Sediment samples collected from the Waiakea Mill Pond, Wailoa
River, and Hilo Bay were analyzed for arsenic. Arsenic was detectable in 10of II
sediment samples, and ranged in concentration from 2 to 715 ppm. Two species
of plant and seven species of animal were collected from the Waiakea Mill Pond
and analyzed for arsenic. No arsenic was detected in the plants, whereas four of
the seven animal species had arsenic concentrations ranging from a trace to
1.3ppm.
Sediments of the Wailoa River estuary have much higher concentrations of'
arsenic than those of Hilo Bay, indicating that most arsenic is located near the
original source of pollution, a factory that once operated on the shores of the
Waiakea Mill Pond. Much of the arsenic is found in anaerobic regions of the
sediment where it has been relatively undisturbed by biological activity. The low
levels of arsenic in the biota of the estuary suggest that there is little remineralization
of the region's arsenic and that it is trapped in anaerobic sediment layers
