3
Degradation of Pesticides in the
Environment by Microorganisms and
Sunlight
Fumio Matsumura
3.1. INTRODUCTION
It may be generalized that pesticide contamination problems in the environment
are directly related to their persistent nature, the most important factor determining the degree of persistence being the chemical characteristics of the pesticidal compound itself.
It is generally agreed that the two most important degradation forces operating on chemicals in the environment are microorganisms and sunlight. A few
reasons are offered to justify the above conclusion: first, most pesticides are
known to end up in soil whether they are aimed at crops or not; second, they
are spread in the environment at relatively low concentrations; third, soil and
aquatic sediments are generally loaded with microorganisms; and fourth, many
of the pesticides have some degree of volatility to escape into the atmosphere
depending on whether they are exposed to, for example, sunlight.
Many excellent books and reviews are available to cover various aspects
of the subject. Examples are those by Hill and Wright (1978), Khan (1977),
Matsumura et al. (1972), and Zabik et al. (1976). The purpose of this chapter,
Fumio Matsumura. Pesticide Research Center, Michigan State University, East Lansing, Michigan 48824.
67
Degradation of Pesticides in the
Environment by Microorganisms and
Sunlight
Fumio Matsumura
3.1. INTRODUCTION
It may be generalized that pesticide contamination problems in the environment
are directly related to their persistent nature, the most important factor determining the degree of persistence being the chemical characteristics of the pesticidal compound itself.
It is generally agreed that the two most important degradation forces operating on chemicals in the environment are microorganisms and sunlight. A few
reasons are offered to justify the above conclusion: first, most pesticides are
known to end up in soil whether they are aimed at crops or not; second, they
are spread in the environment at relatively low concentrations; third, soil and
aquatic sediments are generally loaded with microorganisms; and fourth, many
of the pesticides have some degree of volatility to escape into the atmosphere
depending on whether they are exposed to, for example, sunlight.
Many excellent books and reviews are available to cover various aspects
of the subject. Examples are those by Hill and Wright (1978), Khan (1977),
Matsumura et al. (1972), and Zabik et al. (1976). The purpose of this chapter,
Fumio Matsumura. Pesticide Research Center, Michigan State University, East Lansing, Michigan 48824.
67