US EPA

In 2006, EPA published an inventory of sources and environmental releases of dioxin-like compounds in the United States. This draft report presents an update and revision to that dioxin source inventory. It also presents updated estimates of environmental releases of dioxin-like compounds to the air, water, land and products. The sources are grouped into five broad categories: combustion sources, metals smelting/refining, chemical manufacturing, natural sources, and environmental reservoirs. Estimates of annual releases to land, air, and water are presented for reference years 1987, 1995, and 2000.

While the overall decreasing trend in emissions seen in the original report continues, the individual dioxin releases in this draft updated report are generally higher than the values reported in 2006. This is largely due to the inclusion (in all three years) of additional sources in the quantitative inventory that were not included in the 2006 report. The largest new source included in this draft updated inventory was forest fires. In the 2006 report, this was classified as preliminary and not included in the quantitative inventory. The top three air sources of dioxin emissions in 2000 were forest fires, backyard burning of trash, and medical waste incinerators.

Dioxins are toxic chemicals that naturally exist in the environment and can be released into the environment through forest fires, backyard burning of trash, certain industrial activities, and residue from past commercial burning of waste. When released into the air, dioxins may be transported long distances. Because of this, dioxins are found in most places in the world. Dioxins released to the air will settle onto vegetation and soil that are consumed by animals. Dioxins may enter water bodies through erosion and runoff or from direct discharge of wastes. When dioxins are released into water, they tend to settle into sediments where they can be further transported or ingested by fish and other aquatic organisms. Dioxins break down very slowly in the environment and can be deposited on plants and taken up by animals and aquatic organisms. Dioxins are lipophilic, which means they tend to accumulate in fats. Because of this, they may be concentrated in the food chain so that animals have higher concentrations than plants, water, soil, or sediments. Since humans are at the top of the food chain, our bodies have the highest concentrations of dioxins. Over the past two decades EPA has worked to reduce emissions from all of the major industrial sources of dioxins As a result of the efforts of EPA, state governments and industry, known and quantifiable total dioxin emissions in the U.S. have been reduced by about 75% from 1987 levels and emissions to air have been reduced by about 85% from 1987 levels.

The Report Presents An Update To The Dioxin Source Inventory Published In 2006 (U.S. Epa, 2006). The Peer-Review Panel For The 2006 Document Provided Additional Comments After The Final Report Had Been Issued. The Purpose Of This Document Is To Present Revisions And New Material In Response To These Comments. The Document Presents Estimates Of Environmental Releases Of Dioxin-Like Compounds To The Air, Water, Land And Products. Release Estimates Are Provided For The Years 1987, 1995 And 2000.

Following the public comment period and external peer review, EPA will revise the document and post the final report on the EPA website.

U.S. EPA. Update to An Inventory of Sources and Environmental Releases of Dioxin-Like Compounds in the United States for the Years 1987, 1995, and 2000 (2013, External Review Draft). U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-11/005A, 2013.

Comments on the assessment may be submitted and reviewed using the e-Government Regulations.gov Web site. From the site, select “Environmental Protection Agency” and the keyword “EPA-HQ-ORD-2011-0805 (for the docket ID) to comment on this report.