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Environment
Taming the Silent
Killer
by VK
Joshi
One does read about stalking a silent killer like a man-eating Leopard
and eliminating it. Jim Corbett the famous hunter of the yore killed
many a man eaters by virtually stalking them. The story that unfolds
today is also of a man eater of its kind, but tamed by other means.
Nature had created all the elements much before we came in to existence.
Some of them are essential for our health and some are toxic. The
advents of man lead to an interaction with the environment. Being on the
highest echelon of evolution, his interactions over a period of time
began to continuously modify the environment. For example man is the
only animal that can produce fire. Naturally it affects the purity of
the air we breathe in. The industrial revolution acted as a fuel to the
fire and further contaminated the air. Man's interactions often lead to
release of toxic elements, which would have otherwise remained wherever
they were since they came in to existence.
 Lead is one such element, which has been in use by the mankind for
various purposes.
It was around 1920 after the automobile had been launched when lead was
started to be used as an additive to the petrol to curb the knocking by
the automobile engines. It was found that the vehicle exhaust is one of
the worst polluter of the air and one of the root causes of lead in the
air. Realizing the after effects of lead on their residents the USA
stopped using lead in gasoline since 1974. By 1990 it was also observed
that spurt in crime rate amongst young adults had come down by about
57%.
Lead is injurious: As per the World Health Organization (WHO) standards
presence of lead in blood ≤10µg/dl is injurious. Axel Michaelowa, a
German expert on Clean Development Mechanism in one of his papers (1997)
said that in developing countries all children under two years and 80%
of children between the ages of three and five years have levels of lead
in blood exceeding the prescribed limits of the WHO and they may suffer
permanent brain damage! How toxic lead can be in the blood is evident
from the fact that at low levels lead impairs haem (iron) synthesis in
body and psychological and neurobehavioral functions. At high levels a
lead exposure can damage all organs and organ systems including the
central nervous system and kidneys and blood, often leading to death.
Lead in body system is also one of the main causes for abortions and
damages to the fetal brain.
International efforts to curb poison in the air: Once it was realized
that lead in petrol was the real culprit behind brain damage and falling
health of the children various countries launched the damage control
exercise. Japan was the first country to curb the use of lead in
automobile fuel in 1970. Even after 26 years only 14 countries had
phased out the addition of lead in petrol. By 1999 Bangladesh, China,
Egypt, Haiti, Honduras, Hungary, Kuwait, Nicaragua, Malaysia and
Thailand were able to phase out lead from petrol reported M. Lovei in a
World Bank report.
Indian scenario: Better late than never goes the saying. In India lead
was phased out in the first phase from petrol in metropolitan cities
(Delhi, Mumbai, Kolkata and Chennai) from 1st April 1995 report A.K.
Singh and Munendra Singh of Department of Environmental Sciences and
Geology Department, respectively of Lucknow University, Lucknow in a
paper published in Science Direct in June 2006. It is coincidental that
around that time the growth of the country took rapid turns. There was
no alternative but to curb use of lead as additive in petrol. The goal
was achieved in the country by 1st April 2000.
Collecting data for a study directed towards the impact of removal of
lead from petrol was quite a tough job. As already said, lead being one
of the most widely distributed toxic elements in the environment can
reach the human system. In their study the Singh duo had to ensure that
their data is uncontaminated and unbiased. A scan of the literature took
them to 14 internationally and one nationally published and acclaimed
studies, which finally became the base of their research.
Armed with information about lead content of pre phase out period and
post phase out period from Ganga River Water, urban air of Mumbai and
Lucknow, Dalbergia sissoo tree species of Lucknow and urban children
blood samples (collected from Mumbai, Chennai, Bangalore, Amritsar and
Lucknow) they found what they were looking for.
Ganga River drains through one of the most populated agriculturally rich
valley of Uttar Pradesh and Bihar. During the leaded petrol phase, total
lead content in the River water ranged from 10-115 µg/l in 1988.
Likewise water of the Indus River in Pakistan too had a concentration of
lead ranging from 13-160 µg/l in 1991. The contents of a river depend
upon the rate of erosion in the catchments, geology of the terrain it
flows through and also upon the industrial and agricultural effluents
dumped in the river along its journey to the sea.
Uluberia is a locality in the Ganga delta region and the total lead
content there varied seasonally from 14 µg/l in pre-monsoon to 19 µg/l
in post-monsoon period. Once lead was phased out from petrol the figures
came down to 2.3 and 3.9 µg/l in the pre and post-monsoon periods
respectively. It is generally presumed that atmosphere affects our
systems only. It is not so. Even the river is exposed to the river and
whatever is present is collected by the river too. That is why once the
atmospheric lead content was lowered the river water also displayed a
lower content of the poison in the delta region. It should also be noted
that the lead content of the river does affect the aquatic biota and
once the river meets the ocean the toxins in the water affect the marine
biota too. A higher rate of erosion during monsoon increases the influx
of sediments and along with them the toxins too rise.
One of the significant finds of the duo has been the impact of phase out
of lead from petrol in the air of two major urban centers, viz. Lucknow
and Mumbai. Based on the researches of various scientists, the Singh duo
came to a conclusion that during the transition phase of leaded to
unleaded petrol between 1988 and 1996 at Colaba, Deonar, Goregaon, Khar
and Sion in Mumbai there was a general lowering of lead in the air. For
example at Colaba it came down from 0.18 µg/m3 in 1988 to 0.11 µg/m3 in
1996.
With the withdrawal of lead from petrol, the urban air of Lucknow
started showing decline in mean lead concentration from 1.6 µg/m3 in
1994 to 0.2 µg/m3 in 2001. Leaves of some trees are excellent pollution
indicators. One such species Dalbergia sissoo, a tree that has been
providing shade to the pedestrians since ages (alas, the wave of
development has denuded Lucknow's skyline of those magnificent trees!)
has shown a marked decline in the lead content in its leaves from 18.7
µg/g dry weight in 1994 to 8.3 µg/g dry weight in 2004.
They also collected data about the blood lead levels of children from
Mumbai, Chennai, Bangalore, Amritsar and Lucknow. The outcome was
positive; the lead content came down from 18.1 µg/dl in the leaded
petrol phase to 12.1 µg/dl in the unleaded petrol phase. Though the lead
content has come down, the picture is still gloomy because it is still
above the permissible limits set by the WHO.
The future scenario: The study shows that sincere efforts on part of the
society do pay dividends. Removal of lead from petrol has shown an
improvement of air quality and also there is globally a marked
improvement in terms of lead related ailments. Yet, there are multiple
sources like drinking water, cosmetics, lead-glazed ceramics, industrial
emissions, lead-based paints, lead-based batteries, and lead soldiered
food containers through which lead can secretly enter our body. Lead is
a metal that is most commonly used in our routine lives, including the
insulation of electrical cables. Presence of higher levels of lead in
children's blood in a growing economy like ours is a warning siren which
should not be ignored. It is well established that lead in the minds of
youngsters turns them criminals. We don't want our future to turn to
crime. We don't want lead. Let's curb the use, find alternatives and do
away with lead.
August 10, 2008
Image of Galena crystals (PbS),
the most important ore of Lead, Missouri, USA.
under license with
Gettyimages.com
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