South Pacific Studies Vol.37, No.2, 2017

Pyrethroid Pesticides of Cabbage-Grown Area in Dalaguete,
Cebu, Philippines
CALINAWAN Armstrong1, PAULE Heide Brigette S.1, ADARNA Leonila1, VILLEGAS
Lora Mae G.1 and MENDOZA Concepcion S.1, 2*
1

2

Chemistry Dept., University of San Carlos, Cebu City, Philippines
Department of Applied Sciences, Higher College of Technology, Muscat, Oman
*Corresponding author
E-mail: concepcionsmendoza@yahoo.com

Abstract
This study evaluated the presence of synthetic pyrethroid pesticides, specifically the residue levelsof deltamethrin and lambda-cyhalothrin in soil, water, and cabbage samples from an agricultural farmin Manlapay, Mantalongon, Dalaguete, Cebu, using Gas Chromatography-Electron Capture Detector
technique. Samples analyzed were collected from October 2013 to November 2013. Other environmental
parameters such as pH, total organic carbon (TOC) and cation exchange capacity (CEC) using standard
methods were also done on the samples.
The detected deltamethrin residue concentrations in the cabbage (< 0.001–0.029 ppm), soil samples(0.007–0.008 ppm) and water samples (< 0.0005 ppm) were all below international guideline limits.
Lambda-cyhalothrin residue was detected only in cabbage (0.006–0.007 μg/g) and was below theEnvironmental Protection Agency, Food and Agriculture Organization and World Health Organization
maximum residue limit of 0.4 μg/g. Results of the analyses of pH, CEC, TOC, season and daily temperature
showed that these factors affected the persistence, movement and degradation of deltamethrin and lambdacyhalothrin once applied into the environment.
The lack of awareness of the farmers on pesticide application and use may have contributed to thepresence of pesticide residues. The pesticides found in cabbage and in soil were in very low concentrations
may pose health hazards to the consumers and to the environment. Enhancing the awareness of vegetable
farmers on proper use and management of pesticides and a robust monitoring program for pollutants in
Cebu area is needed, to develop and maintain an adequate level of environmental protection.
Key words: Cebu, Philippines, deltamethrin, lambdba-cyhalothrin, pyrethroid, cabbage

Received: 18 January, 2016
Accepted: 5 January, 2017

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South Pacific Studies Vol.37, No.2, 2017

Introduction
Cebu is an island province and one of the most developed provinces in thePhilippines. Cebu is the main center of commerce, trade, education and industry in theCentral Philippines (Visayas area). Cebu, being one of the mostly densely populatedislands in the Philippines, is serving over 3.5 million people, as of 2010 (NSO
2010); of which 2.3 million live in Metro Cebu. Cebu's central location, proximity tounusually exotic tourist destination, ready access to a diversity of plant, animal andgeological wonders within the island, beaches, coral islands and rich fishing groundand remoteness from earthquake and typhoon activity are some of the special attributesof Cebu.
About 84 kilometers south of Cebu City, is the town of Dalaguete, producing
high quality vegetables the whole year round and supplied to restaurants, hotels andsupermarkets and other consumers within Cebu province and neighboring islands.
Cabbage is one of their vegetable products, a popular table vegetable; consumed as
raw or cooked. Farmers in this area depend heavily on the use of pesticides for theircrop protection. The misuse and misapplication of pesticides may pose risks to humans
and the environment―causing water pollution, resistance of pests to pesticides andnegative impact to non-target organisms. The effect of pesticide application can affectthe health of the farmers, the people living in rural communities and other populations
which consume contaminated food and water.
The use of pyrethroids pesticides had surpassed the more toxic organochlorines,
organophosphates and carbamates as the insecticide of choice (P AP et al. 1996) byapplicators including farmers in Cebu Island. The increasing use of pyrethroids has
generated public concerns. Though, pyrethroids are less toxic to humans, non-target
mammals and birds than organophosphates and carbamates but present a high toxicity
to honey bees and a wide range of aquatic organisms (PÁREZ-FERNÁNDEZ et al. 2010,
LUO and ZHANG 2011). Various formulations of pyrethroids are often combined withother chemicals, known as synergists, to increase potency and persistence in theenvironment (MUELLER-BEILSCHMIDT 1990).
With the continually increasing use of pesticides in Philippine agriculture (DAVIS
1993, MENDOZA 2004), there is still an inadequate pesticide research (DAVIS 1993)
on distribution, occurrence, fate, and environmental impacts resulting from its use
has been done in the Philippines. Likewise, little attention or perhaps, unpublisheddata are available on pesticide studies in Cebu Island. Pesticide treatment history ona large number of samples is unknown. There is also an urgent need for prevention,
monitoring and careful assessment of the benefits and risks of pesticides in this island.
This study aims to present some pesticide-related concerns in Cebu, as a consequenceof continued use of pesticides to sustain its agricultural based economy and forincreased food production. Specifically, the present study is aimed: 1) to determine thepyrethroids pesticide residues (deltamethrin and lambda-cyhalothrin) in soil, water andCALINAWAN et al.: Pyrethroid Pesticides of Cabbage-Grown Area in Cebu

