were much higher. The world river average
concentration is only 0.03 [25] to 0.09 g/L [23] (Table 1);
the dissolved tungsten concentrations measured in this study
were up to three to four orders of magnitude higher. The maximum
allowable concentrations for tungsten in drinking water and
fishing water reservoirs are 50 and 0.8 g/L, respectively ([26]
and references therein). Furthermore, the concentrations of particulate
and sedimentary tungsten were much higher than that
(1.5 g/g) of the average crust composition (Table 2), which is
further confirmed by the pronounced EF values. The excessive
anomalies for many other heavy metals were particularly highlighted
when compared with unpolluted (or slightly polluted)
natural water bodies. For instance, our particulate Ag concentrations
were measured to be higher than those (0.04–0.28) in
Japanese rivers and Tokyo Bay, indicative of Ag pollution in the
Keya Stream.