OMRI proposes limits on heavy metals in fertilizers and soil amendments

June 1, 2006
17 July 2006

Comment period is now closed. View summary of comments received.

OMRI is in the midst of completing a project to establish thresholds for some heavy metals in fertilizers and soil amendments. The public may make comments on the proposal. The OMRI Board will decide whether to accept the pending proposal after the public comment period closes and staff has made any adjustments based on the comments received.  Any policy decision will be implemented within 60 days of the board decision.

Overview:

OMRI proposes that steps be taken to avoid the use of fertilizers that contain levels of heavy metals that can contaminate soil, water, and crops. OMRI has identified arsenic, cadmium, and lead as the top priority metals that need attention. Organic certifiers are advised to restrict the use of fertilizers that may degrade the average levels found in soils in the United States. Organic farmers would be asked to describe and carry out measures to avoid long term accumulation of the metals in those fertilizers in their soils. OMRI proposes to inform users about those products that have the potential risk to accumulate in soil and contaminate crops and water. Fertilizers and soil amendments that exceed limits based on the Washington State Department of Agriculture (WSDA) loading rates are proposed to not be eligible for OMRI Listed® status. OMRI recommends that the US Department of Agriculture explicitly recognize that fertilizers that exceed those loading rates violate NOP standards.

Justification:

Heavy metals in fertilizers and other soil inputs are a threat to the sustainability of organic agriculture, and pose a food safety threat where they are taken up by plants. Heavy metals are present in edible tissue, pollute water resources, and may be toxic to plants themselves. The NOP rule requires producers to manage crop nutrients in a manner that does not contribute to the contamination of crops, soils, or water by heavy metals (7 CFR 205.203(c) and 7 CFR 205.203(d)). Further, arsenic and lead are prohibited for use in organic production, even from natural sources (7 CFR 205.602). Currently, OMRI has thresholds for heavy metals in micronutrient products based on the WSDA standards with some changes, but no standards exist for heavy metals in other fertilizers and soil amendments.

Proposal:

OMRI Staff in consultation with the Advisory Council proposes the following approach:

1. Concentrate on arsenic, cadmium, and lead as priority contaminants. While OMRI reserves the right to restrict or prohibit fertilizers that contain other contaminants of soil, plants, and water, analyses for priority contaminants are required for all fertilizers and soil amendments.
2. Establish three broad categories of fertilizers based on estimated average loading rates.
3. Set two thresholds for each of the priority contaminants.
    
   • Caution – exceeding lower limit results in the issuing of a ‘Caution’ statement and annotation on the OMRI Products List. OMRI Status (Allowed or Restricted) of a given compliant product remains unchanged.
   • Danger – exceeding the higher limit results in informing the supplier and subscribers of the ‘Danger’ of potential accumulation and long-term contamination of organic soil, crop, and water. OMRI will not assign ‘Prohibited’ status to such products in the absence of the establishment of a standard by the NOP, but OMRI will not list such products on the OMRI Products List.

Additional Documents:

To view the full text of this proposal, click here.

Also, as a background study, Brian Baker and Diana Tracy prepared a study entitled Heavy Metals in Fertilizers Used in Organic Production

Finally, as part of the proposal, OMRI would amend our current policies as contained in the OMRI Operating Manual.

Specific Questions for commenters:

1. Do you support the approach suggested in the conclusion section of this report? If not, please explain why. What alternative(s) do you suggest?
2. Are the specific thresholds outlined in Table 5 appropriate? If not, please explain why. What alternative(s) do you suggest?
3. Do you support the three broad categories of products and the assumed application rates? If not, please explain why. What alternative(s) do you suggest?

How to comment:

Clearly indicate if you are for or against the proposal or some part of it and why. Include recommended wording changes as appropriate. Include a copy of articles or other references that support your comments. Only relevant material should be submitted.

Comments can be emailed to HeavyMetalComment@omri.org, faxed to 541-343-8971, or sent by mail to the OMRI office to be received by July 16, 2006, attention: Brian Baker, Research Director.  Comment period is now closed.