Pesticide bioconcentration modelling for fruit trees

Lourival Costa Paraiba' Abstract

The model presented allows simulating the pesticide concentration in fruit trees and estimating the

pes tic ide bioconce ntra tion factor in fruits of woody spec ie s. The mode I allows estima ting the pe sti:; ide

uptake by plants through the waler transpiration stream and also the tire in which maximum pesticide

c once ntra tion occ ur in the fruits. The e qua ti on propose d pre se nts the re Ia tionships be twee n

bioc once ntra tion factor (B CF) and the followin g va ra ble s: pia nt wa e r 'tra nspira tion volume (Q), pe sti:; ide

tra nspira tion stream concentra lion factor (TSCF), pest icide stem-water partition coefficient (Kwood.w), se ill ~

dry biom ass (M) and pe sti:; ide dissip! tion rate in the soil-pIa nt system (kEGS)' Tre mode ling s1a rte d and

wa s de VI! lope d from a pre vious mode I" Fruit Tree Mode l' (FTM), re ported by Trapp and collaborators in

2003, to whic h was a dde d the hypothe sis that tre pesti:; De de gra da tion in the soil follows a fiISt order

kineti:; equation . The model fitncss was evalualed through tre sensitivity analysis of the pesticide BCF

va lue s in fruits with respec t to the mode I entry da 1a varabilty.

Key wo rds : Mangife ra indica; Pac lobutrazol; Woody tree; Mathermti;al mode I; Fruits; Pesti:; ides

I n trod u ction

[n general, the fruit tree production marngement includes the use of pe sti:; ides. Brazil is one of the

world's grea test consumers and exporters of fresh frui ts and fruit juices and ranks among the world's ten

grealest pesticide users (Armas et aI., 2005). Therefore, the Brazililn government concern about fruit

quali ty reated to pesti:;ide concentration in fruits produced in Brazil and exported to other countries

comes with the grea t e xpec ta tions of Brazililn pe ople a nd fore igne rs, consume rs of fre sh fruits.

Ma the mati:;al ~ odels might contribute to pre ve nt c oncentra tions of toxic subs 1a nces in frui ts of

plants cukivated with pesticides and suggest that such substances must be syse matically monitored in

good agriculture practi:e programs. Several mathermti:al models ha ve been developed to simuate the

uptake of subs1ances by plants (Fujisawa eta!., 2002; Hung and Mackay, 1997; Matthies and Behrendt,

1995 ; Paterson and Mackay, 1995; Riederer, 1995 ; Trapp , 1995; Trapp and Matthies , 1995 ; Trapp and

Matthies, 1998; Trapp and McFarlane, 1995 ; Tra pp etaL, 2003 ; Trapp and Pussemier, 1991). There are

'Embrapa Meio Ambiente - Embrapa Environment; CxP. 69, Cep 13820-000, SP 340, Km 127,5. Tel

XX-55-1 9-331 1-2667; e-rm il: louriva I@cnpma .em bra pa .br; Ja guariuna, Sa 0 Pa ulo, Brasil.

r 532 '\

:','

Is developed to simuate eaf uptake (Trapp and Matthies, 1995), the ones to simuate root uptake

etaL, 2003) and others to simuate both eafand root uptake (Fujisawa eta!., 2002).

A substance bioconcentration is de finc d as the concentration increase inside and/or on the surmce

. of an organism (or in specific tissues) in relation to the subs1ance conce ntration in tre exte rrnl medium 1

(OECD, 1981). This research work aimed at modeling the binconcentration and estimating the peste ide

BCF value in fruits woody trees. The pesticides considered in this study are non-ionic organic compounds ,

de gra ding in the soil.

Material and Methods

HypOlh esis for Ihe FTM-p model

T be pes tic ide bioc once ntra tion mode ling in fruits was de VI! lope d from the origina I m ode I na me d

Fruit Tree Model (FTM) , according to Trapp etal (2003), and consisted ofadding to t the hypothe sis that

pesticides degrade in the soi l according to a first order ki1eti: equation. The FTM-p modeling suppose s

that the pesticide dilution processes due to plant growth, peste ide metabo lism in the plant and pestcide

degradation in the soi l are deseribed by first order ki1eti: equations. [n both FTM and FTM-p models, the

ar/pesti: De e xc ha nge by diffusion through the xyem'phloe m, wood-bark and fruits were neglected.

Thus , tre pestic ide transport into the plant was considered a p! ss iVl! process nccurring th rough the plant

transpiration stream. Both models werealso supposed for woody and perennial frut trees.

