fate of pesticides in environment or environmental polution by pesticides
Transcript of fate of pesticides in environment or environmental polution by pesticides
UNIVERSITY OF HORTICULTURAL SCIENCES, BAGALKOT
COLLEGE OF HORTICULTURE, BENGALURU -560 065
HPP 581, SEMINAR (0+1)
SEMINAR REPORT ON
Ecological fate of pesticides used in agriculture
Dr. B. Fakrudin Dr. Mohan Kumar Professor and Head, Asst. Professor, Dept. of Biotechnology and Crop improvement, Dept. of Crop Physiology College of Horticulture, Bengaluru-65 College of Horticulture, Bengaluru
Mr. SUNDARESH UHS13PGM396 Sr. M.Sc. (Hort.),
Dept. of Plant Pathology College of Horticulture, Bengaluru-65
UNIVERSITY OF HORTICULTURAL SCIENCES, BAGALKOT COLLEGE OF HORTICULTURE, BENGALURU- 560 065
PG SEMINAR, HPP 581 (0+1)Name: SUNDARESH Date: 25/04/2015ID No: UHS13PGM396 Time: 9.00 a.m.Class: Sr. M.Sc. (Hort.) Plant Pathology SEMINAR- II Venue: Seminar hall
Ecological fate of pesticides used in agriculture
India has a mixed economy largely dependent on agriculture and its allied sectors. Therefore, agricultural development is one of the prime focuses of Indian planning and policy. After Independence, agriculture in India underwent significant transformation and production has increased tremendously due to the introduction of high yielding varieties and the large scale use of synthetic pesticides and fertilizers. However, there is a trade-off between agricultural production and increasing soil, air and water pollution and associated health hazards.
When the pesticide is entered into the environment, the processes like transfer, breakdown and degradation of pesticide takes place in the ecosystem. Further, transfer which includes processes that move the pesticide away from the target site (volatilization, spray drift, runoff, leaching, crop removal, and absorption). Pesticides are breakdown by microbes, chemical reactions and light or photo degradation in nature. This process may take anywhere from hours or days to years, depending on environmental conditions and the chemical characteristics of the pesticide.
Hussaini et al. (2013) reported that six bacterial isolates were found to show significant ability to carry out the degradation of selected pesticides. These cultures were identified as Acinetobacter radioresistens, Pseudomonas frederiksbergensis, Bacillus pumilus, Serratia liquefaciens, Serratia marcescens, Burkholderia gladioli.
Throughout India 50-70% of vegetables are contaminated with pesticidal residues and frequently DDT and HCH residues were detected. Bacterial cultures capable of degrading HCH have been isolated at CFTRI and successfully deployed as “Agrocure” to combat HCH residues through accelerated degradation of the chemical in soil. Pseudomonas ptm+ strain developed at CFTRI produced an extracellular surfactant, which was exploited as a cleaning agent “Baxeklen” to dislodge pesticide residues in vegetables (Karanth, 2000).
The different pesticides viz., aldrin, dieldrin, heptachlor and lindane were analyzed in selected root and leaf vegetables samples by Kumar et al. (2012). The concentration of individual pesticide aldrin, dieldrin, heptachlor and lindane was 0.48±0.06 ng/g, 0.13±0.02 ng/g, 1.03±0.11 ng/g and 0.52±0.06 ng/g (wet wt.), respectively. The selected vegetables had residue levels, much below the recommended maximum residue limits (MRLs) set by European Commission and Indian government.
Blood samples from 182 people in Delhi, India, were examined for DDT residues. All except 8 contained DDT and its metabolites. The average total DDT concentration in the whole blood ranged from 0.177 to 0.683 mg/litre in males and from 0.166 to 0.329 mg/litre in
females. The DDT metabolites detected were p,p'-DDE, p,p'-DDD, and o,p'-DDT. DDE accounted for most of the total DDT (Agarwal et al., 1976).
Pesticide residues in the blood samples of the general population of major Indian cities were examined and the total organochlorine insecticide content in all serum samples showed an average of 200.3 ppb with a range of 58.3-321.4 ppb. Among these chemicals, HCH and DDT were the chief contaminants and their order of persistency was HCH>DDT>dieldrin>oxychlordane>heptachlor>Aldrin (Anon., 2001).
