Lower Yakima Valley Groundwater | Region 10 | US EPA

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Lower Yakima Valley Groundwater

Questions? ¿Preguntas?
  • Contact Marie Jennings (jennings.marie@epa.gov)
    1-800-424-4372, extension 1893 or 206-553-1893
  • Para Espanol, póngase en contacto con Rochelle Labiosa (labiosa.rochelle@epa.gov)
    800-424-4372, extensión 1172 o 206-553-1172
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Why is Nitrate a Concern?

Nitrate is an acute contaminant, meaning that one exposure can affect a person's health. Too much nitrate in your body makes it harder for red blood cells to carry oxygen. While most people recover quickly (after being exposed), this can be very dangerous for infants and some adults. Infants exposed to high amounts of nitrate may develop a potentially fatal condition known as "blue baby syndrome."

Learn more about nitrate in drinking water:

EPA Responds to Community Concerns

EPA conducted sampling in 2010 as part of a study to identify potential sources of nitrate contamination in local groundwater and residential drinking water wells. The study was in response to community concerns about high nitrate levels in residential drinking water wells and the potential disproportionate impacts on low income and minority rural populations in the area. EPA issued its report in September 2012 entitled, Relation Between Nitrate in Water Wells and Potential Sources in the Lower Yakima Valley. The results of the study indicated that:

  • The dairies in the study are a likely source of nitrate in residential drinking water wells downgradient of these dairies.
  • Several irrigated crop fields are a likely source of nitrate in downgradient residential drinking water wells, however, the data for this finding is not as strong as it is for the dairies.
  • With the information collected, it was not possible to determine whether septic systems are a source of nitrate in residential drinking water wells.

EPA accepted public input on the report in the fall of 2012 and received comments from 43 individuals or organizations. EPA compiled the public input, prepared a responsiveness summary and has revised the report.

2012 Monitoring Well Installation

In December 2012 and January 2013 EPA installed and sampled 10 groundwater monitoring wells in the vicinity of the Yakima Valley dairies that were included in the 2010 study. The new data demonstrate that the dairies are a source of nitrate contamination to the groundwater beneath and downgradient of these dairies, thereby reinforcing the conclusion in the earlier report.

Working with dairies, local community, and federal, state, and local officials

Based on the results of the sampling, EPA negotiated agreements with four dairies requiring them to:

  1. Provide an alternate source of drinking water for neighbors within one mile downgradient of the dairies whose wells have levels of nitrate above EPA’s drinking water standard of 10 parts per million.
  2. Take steps to control nitrogen sources (manure and commercial fertilizer) at their facilities.
  3. Conduct soil and groundwater testing at each dairy to evaluate if nitrogen sources are being controlled.

EPA is also working with the Lower Yakima Valley Groundwater Management Area Exit EPA disclaimer advisory committee to develop a comprehensive plan to reduce nitrate contamination in groundwater to below drinking water standards.


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URL: http://yosemite.epa.gov/R10/WATER.NSF/GWPU/lyakimagw

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