U.S. EPA Contaminated Site Cleanup Information (CLU-IN)

U.S. Environmental Protection Agency
U.S. EPA Technology Innovation and Field Services Division

Adobe PDF LogoReference Guide to Non-combustion Technologies for Remediation of Persistent Organic Pollutants in Soil, Second Edition - 2010

This report is the second edition of the U.S. Environmental Protection Agency's (US EPA's) 2005 report and provides a high level summary of information on the applicability of existing and emerging noncombustion technologies for the remediation of persistent organic pollutants (POPs) in soil.

Persistent Organic Pollutants (POPs)


(Remediation Only)

Persistent organic pollutants (POPs) are toxic chemicals that originate from man-made sources associated with the production, use, and disposal of certain organic chemicals. Many of the chemicals were produced commercially for pest and disease control, crop production and industrial use. Some of the POPs such as pesticides and polychlorinated biphenyls (PCBs) are intentionally produced, while others such as dixion and furans are unintentional by-products of industrial processes or result from the combustion of organic chemicals.

Under the Stockholm Convention on POPs (Stockholm Convention), which was adopted in 2001 and enacted in 2004, parties committed to reduce or eliminate the production, use, and release of the 12 POPs of greatest concern to the global community. In October 2008, the Stockholm Convention’s subsidiary body – the POPs Review Committee (POPRC) held its fourth meeting (POPRC-4) and an outcome of that meeting was that it recommended to the Conference of the Parties (COP) that nine (9) additional chemicals be added to the Stockholm Convention. In October 2009 at POPRC-5 meeting, several chemicals underwent a review process by the Committee.

The 24 POPs currently within the scope of the Stockholm Convention (or under review) include 14 pesticides and 10 industrial chemicals or by-products.

The 14 pesticides targeted by the Stockholm Convention were produced intentionally and used on agricultural crops or for public health vector control.; Over time, significant human health and environmental impacts were identified for these pesticides.; By the late 1970s, these pesticides had been banned or subjected to severe use restrictions in many countries.; However, some of these 14 pesticides are still used in parts of the world where they are considered essential for protecting public health.

The 10 industrial chemicals and by-product POPs within the scope of the Stockholm Convention include PCBs, dioxins, furans, brominated flame retardants (BFRs), perfluorooctane sulfonate (PFOS), and pentachlorobenzene. PCBs were produced intentionally but typically have been released into the environment unintentionally. Most countries stopped producing PCBs in the 1980s; for example, equipment manufactured in the US after 1979 usually does not contain PCBs.; However, older equipment containing PCBs is still in use. Dioxins and furans are usually produced and released unintentionally. They may be generated by industrial processes or by combustion, including fuel burning in vehicles, municipal and medical waste incineration, open burning of trash, and forest fires.

Another treaty regulating POPs internationally is the Basel Convention on the Control of Transboundary Movements of Hazardous Wastes and their Disposal (Basel Convention). In response to Stockholm Convention provisions requiring coordination with the Basel Convention on POPs waste issues, the Basel convention developed guidance on the environmentally sound management of POPs waste. In 2004, the Basel Convention invited signatories of the Stockholm Convention to consider its recommendations on environmentally sound management for POPs wastes. The US is a signatory to the Basel Convention on POPs – but has not yet ratified the Convention.

In addition to the Stockholm Convention, the Convention on Long-Range Transboundary Air Pollution (LRTAP), a regional international treaty addresses environmental issues of the United Nations Economic Commission for Europe (UNECE) with a primary focus on air emissions. The LRTAP Convention has been extended by eight (8) Protocols that include specific requirements for countries to reduce air pollution including long-range air pollution. In 1998, the LRTAP Convention adopted a Protocol on POPs to regulate the production and use of 16 chemicals that were singled out according to agreed risk criteria. The table below lists all of the 26 chemicals identified under the Stockholm Convention on POPs and the LRTAP’s Protocol on POPs - both currently listed and under review.

POPs Identified by the Stockholm Convention and Long-Range Transboundary Air
Pollution Convention


Stockholm Convention Long-Range Transboundary Air Pollution Convention
Currently Listed Under Review (2009)
Dichlorodiphenyltrichloroethane (DDT)  
Hexachlorobenzene (HCB)  
Industrial Chemicals or By-Products
Hexabromocyclododecane (HBCDD)  
Hexachlorobutadiene (HCBD)    
Octabromodiphenyl ether  
Pentabromodiphenyl ether (penta-BDE)  
Perfluorooctane sulfonate (PFOS)  
Polychlorinated biphenyls (PCB)  
Polychlorinated naphthalenes (PCN)    
Short-chained chlorinated paraffins (SCCP)  

Note: Nine additional chemicals that were recently listed by the Stockholm Convention in May 2009 are shown in bold.