In modern agriculture, usage of pesticides is must and many pesticides have potential to cause the harmful effects in the environment, if they are not used judiciously. To save the current and future generation, ecology, judicious and efficient uses of pesticides are recommended. In addition, we can use alternative strategies for pesticide in the form of botanicals, bio-pesticides as one of the component in integrated disease management to minimise the environmental risks.
AGARWAL, H. C., PILLAI, M. K. K., YADAV, D. V., MENON, K. B. AND GUPTA, R. K., 1976, Residues of DDT and its metabolites in human blood samples in Delhi, India. Bull. World Health Org., 54: 349-351.
ANONYMOUS, 2001, Pesticide pollution: trends and perspective. ICMR Bulletin, 31(9): 1-12.
HUSSAINI, S. Z., MOHAMMED, S., MOHAMMED, A. I., 2013, Isolation of bacterial for degradation of selected pesticides. Adv. Biores., 4(3): 82-85.
KARANTH, N.G.K., 2000, Food safety management in developing countries. Proceedings of the International Workshop , CIRAD-FAO, 11-13, CIRAD CD-ROM, Montpellier,
KUMAR, B., KUMAR, S., MISHRA, M., DEV PRAKASH, SINGH, S. K. AND SHARMA, C. S., 2012, Persistent chlorinated pesticide residues in selected market
vegetables of root and leaf origin. Asian J. Pl. Sci. Res., 2(3): 232-236.
Seminar would answer the following questions:1. Definitions of Ecology and pesticide?2. Fate of pesticides in the environment?3. Effects of pesticide pollution on environment?4. Strategies to manage pesticide pollution?
TABLE OF CONTENTS
Sl. No. Contents Page No.
1 Pesticide consumption scenario in India 5-6
2 History of pesticide production and application 6-7
3 Environmental fate of pesticides 7-12
4 Ecological effects of pesticides 12-14
5 Reviews 15-21
6 Way to minimize pesticides impact 22-23
7 Pesticide tragedies happened in India 23-24
8 Conclusion 24
Modern agriculture depends on the four main factors viz., water, fertilizers, seed and
pesticides. Pesticides are the integral part of modern agriculture. About 35-45 % crop
production is lost due to insects, weeds and diseases, while 35% crop produces are lost during
storage. Indian Agrochemical Industry size in estimated to be US$ 3.8 billion in year 2012.
Over the 12th plan period, the segment is expected to grow at 12-13% per annum to reach 7.0
billion. The Indian domestic demand is growing at the rate of 8-9% and export demand at 15-
The per capita consumption of pesticides in India is 0.6 Kg/ha which is the lowest in
the world. The per capita pesticide consumption in China and USA is 13 Kg/ha and 7 Kg/ha,
respectively. The main reason for low per capita consumption of pesticides in India is low
purchasing power of farmers and small land holdings. The majority of agricultural farm land
belongs to Marginal farmers but maximum contribution to the produce is also from marginal
farmers. The large scale farming is increasing and therefore, there is good scope for increase
of per capita consumption of pesticides in India.
Definition of pesticide
A pesticide is any substance or mixture of substances intended for preventing, destroying,
repelling, or mitigating any pest (insects, mites, nematodes, weeds, rats, etc.), including
insecticide, herbicide, fungicide, and various other substances used to control pests.
Definition of pesticide varied with times and countries. However, the essence of pesticide
remains basically constant, i.e., it is a (mixed) substance that is poisonous and efficient to
target organisms and is safe to non-target organisms and environments.
History of pesticide production and application
History of pesticides can be divided into three phases (Zhang et al., 2001): (1) in the
first phase (the period before 1870s) natural pesticides, for instance sulfur in ancient Greece,
were used to control pests; (2) the second phase was the era of inorganic synthetic pesticides
(the period 1870s-1945). Natural materials and inorganic compounds were mainly used
during this period; (3) the third phase (since 1945) is the era of organic synthetic pesticides.
Since 1945, the man-made organic pesticides, e.g., DDT, 2,4-D, and later HCH, dieldrin,
have terminated the era of inorganic and natural pesticides. Since then most pesticides have
been synthesized by humans, and they were named chemical pesticides. The application of
chemical pesticides, in particular the organic synthesized pesticides has been a significant
mark of human civilization, which greatly protects and facilitates agricultural productivity.
