  Demand to use gadolinium (Gd) in detectors is increasing in the field of
elementary particle physics, especially neutrino measurements and dark matter
searches. Large amounts of Gd are used in these experiments. Therefore, to
access the impacts of Gd onto the environments, it is becoming important to
measure the baseline concentrations of Gd in the environments. The measurement
of the baseline concentrations, however, is not easy due to interferences by
other elements. In this paper, a method for measuring the concentrations of
rare earth elements including Gd is proposed. In the method, an inductively
coupled plasma-mass spectrometry is utilized after collecting the dissolved
elements in chelating resin. Results of the ability to detect anomalous
concentrations of rare earth elements in river water samples in the Kamioka and
Toyama areas are also reported.
