and Integrated Pest Management - part - usaid

362 PFS'l1CJDF MANAGEMINT AND 1PM IN SOU'DW[EAST ASIA
Human Tissue
Most studies on the pesticide residue
published
levels
and are
of Filipinos
basically have
inaccessible
not been
al.
to the
1985,
general
Bautista
public
et al.
(Simbul-Nuguid
1985, Librojo
et
(1977)
1985).
reported
In 1977,
that
however,
90% of 64
Barril
human
et al.
above
milk samples
the W\I-1O
had
recommended
total residue
maximum
levels
DDT on
concentration
a whole coV's
of 0.05
milk
mg/kg
basis.
total
DDE,
The most
DDT
common
and DDD.
residues
Other chlorinated
found were
lindane,
hydrocarbon
heptachlor,
insecticides
aldrin, and
observed
chlordane.
were
sample
The
ranged
number
from
of pesticide
2 to 7. Ina
residues
related
in
study
a
(1985)
conducted
161 abdonli;:al
by Simbul-Nuguid
fat samples
et al.
analyzed for DDT
combined
and DDE
samples
showed
range
a
of 0.15 ppm to 11.53 ppm.
COMPONENTS OF TIlE RICE PADDY ENVIRONMENT
The potcntial hazalrd from pesticide application on agricultural crops is not
only from the harvested produce, but also from the overall contamination of the
environment, In the rice paddy ecosystem, for example, the bulk of the
insecticides will not remain with the target plant, but will be deposited in paddy
water from where it will disperse to the soil, plants, and animals present in the
paldy (Librojo 1985). In addition, the insecticide may contaminate other bodies
of water when the paddy is drained during the later stages of rice growth. For the
1:-st several years tie NCPC residue laboratory, as p~ut of its impact monitoring
program, has been evduating the fate of insecticides in the rice paddy ecosystem
using nuclear !,chniquces (13ajet & Magallona 1982, Zulkifli et al. 1983, Varca
1983, Tejada & Magallona 1985a, 1985b).
Isoprocarb
B,ijet and Nlagallona (1982) have
in
studied
rice paddy
the
ecosystems.
chemodynamics
The
of
granular
isoprocarb
insecticide,
mg/L), was applied
at the rate
at tillering
of 2 kg/ha
stage
(3.9
and
was delected
a maximum
one
concentration
day after broadcast
of 2.7 mg/L
application.
observed followed
A rapid
by
decline
a relatively
was
slower
then
is the
degradation
major degradation
after three days.
route
Hydrolysis
in water
fluctuations
and this
of
is
pH
influenced
ant iemperature
by diurnal
(Sieber
in unfloded
et al. 1978,
and
Catahan
flooded soils
1977).
were
F-alf-lEfe
6.4
labelled
and 38.5
isoprocarb
days, respectively.
could be detected
Radioactive­
in the stein
-ixhours
and older
after
leaves
exposure.
of rice
After
plants
two days,
ip of
radioactivity
the leaves.
was
Isoprocarb
concentrated
was found
on the
uzonica,and
in Tilapia nilotica,
kangkong edible
Ipomoea snails
aquatica,
Pila
vas
one
higher
day after
in kangkong
exposure.
than
Radioactivity
in rice plants, implying effective
torag.'
uptake
of pesticide
and
in the latter.