(A case for removing apprehension regarding perceived environment
negatives of plastics.)
By
Dr. A.N. Bhat, Director General
Indian Centre for Plastics in the Environment
Criteria for environment friendliness
For discussing environment friendliness of any product we
need to keep a few important criteria in mind. These are (i)
conservation of resources e.g. raw materials, energy, water
and minimization of emission to air/water during manufacture
(ii) performance superior to alternatives, help conserve resources
and (iii) recyclability, biodegradability, reusability or
alternative disposal methods with least burden on environment.
If one strictly applies these criteria, plastics will clearly
be seen to be an environment friendly material.
Processing and resource conservation
Take the case of first criterion. Plastic processing involves
mild temperatures, thereby using less energy, and does not
result in polluting water or air, the way paper or jute manufacturing
pollutes. It is perhaps for this reason that Central Pollution
Control Board in their Guidelines for Management of Consent
and Authorization (2001) has classified plastic processing
under Green category while paper and jute belong to Red category.
In view of this, it is difficult to understand why many times
the so called environmentalists appeal to consumers to use
paper bags instead of plastic bags!
Performance/weight ratio
On the second criterion, plastics out performs other substitutes.
This is because of an inherent property of plastics. Their
performance/weight ratio is very high. It has been estimated
that for packing 500gm. of coffee one would need 500gm of
glass container, 130gm of tin container, but only about 12gm
in case of plastic packaging. Imagine the extent of conservation
of resources by plastic. The advantage does not stop here.
If we had to transport one tonne of packed coffee from one
part of the country to another, one would need to transport
one additional tonne in case of glass packaging, 260kgs in
case of tin, while it would be only 24kgs in case of plastics.
This would result in saving on fuel, wear and tear or carrier
trucks, as well as that of road etc. Indirectly plastics usage
as a packaging material is a great boon on environment grounds.
Plastic has also prevented massive deforestation by offering
wood substitutes like furniture, building material, crates
etc. In fact plastics have rendered help in afforestation
programnmes in a major way e.g. nursery bags, drip irrigation
etc. Minor irrigation system using sprinklers (drip and minor)
have been reported to help in conserving water to an extent
of 40% to 70%. Plastic packaging prevents wastage of agricultural
products and processed foods to an extent of 25-30%. Plastic
woven sacks conserve 4 million tones of cement avoiding losses
via seepage as in traditional sacks. Similarly plastic pipes
conserve material e.g. 1 Km of plastic pipe uses 1.7 MT while
1Km metal pipes need 10 MT. Thus plastic enables to get more
out of less, and ensures sustainable development programmes.
Recyclability and Disposal
Coming to the third criterion, viz disposal issues, it should
be noted that plastics are crushable and highly compactable
occupying less space in land fills. They are predominantly
eco-neutral and do not leach any chemicals to contaminate
soil and ground water. In fact plastic films and sheets are
used for protecting lining of hazardous landfills. Some people
fear that plastic being non-biodegradable can cause harm to
environment. For the types of application of plastics, its
non-biodegradability is an asset. In any case, total mineralisation
of a solid waste is a very lengthy process requiring special
anaerobic conditions and methanogenic bacteria. Newspapers/telephone
directories from landfills after 40 years were readable. Similarly
perishable products like waste food, raked loaves and lumber
was found in landfills even after 25 years.
Plastics are 100% recyclable via various routes:
(i) Mechanical recycling by which plastics can be recycled
several times into economically useful low cost products e.g.,
Footwear, Mats, Sewer Pipes etc.
(ii) Waste plastics are also recycled without sorting into
synthetic lumber/wood products like rails, fencing, ports
etc.
(iii) Plastics can be thermally recycled to recover energy.
(iv) Plastics can be chemically recycled to recover monomer
e.g. engineering plastics.
In India we already recycle 60% of plastics from both industry
and urban waste stream.
Briefly, let us look at a scenario if plastic packaging were
replaced with traditional materials like paper, cloth, jute,
metals etc. This will lead to a major penalty on the economic
system. Phenomenal increase would be affected in weight of
packaging (300%), volume of waste (160%), energy requirement
(100%), and cost of packaging (210%). There are thus no eco
viable alternatives to plastics in modern society.
If from the above analysis plastics are environment friendly,
why is there so much of opposition to use of plastics from
environmentalists or regulatory agencies in the country? The
indiscriminate littering of light plastic bags by our people
on the roads, parks, beaches and other public places results
in ugly sight. Inefficient and inadequate management of solid
waste in our country compounds the problem. There is thus
a need to educate masses against littering, and improving
solid waste management by civic authorities. This can be achieved
by combined efforts from Government, Industry and Citizen
groups.
Before concluding this paper, it would be useful to refer
to some of the myths regarding safety issues in use of plastics,
and provide factual details. It is particularly widespread
in case of PVC products.
PVC and safety issues: Myths and Facts
Some people are worried that PVC may contain Vinyl chloride
monomer (VCM), which is believed to be a carcinogen. Actually
this link was made in the 70's. With introduction of revised
production technology, since late 70's, not a single case
of angiosarcoma has been identified among workers in any PVC
factories. The problem has been eliminated.
Have most of our NGOs been fair in terming plastic as the
main environmental pollutant while ignoring the lax attitude
of citizens about littering particularly of thin plastic carry
bags and absence of litterbins?
Another wide spread myth is that PVC is a potential source
of dioxin. The fact is that dioxin emissions have declined
by 50% since 1970 even though PVC production has more than
doubled. There is also an allegation that burning of PVC results
in dioxin generation. The fact is that most types of combustions
produce dioxin. It is wrong to blame any specific material
for dioxin production. There are reports that after a fire
in a PVC recycling warehouse in Germany, dioxin levels in
fire gases were comparable to the amount of dioxin found in
unrestricted agriculture soil. Similarly when blood test of
26 people exposed to the fire was carried out, dioxin content
did not exceed that of unexposed subjects.
PVC does not cause disposable problem in Municipal solid
Waste (MSW) to the extent it is made out. Nearly 75% PVC is
used in pipes, profiles and cables which have a long (50-100
years) that do not form part of MSW. About 10-15% PVC consumption
is in packaging and disposal application. MSW has been less
than 0.5% weight of PVC. The contribution of acid generation
from PVC is less than 0.25% of the total. Major sources are
sulphur dioxide from thermal power station (69%), nitrogen
oxide (29%) from auto emission.
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