59

cabbage from Mantalongon, Dalaguete, Cebu, towards a start in a systematic approachof pesticide pollution prevention in a specific area and, 2) to look into the practicesof local farmers of Dalaguete during pesticide use and application. Likewise, thispaper endeavors to support the pesticide monitoring program by information-sharing
the obtained analytical findings about pesticide residues and also to know about theawareness level of farmers regarding pesticides and their use. With the trans-boundary
nature of the Cebu aquatic environment, there is the need of collaborative analysis andsharing of accurate data for effective pesticide management strategies in the region.

Materials and Methods
Description of sampling site and sample collection
The Municipality of Dalaguete has fertile agricultural areas, abundant water andsun; and thus, has kept agriculture as its most important activity and livelihood. Highquality vegetables, crops and other products are produced the whole year round. The
use of pesticides in this agricultural area is a common practice to sustain productivity
and enhance the quality of farm products.
Specifically, the research area considered is an agricultural farm in Manlapay,
Mantalongon, Dalaguete, Cebu, as shown in Fig. 1, producing cabbages and othervegetables. The farm uses terracing techniques to prevent soil erosion and rapid
nutrient leaching. Table 1 shows the GPS coordinates of the sampling sites.
Fresh matured cabbages samples, soils and water samples were randomly collected
at the farm site, once a month from August 2013 to November 2013; about a week after
pesticide application and few days
prior harvesting. Four matured
cabbages, heads and roots, wererandomly collected. Soil strongly
bound to the root system, therhizosphere, was mixed with thecomposite soil samples before all
the cabbages were mixed. Cabbage
samples were placed in properly
labelled re-sealable plastic bags
and temporarily stored in a cooler
with ice before transporting it to
the laboratory.
Several five-inch deep holes,
about one meter distance fromeach hole, were dug in eachsampling site. Soil samples takenfrom different holes of a common
Fig. 1. L ocation map of Dalaguete, Cebu, Philippines.

60South Pacific Studies Vol.37, No.2, 2017

Table 1. GPS coordinates of the sampling sites.
Sample Collected

Area Assignment

Cabbage and SoilTop

Cabbage and SoilMid

Cabbage and Soil

BottomWater

Water Effluent

GPS Coordinates
N 09°52’16.9”
E 123°29’01.1”
N 09°52’16.4”
E 123°29’01.6”
N 09°52”16.9”
E 123°29’02.4”
N 09°52’28.3”
E 123°28’30.3”