In the earlier period of organic synthesized pesticides, there were mainly three kinds
of insecticides, carbamated insecticides, organophosphorus insecticides and organochlorined
insecticides. Sooner after that herbicides and fungicides achieved a considerable development
as well. The consumption of insecticides is estimated to decline gradually and the use of
herbicides would be popular in the future. This trend may be found from the changes of the
structure of pesticide consumption worldwide.
Environmental fate of pesticides
What Happens to Pesticides?
When a pesticide is released into the environment many things happen to it. Sometimes what
happens is beneficial.
Sometimes, releasing pesticides into the environment can be harmful. For example, runoff of
herbicide can move away from target weeds. The chemical is wasted, weed control is
reduced, and there is more chance of damaging other plants and polluting soil and water. Or
some of the pesticide may drift downwind and outside of the intended application site.
When we spray pesticide many processes happens those include adsorption, transfer,
breakdown and degradation. Transfer includes processes that move the pesticide away from
the target site. These include volatilization, spray drift, runoff, leaching, absorption and crop
Each of these processes is explained in the following sections.
Adsorption: is the binding of pesticides to soil particles. The amount a pesticide is
adsorbed to the soil varies with the type of pesticide, soil, moisture, soil pH, and
soil texture. Pesticides are strongly adsorbed to soils that are high in clay or organic
matter. They are not as strongly adsorbed to sandy soils.
Most soil-bound pesticides are less likely to give off vapors or leach through the
soil. They are also less easily taken up by plants. For this reason you may require
the higher rate listed on the pesticide label for soils high in clay or organic matter.
Volatilization: is the process of solids or liquids converting into a gas, which can
move away from the initial application site. This movement is called vapour drift.
Vapour drift from some herbicides can damage nearby crops.
Pesticides volatize most readily from sandy and wet soils. Hot, dry, or windy
weather and small spray drops increase volatilization.
Where recommended, incorporating the pesticide into the soil can help reduce
Spray Drift: is the airborne movement of spray droplets away from a treatment site
Spray drift is affected by:
spray droplet size - the smaller the droplets, the more likely they will drift
wind speed - the stronger the wind, the more pesticide spray will drift
distance between nozzle and target plant or ground - the greater the distance,
the more the wind can affect the spray
Drift can damage nearby sensitive crops or can contaminate crops ready to harvest.
Drift may also be a hazard to people, domestic animals, or pollinating insects. Drift
can contaminate water in ponds, streams, and ditches and harm fish or other aquatic
plants and animals. Excessive drift also reduces the pesticide applied to the target
and can reduce the effectiveness of a treatment.
Runoff: is the movement of pesticides in water over a sloping surface. The
pesticides are either mixed in the water or bound to eroding soil. Runoff can also
occur when water is added to a field faster than it can be absorbed into the soil.
Pesticides may move with runoff as compounds dissolved in the water or attached
to soil particles.
The amount of pesticide runoff depends on:
the texture of the soil
the soil moisture content
the amount and timing of a rain-event (irrigation or rainfall)
the type of pesticide used
Runoff from areas treated with pesticides can pollute streams, ponds, lakes, and
wells. Pesticide residues in surface water can harm plants and animals and
contaminate groundwater. Water contamination can affect livestock and crops
Pesticide runoff can be reduced by:
using minimum tillage techniques to reduce soil erosion
grading surface to reduce slopes
diking to contain runoff
leaving border vegetation and plant cover to contain runoff
Pesticide losses from runoff are greatest when it rains heavily right after you spray.
Reduce the chances of runoff by watching the weather forecast. If heavy rains are
expected delay spraying to avoid runoff. Irrigate according to label instructions.
Leaching: is the movement of pesticides in water through the soil. Leaching occurs
downward, upward, or sideways. The factors influencing whether pesticides will be
leached into groundwater include characteristics of the soil and pesticide, and their
interaction with water from a rain-event such as irrigation or rainfall.
Leaching can be increased when:
the pesticide is water soluble
the soil is sandy
a rain-event occurs shortly after spraying
the pesticide is not strongly adsorbed to the soil
Groundwater may be contaminated if pesticides leach from treated fields, mixing
sites, washing sites, or waste disposal areas.
