Copyright © 1997 The Seattle Times Company
Thursday, July 3, 1997

Heavy Metals in Fertilizers

(A supplement to The Seattle Times Special Report 'Fear in the Fields')


Heavy metals tested in fertilizers by the Washington Department of Agriculture. Fertilizer samples were collected in 1993 and 1994. Lab tests were performed April 30, 1997, by Columbia Analytical Services, Kelso, Wash. Source: WSDA May 16 memo to The Seattle Times.

Cadmium (ppm)Lead (ppm)Arsenic (ppm)Zinc (ppm)Zn/Cd ratio
> 100:1 recommended

U.S. limit for heavy metals in fertilizerno limitno limitno limitno limitna
Canadian limit for heavy metals for each 5% N*20500751850na
Guaranteed nutrients (NPK) (%) Fertilizer registered by:
10.9-18.2-25.5Cenex Supply, Quincy563002364065
14-15-21Pacifex, Moses Lake3434603730110
18-8-0Simplot Soilbuilders, Yakima250236615
31-10-0Wolfkill Feed & Fertilizer, Othello200097249
5-23-23-6, w/sulfur 6Wolfkill Feed & Fertilizer, Royal City15046800453
16-20-0-14, w/sulfur 14Saddle Mountain Supply Co., Royal City132405430418
4/15/34Crop Production Services, Quincy6313962701045
5-21-21-16, w/sulfur 15.9Wolfkill Feed & Fertilizer, Othello401060001500
23-11-13Quincy Farm Chemical30102990997
15-40-0Pacifex, Pasco,1006767
37-0-0 Wolfkill Feed & Fertilizer, Othello00012na
27-0-14Full Circle Inc., Ephrata00012na
39-0-0-6, w/sulfur 6Full Circle, Inc., Quincy0004na
37-0-0-7, w/sulfur 7Full Circle, Inc., Quincy0004na
28-9-9Crop Production, Othello00103530na
28-0-7Saddle Mountain Supply Co., Royal City000150na
Nitro Cal 21-0-0, w/ calcium 11, sulfur 9Cominco Fertilizer, Spokane00016na
27-0-8Pacifex, Pasco,00024na
34-0-0Nexus Ag Chemical, Inc., Quincy.0002na

* Standard shows Canada's maximum acceptable metal concentration in fertilizers and soil supplements containing processed sewage or industrial byproducts. Acceptable concentrations in these products increase proportionally with total nitrogen conduct above 5%. (U.S. has no similar limit. U.S. sludge standards are not comparable.) Sources: Ag Canada, World Health Organization.

Let us know what you think. E-mail Duff Wilson at dwil-new@seatimes.com

Background & related info.

  • Fear in the Fields, Part 1 & 2
  • Examples throughout the country
  • Tag-along toxics
  • From factories to fields
  • Two approaches to toxins in fertilizer
  • What's known, and not known, about toxics, plants and soil
  • Experts: How to reduce risk
  • Resources on the World Wide Web
  • Here are some officials to call or write