Skip directly to search Skip directly to A to Z list Skip directly to site content




The Agency for Toxic Substances and Disease Registry (ATSDR) received letters from two residents living in the vicinity of the Union Pacific site in Sacramento. In the letters, the residents described their concerns about exposures to metals coming from the site. The California Department of Health Services and ATSDR conducted an exposure assessment of the Union Pacific site and summarize the findings in this health assessment.

The Union Pacific site is located in Sacramento, California and one part of the yard is a former railroad maintenance yard and the other portion is a current and former switching yard. Residential property borders the site on all sites. Union Pacific site is a State of California Superfund site. Soils in the former maintenance yard have been found to be contaminated with arsenic, lead, petroleum hydrocarbons, and polycyclic aromatic hydrocarbons. In addition, several underground storage tanks apparently had leaked, resulting in two plumes of contaminated groundwater. The groundwater is contaminated with several volatile organic compounds, volatile aromatic compounds and nickel. Several remedial activities have been performed.

CDHS considers that no current exposure pathway exists for residents living near the Union Pacific site because: 1) air monitoring indicates that contamination is not moving from the site with current use; 2) no one is drinking the contaminated water emanating from the site and the municipal water that serves the neighborhood is of good quality; and 3) current soil levels do not indicate that contamination from the site exists in the neighborhood yards at levels of health concern. Further, CDHS considers that past exposure to contaminants in the soil may have occurred for residents who lived at 2206 6th Avenue (not the home of either resident writing the letters). The contaminated soil has been removed so this pathway has been eliminated.

A toxicological evaluation of past exposure to contaminated soil at 2206 6th Avenue estimatedthat exposure to arsenic in the soil might have resulted in non-cancer health effects such as skinchanges for children if the child was exposed on a daily basis for a year or longer to the areas ofthe backyard with the highest concentrations of arsenic, but not if the exposure is assumed toresult from the average concentrations of arsenic in the backyard. Past adult exposure to thearsenic in the soil on a chronic daily basis in the backyard would not have been expected to resultin non-cancer health effects. If any resident lived at 2206 6th Avenue for seventy years, theywould have an additional low increased cancer risk based on a life-time exposure to the arsenicin the backyard.

A toxicological evaluation of past exposure to contaminated soil at 2206 6th Avenue estimatedthat exposure to lead in the soil on a daily basis would not result in non-cancer health effects fora child or an adult.

Past exposure to the drinking water is also an eliminated pathway since no one ever drank thecontaminated water and the municipal water that served the neighborhood, including thepetitioners' residences is of good quality. Since no air modeling was conducted at the site whenit was an active railroad maintenance yard, it is not possible to evaluate whether or not the airpathway occurred at a level of health concern in the past. Thus, this is considered a potentialexposure pathway that may have occurred in the past.

CDHS is not aware of any other community health concerns other than those raised by theresidents writing the letters.

The Union Pacific site does not pose a current health hazard and appears to not have been a health hazard in the past based on lack of exposure to the contaminated soil and groundwater. CDHS and ATSDR recommend continued cleanup activities be conducted so that no future exposures will occur at a level of health concern.


Two residents who lived with their families in the vicinity of the Union Pacific Railroad Yard in south Sacramento individually petitioned the Agency for Toxic Substances and Disease Registry (ATSDR) in 1991 to do a health assessment. In the letters, they stated that they were very concerned about the elevated levels of selenium, copper, cobalt, and lead that had been measured in the bodies of the family members. The director of ATSDR sent a letter to the petitioners in October 1991 acknowledging the receipt of their letters. In 1993, ATSDR Regional staff prepared a scoping report in which they identified two plausible pathways of exposure to these nearby residents: inhalation of soils and particulates containing heavy metals and ingestion of contaminated waters and garden produce (1). The site was recommended for a petitioned public health assessment. In March 1996, ATSDR asked the ATSDR cooperative agreement staff of the California Department of Health Services (CDHS) to look into the issues that these petitioners raised. In this public health assessment (PHA), CDHS will review past and current exposures related to the Union Pacific site and thus address the concerns that have been raised by those community members and by the scoping report.

A. Site Description and History

The Union Pacific site is located in south Sacramento (Figure 1). The site encompasses an area of approximately 94 acres, consisting of two portions: an active switching yard operation in the western part of the site, and the inactive portion which makes up the eastern part of the site (Figure 2) (2). The railroad maintenance yard was established by Western Pacific Railroad in the early 1900s to maintain and rebuild steam locomotives and boilers, refurbish rail cars, and assemble trains. Activities conducted at the facility included sand-blasting, painting, machining, welding, dismantling, reassembling locomotives and rail cars, and switching operations. Diesel engine repair and maintenance began in the mid-1950s. Union Pacific Railroad purchased the operations in 1982, but discontinued maintenance yard operations in 1983. Remaining buildings and structures in the maintenance yard were demolished by Union Pacific in 1985 and 1986. Union Pacific is a State of California Superfund site. Under the direction of the Department of Toxic Substances Control (DTSC, formerly within CDHS), Union Pacific and its contractor,

Dames and Moore, began site investigations of the nature and extent of contamination in 1987 (2). A final Remedial Investigation and Feasibility Study was completed in May 1991 (2).