Elevation
595 m
592 m
578 m
554 m

site were combined to represent the composite soil sample for analysis. Soil samples
were placed in properly labelled re-sealable plastic bags and temporarily stored in acooler with ice before transporting it to the laboratory.
Water samples were collected from the water catchment located downhill about
20 meters from the farm. One liter of water effluent was collected and placed in acidwashed polypropylene bottles and stored in a cooler with ice.
Pesticide analysis
The cabbage, soil and water samples were analyzed for pesticide residue ofdeltamethrin and lamda-cyhalothrin. Lambda-cyhalothrin (C23H19ClF3NO3) with an
IUPAC name of (R)-cyano-(3-phenoxyphenyl)-methyl-(1S,3S)-rel-3-[(1Z)-2-chloro3,3,3-trifluoro-1-propenyl]-2,2-dimethylcyclopropanecarboxylate, and deltamethrin(C22H19Br2NO3) with IUPAC name of (S)-α-cyano-3-phenoxybenzyl (1R,3R)-3-(2,2dibromovinyl)-2,2-dimethylcyclopropane carboxylate; both belong to the synthetic
cyano-containing type II pyrethroid pesticide (EPA 2011). Due to poor water solubilityof pyrethroids, gas chromatography is the instrumental technique generally used forroutine pyrethroid analysis.
1. Sample preparation
Water. Liquid―liquid extraction with a 1:2 sample to acetone ratio was performed
on a filtered water sample. The filtered acetone layer was concentrated to near dryness
in a rotary evaporator at a water bath temperature of 40°C.
Soil. A 15 g of homogenized, screened and air dried samples and spiked soil
samples were obtained and added with 80 mL acetone. Approximately 10 g ofanhydrous Na2SO4 was added and the mixture was shaken for 1 hour. The mixture wasfiltered and the residue further washed with 20 mL of acetone. The combined filtrate
was concentrated to near dryness in a rotary evaporator at a water bath temperature of
40°C.
Cabbage. A 15 g of homogenized samples were obtained, added with 15 mL
acetonitrile and shaken for 1 minute. Approximately 6.2 g of anhydrous MgSO 4

CALINAWAN et al.: Pyrethroid Pesticides of Cabbage-Grown Area in Cebu

61

was added and the mixture was vigorously shaken for 1 minute. The mixture wascentrifuged and about 6 mL of the clear liquid solution was allowed to pass through a
C18 column and eluted with 20 mL dichloromethane. The eluent was concentrated tonear dryness in a rotary evaporator at a water bath temperature of 40°C.
2. Extraction and GC-ECD injection
The remaining extracts collected during water sample preparation was redissolved
with 5 mL of n-hexane: acetone mixture (70:30) and sonicated for complete
dissolution. A florisil solid phase extraction cartridge was conditioned and washed with
5 mL of of n-hexane followed by 5 mL of n-hexane-acetone mixture (70:30). Samples
were then loaded to the prepared cartridge and eluted with 10 mL n-hexane: acetone
mixture (70:30). The eluate was collected, evaporated to near dryness, redissolved with
2 mL and injected into the GC instrument.
The above step was also done for extracts collected during soil sample preparation.
Similar step as stated above was performed for the extract collected during cabbage
sample preparation. However, instead of using hexane-acetone mixture, acetonitrile
was used in the washing the florisil solid phase cartridge and in the GC elution process.
3. Gas Chromatography―Electron Capture Detection (GC-ECD) Analysis
The extracts were analyzed for the presence of lambda-cyhalothrin anddeltamethrin using GC-ECD at retention time of 9.78 minutes and 12.32 minutes,
respectively. The working condition for the GC-ECD analysis is summarized in Table 2.
4. Quality Assurance
External calibration method and standard spiking was done for the determinationof lambda-cyhalothrin and deltamethrin in the samples analyzed. Recovery tests werealso performed through solid and liquid matrices. Fortification of control samples andrecovery percentages from spiked samples were done. The averaged % recovery is
shown in Table 3.

