Degradation process of pesticides
Degradation process of pesticides
Pesticides
degradation is transformation to environmentally compatible, harmless
substances after practice. Approximately 2.5 million tons of pesticides used
each year, predominantly in agriculture. Greater than 95% is not reaching
target. They spread into environment in ways such as evaporation, infiltration
and surface flow and involve in ecosystem without specific targets. Active
process may take days to years depending on pesticide and environmental
settings. Every year remaining pesticides in soil and water accumulate through
bioaccumulation and biomagnification. It may reach surface waters by the
accumulation of groundwater or may be found in higher regions through the
atmosphere. Degradation is using two types of transformation, being biotic and
abiotic. Biotic transformation takes place through microorganisms, abiotic
transformation is through chemical and photochemical reactions. Different
metabolites may occur in variety of conditions and their potential effects are
not fully known. Biotic transformation: Makes biggest contribution to
degradation. While human organism detoxify pesticides, bacteria metabolize.
Degradation takes place faster in a suitable environment and living conditions
for the growth of microorganisms. There is a wide network of enzymes and other
bacteria also can have this feature with gene transfer. High concentrations of
pesticides or repeated administration makes degradation faster. Abiotic
transformation: Surface water pesticides may transform with the impact of
sunlight. Factors affecting the photochemical decomposition of pesticides are
sunlight intensity, application method and characteristics of area and the
pesticide. Chemical transformations happen without any microorganism. Physical
factors such as pH, temperature, humidity and properties of pesticide determine
reaction type and affect their speed. Reduction of temperature leads
deceleration of chemical degradation. One of the most common degradation is
hydrolysis through reaction with water. Depending on pesticide type it may
occur in either acidic or basic conditions.
Keywords:
Degradation,
Pesticides, Transformation
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- Hüseyin İlter, Muhsin Akbaba, Volkan Recai Ötegen
1Ministry of Health of Turkey, Public Health Institution, Environmental health department 2Çukurova University Faculty of Medicine Department of Public Health
