This document specifies the determination of nickel-59 and nickel-63 (⁵⁹Ni and ⁶³Ni) activity concentration in samples of all types of water using liquid scintillation counting (LSC). Using currently available liquid scintillation counters, this test method can measure ⁵⁹Ni activity concentrations of 50 mBq·l⁻¹ and ⁶³Ni activity concentrations of 20 mBq·l⁻¹ with a counting time of 200 min and a sample volume of 1,5 l.

NOTE      These performance indicators are wholly dependent on the measurement regimes in individual laboratories; in particular, the detection limits for ⁵⁹Ni are entirely dependent on the levels of ⁶³Ni that can be present.

The range of application depends on the amount of dissolved material in the water and on the performance characteristics of the measurement equipment (background count rate and detection efficiency).

It is the laboratory’s responsibility to ensure the suitability of this test method for the water samples tested.