Characterization of arsenic transport in northeastern Honey Lake Basin, Lassen County, California.

摘要

High concentrations of arsenic exist in the shallow ground water of northeastern Honey Lake basin. The models EQ3/6, PHREEQC, and HYDRUS-1D were used to evaluate the processes controlling arsenic transport in this part of the basin. Results show that an arsenic concentration of 0.076 mg/L is derived from a mixture of geothermal water and recharge near the Amedee Mountains. As ground water moves toward the playa, this water enters a large pool of older, high TDS water with an arsenic concentration of approximately 0.25 mg/L. Arsenic in the high TDS zone is likely derived from the long-term evaporation of historic Lake Lahontan. Modeling with HYDRUS-1D shows that it is unlikely that arsenic would be transported from the ground surface to the water table by natural processes, but a risk for contamination exists if an anthropogenic source and an increased surface flux were present.