Natural Background
                    Soil Metals Concentrations
                    in Washington State

                
Chemical   CAS
Number
   Region/
County
 90th  percentile (mg/kg)  50th  percentile (mg/kg)    mean
(mg/kg)
   median
(mg/kg)
Aluminum 7429-90-5 Statewide 37206.00 19277.87 21956.00 21956.00
Puget Sound 32581.00 18376.61 20354.00 17900.00
Clark County 52276.00 32446.91 34355.00 31192.00
Yakima Basin 33379.00 20892.85 22263.40 20800.00
Spokane Basin 21376.00 15380.88 15842.10 15000.00
West (all) 45735.00 21899.36 25460.15 21760.00
East (all) 28299.00 67234.76 18190.00 16600.00
Group "W" 62905.00 18748.95 25392.70 21700.00
Group "E" 25591.00 13525.62 15003.00 14800.00
Arsenic 7440-38-2 Statewide 6.99 3.10 3.82 2.92
Puget Sound 7.30 3.24 3.96 2.86
Clark County 5.81 3.26 3.56 3.045
Yakima Basin 5.13 2.64 3.73 2.64
Spokane Basin 9.34 4.39 5.02 4.99
West (all) 6.37 3.19 3.71 2.91
East (all) 7.61 3.03 3.90 2.95
Group "W" 8.47 2.80 3.49 2.80
Group "E" 5.76 2.14 2.70 2.53
Beryllium 7440-41-7 Statewide 1.44 0.59 0.76 0.67
Puget Sound 0.61 0.35 0.41 0.36
Clark County 2.07 1.43 1.43 1.48
Yakima Basin 1.57 0.97 1.03 0.93
Spokane Basin 0.84 0.64 0.65 0.66
West (all) 1.51 0.51 0.75 0.53
East (all) 1.27 0.70 0.77 0.72
Group "W" 0.75 0.39 0.39 0.40
Group "E" 0.61 0.35 0.38 0.31
Cadmium 7440-41-9 Statewide 0.99 0.32 0.63 0.49
Puget Sound 0.77 0.37 0.80 0.49
Clark County 0.93 0.49 0.55 0.83
Yakima Basin 0.93 0.49 0.55 0.49
Spokane Basin 0.72 0.36 0.40 0.40
West (all) 1.20 0.40 0.83 0.83
East (all) 0.81 0.30 0.48 0.48
Group "W" 0.10 0.10 N/A N/A
Group "E" N/A N/A N/A N/A
Chemical   CAS
Number
   Region/
County
 90th  percentile (mg/kg)  50th  percentile (mg/kg)    mean
(mg/kg)
   median
(mg/kg)
Chromium 7440-47-3 Statewide 41.88 18.69 23.37 18.42
Puget Sound 48.15 22.00 30.29 22.00
Clark County 26.57 21.99 20.64 21.99
Yakima Basin 38.27 16.43 21.67 16.42
Spokane Basin 17.81 11.43 11.95 11.78
West (all) 47.40 22.00 28.67 22.00
East (all) 31.88 14.51 17.67 13.15
Group "W" 78.46 28.18 37.74 26.70
Group "E" 37.80 14.69 18.92 12.60
Copper 7440-50-8 Statewide 36.01 16.80 20.46 17.07
Puget Sound 36.36 15.00 24.43 15.00
Clark County 34.43 20.49 22.04 21.78
Yakima Basin 26.47 19.23 20.16 19.23
Spokane Basin 21.61 14.42 14.42 14.14
West (all) 43.23 17.36 23.15 17.80
East (all) 28.40 16.22 17.58 16.30
Group "W" 52.85 12.75 21.24 8.05
Group "E" 26.42 14.70 17.69 14.70
Iron Unavailable Statewide 43106.00 22987.15 25903.72 22033.00
Puget Sound 36128.00 17050.00 21680.10 17050.00
Clark County 58665.00 39180.95 40734.60 38508.00
Yakima Basin 51451.00 27689.82 29780.40 28821.00
Spokane Basin 25026.00 18278.16 18744.84 18150.00
West (all) 50125.00 24152.41 28192.00 21433.00
East (all) 36644.00 21810.59 23471.67 22116.00
