|
|
|
|
HEALTH ADVISORY ON POLYCHLORINATED BIPHENYLS (PCBs)
The Department of Health recognizes the need to increase the level of awareness about the
health and environmental effects associated with PCB exposure since the Philippines is one of
the countries which recently ratified the Convention on Persistent Organic Pollutants. Under
the provisions of the convention, PCBs will be one of the 12 chemicals that will be phased
out/eliminated or reduced in production in the global market by the year 2025.
What are PCBs?
Commercial PCBs are light or dark yellow in color, fire resistant mixtures of synthetic
aormtic chemicals, manufactured by the chlorination of biphenyl in the presence of a suitable
catalyst. Theoretically, there are approximately 209 varieties (congeners) of PCBs, but only
130 are likely to occur in commercial products. They were popular because they were
inexpensive, did not conduct electricity. Tolerate high temperatures and last for a very long
time. without degrading. They were marketed as as Arochlor, Kennechlor, Pyrochlor, Hyvol,
etc.
Sources and Uses of PCBs
Commercially, PCBs are used as dielectric and heat exchange fluids and in a variety of
other applications. Some other commercial applications of the product were g\for heat transfer,
hydraulic fluids, dye carriers in carbonless copy paper, adhesives and as a plasticizer in
paints. Current sources of PCB release include volatilization from landfill containing
transformer, capacitor and other PCB-wastes, sewage sludge, spills and improper (or illegal)
disposal to open areas. AT present, a major source of PCB exposure in the general
environment is the distribution of PCBs previously introduced into the environment. Explosions
or overheating of transformers and capacitors may release significant amounts of PCBs into
the local environment. PCBs can be converted into furans upon heating at 550- 700 o C
Characteristics of PCBs:
PCBs are fat-loving (liphophlic) substances and as a result they easily enter into the food
chain and accumulate in fatty tissues. PCBs were banned in some countries because they are
persistent in the environment and because widely distributed in the environment throughout the
world and are persistent and accumulate in food webs. PCBs are chemically very stable.
Labeling
PCB containing materials should be properly labeled
Testing for PCBs
PCBs can be determined initially by simple tests thru detection kits; and later on analyzed
thru laboratory analytical tests such as thin layer chromatography and gas chromatography
methods.
Human Exposure:
Human exposure to PCBs has resulted largely from the consumption of contaminated food,
but also from inhalation and skin absorption in work environments.
PCBs accumulate in the fatty tissues of humans and other animals and have caused toxic
effects in both, particularly if repeated exposure occurs. The skin and liver are the major sites
affected, but the gastrointestinal tract, the immune system and the nervous system are also
targets. The results of studies on rodents suggest that some PCB varieties may be
carcinogenic.
Exposures to PCBs may come from any of the following:
workplace practices
hazardous waste sites
leakage or spills from PCB transformers and capacitors
drinking contaminated water
skin contact with contaminated soil
eating contaminated food
breathing contaminated air
fluorescent light ballasts
There have been reports that used transformers and capacitors containing PCBs were
indiscriminately handled and disposed of, by junk shops/dealers, recyclers and other users.
The Department of Health strongly advocates that recycling of materials containing PCBs
should be handled by those who have the adequate training and expertise on PCB retrofitting
and disposal; and the necessary equipment and facilities in handling PCB containing
materials. For PCB disposal, the Environment Department has accredited waste disposal
facilities equipped to handle such materials.
Health Effects
Chloracne is one of the most prevalent findings among PCB-exposed workers. Aside from
this, liver disturbances, irritation of the respiratory tract, dizziness, headache, depression,
sleep and memory disturbances fatigue and impotence.
How to reduce exposure?
PCBs are probable cancer-causing agents; therefore, all contact should be reduced to the
lowest possible level. Many scientists belies that there is no safe level of exposure to PCBs.
Other means to reduce exposure are as follows;
do not eat, drink or smoke in areas where PCBs are handled
after working in the area, wash hands thoroughly before eating
Wear full body protective clothing when working with the chemical
If possible skin contact occurred, wash the contaminated area with copious amounts of
water for 20-30 minutes
What to do if you believe you have an exposure problem?
If you believe you may have some health problems associated with exposure to PCBs,
seek help from a medical physician or call the Environmental and Occupational Health Office of
the Department of Health at Tel Nos. 7116297 or 743 8301 loc. 2325-2327 or the UP-National
Poisons Control and Information Service at Tel No.5241078.