Similar factors influence pesticide movement in surface runoff, except that
pesticides with low water solubility may move with surface runoff if they are
strongly adsorbed to soil particles and have some degree of persistence.
Soil characteristics are important to pesticide movement. Clay soils have a high
capacity to adsorb many chemicals including pesticides and soil nutrients. Sandy
soils have a much lower capacity to adsorb pesticides. Organic matter in the soil
also can adsorb pesticides. Soil structure influences the movement of water and
pesticides. Coarse textured sandy soils with large air spaces allow more rapid
movement of water than fine textured or compacted soils with fewer air spaces.
Other characteristics of the site, such as depth to groundwater, or distance to
surface water, are important. Finally, the pattern of water falling on the soil through
irrigation or rainfall is significant. Small volumes of water at infrequent intervals
are less likely to move pesticides than large volumes of water at more frequent
Absorption: is the uptake of pesticides and other chemicals into plants or
microorganisms. Most pesticides break down once they are absorbed. Pesticide
residues may be broken down or remain inside the plant or animal and be released
back into the environment when the animal dies or as the plant decays.
Some pesticides stay in the soil long enough to be absorbed by plants grown in a
field years later. They may damage or leave residues in future crops.
Crop Removal through harvest or grazing may remove pesticide residues.
Degradation or Breakdown Processes
Degradation is the process of pesticide breakdown after application. Pesticides are
broken down by microbes, chemical reactions, and light or photodegradation. This
process may take anywhere from hours or days to years, depending on
environmental conditions and the chemical characteristics of the pesticide.
Pesticides that break down quickly generally do not persist in the environment or
on the crop. However pesticides that break down too rapidly may only provide
Microbial breakdown: is the breakdown of chemicals by microorganisms such as
fungi and bacteria.
Microbial breakdown tends to increase when:
temperatures are warm
soil pH is favorable
soil moisture and oxygen are adequate
soil fertility is good
Chemical breakdown: is the breakdown of pesticides by chemical reactions in the
soil. The rate and type of chemical reactions that occur are influenced by:
the binding of pesticides to the soil
pH levels - Many pesticides, especially the organophosphate insecticides,
break down more rapidly in alkaline soils or in spray tank water with a high
Photodegradation: is the breakdown of pesticides by sunlight. All pesticides are
susceptible to photodegradation to some extent. The rate of breakdown is
influenced by the intensity and spectrum of sunlight, length of exposure, and the
properties of the pesticide. Pesticides applied to foliage are more exposed to
sunlight than pesticides that are incorporated into the soil. Pesticides may break
down faster inside plastic-covered greenhouses than inside glass greenhouses, since
glass filters out much of the ultraviolet light that degrades pesticides.
Pesticide characteristics are also important in determining the fate of the chemicals in the
environment. These characteristics include:
1. solubility in water (water solubility)
2. tendency to adsorb to the soil (soil adsorption)
3. pesticide persistence in the environment (half-life)
Pesticides with high water solubility, low tendency to adsorb to soil particles and long
persistence or half-life have the highest potential to move into water. Adsorption, water
solubility and persistence are commonly used factors to rate the pesticides for their potential
to leach or move with surface runoff after application.
No one factor--adsorption, water solubility, or persistence--can be used to predict pesticide
behavior. It is the interaction of these factors and their interaction with the particular soil type
and environmental conditions that determines pesticide behavior in the field.
Ecological effects of pesticides
At community level, ecology can be defined as complex interactions that exist among
interdependent organisms that cohabitate the same geographical area and with their
At individual level, it entails the relationships that exist between particular individual
with numerous physical and biological factors
The effects of pesticides on ecology as follows:
• Loss of species diversity among the food chains and food webs
• Effects on pollinators
• Effects on nutrient cycling in ecosystem
• Effects on soil erosion, structure and fertility
• Effects on water quality
• Effects on human beings
• Effects on birds
• Contaminate the food
• Effects on fish and other aquatic organisms
• Pesticides disrupt the natural balance between pest and predator insects
• Pesticides cause pest rebound and secondary pest outbreaks
• Pesticides may cause pest resistance
Review on effects of pesticides on water quality
Fig: Dissolved pesticides in various river water in south Asia (James, 2000)
Table: State wise polluted stretches in rivers and lakes in India.
