brooms for the environment
By Suvira Srivastav
Indian scientists, in collaboration
with Swiss counterparts, have found a novel way to clean up the
environment: add teeth to pesticide-chomping microbes and keep
them rejuvenated through stimulants. This microbial broom, they
hope, will hold the key to clean global environs, devoid of pesticide
The finding can be aptly termed 'revolutionary'
for identifying the right bacteria amongst 50 billion micro-organisms
present in a teaspoonful of soil is not only an uphill task but
also requires immense microbiological sleuthing and, of course,
that little bit of luck! Indian scientists got an overdose of
both as they have not only been able to identify the strains that
degrade different pesticides but have also achieved phenomenal
success in reducing the degradation time span from 30-50 years
to a mere 15 days.
The marathon hunt got a boost when
eminent microbiologists like Professor Rup Lal from the Department
of Zoology, University of Delhi; Dr Banwari Lal from the Bioresources
and Biotechnology Division, TERI (the energy and resources institute),
Delhi; and Dr Rakesh K Jain from the Institute of Microbial Technology,
Chandigarh, joined hands in April 2000, under the aegis of the
Indo-Swiss collaboration on biotechnology for 'Bioremediation
of pesticide-contaminated soils and its effect on soil functionality'.
Each scientist zeroed down on a particular pesticide to work on:
Dr Lal focused on endosulfan, Prof. Lal chose hexachlorohexane
or lindane; while Dr Jain identified PNP (para-nitro phenol).
'Most of these pesticides were banned
or restricted in the US and Europe years ago but are still applied
in India to control insect pests affecting pulse and wheat,' reads
the project report. Indian scientists zeroed down on these as
'pesticides like endosulfan are lipid-soluble and once inside
human body, it is impossible to extricate them,' says Ms Nutan
Kaushik, Fellow, TERI. To worsen matters, this happens to be the
'one of the safest' pesticides available, she adds, making it
an obvious choice for farmers. However, Dr Lal concentrated his
efforts on endosulfan, as any accumulation of this pesticide in
human body can be dangerous. Dr Jain choice was PNP, as it happens
to be the 'immediate by-product of three widely used pesticides,
is very toxic, and persists in the soil'.
This handholding, it was believed,
would relieve the nagging environmental concerns over the extensive
use of chemical pesticides, which do keep crops healthy but also
contaminate soil, food, and water. And what a contamination it
is: the pesticide residues, once accumulated in the soil, can
linger on for years and years, affecting crops and human health
down through many generations.
Armed with the arsenal of knowledge
about the side effects of pesticide contamination, the scientists
got down on their knees to collect soil samples from different
contaminated sites. 'We endeavoured to develop and test an efficient
and cost-effective biological treatment technique for agricultural
sites, with the ultimate objective of restoring soil functionality,'
says Dr Lal. The efforts are laudable as identification of the
right strains and mixing with contaminated soil has given encouraging
results. Fortunately, the process of degradation is also eco-friendly.
Scientists have not only been able
to identify the right strains that can accelerate degradation
of pesticide in soil, but have also realized that a concentrated
dose of these bacteria can reduce the time span of degradation.
According to laboratory experiments, two of the bacteria strains
take merely 15 days to degrade 90% of the pesticide present in
contaminated soil. This is astounding, considering that the half-life
(time taken by a chemical to decompose in natural conditions)
of pesticides like endosulphan is well over 30 years.
Half the battle won, scientists are
hopeful of coming up with a unique product that takes this remediation
technology a step further. However, critics like Ms Pabia Sarkar,
Senior Programme Officer with Toxics Link, a Delhi-based NGO,
feel that it is too early to bet on these technologies. She adds,
'It is safer to emphasize on integrated pest management and organic
farming, for the long-term impact of these techniques needs to
be studied and analysed.'
Whatever sceptics or experts may
feel, there is no doubt that a microbe revolution is about to
take us by storm. For a change, this storm will stabilize our
lives and make us more confident to eat and drink whatever is
freely available in the market. Dr Jain adds, 'The beauty of this
solution is that it offers no potential threat to human health,
since these are non-pathogenic bacteria.'
Will it or won't it? The debate will
linger on in intellectual forums. However, as long as microbes
hold promise, there should be many takers…