Dioxin and Furan Standard Mixtures

Dioxins is the abbreviated name for a family of toxic, structurally related chemicals. In their pure form, dioxins are typically colourless crystalline solids. Most dioxins and furans are not intentionally manufactured; instead, they are commonly formed as unwanted by-products of industrial and combustion processes.

The most well-known dioxin is 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), often referenced as one of the most toxic members of this chemical family. The broader term “dioxins” is frequently used to include:

• Polychlorinated dibenzo-p-dioxins (PCDDs)

• Polychlorinated dibenzofurans (PCDFs)

• Certain dioxin-like PCBs (polychlorinated biphenyls) with similar toxicological profiles

Hundreds of dioxin-related compounds have been identified, but only a smaller subset is considered highly toxic—with TCDD among the most potent.

Dioxins and furans are environmental pollutants classified within the broader group of persistent organic pollutants (POPs). They are of concern because they are:

• Highly toxic at very low concentrations

• Persistent and resistant to degradation

• Able to bioaccumulate in fatty tissues

• Capable of biomagnification through the food chain

Human exposure has been associated with adverse biological effects, including changes in hormone regulation and dermatological effects such as chloracne. Animal studies have also shown impacts on reproductive systems, fetal development, and immune function.

These contaminants can enter the body via:

• Breathing contaminated air

• Drinking contaminated water

• Eating contaminated food

Because dioxins and furans are readily absorbed into fat tissue, they can remain in the body for extended periods. Reported biological half-lives are often measured in years, reflecting their persistence.

How Dioxins Enter the Food Chain

In the environment, dioxins and furans tend to accumulate in the food chain. Concentrations generally increase at higher trophic levels, meaning animals higher in the food chain can carry higher burdens.

While dioxins may be detected in air and soil, dietary intake is typically the dominant exposure pathway, especially through foods with higher fat content. Higher levels have been reported in foods such as:

• Dairy products

• Meat

• Fish and shellfish

Additional exposure risks can occur near certain industrial operations (e.g., incineration and high-temperature processes), and even wildfires may contribute small amounts due to combustion-related formation pathways.

Other Sources of Contamination

Large stores of PCB-based industrial oils and waste still exist globally, and some of these materials can contain significant levels of PCDFs. Long-term storage, leaks, or improper disposal may lead to environmental release and contamination of animal and human food supplies.

Because PCB waste is difficult to dispose of safely, it must be managed as hazardous waste, often requiring destruction via high-temperature incineration in specialised facilities.

Many countries now monitor dioxin and furan levels in food and feed. Ongoing surveillance supports early detection of contamination events and helps reduce wider public health impacts.

Prevention and Control

The most effective way to reduce exposure is preventing formation and release at the source. Key measures include:

• Tight control of industrial processes that can generate dioxins and furans

• Minimising emissions from combustion-related activities

• Preventing secondary contamination throughout the food chain

When contaminated materials must be destroyed, proper high-temperature incineration is widely regarded as the most effective option, typically requiring temperatures in the range of ~850°C to 1000°C, depending on system design and waste characteristics.

Ensuring food safety also requires strong controls during production, processing, distribution, and sale to reduce the risk of contamination reaching consumers.