The polluted river stretches were intensively surveyed by Central Pollution Control
Boards (CPCB) and State Pollution Control Boards (SPCBs) to identify the sources of
pollution such as Urban Centres and Industrial Units. With the expansion of
monitoring network and coverage of more number of rivers for regular monitoring,
the numbers of polluted water bodies identified during 2002 are 86 (71 rivers and 15
lakes/ponds/creeks), which are not meeting the de- sired criteria.
Review-1: Study on Bioaccumulation of Lindane in Various Tissues of
Channa gachua from Aurangabad District, India (Shingare et al., 2009)
Fig: Concentration of lindane in liver, kidney and body muscle of Channa gachua fish.
The higher lindane bioaccumulation in liver and kidneys as compared to body muscles can be
correlated to the fact that, the lindane being lipophilic in nature gets more accumulated in the
high lipid containing organs of body.
Review-2: Isolation of Bacteria for Degradation of Selected Pesticides
(Hussaini et al., 2013)
Study focuses on the isolation and characterization of bacterial cultures for
biodegradation of pesticides commonly used in the agriculture
During this study six (06) bacterial isolates were found to show significant ability to carry out the degradation of selected pesticides, these cultures were identified as Acinetobacter radioresistens, Pseudomonas frederiksbergensis, Bacillus pumilus, Serratia liquefaciens, Serratia marcescens, Burkholderia gladioli.
Table: Per cent Pesticide degradation by the isolated cultures
Acinetobacter radioresistens, has shown considerable degradation of Chlorpyrifos with 38%
degradation and marginal degradation of Malathion with 1% degradation, while for rest of the
pesticides there was no degradation by this culture. Pseudomonas frederiksbergensis, was
found to be capable of degrading Endosulfan, Chlorpyrifos and Malathion, but this ability
was only marginal with 4%, 4% and 9% degradation respectively. Bacillus pumilus, has
shown effective degradation of Malathion and Dimetoate with 45% and 37% degradation
respectively and was also able to partially degrade Chlorpyrifos and Igepal-CO 210 with 15%
and 8% degradation respectively. Serratia liquefaciens, was found to degrade Diazinon at
51% and marginal degradation of Malathion with 11% degradation. Serratia marcescens, has
shown partial degradation of Diazinon (34%) and marginal degradation of Chlorpyrifos,
Igepal CO-210 and Methyl Parathion with 8%, 2% and 1% degradation. Burkholderia
gladioli has only shown marginal degradation of Dimetoate with 3% degradation, while other
pesticides were not degraded at al by this culture.
Review-3: Pesticide pollution: trends and perspective (Anonymous, 2001)
Since blood is the most accessible body fluid for ascertaining residue levels, scientists at the
NIOH, Ahmedabad have attempted to provide a database on the residues of DDT and HCH
including other cyclodiene derivatives eg.heptachlor, heptachlor epoxide, aldrin,
oxychlordane, HCB and dieldrin in blood samples from general population of Ahmedabad
(rural) area28. Heptachlor epoxide and HCB were not detected in these blood samples. The
total organochlorine insecticide content in all serum samples showed an average of 200.3 ppb
with a range of 58.3-321.4 ppb. Among these chemicals, HCH and DDT were the chief
contaminants and their order of persistency was as follows
Table: Levels of DDT and HCH residues in human fats samples in general population in India
Studies conducted by the NIOH to monitor pesticide residues in autopsy fat samples
from subjects from different parts of the country indicated a wide variation34. The maximum
DDT residues were detected in age group of 20-39 years and the higher levels of HCH
residues were found in the age group of 40 years. No sex wise difference was observed for
DDT and HCH residues. The wide variation seen may be due to the geographical variations
in consumption and use of these chemicals.
Table: Levels of DDT and HCH residues in human milk samples in general population in India
Higher level of these chemicals in mother’s milk is a reflection of their increased burden and
their translactational passage. The toxicological implication of these findings could not be
assessed precisely, however, preventive measures are warranted to reduce their body burden
to avoid any potential health effect.
Reproductive performance of persons involved in spraying operation
Data on reproductive toxicity were collected from 1,106 couples when the males were
associated with the spraying of pesticides (OC, OP and carbamates) in cotton fields was
given in the table.
