Maple syrup analysis for137Cs,K, and B,using a low-background counting system and PGAA

Fifteen maple syrups were analyzed for¹³⁷Cs and K (via⁴⁰K) by using a low-background -ray counting system, and for B and K by using neutron capture prompt -ray activation analysis (PGAA). For low-background -ray counting, 3 limits of detection (24-hour counts) were 0.03 Bq¹³⁷Cs/kg and 10 mg K/kg for 3.5-L portions and 0.08 Bq¹³⁷Cs/kg and 20 mg K/kg for 1.0-L portions. K concentrations determined by the two methods (using 2-g portions for PGAA) were in excellent agreement. The products were obtained in 1991, with one produced in Maryland, three in New York, four in Pennsylvania, two in New Hampshire, and five in Canada. The average activity concentration for Canadian syrups (2.8 Bq¹³⁷Cs/kg) was nearly a factor of 20 greater than the average (0.15 Bq¹³⁷Cs/kg) for the other syrups, but all¹³⁷Cs activity concentrations were at least 100 times lower than those for which controls would be recommended according to Federal Radiation Council guidance. The data exhibited distinct groupings related to the sources of the products when the ratios of¹³⁷Cs activity to K content (Bq_Cs/mg_K) were plotted vs. B concentrations.