Table 2. GC-ECD working conditions.
Injector temperature

250 ˚C

Detector Temperature

300 ˚C

Oven Temperature Program120 ˚C hold for 1 minute, 9 ˚C/min to 285 ˚C

Carrier Gas

Nitrogen (GC grade)

Make-up Gas

Hydrogen (GC grade)

Column Flow Rate

3.0 mL/min

Column

2.7 m x 4 mm i.d. glass on 5% OV-210 on 80–100 mesh
Cromosorb W-HP

Amount Injected

2 microliters

Data System

HP Chem Station

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South Pacific Studies Vol.37, No.2, 2017

Table 3. Retention time and % recovery of tested insecticide after extraction and clean-up using GC/ECD.
Insecticide

Retention time (Rt), minutes

Solid Matrix

Liquid Matrix

Mean % Recovery

Mean % Recovery

Lambda-cyhalothrin

9.78

90.46

90.17

Deltamethrin

12.32

83.39

94.45

Other analyses on soil and water samples
The various parameters: organic matter in soil (Walkey-Black method); chemical
oxygen demand (COD) in water (dichromate open reflux method); cation exchange
capacity of soil (ammonium acetate method); and pH (electrode method) in soil andwater were determined using recommended procedures (RADOJEVIC et al. 1999).
Rainfall and ambient temperature
Rainfall and temperature data were obtained from one of the monitoring stationsof PAG-ASA (2013).
Local Practices in Pesticide Application
During the cabbage, soil and water sampling, the farmers were interviewed toobtain information regarding their knowledge and practices on pesticide management.
Farmers were asked about their training on the safe and effective use of pesticide,knowledge of withholding period and source of recommendations regarding time,
application rate and method of application and the subsequent harvest and sale oftreated crops and also the contacts they make with pesticide dealers, researchers,
extension workers for making decisions regarding the use of pesticides. They wereasked whether they use protective clothing while they handle and spray the field, andwhether they suffer of any discomfort during pesticides application.

Results
Pyrethroids in Cabbage, Soil and Water
Deltamethrin and lamda-cyhalothrin were used to represent the pyrethroid groupof pesticides. Deltamethrin and lamda-cyhalothrin were detected and observed tobe higher in concentration in cabbage heads than in soil samples and least in water
samples (Table 4). Lamda-cyhalothrin was detected only in cabbage while values of
below the method detection limit for soil and water samples.
At the moment, no existing norms for pesticides in the Philippines and such,other international guidelines are used for comparison (Table 4). The deltamethrin
and lamba-cyhalothrin levels in cabbage, in soil and in water are way below theenvironmental guideline values.

CALINAWAN et al.: Pyrethroid Pesticides of Cabbage-Grown Area in Cebu

63

Some Factors Affecting Pesticide Persistence and Transfer
The organic matter, CEC and pH values showed significant correlation withadsorption of deltamethrin in soil while inversely proportional to rainfall (Table 5).
Deltamethrin residue in cabbage showed inverse relationship with deltamethrin residue
in soil; and rainfall data supports to this observation. Residue in water does not show
any correlation to any other parameters as its concentration is beyond detection limit.
The amount of precipitation during sampling also correlates to the lambdacyhalothrin residue level detected in cabbage. Lambda-cyhalothrin residue in water andin soil did not show any correlation to any other parameters as it was below the method
limit of detection (Table 5).
The rainy/moisture condition maximizes the pesticide (deltamethrin and lambda-

Table 4. Pesticide residue on cabbage, soil and water samples together with guideline values.
MonthDeltamethrin (ppm)

Lambda-cyhalothrin (ppm)

Cabbage

Soil

Water

Cabbage

Soil

Water

Oct-13

0.029

0.007

<0.0005

0.007<0.001<0.0005

Nov-13<0.0010.008<0.0005

0.006<0.001<0.0005

Guideline limit (ppm)

0.5(a)

1290(b)0.0025(c)0.3(d)

68.5–229(e)5.2x10-5(f)(a)

ASEAN 2002: maximum residual limit (MRL) for leafy vegetables like cabbage.

(b)

EC 2002: acute toxicity for earthworms: LC50 (14 days) for Eisenia fetida > 1290 mg/kg soil.

(c)Kegley et al. 2014: Canadian water standard for agricultural use / livestock water guidelines.

(d)

FAO/WHO Codex 1993: MRL for leafy vegetables like cabbage.

