Transcript ปัญหา สาเหตุ และผลกระทบจาก

ปัญหา สาเหตุ และผลกระทบจากการใช้
สารเคมีกาจัดศัตรู พชื ต่ อสิ่ งแวดล้ อม
โดย
ผศ.ดร. อรัญ งามผ่องใส
ภาควิชาการจัดการศัตรู พืช
คณะทรัพยากรธรรมชาติ มหาวิทยาลัยสงขลานคริ นทร์
Problems and Background
World’s population increase
1997 ~ 5.8 Billion
2030 ~ 8.4 Billion
Lack of foods
Green Revolution
“The Green Revolution is a process of
technological development of a techniques
that began in Mexico in 1944 and has
since spread throughout the world”
Technology
Hybrid strains
Agricultural techniques
• Chemical fertilizers
• Irrigation
• Heavy machinery
• Pesticides
What is pesticides?
“A substance or mixture of substances
intended for preventing, destroying,
repelling, or mitigating any pest. Also,
any substance or mixture of substances
intended to regulate plant or leaf growth”
Use situation of pesticides
Global pesticide market > US$ 30,000 million (1996)
> US$ 31,250 million (1997)
1996
1997
North America
29.4 % 30.6
%
Western Europe
26.2 % 26.0
%
Asia
24.5 % 22.5
Source:
Agrow:
World
Crop
Protection
News
(1997)
%
Latin America
10.4 % 11.9
World market of pesticides
World market of pesticides
(2001 estimates)
Use situation of pesticides
Global pesticide market share (1997)
Herbicide
Insecticide
Fungicide
Others
48 %
28 %
19 %
5 %
Source: Agrow: World Crop Protection News (1997)
Use situation of pesticides in Thailand
2542
Herbicide
%
Insecticide
%
Fungicide
%
Others
2540
2541
49.5 %
43.5 % 29.5
33.0 %
40.1 % 59.7
12.6 %
11.4 % 8.3
4.9 % 5.0 %
2.5
Where are pesticides used?
• Agricultural areas
• Non-agricultural areas
– household pest control
– vector control
– golf course
Problems of pesticide use in Thailand
1. Most pesticides are imported
increasingly every years
ปริมาณสารออกฤทธิ์ (ตัน)
20000
สารฆ่าแมลง
15000
สารฆ่ารา
สารฆ่าวัชพืช
10000
5000
0
2520
2522
2524 2526
2528
2530 2532
2534
2536 2538
2540
2542
Problems of pesticide use in Thailand
2. Rapid increase of pesticide use
– Fruit and vegetable crops have been
extensively produced.
– The government’s reduction of the import
duty of pesticides from 5% to 0% in
1992
– DOAE provided farmers with free pesticides
Problems of pesticide use in Thailand
3. Inefficient use
– Lack of knowledge
– Misuse of application
• Over recommended dose spray
• “Cocktail” spray
Effects of pesticide use on environment
•
•
•
•
•
•
•
What is the environment?
Sources of pesticide contamination
Sensitive areas
Pesticide movement in the environment
Harmful effects on non-target plants and animals
Effects on aquatic ecosystems
Effects on soil ecosystems
What is the environment?
“The environment is everything around us. It includes
not only the natural elements that the word
"environment" most often brings to mind, but also
people and the manmade components of our world.
The environment is not limited to the outdoors -- it
also includes the indoor areas where we live and
work”
Sources of pesticide contamination
• Point source contamination
• Non-point source contamination
Sensitive areas
• Sensitive areas are sites or living things that are easily injured by a
pesticide
• Sensitive areas outdoors include:
• areas where ground water is near the surface or easily accessed
(wells, sinkholes, porous soil, etc.);
• areas in or near surface water;
• areas near schools, playgrounds, hospitals, and other institutions;
• areas near the habitats of endangered species;
• areas near apiaries (honeybee sites), wildlife refuges, or parks; and
• areas near ornamental gardens, food or feed crops, or other
sensitive plantings
Sensitive areas
• Sensitive areas indoors include:
– areas where people -- especially children, pregnant women,
the elderly, or the sick -- live, work, or are cared for;
– areas where food or feed is processed, prepared, stored, or
served;
– areas where domestic or confined animals live, eat, or are
otherwise cared for; and
– areas where ornamental or other sensitive plantings are
grown or maintained.
