Fact Sheet

1998 Washington State
fertilizer and soils studies

Washington State has passed the first law in the nation that sets standards for heavy metals in fertilizers sold to farmers and home consumers. Its aim is to protect consumers and the environment from excessive buildup of metals in Washington's soils. When it passed the law in early 1998, the Washington State Legislature also ordered the state Department of Ecology (Ecology) to sample fertilizers for dioxins to give the state baseline information. In addition, Ecology was directed by the Legislature to study the levels of dioxins in soils around the state to estimate background levels of these substances. Similar fertilizer and soils studies were conducted for metals as part of Ecology's effort to evaluate the effectiveness of the new fertilizer law. This fact sheet outlines the preliminary results of those studies.

General Observations

Study results confirm that most fertilizers have low levels of heavy metals, and most fertilizers had non-detectable or extremely low levels of dioxins. The tested soils had dioxins at low concentrations with a few exceptions, but the study is incomplete at this time because we were unable to test for dioxins on agricultural lands.

We do know that metals have been added to the soil by agricultural practices. The studies conclude, however, that heavy metals in agricultural soils do not appear to pose a threat to human health or the environment in the region studied. State regulators believe additional sampling of fertilizers and soils is needed to refine these initial results and to detect any future changes. To that end, metals in fertilizers will be monitored through Washington's fertilizer law, and Ecology will recommend periodic soil sampling as well.

Final results and recommendations for action are expected in spring 1999 after Ecology discusses the information with experts in the field and with the state's Fertilizer Advisory Workgroup, which is made up of representatives from agriculture, environmental and labor groups, the fertilizer industry, and government agencies.

Metals in fertilizers

Ecology tested 50 commercial and home-use fertilizers and one soil amendment for eight heavy metals: Arsenic, barium, cadmium, chromium, lead, mercury, selenium, and silver. (In the interest of brevity, all 51 will be referred to as "fertilizers".) Listed below are the five fertilizers that had the highest levels of metals for which Washington has standards. As with all fertilizers, they are going through review under Washington's fertilizer law. If they do not meet the state's new fertilizer standards, the manufacturer of each product will have the opportunity to appeal the test results or change the product before it is removed from sale in Washington.

Products with highest level of each metal
covered under Washington fertilizer standards

All values are in parts per million, dry weight

Product	Metal/Level	Status under WA fertilizer law
Commercial Fertilizers
Frit F-420G	9,490 ppm lead	Sample taken from a regional distributor in Oregon. Not registered for distribution in Washington.
Frit F-503G	10.06 ppm mercury	Registered in WA with revised labeling that sets a maximum application rate.
Agrium Ammonium Phosphate Sulfate	160 ppm cadmium	Registered in WA with revised labeling that sets a maximum application rate.
Home Use Fertilizers
NuLife All-Purpose Trace Elements	75.2 ppm arsenic	Not registered for distribution in Washington.
Thrifty-Payless Tomato & Vegetable Food 5-10-10	5.71 ppm selenium	In registration process. No determination at this time.

Potential action on waste-derived fertilizers

Of particular interest to the state are fertilizers that contain recycled industrial waste products. In addition to meeting Washington's new fertilizer requirements, these "waste-derived" fertilizers also must meet state and federal regulations for industrial wastes that are recycled by being applied to the land as a fertilizer or soil improvement product. These standards are more stringent than those applied to fertilizers that do not contain recycled industrial wastes.

The state subjected all of the fertilizer samples to the metals test that must be passed by waste-derived fertilizers. All of the seven products that failed this test did so only for cadmium. All of the products passed for all other metals.

Ecology is investigating the products that failed the recycled waste test in order to determine whether they include certain industrial wastes. Any of the fertilizers that contain hazardous waste could be found in violation of hazardous waste regulations and removed from the market in Washington unless the manufacturer is able to reformulate the product.

There is, however, a notable exception. Some of the products may not be subject to regulatory action because their recycled ingredient, steel mill flue dust, was exempted by the U.S. Environmental Protection Agency (EPA) from federal requirements. This is of concern to the state because fertilizers containing some of the highest levels of metals and dioxins of all products tested are likely derived from recycled steel mill flue dust. Washington proposes to eliminate the federal exemption that allows steel mill flue dust to bypass hazardous waste regulations when it is recycled into fertilizer. This proposed change, which must be subjected to a formal public process, would apply to Washington State only.