The F TM-p mod eling fro m FTM model

Pesticide is trans porled via transpiration stream to all plant pa rts (roots, siems, leave s and fruits).

In the pia nt, the pestic ide is transformed tbrough meta bole proce sse s, dilute d in func tion of pIa nt growth a

adsorbed in the woody parts . Thus, the pestcide total balance mass in the plant was cal:uated by

(T ra pp et a I., 2003):

dm,,, ~., ., .) •• ,,, .11:;" dl K,,,, .,

(I)

where m • (I) (~day' l ha' l) E the pesti: De tota I rmss i1 the stem per hectare, Q (I day'l ha'l ) E ill ' /J, .

the water transpration rate (transpratiJn stream) by pa nts, C (mg r') E the pesti:de concentratim i1 "

the transpratioo stream, M (kg ha'l) E the stem tolal dry rmss, k , (day' I ) E the peste de transforrmtion

rate i1 the stem, k (da/) E the pant growth rate, C (mg kg·l) E the pesti:ide concentratbn i1 the , ~ r I •

stem and K,,,, ., (I kg'l) E the stem-water pesti:de parttion coeffi: ent.

r 533 11-----------

Pesticide bioconcentration modelling for fruit trees

Lourival Costa Paraiba 1

Abstract

T he mode 1 pre se nte d allows simula ting the r:e sticide c once ntra tion in fruit tre es and estima ting the

pesticide bioconcentration factor in fruits of woody species. The model allows estimating the pesti::ide

uptake by plants through tbe waler transpiration stream and also the tire in which maximum pesticide

concentration occur in the fruits . The equation proposed presents the relltionships between

bioconcentration factor (BCF) and the following varBbles: pllnt wal::r 'transpiration volume (Q), r:esti::ide

tra nspira tion stream concentra tion factor (TSCF), pes tic ide stem-water partition coefficient (KWood.w), sl:: m ~

dry biomass (M) and r:esti::ide dissillltion rate in the soil-plant system (kEGs), The modeling s~rted and

was developed from a previous model " Fruit Tree Moder' (FTM), reported by Trapp and collaborators in

2003, to whic h was a dde d the hypothe sis that the pestei:le de gra da tion in the soil follows a fi~t order

kinete equation. The mode l fitness was evalualed through the sensitivity analysis of the pesticide BCF

va Iu:: s in fruits with respec t to the mode I entry da ~ varnbiliy.

Key words: Mangifera indica; Paclobutrazol; Woody tree; Mathermti;almodel ; Fruits; Pe sti::ides

Introduction

In ge ne ra l, the fruit tree produc tion manage ment include s the use of r:e sti:: ide s. Brazil is one of the

world's grea test consumers and exporters of fres h fruits and fruit juices and ranks among the world's ten

grea Ie st pes tic ide users (Armas et a I., 2005) . The re fore, the Brazilnn gove rnme nt c once ro a bout fruit

quality reated to pesti::ide concentration in fruits produced in Brazil and exported to other countries

comes with the greatexpectations of Brazilnn people and foreigners,consumers offresh fruits.

Mathemati::al models might contribute to pre ve nt concentrations of toxic subs~nce s in fruits of

plants cukivated with pesticides and suggest that suc h substances must be syslematica lly monitored in

good agriculture practee programs. Se ve ra I mathermteal mode Is ha ve bee n developed to simuate the

uptake of s ubs~ nces by pllnts (Fujisawa et aI., 2002; Hung and Macka y, 1997; Matthies and Behrendt,

1995 ; Pa terson and Mackay , 1995; Riederer , 1995; Trapp, 1995; Trapp and Matthies, 1995; Trapp and

Matthies, 1998 ; Trapp and McFarllne , 1995; Trapp et aI., 2003; Trapp and Pu sse mier, 1991). There are

lEmbrapa Meio Ambiente - Embrapa Environment; expo 69, Cep 13820-000, SP 340, Km 127,5. Tel

XX-55-19-3311 -2667; e-rmil:lourival@cnpma.embrapa.br;Jaguariuna, Sao Paulo, Brasil.

( 532 '\

-., ... '

Is de veloped to simuate eaf uptake (Trapp and Matthies, 1995), the ones to simuBte root uptake

et a I., 2003) and othe rs to simuate both eaf a nd root upta ke (Fujisawa et a I., 2002).