Pesticide movement in the environment
Pesticide movement in the environment
• In air, through wind or through air currents generated by
ventilation systems,
• In water, through runoff or leaching,
• On or in objects, plants, or animals (including humans)
that move or are moved offsite.
Harmful effects on non-target organisms
• Non-target organism: Any plant or animal other than the
pest that is being controlled
• Two ways of harmful effects
– the pesticide may cause injury by contacting the nontarget
organism directly, or
– the pesticide may leave a residue that causes later injuries
Effects of pesticide on aquatic ecosystems
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•
•
•
Sources and roles of water
How pesticides enter surface and ground water?
How pesticides influence aquatic animals?
Factors affecting pesticide toxicity to aquatic
animals
• How to reduce pesticide risks in aquatic systems?
Sources of water in the world
• ~ 1.7 % of all of Earth's water is
ground water
• about 30.1 % of freshwater on Earth
occurs as ground water
• about 5,614,000 cubic miles (mi3),
or 23,400,000 cubic kilometers
(km3), of ground water exist on
Earth
• About 54 percent is saline, about 46
percent, being freshwater.
Roles of water
– Industrial utilization
– Household utilization
– Drinking water
How pesticides enter water?
• Surface runoff
• Leaching
• Erosion
Pesticide properties influencing water pollution
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Formulation
Toxicity
Persistence
Volatility
Water solubility
Soil adsorption
How pesticides influence aquatic
animals?
• Lethal effects
• Sublethal effects
• Habitat alteration
-reduce the availability of plants
and insects that serve as habitat and food for
fish and other aquatic animals
-Fish behaviour
-Weight loss
-Impaired reproduction
-Inability to avoid predator
-lowered tolerance to
extreme temperatures
Factors affecting pesticide toxicity to
aquatic animals
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Toxicity values
Exposure time
Dose rate
Persistence
LD50 or LC50
The length of time the animal
is in contact with the pesticide
Time pesticides exist in the environment
How to reduce pesticide risks in
aquatic systems
Guidelines to help safeguard water sources
– The site
– Planning
– Mixing and loading
– Application
– Storage
– Disposal
Maximum Contaminant Level (MCL)
• M CL is the standard for drinking water set by EPA
Contaminants
M CL (ppm)
2,4-D
Alachlor
Atrazine
Ethylene dibromide
Glyphosate
0.07
0.002
0.003
0.00005
0.7
Effects of pesticide on soils
• Role of organisms in soils
• Effect of pesticides on soil microbial population
• Effect of pesticides on nitrification
Role of organisms in soil
• Many organisms living in soils
– bacteria
– fungi
– nematodes
– arthropods
– crustaceans
– earthworms
Degradation of
• plant and animal residues
• other organic matter
• nitrogen fixation
• nitrification
• release of nutrients from soil
mineral
Effect on soil microbial populations
Pollution with
xenobiotic chemicals
Environmental
change
Microbial
population
How pesticides affect microbial population?
• Reduction in population (long term effect)
– atrazine bacteria and fungi reduction (Canada)
– methamidophos
bacteria (China)
– monocrotophos, carbaryl and methomyl
bacteria & fungi (Egypt)
Effect of pesticides on nitrification
What is nitrification?
• Nitrification or 'ammonium oxidation' is a two-step
respiratory process occurring in sediment (benthic
nitrification) or the water column (pelagic
nitrification) in which bacteria oxidise ammonium
(NH4) to nitrite (NO2) and nitrate (NO3)
• Nitosomonous spp. and Nitrobacter spp. are the main
organisms responsible for nitrification process
Effect of pesticides on nitrification
• Reduction in nitrification process (long term effect)
– atrazine nitrification reduction (Canada)
– methamidophos and dimethoate
Nitrification reduction (China)
Factors affecting pesticide behavior in soils
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Adsorption
Absorption
Volatilization
Runoff
Leaching
Degradation
Environmental risk of pesticides
Environmental Risk =
Persistence x Mobility x Nontarget toxicity x Volume of use