Abortion 15 %
Still births 2.6 %
Neonatal deaths 2.2 %
Congenital defects 0.1 %
A cytogenic study revealed a significant increase in chromatid breaks and gaps in
chromosomes in the workers exposed to pesticides.
Review-4: Residues of DDT and its metabolites in human blood samples
in Delhi, India (Agarwal et al., 1976).
Table: Concentrations of DDT and its metabolites in human whole blood samples from
In males, the mean of total DDT was 0.177-0.683 mg/litre, the lowest being in the age group
71-86 years and highest in the age group 41-50 years. Especially in males, the total DDT
content was comparatively smaller in the age groups 51 years and older. In one male aged 14
years the level of total DDT in blood was very high (8.40 mg/litre). In females, the mean of
total DDT was 0.166 in the age group 61-70 years to 0.329 mg/litre in the age group 31-40
years. The total DDT content of whole blood samples from the Delhi area is about 10 times
higher than values generally reported from other countries but somewhat similar to DDT
residue levels found in the blood of people connected with the manufacture of DDT.
Compared with males, females generally had lower amounts of total DDT. A higher
concentration of DDT in the blood indicates a higher total body burden of DDT in the
population. In addition to DDT the blood also contained p,p'-DDE, p,p'-DDD, and o,p'-DDT.
DDE was the major metabolite and was generally present in larger quantities than DDT,
indicating that DDE is stored in the human body in preference to DDT or its other
metabolites. A similar relationship is found in human adipose tissue and in many animals.
Review-5: Challenges of limiting pesticide residues in fresh vegetables: The
Indian experience (Karanth, 2002).
Table: Extent of pesticide contamination in vegetables in Mysore City (%)
Vegetables sold in Mysore market are mainly grown in villages around the city and are
harvested and sold fresh. As many as 514 samples collected over 4 different seasons were
checked for the residue burden. The data clearly indicate the presence of HCH and DDT
residues, the 2 major farm chemicals present in the soil that have migrated in to the
vegetables. These results make a strong case for intensifying a pesticide "policing" program
through inexpensive methods and the need for control measures to abate pesticide residues in
vegetables and other foods.
Table: Accelerated degradation of HCH in soil with application of Agrocure (residual HCH in
soil - ppm)
Microbial preparation has been developed to degrade HCH in the soil. A Pseudomonas strain
Ptm+ was isolated from soil treated with HCH and shown to degrade HCH. This strain was
cultivated in a mineral medium in the laboratory and then the culture was poured into a
mixture of neutral lignite powder and neutral coir pith taken in a sterile polythene pouch.
After thorough mixing, the preparation was "cured" in polythene pouches by incubating at
ambient temperature (25+2oC). The resultant product, “Agrocure”, has a 90-day shelf life
and contains about 3 billion cells per gram of the product. Pot culture experiments with
tomato and groundnut have proved that augmenting the soil with this bio-powder accelerated
HCH degradation in the soil. At the same time, application of Agrocure minimized the uptake
of the insecticide by crops from the soil due to reduced availability as a result of degradation.
Decrease in the residue level by increased rate of degradation led to a cascade of beneficial
effects. The bioaugmentation thus protected the soil enzyme activity and thus promoted the
growth of plants, improved the nutrient quality of the vegetables and removed the phytotoxic
effect of HCH.
Table: Efficacy of Baxeklen in the removal of HCH from vegetables
“Baxeklen” a biosurfactant produced by an HCH-degrading bacterial strain, is useful in
dislodging HCH residues from vegetables. For pesticide container cleaning, in washing of
pesticide mixing tanks in the pesticide manufacturing industry and also in preparing pesticide
EC (emulsifiable concentrate) formulations. This is again a redeeming technology in the
management of objectionable lipophilic molecules posing occupational health hazard.
Ways to Minimize Pesticide Impact
The following are several practices which reduce the potential for pesticides to cause
environmental damage or water contamination apply
Integrated Pest Management
Follow integrated pest management (IPM) principals. IPM doesn't rely solely on
chemicals for pest control. Biological control, cultural practices, and timely
chemical applications are used to obtain the necessary level of control. Pesticides
are the last line of defense and are used only when pest levels are causing sufficient
damage to offset the expense of the application. IPM also requires the following
Scout or monitor crops regularly to check the levels of pest populations and
Implement available non-chemical control practices, including mechanical,
cultural and biological controls, sanitation, and plant resistance. For example,
use crop rotation to manage corn rootworms and cut alfalfa early to manage
weevils (cultural controls); select resistant varieties (plant resistance);
thoroughly clean combines between fields to reduce weed seed introductions
(sanitation); and use cultivation to control weeds (mechanical control).
