Groundwater Contamination at Hanford

Through a network of more than 1500 wells, scientists keep track of groundwater contamination at Hanford. This brochure outlines Ecology's main concerns regarding groundwater. The Pacific Northwest National Lab prepares an annual report on Hanford Site Groundwater Monitoring. The tables below show the contaminants of greatest concern.

Major groundwater radiological plumes on the Hanford Site and their impact on the Columbia River

Contaminant	General Location	Approximate Plume Size	Reached the Columbia River	Observed Concentration in Wells Nearest River (Over drinking water standard)	Highest Plume Concentration (Over drinking water standard)	Remedy in Place
Strontium-90	Mainly N, B, C Reactor areas (river corridor) and 200 East Area	.4 Square Miles	YES	9,000 pCi/L Pico curie per liter (measure of radioactive decay)	18,000 pCi/L in N area	Yes, Pump and Treat in N area to stop Sr-90 entering river
Iodine-129	Sitewide	33 Square Miles	NO	None	24.8 pCi/L in 200 W (ZP-1)	No, no practicable treatment technology for dispersed plume
Tritium	Sitewide	70 Square Miles	YES	39,100 pCi/L in aquifer tubes in N area	2,320,000 pCi/L in 300 area	No, disperse with short half life
Uranium	300 and 200 West Areas	.4 Square Miles	YES (300 area) NO (200 W)	127 pCi/l in 300 area	2,258 pCi/L	Yes, Pump and Treat in 200 West No, source control only in 300 area
Technetium-99	200 West Area	.3 Square Miles	NO (predicted within 80 years)	None	22,867 pCi/L	Yes, Pump and Treat for containment and mass reduction

Major groundwater chemical plumes on the Hanford Site and their impact on the Columbia River

Contaminant	General Location	Approximate Plume Size	Reached the Columbia River	Observed Concentration in Wells Nearest River (Over drinking water standard)	Highest Plume Concentration (Over drinking water standard)	Remedy in Place
Chromium	Mainly H, D, K reactor areas (river corridor)	1 Square Mile	Yes	390 ppm	2,130 ppm	Yes, Pump and Treat in H, D, K and ISRM barrier in D to prevent Cr-6 from entering the river
Carbon Tetrachloride	200 West Area	4.2 Square Miles	No (predicted within 80 years)	None (expected to be 3,000 ppb in 100 years)	6,500 ppb	Yes, Pump and Treat and vapor extraction for containment
Nitrate	Sitewide	16 Square Miles	Yes	491 ppm in aquifer tubes in N area	3,430 ppm in 200 West Area	No, extent and dispersion of plume makes treatment impracticable