(e)

Garcia et al. 2011: acute toxicity for earthworm, Eisenia fetida: soil at tropical region: LC50 (14 days)= 68.5–229 mg applied insecticide/kg dry weight soil; EC50 = 54.2–60.2 mg applied insecticide/kg dryweight soil (soil at temperate region: LC50 = 99.8–140 mg a.i./kg soil; ED50 = 37.4–44.5 mg applied
insecticide/kg soil).

(f)

EPA 1998: maximum concentration detected in simulated water pond = 0.52 ppb.

Table 5. Some physical properties of soil and water samples, together with the weather condition during sampling.
Cabbage
Parameter

Soil

Water

Oct-13

Nov-13Oct-13

Nov-13Oct-13

Nov-13

Mean

Mean

Mean ± SD

Mean ± SD

Mean ± SD

Mean ± SD

Deltamethrin (ppm)

0.029<0.001

0.007

0.008

<0.0005<0.0005

Lambda-cyhalothrin (ppm)

0.007

0.006

<0.001<0.001<0.0005<0.0005

51,942.2 ±
3,832.1

54,639.1 ±1,818.6

2.011.2 ±6.13

1,304.0 ± 4.0

Organic Matter (ppm)－－

Cation Exchange Capacity (meq/100g)－－

30.5 ± 0.8

36.0 ± 0.6

－

－

pH

－

－

6.97 ± 2.03

7.01 ± 0.03

6.50 ± 0.01

6.80 ± 0.0－－

2.92 ± 0.01

8.14 ± 0.12－－

Oct-13

Nov-13

Moisture (%)
Weather condition
Rainfall (mm)

154.6

240.8

Temperature (oC)

18.7–23

17.6–23

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South Pacific Studies Vol.37, No.2, 2017

cyhalothrin) transfer and leaching from cabbage to sediment to water media. High day
temperature also facilitated pyrethroid degradation and volatilization.
Local Practices in Pesticide Application
Cabbage cultivation takes 2.5–3 months and within this cultivation period,
pesticide application is primarily directed to cabbage heads. After the fifteen day ofcultivation, pesticide spraying is done twice a month on normal harvest cycles andsprayed one last time before harvest to ensure that the inner portion of cabbage headis protected from pest attack, or as often as needed to prevent pest attack using therecommended dosage of the pesticides. On the event of a big infestation, the doseof the pesticide is increased based on farmers’ personal assessment and experience.
Cocktailing is a common practice in pesticide application. A dose of one pesticide ismixed with a dose of another in the same dilution volume which makes the resulting
solution very potent. Sometimes, the pesticide is applied too close to the crop’s
harvest. In unforeseen events arising like unseasonal weather, high market demands
and farmers’ urgent need for a daily source of income from sale of cabbages, thewithholding period of the pesticide is not properly taken into account in the harvestand sale of cabbage products by the local farmers. Buyers or consumers are not also
informed by the farmers that the withholding period of the pesticide has not expired.
Most of the farmers are unaware about the recommended doses, spray intervals and notraining on the safe use of pesticides and application techniques. They only consulted
pesticide dealers for recommendation of pesticide use but only a few were foundspraying on the recommendationsof agriculture experts.
Farmers wore inappropriate
protective clothing during spraying―no gloves, no goggles or old
clothing used as mask during
pesticide application (Fig. 2). They
just leave the pesticide containers
at farm borders. Local farmers
experienced various health effects
like dizziness, vomiting, headache,sneezing, nausea, skin and eye
irritations and chest discomfort,
after pesticide application.
The farmers did not experienceany pesticide residue monitoringwith their environmental samples,
except from this study. While,Fig. 2. A farmer spraying a cocktail pesticide to
the researchers experienced
cabbage plants with improper protectivethat pesticide residue analysis
clothing.

CALINAWAN et al.: Pyrethroid Pesticides of Cabbage-Grown Area in Cebu

65

was costly and can only be done by few analytical laboratories in Luzon area (North
Philippines).

