Occurrence of natural and anthropogenic hexavalent chromium (Cr VI) in groundwater near a mapped plume, Hinkley, CA


The purpose of this study is to evaluate the occurrence of natural and anthropogenic Cr VI in groundwater, and estimate background Cr VI concentrations upgradient, near the plume margins, and downgradient from the mapped Cr VI contamination plume near Hinkley, CA.

In addition to data collected to evaluate Cr VI occurrence and determine background Cr VI concentrations in groundwater within the study area, there also is concern within the TWG about: 1) the occurrence of other trace elements in the study area that are of public health concern including: manganese, arsenic, and uranium, and 2) potential fate of chromium within the IRZ on decadal, or longer, time-scales as groundwater reoxygenates by natural processes. Data collected as part of this study provide an opportunity to collect and interpret data that address these concerns.

Relevance and Benefits

Results of this study will be used to evaluate variations in naturally-occurring Cr VI, and the extent of anthropogenic Cr VI contamination from the PG&E compressor station near Hinkley, CA. This information may be used in the future by regulators to establish clean-up goals for Cr VI contamination plume near Hinkley, CA.

This proposal will contribute to the U.S. Geological Survey's ability to "ensure adequate quantity and quality of water to meet human and ecological needs in the face of growing competition among domestic, industrial-commercial, agricultural, and environmental uses" (National Research Council, 2004) as described in the U.S. Geological Survey Science Strategy (U.S. Geological Survey, 2007; Evenson and others, 2013). The proposal is within U.S. Geological Survey Water Resources Mission Areas objective to "define and better protect the quality of the Nationís water resources". The project complies with the Federal role for the U.S. Geological Survey in that it provides services not readily available from the private sector (WRD Memorandum 04.01) and it:

  1. advances knowledge of the regional hydrologic system
  2. advances field methodology
  3. advances understanding of hydrologic processes, and
  4. provides data and results useful to multiple parties in potentially contentious conflicts over water resources.

Cooperating Agency: Lahontan Regional Water Quality Control Board
Project Chief: John A. Izbicki
Phone: 619-225-6131
Email: jaizbick@usgs.gov

California Water Conditions

Real-Time California Streamflow Conditions