a carcinogenic environmental contaminant that is usually present in a complex
mixture of dioxin-like compounds and is responsible for various adverse effects.
14.3 Sources
Because of awareness and regulatory bodies, many countries have restricted their
production of manufactured products with PCBs (EPA 2019). Halogenated especially brominated or chlorinated DDs and DFs are not formed intentionally; however, these are formed due to various anthropogenic activities, i.e. burning of trash.
In addition to this, natural processes such as forest fires can also trigger formation of
dioxins. Broadly, sources can be identified as following:
14.3.1 Industrial Activities
Dioxin is a contaminant formed as a by-product during production/synthesis of few
chlorinated organic compounds, such as silvex (a commonly used herbicides). In
recent years, regulatory agencies have been putting lots of efforts to reduce/eliminate
the formation of dioxin. Although the concentrations of dioxins have reduced
significantly in last three decades, however, a larger portion of the dioxins exposure
in the environment is mainly due to previous releases that has occurred years ago
(EPA 2019).
14.3.2 Burning
Municipal combustion processes (which use waste incineration and/or from burning
fuels such as oil, coal or wood) are another source of dioxins formation. EPA (2006)
summarizes that anthropogenic emissions are the major source for existing exposure
in the USA, but also without ruling out the possibility of natural sources (EPA 2019).
Burning of household waste or backyard burning can also lead to the formation of
dioxins.
14.3.3 Industrial Bleaching
As per practice, chlorine bleaching based on various industrial processes is also
responsible for production of dioxins leading to environmental hazard.
14.3.4 Smoking
Cigarette smoke is also responsible for production of dioxins in minute quantities.
14 Metabolism of Dioxins and Dioxins-Like Compound, Its Regulation and. . .
295
mixture of dioxin-like compounds and is responsible for various adverse effects.
14.3 Sources
Because of awareness and regulatory bodies, many countries have restricted their
production of manufactured products with PCBs (EPA 2019). Halogenated especially brominated or chlorinated DDs and DFs are not formed intentionally; however, these are formed due to various anthropogenic activities, i.e. burning of trash.
In addition to this, natural processes such as forest fires can also trigger formation of
dioxins. Broadly, sources can be identified as following:
14.3.1 Industrial Activities
Dioxin is a contaminant formed as a by-product during production/synthesis of few
chlorinated organic compounds, such as silvex (a commonly used herbicides). In
recent years, regulatory agencies have been putting lots of efforts to reduce/eliminate
the formation of dioxin. Although the concentrations of dioxins have reduced
significantly in last three decades, however, a larger portion of the dioxins exposure
in the environment is mainly due to previous releases that has occurred years ago
(EPA 2019).
14.3.2 Burning
Municipal combustion processes (which use waste incineration and/or from burning
fuels such as oil, coal or wood) are another source of dioxins formation. EPA (2006)
summarizes that anthropogenic emissions are the major source for existing exposure
in the USA, but also without ruling out the possibility of natural sources (EPA 2019).
Burning of household waste or backyard burning can also lead to the formation of
dioxins.
14.3.3 Industrial Bleaching
As per practice, chlorine bleaching based on various industrial processes is also
responsible for production of dioxins leading to environmental hazard.
14.3.4 Smoking
Cigarette smoke is also responsible for production of dioxins in minute quantities.
14 Metabolism of Dioxins and Dioxins-Like Compound, Its Regulation and. . .
295