Discussion
Pyrethroids in Cabbage, Soil and Water
Cabbage sampling was done seven days after pesticide application to the matured
and ready to be harvested cabbages. Thus, presence of pesticide in cabbage is expected
as pesticide application by local farmers is directed to cabbage heads prior to harvest.
Pyrethriods are highly lipophilic, too and easily adsorbed into the waxy layer of plants(SPIOC 1986). The presence of deltamethrin in the soil indicated a movement of thepesticide away from the target host. Pesticide transfer in soil and water may be due tovolatilization, run-off, leaching and crop removal (FISHEL 1991).
The allowed daily intake without causing harm to humans is 0.01 mg/kg/day
as an acceptable daily intake (ADI) for deltamethrin (WHO 2002) and 0.005 mg/kg/
day as reference daily dosage (RfD) for lambda-cyhalothrin (EPA 1998). Ingestion of
cabbage, soil or water might not be an important pathway of exposure for farmers andrural people considering the low concentration of deltamethrin and lambda-cyhalothrin
in cabbages, in Dalaguete agricultural soils and in water, of this study. Pyrethroids havestrong affinity to soil environment but the variability in toxicity on different soils is notclear. The available information on the acute toxicity to earthworms by deltamethrin of
LC50 > 1290 mg/kg soil (EC 2002) and for lambda-cyahalothrin is LC50 = 229 mg/kg
soil (GARCIA et al. 2011); and pyrethroids in general have acute toxicity (LC50 > 1000
mg applied insecticide/kg dry weight soil) to worms (INGLESFIELD 1989) is used as
reference. Comparing this reported LC50 values to the pesticide values in soil obtainedin the study, indicates that Dalaguete soil is still a good environment for earthworms.
The presence of pesticides detected in the cabbage samples may be due to greatamount of pesticide applied and/or an early harvest of cabbage which did not allow
most of the deltamethrin and lambda-cyhalothrin to be decomposed or degraded by thecabbage plant. Such contamination of cabbage with pesticide residue may be expected
to happen often in later scenarios in relation to the information obtained from theinterview of farmers with respect to excessive use of pesticides and the disregard ofwithholding periods.
Some Factors Affecting Pesticide Persistence and Transfer
Once applied, many pesticides are mobile in the environment due to several
factors influencing the fate of the pesticide like properties of the pesticides and various
conditions at the application site. The soil characteristic of the farm with high CEC
value (Table 5) indicating a clay and clay loam category (DONAHUE et al. 1977), in
addition to the neutral pH and high organic content, are considered to be reasonableconditions for the persistence of pyrethroids (repesented by deltamethrin) in soil. In

