The UNDP-GEF POPs Resource Kit - International POPs Elimination ...

treatment, especially for control of bunt of wheat. HCB has also been used as a solvent in
pesticide applications.
Most pesticide applications of HCB may already have been discontinued in most
countries. Nor do there appear to be significant remaining economic or technical barriers to
the complete elimination of HCB for intentional use in pesticide applications. However, HCB
has also been widely produced as an intentionally produced chemical intermediate in
production processes. Some military applications of HCB have also been reported, including
use of HCB in smokescreens and in tracers.
Finally, HCB is also produced as an unintended byproduct in the manufacture of
some industrial chemicals (especially some chlorinated solvents), and in the manufacture of
some pesticides. When this happens, HCB may be present as an impurity in the product.
Significant quantities of HCB can also be generated and released to the environment in some
combustion processes.
Under the Stockholm Convention, intentional uses of HCB will be phased-out and
banned. In addition, measures will also be required to reduce and minimize releases of HCB
when it is generated as an unwanted byproduct, and the aim of these measures should be
elimination. Implementation of measures to eliminate non-pesticide uses of HCB, and to
effectively minimize HCB as an unwanted byproduct may encounter economic, technical or
other barriers.
Polychlorinated Biphenyls. Polychlorinated biphenyls (PCBs) are a class of
chlorinated hydrocarbons that have been widely used as industrial chemicals since 1930.
There are 209 varieties of PCBs, and most commercial PCB applications have involved
mixtures of these PCB varieties. Under the Stockholm Convention, intentional production of
PCBs will be banned, and PCB use will be phased out.
Large quantities of PCBs were produced for use as a cooling and dielectric fluid in
electric transformers and in large capacitors. PCBs have also been widely used as hydraulic
fluids and as heat exchange fluids. Other PCB applications have included use as a sealant, as
a paint additive, as an additive in some plastics, as a component of carbonless copy papers,
and others.
PCBs can also be formed and released as unwanted byproducts in some chemical and
combustion processes.
Intentional PCB production was ended in most countries by 1980. The major
exception to this was in the former Soviet Union and some Central European countries. Most
transformers and capacitors built after 1980 do not contain PCBs. New PCBs in other
applications also became rare. The major exception to this is transformers and other PCB
applications produced since 1980 in the former Soviet Union.
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