Maximize the benefits of naturally occurring biological controls by using
pesticides only when necessary and selecting pesticides which are the least
harmful to beneficial. For example, some insecticides and fungicides kill
predatory mites, which can cause mite outbreaks later in the season.
Prevent back siphoning and spills
Never allow a hose used for filling a spray tank to extend below the level of the
water in the tank. Contain all spills as quickly as possible and handle according to
label directions. Use anti-siphon devices in the water line. They are inexpensive and
Consider weather and irrigation plans
Application just before rainfall or irrigation may result in reduced efficacy if the
pesticide is washed off the target crop, resulting in the need to reapply the pesticide.
Heavy rainfall may also cause pesticide-contaminated runoff at the application site.
Pesticide use and storage
Always read and follow the label directions on the pesticide container. Use
pesticides only when economic thresholds are reached and buy only what you need.
Use appropriate protective equipment and clothing according to label instructions.
Avoid mixing pesticides near wells or other sources of water. Store all pesticides
safely, and according to legal requirements.
Dispose of pesticide and chemical wastes safely
Dispose of excess chemical and pesticide containers in accordance with label
directions. Triple-rinse empty pesticide containers (use this water in the spray tank),
punch holes in containers, and dispose of them at approved waste disposal sites.
Leave buffer zones around sensitive areas
Read the pesticide label for guidance on required buffer zones around water,
buildings, wetlands, wildlife habitats and other sensitive areas.
Reduce off-target drift
Never begin an application when wind or temperature favors pesticide drift to an
off target area. Use appropriate spray pressure and nozzle selection to minimize
Maintain all application equipment in good working order and calibrate it regularly.
Kasaragod Endosulfon tragedy
• Aerial spraying of Endosulfan since 1976 in cashew plantations spread over 4500
hectares three times in a year around 15 villages in Kasaragod district. The cashew
plantations belong to the state owned public sector company – Plantation Corporation
of Kerala (PCK) Aerial spray of Endosulfan using helicopters was recommended by
Government scientific bodies to cut cost of manual labour. This was responsible for
the contamination of soil and different sources of water bodies lead to the tragedy in
and around areas of Kasaragod district, Kerala. This was caused the many defects in
the neonatal births and also adults. Due to this reason Endosulfan has been banned by
the Supreme Court of India w.e.f. 13-05-2011 for production, use & sale, all over
Bhopal Gas Tragedy
Bhopal’s pesticide plant was built in 1969 to manufacture Sevin, a pesticide used
throughout Asia to kill beetles, weevils and worms. The plant was operated by Union Carbide
India, Limited, but an American company, Union Carbide Corporation, held more than half
the stock. The leak began on December 2, 1984, when water entered a tank that was used to
store methyl isocyanate, a toxic gas and a key ingredient in Sevin. The water reacted with the
gas, causing extreme pressure and heat that possibly caused the tank to explode. The tank
spewed 40 tons of poisonous gas into the air. The toxic cloud was mostly methyl isocyanate,
a compound that can irritate the throat and eyes, cause chest pain and shortness of breath,
and, in large doses trigger convulsions, lung failure and cardiac arrest. It is also presumed that
the reactions inside the tank generated enough heat to turn methyl isocyanate into its even
deadlier cousin: hydrogen cyanide. The areas engulfed by gas were some of Bhopal’s poorest
neighborhoods. Many of the gas survivors are still too ill to work and a number of additional
health problems continue to crop up such as blindness, respiratory illnesses, reproductive
problems and neurological and immune disorders, to name some of them.
In modern agriculture, usage of pesticides is must and many pesticides have potential to
cause the harmful effects in the environment, if they are not used judiciously. To save the
current and future generation, ecology, judicious and efficient uses of pesticides are
recommended. In addition, we can use alternative strategies for pesticide in the form of
botanicals, bio-pesticides as one of the component in integrated disease management to
minimise the environmental risks.
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