PCBs What’s this ?PCBs What’s this ?

But really … But really …

They are more or less viscous or resinous liquids,

insoluble in water, colourless or yellowish. 

They only break down at temperatures exceeding 1000 ° C.

They can dissolve or soften some rubbers and plastics.

These persistent pollutants (half-life of 94 days to 2 700 years depending on the molecules) have a high toxicity.

They are found in some fatty tissues in humans, including human milk.

Blood test is generally used to detect contamination.

P……,C……,B……P……,C……,B……

poly = severalpoly = severalchloro = chlorine atomschloro = chlorine atomsbi = twobi = twophenyl = phenyl = group of atoms of carbon and hydrogengroup of atoms of carbon and hydrogenbiphenyl = Cbiphenyl = C1212HH1010

polychlorobiphenyl = Cpolychlorobiphenyl = C1212HH(10-x-y)(10-x-y)ClCl(x+y)(x+y)

ExampleExample

PCB 2,3,5’,6’- tetrachlorobiphenyl PCB 2,3,5’,6’- tetrachlorobiphenyl

is represented by the formula :is represented by the formula :

CC1212HH66ClCl44

A living molecule …A living molecule …

What are the dangers to humans and What are the dangers to humans and the environmentthe environment??

PCBs are toxic, subject to bioaccumulation, they persist in PCBs are toxic, subject to bioaccumulation, they persist in

the environment due to their slow biodegradability.the environment due to their slow biodegradability.

They are strongly suspected of being carcinogenic, without They are strongly suspected of being carcinogenic, without

this having been provedthis having been proved..

The safety standards of PCBs The safety standards of PCBs

The protection of health is the main axis of these standards.

These contaminants are hazardous to health.

Food is the major route of exposure to contaminants.

The dioxin-like PCBs are both highly toxic and carcinogenic.

-The new standards which were adopted constitute a major

advance in the protection of health as they set new

maximum levels.

- So from now on the countries affected by the presence of

dioxin-like PCBs may take measures to protect consumers.

The new standardsThe new standards

The standards in figuresThe standards in figures

Accepted standard of PCB content in fish :

8 pg / g

Accepted standard of PCB content in food :

70 picograms / kg / month