The resources found on this page contain information concerning heavy metals in inorganic fertilizers. The information includes sample analysis data for fertilizer samples collected by the Minnesota Department of Agriculture (MDA), heavy metals screening evaluations conducted by the Minnesota Department of Health (MDH), and specific heavy metal product information available from other states.
The following reports contain analytical data for metals found in fertilizers being distributed in Minnesota. Since 1997 the MDA has sampled fertilizer products and tested for metals including arsenic, cadmium, lead and mercury. The fertilizer manufacturer, product names and analytical results are included in the reports listed below. However, please note that several products that were tested are no longer registered or licensed for sale in Minnesota. In addition, other products have been reformulated from new source materials with lower metals content.
For questions about specific fertilizer products and data, contact: Paul McNelly, Minnesota Department of Agriculture, 651-201-6560.
Key to terms or symbols within the reports:
From 1997 to the most recent data, the reporting limits for each metal (< values) have changed, and in most cases decreased, for several reasons. The MDA had originally requested that the data be reported as less than a defined Action Reporting Limit (ARL). The actual levels found in the sample may have been significantly less than the ARL value that was reported. The ARL’s originally used were identical to the pollutant concentration limits, established for exceptional quality biosolids by the U.S. Environmental Protection Agency (40 CFR Part 503), since no other standards for metals in fertilizers had been established at that time. The ARL’s were later discontinued and use of standard MDA Laboratory Method Reporting Limits (MRL’s) was implemented. The MRL is the lowest value that a laboratory can accurately or confidently report a given metal analysis. Over time the MDA Laboratory methodologies have implemented even lower MRL’s.
The MDH has conducted screening evaluations of heavy metals in inorganic fertilizers at the request of the MDA. Screening evaluations were completed by MDH staff in 1999 and again in 2008. The 2008 screening evaluation was requested since several new risk assessments were made available or older risk assessments were reevaluated since the original 1999 MDH evaluation. Information concerning potential health risks associated with metals in fertilizer and copies of the screening evaluations can be found on the MDH web site:
For questions about potential health risks from fertilizers, contact: Chuck Stroebel, Minnesota Department of Health, 651-201-4927.
Other states provide specific information on heavy metals in fertilizers on the internet at the links found below.
Carol DurdenState Program AdministratorCarol.Durden@state.mn.us651-201-6379
Pesticide & Fertilizer Management Division