Washington — WSDA

Washington State Department of Agriculture (WSDA) requires laboratory heavy-metal testing for fertilizers and soil amendments.

Metals that must be submitted:
Arsenic (As), Cadmium (Cd), Cobalt (Co), Mercury (Hg), Molybdenum (Mo), Nickel (Ni), Lead (Pb), Selenium (Se), Zinc (Zn)

Accepted Methods
1. Only use the methods and revisions approved by WSDA as noted in the table below. 

2. The report must include: 
• Digestion/Preparation method(s) and revision(s) used. 
• Analysis method(s) and revision(s) used. 
• A detection limit (MDL, RL, PQL, etc.) for each element. Do not list results below this limit. 
• Units (ppm or mg/kg) 
• Results for all nine metals, either: value above reporting limit, or BDL(Below Detection Limit), ND (Not Detected)

What are the Washington standards for metals?

(1) The standards for metals in Washington are the maximum acceptable annual metals additions to soils adopted in RCW 15.54.800 and are presented in Table 2. Because the Canadian standards contained in the Canadian Trade Memorandum T-4-93 dated August 1996 are based on long-term (forty-five-year) cumulative metals additions to soils, the maximum acceptable annual metals additions to soils are determined by dividing the Canadian standards by forty-five. The Washington standards are expressed as pounds per acre per year.
Table 2. Washington Standards For Metals.
Metals
Lbs./acre/yr.
Arsenic (As)
.297
Cadmium (Cd)
.079
Cobalt (Co)
.594
Mercury (Hg)
.019
Molybdenum (Mo)
.079
Nickel (Ni)
.713
Lead (Pb)
1.981
Selenium (Se)
.055
Zinc (Zn)
7.329
(2) To be registered with the department and distributed in Washington, a commercial fertilizer must not exceed the above standards. Because cobalt (Co), molybdenum (Mo), and zinc (Zn) are also plant nutrients, higher concentrations than those presented in the table may be permitted. Commercial fertilizers which contain cobalt (Co), molybdenum (Mo), and/or zinc (Zn) concentrations may be registered and distributed in Washington if those metals are used as plant nutrients and those metals meet all applicable minimum guarantees and labeling requirements of chapter 15.54 RCW and the rules adopted thereunder.
(3) If a commercial fertilizer contains cobalt (Co), molybdenum (Mo), or zinc (Zn) and any one or more of those metals are not intended to be used as a plant nutrient, then the nonplant nutrient metals must meet the Standards shown in Table 2.
 

Micronutrients & Waste-Derived Products

Fertilizers that do not guarantee nitrogen, phosphoric acid, available phosphorus, potash, calcium, magnesium, or sulfur, but meet the minimum guarantees for micronutrients, are classified as micronutrient fertilizers. 

Minimum Guarantees Allowed by Nutrient

NOTE: These minimums do not apply to Hydroponic or Liquid Continuous Feed Fertilizers.

Nutrient  %
Calcium (Ca) 1.0000
Magnesium (Mg) 0.5000
Sulfur (S) 1.0000
Boron (B) 0.0200
Chlorine (Cl) 0.1000
Cobalt (Co) 0.0005
Copper (Cu) 0.0500
Iron (Fe) 0.1000
Manganese (Mn) 0.0500
Molybdenum (Mo) 0.0005
Sodium (Na) 0.1000
Zinc (Zn)  0.0500

Micronutrient fertilizers and waste-derived products require an Ecology Questionnaire and have their own specific metal requirements. 

Metals Concentration TCLP Laboratory Analysis Report

Toxicity Characteristic Leaching Procedure (TCLP): EPA SW 846 Method 1311

  • Concentration analysis reported in parts per million (ppm) of: Arsenic (As), Barium (Ba), Cadmium (Cd), Chromium (Cr), Lead (Pb), Mercury (Hg), Selenium (Se), and Silver (Ag).
  • Use EPA SW 846 Method 1311 (Toxicity Characteristic Leaching Procedure) extraction prior to concentration analysis.
  • The laboratory report clearly states the use of EPA Method 1311 for analyte extraction.
  • Analysis uses a detection limit at, or below, the regulatory limit for each metal (limits listed in Instructions).
  • The laboratory analysis must be conducted 8 months or less from the date your registration application is received by WSDA.

If the product contains only organic ingredients that originate from within the USA, then a Total metal concentrations may be sufficient. The analysis must contain concentrations for barium (Ba), chromium (Cr), and silver (Ag), in addition to the nine metals required by the WSDA.

 

Reference:
https://agr.wa.gov/departments/pesticides-and-fertilizers/fertilizers
https://agr.wa.gov/departments/pesticides-and-fertilizers/fertilizers/heavy-metals

Washington Heavy Metals Analytical Methods Accepted