.. A substa nce bioc OIl:e ntra tion is define d as the COIl: entra ti on inc rea se inside and/o r on the surfu ce

~' ~f an organism (or in specific tissu::s) in relation to the subs~nce cOIl:entration in the extem!l medium

(OECD, 1981). This research work aimed at modeling the bioconcentration and estimating the pesti::ide

BCF va lue in fruits woody trees. The pesticides considered in this study are non-ionic organx:: compounds ·

de gra ding in the soil.

Material and Methods

Hypoth esis for the FTM-p model

The pesticide bioconcentration modeling in fruits was deve loped from the or iginal model name d

Fruit Tree Model (FTM), according to Trapp etal (2003), and consisted of adding to t the hypothesis that

pes tic ides degra de in the soil accord ing to a first orde r met i:: e qua tion. The FT M-p m ode lin g supposes

that the pesticide dilution proce sse s due to plant growth, r:e sti:: ide me ta bolism in the pll nt and pe sti:: ide

degradation in the soil are deseribed by first order meti:: equation s. In both FTM and FTM-p models, the

ar/pesti:: i:le e xc ha nge by diffusion through the xyem'ph loe m, wood-bark and fruits were neglected.

Thus, the pest icide transport into the plant was considered a plssive process occurring through the pllnt

transpiration stream. Both models were also supposed for woody and r:erennial frut trees .

The FTM-p modeling from FTM model

Pesticide is transporled via transpiration stream to all plant parts (roots, siems, leaves and fruits).

In the pa nt, the pes tic ide is transformed through meta boli:: proce sse s, dilute d in func tion of pia nt growth a

adsorbed in the woody parts. Thus, the r:esti::ide total baance mass in the pant was cal::uated by

(T rapp etal., 2003):

dm,,, 11211:;, . , . ) •• ,,, .11;" dt K'"I .'

( I)

where m • (t) (mg day" ha-I ) E the pesti:: i:le tota 1 rmss i1 the stem rer hectare, Q (I day' l ha·l ) E III . Ji ll

the water transpration rate (transpratiln stream) by pants, C (mg n E the pesti::i:le concentratiln i1 "

the transpration stream, M (kg ha· l) E the stem total dry rmss , k , (da/) E the pestei:le transforrmtion

rate n the stem, k (day'l) E the pant growth rate, C (mg kg· l ) E the pesti::ide concentratiln n the , ", , ,

stem and K,,, I, ' (lkg-I) E the stem-waterpesti::i:le parttioncoeffi::ent.

( 533 '\

The pes ti: i:!e concentratDn iJ the transpi-ation stream was esti-nated from tre pesti: i:!e

co,',centratnn in the soi l so lutnn and from the pesti: i:!e transpi-ation stream concentratnn factor, using

the expressnn C" II'SCF ., ' where C, (mg r l ) il the pesti:i:!e concentratDn in the soilsolutnn '

and TSCF il the pesti: i:!e concentration factor in the transpi-ation stream The TSCF vaue was estmated

from the octano~water parttion coeffi: ent given by the express nn (Burken and Schnoor, 1998)

. ogKOII' • .50)'

TSCF a .756e lSg , where bgK" il the logarthm of the octano~water parttion coeffi:ent.

The K,,,,, va ue was estmated from the octano~water parttion coeffi: ent given by the expressnn

(TrappetaL,2001) K,,,, ., .0,.".",.,1" , .

It wa s suppose d that the pestei:!e degradation rate iJ the soil so lu tion at the phnt riz osphe re can.

be descrbed by a frst ordc r knet e equatnn give n by:

• C' Is, c:; (t) . ' e (2)

(I.i" K" .... ~, )

whe re C; . • • : nil .. (m g r l ) il the soil solution peste' i:!e in~ al concentration, C,',,, (fo K oc W AwfA)

(m g kg'l) il the peste de inial concentration iJ bulk soi~ k I (da /) il the pesti:ide dils pat ion da ily rate

i1 the soil, • (kg rl) and . (kg rl) are the soildenshs iJ a humi:! basis and dry resis, respectively.

KA w il the pestci:!e ar-water parttion coeffcent. The coeff'x;ents f or (g g'I), J; and f , are the soil

volume tre fractnns of org)! nie ca rbon, water and ai-, respectively. The pararreter K " (I kg'l) il the

peste ide organic carbon-water partiion coeffcent and was estinated by the expression (EUSES, 1996)

K" • 101' ". 1 '0.' . 'I, .