Group "W" 49170.00 21446.18 25557.33 18200.00
Group "E" 29631.00 19027.40 19935.70 21300.00
Lead 7439-92-1 Statewide 17.09 6.98 10.05 7.90
Puget Sound 16.83 4.47 15.90 9.80
Clark County 24.02 9.50 10.65 6.86
Yakima Basin 11.00 6.56 11.29 6.53
Spokane Basin 14.91 11.01 7.00 10.80
West (all) 20.42 5.92 11.90 8.20
East (all) 13.10 7.84 8.44 7.82
Group "W" 10.67 4.75 5.63 4.00
Group "E" 9.85 6.64 6.92 6.40
Chemical   CAS
Number
   Region/
County
 90th  percentile (mg/kg)  50th  percentile (mg/kg)    mean
(mg/kg)
   median
(mg/kg)
Manganese 7439-96-5 Statewide 1094.85 492.82 592.60 509.58
Puget Sound 1146.00 461.62 592.21 474.00
Clark County 1511.00 924.17 924.20 915.50
Yakima Basin 1104.84 611.46 669.00 589.00
Spokane Basin 663.48 494.78 506.5 470.00
West (all) 1337.27 494.28 646.71 531.25
East (all) 836.00 491.30 534.40 490.75
Group "W" 691.75 257.06 329.30 231.00
Group "E" 526.59 348.73 364.95 345.00
Mercury 7439-97-6 Statewide 0.07 0.02 NO DATA 0.03
Puget Sound 0.07 0.04 0.05 0.04
Clark County 0.04 0.03 0.03 0.03
Yakima Basin 0.05 0.02 0.03 0.02
Spokane Basin 0.02 0.01 0.02 0.01
West (all) 0.08 0.04 0.04 0.04
East (all) 0.04 0.01 0.02 0.01
Group "W" 0.13 0.03 0.05 0.04
Group "E" 0.02 0.01 0.01 0.01
Nickel 7440-02-0 Statewide 38.19 16.92 21.49 16.43
Puget Sound 38.19 23.00 29.82 23.00
Clark County 21.04 16.23 17.72 16.23
Yakima Basin 45.89 16.23 24.83 16.30
Spokane Basin 16.19 10.49 10.96 10.15
West (all) 44.20 20.57 25.44 19.20
East (all) 25.54 12.40 17.25 12.50
Group "W" 54.19 19.12 25.66 19.10
Group "E" 22.41 12.54 13.77 11.70
Zinc 7440-66-6 Statewide 85.82 51.56 55.53 51.12
Puget Sound 85.06 46.52 51.45 43.65
Clark County 95.52 78.5 76.01 78.50
Yakima Basin 78.71 55.66 57.54 52.90
Spokane Basin 66.40 50.83 51.77 50.90
West (all) 98.39 52.50 58.34 54.08
East (all) 80.91 52.29 55.55 50.64
Group "W" 85.56 42.85 48.41 44.5
Group "E" 67.47 43.40 45.74 41.00
            

                
Definitions
State Wide all statewide sampling locations.
Puget Sound Snohomish, King, Pierce, Thurston, Mason, Jefferson, Island, San Juan, and Clallam
Counties.
Clark County Clark County.
Yakima Basin Yakima, Kittitas, Chelan, and Grant Counties.
Spokane Basin Spokane, Lincoln, Adams, Okanogan, and Whitman Counties.
West (all) all sampling locations west of the Cascade Mountain Range.
East (all) all sampling locations east of the Cascade Mountain Range.
Group "W" Whatcom and Skagit Counties, Pacific Coast (Grays Harbor, Lewis, and
Pacific Counties).
Group "E" Benton, Spokane, Lincoln, Adams, Okanogan, and Whitman Counties.

Source: San Juan, Charles (Washington State Department of Ecology, Toxics Cleanup Program);
Natural Background Soil Metals Concentrations in Washington State, October, 1994;
Publication No. 94-115.