Because most of the maintenance activities took place on the eastern side of the property, the majority of the contamination problems were found there (2). These problems included soils contaminated with arsenic, lead, petroleum hydrocarbons, and polycyclic aromatic hydrocarbons.

In addition, several underground storage tanks apparently had leaked, resulting in two plumes of contaminated groundwater (2). The groundwater is contaminated with several volatile organic compounds, volatile aromatic compounds, and nickel. The groundwater contamination spreads from the eastern and central areas to one-half mile outside the southeast corner of the site.

The western side of the Union Pacific site contains arsenic and lead contaminated slag (2). Slag is the waste that is created from metal extraction processing. This slag was used as a structural base for the railroad tracks. The railroad tracks are still in use.

Since 1991 Union Pacific and its contractor, Dames and Moore, have performed a number of additional studies and interim remedial activities including air monitoring of the site activities, installation groundwater extraction and treatment, soil cleanup of off-site lots, and slag removal (3). The Remedial Action Plan was finalized in June 1995 (3). Pumping and treating of the two impacted groundwater plumes continues. Other on-going remedial actions includes vapor extraction and in-situ treatment to address volatile organic compounds in the soil and groundwater and excavation and off-site disposal of impacted soil, which will continue to occur for the next two years.

B. Site Visit

On the morning of October 11, 1996, CDHS staff walked the exterior of the Union Pacific siteand viewed the site from the perimeter fence. Several train tracks run through the site, while therest of the site was observed to be covered with grasses and weeds. No buildings or structureswere left on-site. As described below, residential area surrounds two sides of the site.

C. Demographics, Land Use, and Natural Resources


Census information was gathered for the population living within the zip code 95818. Accordingto the 1990 census, 22,249 people lived within the zip code. Approximately 46% of thispopulation is male. Approximately 61% are white, 23% Asian or Pacific Islander, 8% black. Thirteen percent of the population are of hispanic origin. In 1990, the population had thefollowing age distributions: 6 years and younger, 4.7%; 7-14 years, 7.9%; 14-18 years, 4.7%;19-29 years, 15.7%; 30-49 years, 33.4%; 50-64 years, 10.7%; and 65 years and older, 17.7%.

Land Use

Residential property borders the site to the north and east; Western Pacific Avenue and Sutterville Road border the site to the south and further south of these busy streets is a residential neighborhood; Sacramento City College, commercial, light industrial, and residential properties border the site to the west (Figure 2). One of the petitioners used to live several blocks to the south of the site. The other petitioner used to live five blocks to the west of the site. Neither petitioner lived immediately adjacent to the site.

Natural Resources

Groundwater beneath the site is first encountered at a depth approximately 25 to 35 feet below ground surface, and extends 50 to 60 feet below ground surface (bgs) (2). Groundwater flows to the southeast. Groundwater is a source of drinking water in this part of California.

The area residences in the area surrounding the site, including the petitioners' residences, are serviced by the City of Sacramento Water District (Figure 2)(7). The City of Sacramento gets their water from 29 active groundwater wells and surface water from the American and Sacramento Rivers. None of the City of Sacramento wells are located closer than four miles to the site, and they have not been impacted by the Union Pacific site. Surface water supplies 77.2% and groundwater the other 12.8% of the total. The water is of good quality; the typical water quality exceedances are for manganese, iron, and turbidity.

Union Pacific contractor reviewed the California Department of Water Resources files and found that a total of seven off-site water wells are located within one mile of the site (2). None of these wells are owned by residents in the immediate vicinity of the site. All of these wells are used for irrigation and none have been impacted by the Union Pacific site.

The nearest downgradient drinking water wells, operated by the Fruitridge Vista WaterCompany, are located quite a distance from the site, approximately one and one-half miles.

The predominant wind direction is from the south/southwest (3). Immediately following the passing of low-pressure systems, winds from the north/northwest are common. The petitioners' residences are located on the western and southern sides of the site, essentially upwind from the site. This means that any contamination that might become airborne from the site would not be expected to be blown in the direction of the petitioners' residences.

D. Health Outcome Data

Sources of existing health related data in California that may be useful in evaluating hazards from environmental exposures include the California Birth Defects Monitoring Program, the California Cancer Surveillance Program, birth certificates, death certificates, hospital discharge data, and medical records as exist in employment records and local hospitals and clinics. The pertinence of these databases to the Union Pacific site will be discussed in the Public Health Implications section.

Next Section    Table of Contents The U.S. Government's Official Web PortalDepartment of Health and Human Services
Centers for Disease Control and Prevention   1600 Clifton Road Atlanta, GA 30329-4027, USA
800-CDC-INFO (800-232-4636) TTY: (888) 232-6348 - Contact CDC–INFO

A-Z Index

  1. A
  2. B
  3. C
  4. D
  5. E
  6. F
  7. G
  8. H
  9. I
  10. J
  11. K
  12. L
  13. M
  14. N
  15. O
  16. P
  17. Q
  18. R
  19. S
  20. T
  21. U
  22. V
  23. W
  24. X
  25. Y
  26. Z
  27. #