It was supposed that the pestcde intalconcentration iJ the soilsolution il known and the one iJ

the phnt il null, that il , C, (0) "',' and c"" (0) •. Under these condtions an:! consi:!ering

m I" (t) •• I" (t) , the resoutirn of Eq. (1) that descrbes the pesti: de concentratirn in the stems il

given by:

A .... O

Cs". (t).~[e·sl •• ' ] (B . s )

(

l

(3)

534 )1--------------

'P" ... .. -)'1

I I

where the constants A (I kg' I dail) and B (dail) are given by AW·SCF

M and

8 I k 1 . , ) I M Q . Crnstant A il the pestcde uptake rate by phnts and constant B il the '-'" I.f

pesti: ide dils pat nn rate from the phnt. From Eq. (3) the pestcde concentratnn iJ the frui was

estimated by the equatnn given by:

C . (t) lf2'h,,,.4,.(t)r~h',,,"' C;,~ [ell , •• ,] Frul/ KWoad./I' K wood.H' (B . s ) (4)

where C;"" 11=; "" (t) (mg kg-I

da / of frut fresh mass) il the frut daily pesti:ide concentratbn and

QPhlocm(1 kg·l) il the vourre of water fbw i1 the phloem necessary to produce 1.0 kg of fresh frut (Trapp

et al, 2003). The Eq. (4) anows estimat ing the time necessary to reach max imum pesti: ide concentratnn

ri fruit and the frui maximum concentratnn. The tirre to reach maximum pesti:ide concentration in fruit

il oiven by Ii" . 00B) . (k). And the fruit max imu m concentratnn was cal::uhted by 0 " ' " '' B_1

C"" ~ (I "") . r,.. f, • ., f',.i

The pesti:de bi:lconcentration il frui. was es tffilted suppos rig steady sta te equilibrllin of the

quotent between the pestci:!e concentration in soil solut nn and in fruts and was cal::ufited by:

BCF .. C, .. " (t) (5) C,(t)

where BCF (I kgl) il tre pesti:i:!e bnconccntration factor i1 fruit. For the solIton of Eq. (I) and to

cal::uhte the limt of Eq. (5) t was supposed that the pesti:ide degradatnn rate in soil il bwer than the

peste ide dils pat nn rate from phnt, that il, k, < B . In thil case, the lim i. for Eq. (5) il given by:

BCF = Aa lJ '"' • QlI2wl" . SCF k,,,,, (8 . 1) Q . ,11 . ,,,' , • (6)

where kill .'.'.' (day'l) il the pestcde dilsipation rate from the soi~phnt sys tem, whch albws

estimatrig the half-life tUre of pesti:ire dilspat ion in the soil-phnt system, t il' (day), by the equati:m

t Il , .0(2) I k " ' .

( l 535 J

The pesti:ile concentratim n the transpration stream was estimted from tre pesti:: ile

co,",centrati:m in the soil solutim and from the pesti:: ile transpration stream concentratim factor, using

the expressi:m C" II'SCF ., ' where c:; (mg r l ) i; the pesti::ile concentratim in the soilsolutim "

and TSCF i; the pesti:: ile concentration factor in the transpration stream The TSCF vaue was esti-nated

from the octano~water parttion coeffi:: ent given by the expressi:m (Bmken and Schnoor, 1998)

. og KOII' • .50)'

TSCF a .756e 158 , where bg K" i; the logarthm of the octano~water parttion coeffi:: ent.

The K,,,, ., vaue was esti-nated from the octano~water parttion coeffi::ent given by the expressim

(Trapp eta1, 2001) K,,, , , . 0,. "1 Il: . ! I,,' .

It wa s suppose d that the pesti::ile degradation rate n the soil so lut ion at the pant riz osphe re call<

be descrbed by a frst orde r knet i:: equatnn give n by:

• C' Is, C; (I) . ' e (2)

(Ii" K" .... 1(" )

whe re C; . • • ~nil a- (m g r l ) i; the soil solution pesti::"ile in~ al concentration, C,',,, (fo Koc I/' AwfA)

(mg kg") i; the pesti::ile intalconcentration n bulk so il k, (da/) i; the pesti::ide di;spation daily rate

n the so il , • (kg r') and . (kg rl) are the soil dens iCs i1 a humil basis a nd dry basis, respectively.

