies and water balance calculations pointed to times when nitrate-nitrogen migrated downward. Nitrogen stable isotopes demonstrated that as much as 1550 mg/l/day/m were reaching a stream through baseflow from beneath one of the fields.