Dioxins in fertilizers

A little background is needed in order to understand dioxin test results.

There are 17 similar chemicals of varying toxicity that are often referred to simply as dioxins. Mixtures of these 17 are typically found when a material such as soil or fertilizer is analyzed. The relative toxicity of these mixtures is usually measured using "Toxic Equivalents" (or TEQs). The most toxic dioxin is called 2,3,7,8-TCDD. Other similar dioxins have been assigned toxicities relative to it. The concentrations and relative toxicity of each form are used to determine the overall toxicity (TEQ) of a material. TEQs in this study are reported in parts per trillion.

Standards for dioxins in fertilizers have not been developed at this time.

Of the fertilizers tested, more than 70 percent had dioxin TEQs of less than one-tenth of one part per trillion (0.1ppt), and only three fertilizers (about 6 percent) had TEQs of more than 10 ppt. The three fertilizers that tested above 10 ppt TEQ merit further research into the source of dioxins found in those products.

Sampled products with dioxins
greater than 10 parts per trillion TEQ

Bulk/Packaged Agricultural Fertilizers/Micronutrients	Dioxin TEQ
Frit F-420G -- Sample taken from a regional distributor in Oregon. Not registered for distribution in WA.	287 ppt
Frit F-503G (2 samples)	26.8/145
Home Use Packaged Fertilizer Products
NuLife All-Purpose Trace Elements -- Not registered for distribution in Washington.	54 ppt

Metals in soils

Since Washington's new fertilizer law is designed to limit the buildup of heavy metals in state soils, it is important to know the level of metals currently in agricultural soils so we can track any changes over time. In 1998, Washington tested 20 sites that are regularly used to grow crops and 13 corresponding sites that have never been farmed. All of the sample sites were in the Columbia Basin because the federal irrigation project there provides a clear history of where and how long the land has been cultivated.

Data from this study indicate that arsenic, copper, mercury, nickel, and lead do not show significant differences in concentration between the agricultural fields and non-farm background sites. Only cadmium and zinc concentrations were significantly higher in farmed sites than never-farmed locations. Agricultural practices in the past 50 years are the most likely cause of increased zinc and cadmium.

Current levels of these metals do not cause an immediate concern for human health and the environment for the following reasons:

All samples in this study, including cadmium and zinc, were at the low end of the background range for metals as determined in three earlier studies, including one study conducted in Washington by Ecology in 1994;
Zinc is a necessary plant nutrient that is regularly added to soil in Eastern Washington because it does not have adequate zinc to support healthy crops. The levels found in the soil do not pose a threat either to human health or the environment.
Cadmium is of particular concern in the long term because of its toxicity and tendency to be taken up by plants and eventually accumulated in the tissues of fish and mammals. This concern is balanced in the agricultural setting because plants preferentially uptake zinc rather than cadmium, and zinc from fertilizers is in a form that is more readily available to plants than cadmium.

Ecology will recommend that metals levels in state soils be periodically monitored to ensure levels do not become a concern in the future.

Dioxins in soils

At this time, only part of the dioxin soil study has been completed. All of the 30 samples in this preliminary report were taken from non-farm sites because of growers' concern over confidentiality of sample locations. A study of dioxin levels in agricultural soils may be conducted in 1999. The results of sampling conducted to date show that:

Dioxins are found in soils throughout the state. Even remote wilderness areas had detectable levels of dioxins;
Open areas, prairies, rangeland and forested areas in Western Washington have higher levels of dioxins than similar areas in Eastern Washington;
Urban areas have higher levels of dioxins in soil than open or forested areas.
Tacoma had the two highest dioxin samples (9.47, 19.5 ppt TEQ). However, the results cannot be compared to other cities because sample sites in Tacoma were closer to historical industrial areas than samples taken from other urban areas;
The results of this study indicate that the levels of dioxins detected in Washington State are similar to levels found in studies conducted in other parts of the world.

For More Information

Greg Sorlie, Department of Ecology, (360) 407-6702
Ted Maxwell, Department of Agriculture, (360) 902-2026
Jim O. White, Department of Health, (360) 236-3181

If you have special accommodation needs or require this document in alternative format, please contact Ron Langley at (425) 649-7009 (voice) or (425) 649-4259 (TTY).

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