FRONTIER FERTILIZER
DAVIS, YOLO COUNTY, CALIFORNIA
CONCLUSIONS
This public health assessment identified and evaluated exposure pathways by which site-related contaminants may impact workers on the Frontier Fertilizer Property or community members in the general vicinity of the site.
No completed exposure pathways currently exist or are expected to exist in the future. Therefore, the site currently does not pose a public health hazard. Significant future exposure to site-related contaminants is unlikely if: 1) migration of groundwater is controlled via current and future remedial actions; 2) remedial actions reduce groundwater contamination to below levels of health concern; 3) deed restrictions are maintained in areas of groundwater contamination until remediation has reduced contaminant concentrations below levels of health concern; 4) any future excavation/construction projects at the site take the necessary precautions to insure that workers are not exposed to contaminants above levels of health concern; 5) potential exposure to carbon tetrachloride released from contaminated groundwater/soil gas is evaluated prior to any
development of the land over the carbon tetrachloride plumes; and 6) deed restrictions restrict future development of the site until soil contamination is remediated.
Based on the information reviewed, ATSDR and CDHS conclude that the Frontier Fertilizer site posed a past public health hazard due to exposure of workers on the property to contaminants in a water supply well. Specifically, workers may have been exposed to 1,2-DCP and EDB by drinking or otherwise using water from the Labor Camp well from about the mid 1970's until 1992. This was the only completed exposure pathway identified in this public health assessment. Based on rough estimates of exposure to workers from drinking water contaminated with 1,2-DCP and EDB, workers may be at increased risk for both cancer and possibly other adverse health effects. However, an accurate toxicological assessment of the site is not possible due to lack of data and information on actual exposure levels.
ATSDR's Health Activities Recommendation Panel (HARP) determined that primary care providers should be made aware of past worker exposure.
The Planning and Building Department of the City of Davis has place deed restrictions that will restrict development of the area north of the northern boundary of the Property. The land use will be limited to light industrial/business park, industrial, service commercial, office, retail/commercial, single-family, and multi-family uses (31).
According to the California Health and Safety Code Section 25220, "a border zone property determination is required prior to new construction of any hospital, school, day-care facility, residential structure, or other permanently occupied human habitation within 2,000 feet of the property boundaries of the hazardous waste site."
The soil investigation for the Second Street right-of-way has been completed.
An underground storage tank suspected of leaking has been removed.
Ten new extraction wells have been installed; a total of eleven are planned.
In May 1995, U.S. EPA began additional groundwater and soil investigations and installed three temporary monitoring wells (called hydropunches) in the A2 zone in order to sample the groundwater in this aquifer and to delineate the EDB and 1,2-DCP plumes.
The groundwater pump-and-treat system is currently being upgraded from 1 gallon per minute to between 30 and 50 gallons per minute (37).
A comprehensive soil sampling event to characterize the extent of contamination and the removal of several existing monitoring wells suspected to be providing a conduit for downward migration of contaminants began in May 1995 (37).
The potential for exposure and associated risk from carbon tetrachloride should be assessed prior to development of the area (especially the area within the drainage channel north of the Property) over the carbon tetrachloride plume.
In the areas of known ground water contamination, existing deed restrictions should be continued until remediation has reduced contaminant concentrations to below levels of health concern.
To minimize exposures during any future excavation or construction on the site, the work site should be limited to authorized personnel using appropriate personal protective equipment and applicable Occupational and Safety Health Administration (OSHA) and National Institute for Occupational Safety and Health (NIOSH) guidelines should be followed.
ATSDR and CDHS plans to contact the primary health care providers so that they are made aware of the potential of past exposure to the transient farm labor families from the contaminated groundwater from the Labor Camp well.
ATSDR and CDHS plans to provides health education for the community residing near the Property.
Sherry Chan, M.P.H.
Industrial Hygienist
Impact Assessment, Inc., Consultant to
Environmental Health Investigations Branch
California Department of Health Services
Marilyn C. Underwood, Ph.D.
Associate Toxicologist
Environmental Health Investigations Branch
California Department of Health Services
David J. Borgeson, M.S.
Epidemiologist
Impact Assessment, Inc., Consultant to
Environmental Health Investigations Branch,
California Department of Health Services
(no longer with Impact Assessment, Inc.)
B. COMMUNITY RELATIONS COORDINATOR
Jane Riggan, M.S.W.
Impact Assessment, Inc., Consultant to
Environmental Health Investigations Branch,
California Department of Health Services
Gina A. Margillo, M.A.
Impact Assessment, Inc., Consultant to
Environmental Health Investigations Branch,
California Department of Health Services
ATSDR REGIONAL REPRESENTATIVES
Gwendolyn Eng
Regional Services, Region IX
Office of the Assistant Administrator
William Nelson
Regional Services, Region IX
Office of the Assistant Administrator
ATSDR TECHNICAL PROJECT OFFICER
Gail Godfrey
Division of Health Assessment and Consultation
Remedial Programs Branch, State Programs Section
CERTIFICATION
The Frontier Fertilizer Site Public Health Assessment has been prepared by the California Department of Health Services under a cooperative agreement with the Agency for Toxic Substances and Disease Registry (ATSDR). It is in accordance with approved methodology and procedures existing at the time the public health assessment was initiated.
Gail D. Godfrey
Technical Project Officer, SPS, RPB, DHAC
The Division of Health Assessment and Consultation, ATSDR, has reviewed this public health assessment and concurs with its findings.
Robert C. Williams, P.E., DEE
Director, Division of Health Assessment and Consultation