66South Pacific Studies Vol.37, No.2, 2017

soil, deltamethrin degradation occurs within 1–2 weeks (RSC 1983). Deltamethrin andfenvalerate are the most persistent pyrethroids in commercial use, especially in soil
with high organic matter (SPIOC 1986). The nearly neutral pH condition (pH~-7) of thesoil prevents chemical degradation of deltamethrin. Many insecticides are susceptible
to rapid pesticide breakdown under alkaline medium (FISHEL 1991). However, thewarm average temperature of 29 °C, low vegetation cover of the farm and the adequate
soil moisture of > 5%; might justify the disappearance of pyrethroids (represented bylambda-cyhalothrin) (NABIL et al. 1996). Heavy rains causing wind-soil and watererosion, leaching, volatilization, photochemical and microbial degradation processes,
and desorption may have enhanced the decreased or absence of pyrethroids in soil.
The cabbages in October 2013 were sprayed twice, while the cabbages in
November 2013 were of the second harvest and sprayed only once prior to sample
collection. In such wet situation (like in November 2013), the dispersion of pesticide
residue maybe easier to other areas. The lower pesticide residue in November
maybe caused by the washing out of the adsorbed pesticides on the cabbage leaves.
The high amount of precipitation during the wet months of October and November
also permitted the leaching of pesticide from the vegetable to the soil. This result is
consistent with the results of ZHANG et al. (2008) which showed the close relationshipof amount of pesticide residues with dosage of application, and with weather conditions
after spraying. Pesticide run-off is usually greatest when a heavy or sustained rainfollows soon after an application (FISHEL 1991).
Deltamethrin and lambda-cyhalothrin were not detected in the water samples(Table 5), because these pesticides have low solubility in water at 0.002–0.0002
mg/L and 0.005 mg/L at 20 °C respectively. By pesticide movement, pesticide canpossibly enter and contaminate water sources through spray-drift, leaching, pesticide
persistence, soil and topography, and weather (CAST 1994).
The low level of deltamethrin and lamba-cyhalothrin in cabbage, in soil and inwater are below the environmental guideline values and also suggesting efficient use
and degradation of the pesticide in the area.
Local Practices in Pesticide Application
The improper practices of the farmers due to the lack of awareness on pesticide
use and application can be linked to the pesticide contamination in the cabbage
samples. The contaminated cabbage samples may pose health hazards to the consumers.
Their practices indicating lack of awareness on the hazardous effect of these hazardous
chemicals on human health and lack of knowledge on pesticide disposal may enhance
the presence of pesticide contamination on the environment (soil, water, air and biota),
in addition to excessive use of pesticide and not considering withholding period ofpesticides.
In other studies, pyrethroids and organophosphates residues in cabbage samples
exceeded the maximum residue limits for cabbage due to wrong application method
techniques (ARMAH 2011) and higher doses with shorter interval of deltamethrin

CALINAWAN et al.: Pyrethroid Pesticides of Cabbage-Grown Area in Cebu

67

applications (FAO/WHO 1984). As a good agricultural practice, the applicationof deltamethrin and lambda-cyhalothrin on cabbage is limited to two applications
only during the growing season and with a seven-day harvest interval for these two
pesticides (RHS 2015). At about 10 days after use, deltamethrin have undergone
chemical breakdown in the vegetation and no deltamethrin residues are observedon plants, as well, no phytotoxicity to crops. (RSC 1983, THOMSON 1989). The
unintended movement of pesticides from target site to non-target site often causes
toxicity symptoms on a non-sprayed site or serious hazards to non-target organisms.
Deltamethrin and lambda-cyahalothrin have been found to be highly toxic to birds,
fish and bees (BRADBURY et al. 1989). Acute exposure to pyrethroid formulations had
demonstrated to cause a range of potentially hazardous health effects in humans (HE etal. 1988, (WHO 1990).
In this study, the local farmers used deltamethrin (trade name: Deltacide 2.5 EC
and Astro 2.5 EC) and lambda-cyhalothrin (trade name: Karate 2.5 EC and Blast 2.5
EC), among a variety of other pyrethroids products available in the local market (DFAFPA 2007). Most of these applied pesticides are in emulsified concentrate (EC) form,and some points of the farm may be considered the mixing and loading sites of thesepesticides and thus, can also contribute to the presence of pesticides in the biota. The
use and effect of these pesticide products needs monitoring, too.
Within the study area, the inadequate facilities for pesticide analysis (likedifficulty to acquire expensive and new analytical equipment, inadequate stock of spareparts, relatively expensive chemicals, or few technicians who can handle equipment
repair) can be one of the reasons for the limited pesticide studies in Cebu.
The use of pesticides still provides the main treatment against pests in agriculturalactivities in Cebu. Consequently, problems concerning their use may emerge in thenear future that might pose serious threat to the health of the farming families, theconsumers in urban areas and the environment in general; if necessary controls andmeasure are not in place. There is a need to promote more effort for an integrated pest
management in Cebu towards minimizing pesticide hazards.

Acknowledgements
The researchers would like to thank Jefcor Laboratories Incorporated in Cavite(North Philippines) and USC Water Laboratory for the support extended during
the laboratory analyses; and the cooperation of the farmers of the cabbage farm in
Manlapay, Mantalongon, Dalaguete, Cebu, Philippines during sample collection andinterview.

68South Pacific Studies Vol.37, No.2, 2017

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