K , w i; the pesti::ile aT-water parttion coeffi::ent. The coeffr:;ents I. , (g g' I), f, and f, are the soil

volume tri:: fractnns of orgp nic ca rbon, water and ar, respectively. The parameter K " (I kg'l) i; the

pesti:: ide orga nic ca rbon- wa te r parttion coeffi:: ent a nd was esti-nated by the expression (E USES, 1996)

K" 1101" ' . ' '0."1 II • •

It was supposed that the pesti::ile int a l concentration n the soil solut ion i; known and the ore n

the pant i; null, that i;, C, (0) ~,' and C;'" (0) •. Under these conditions arxl consilering

m I " (I) •• I" (I) , the resoution of Eq. (I) that descrbes the pesti:: ile concentration in the stems i;

give n by:

CS"m (t) . A •• ~ [el s' •• ' ] (B s )

(3)

-----------t( 534 )1-------------

~.

I I I

!

where the constants A (I kg' I dal) and B (dal) are given by AW·SCF

M and

Q 8 . kla ,)1 Mil',,,,, Constant A i; the pesti::ile uptake rate by pants and constant B i; the

pes ti:: ide di;s pat nn rate from the pant. From Eq. (3) the pesti::ile concentratnn n the frut was

estimated by the equati:m given by:

C " (t)W"I,,",Cs"m (t)r~h1O!' "' C;,~ [ea , •• ,] Frl/l/ KWood ,/I' K wood .1I' (B . s ) (4)

where C;"" a;"" (I) (mg kg' I da / of fru t fresh mass) i; the fruit da ily pesti:: ide concentrafun and

QPhlocm( 1 kg" l) i; the voume of water fbw n the phloem necessary to produce 1.0 kg of fre sh frut (Trapp

et a1, 2003). The Eq. (4) anows estimat ing the time recessary to reach max imum pesti:: ide concentratnn

il fruit and the frut ma ximum concentratnn. The tme to reach maxiIrum pesti:: ide concentration in fruit

6 given by ti " III'(B) a (k ,) . And the fiuit max iIru m concentratnn was cacuated by "'" 8. ,

e M,, " (I "" ). r, . . ;, .. , f,.,

The pes ti::ile boconcentration n frut was estirmted suppos ilg steady state equilibriun of the

quotent between the pesti:: ile concentration in so il solut nn and in fruts and was cacuated by:

BCF .. C,'" , (t) . (5) C, (t)

where BCF (I kgl) i; the pesti::ile bnconccntration factor in fru it. For the soutnn of Eq. (I) and to

caeuate the limi: of Eq. (5) t was supposed that the pesti:: ide degradatnn rate in soil i; bwer than tre

pesti::ide di;s patnn rate from pant, that i;, k, < B. In thi; case, the limt for Eq. (5) i; g iven by:

BCF = A a lJ'''' • Q a wl" .-SCF k, ,,, , (8 . ,) Q . 11' .''' ',1 ~ (6)

where k," . , . , . , (day·l) i; the pesti::ile di>sipation rate from the soi~pant system, whi::h albws

estimatilg the half-life time of pesti::i<i: di;s pation in the soil-pant system, t Il ' (day) , by the equati:m

t", . 1"(2) / k "' .

-----------I( 535 )1-------------

esults and Discussion

umerical simulation

The pesti:iie paclobutrazol and a hYJXltheti:al rmngo crop were sek:cted to ilhstrate the pesti:;ide

:CF vaue estirmte n fruts using the FfM-p rmdel In rmngo orchards, the pesti:;iie pacbbutrazol i;

so used as growth reguator to control pant growth, nnximi2e rmngo prodocti:m, reduce the IlIlIIDer of

uts and tum easi:r the crchard d:anng procedures. Soil appli:atim of pac lorutra zol has reen found to

~ rrore responsive n re g;lrd to suppress ng the vegetative growth and enbanc ng the reprcrluct ive growth

I rmngo than folar app)i:;ati:m (S ngh, 2000). Sharrm and Awasthi (2005) stated that there i; an

Dvionrrenta I contamilation rEk in areas where paclorutrazol i; reguarly appli:d, because thE pesti: iie

:siiue m~ht pers Et n the soil for a bng per Dd of tlire. The appli::ation of pac lobutrazol n the Brazilan

ortheastem semi-arid regilD has becorre a common practi:e in comrrerca I rmngo orchards. The

hy.; i:akhemi:al characterEti:s (ntrinsi: propertes) of pacbbutrazol were obtaned from Syracuse

~esearch Corporatim (SRC , 2006) (http://www.syrres.com.esc/phYSderro.htm) and are presented n Tabe

'abe I - P hy.;i:akhemi:al characternti:s of pacbbutrazol growth reguhtor used n the FTM-p to imuate the pacbbutrazolBCF vaue in fruts. :ommon na rre : pac lobutra zo I :hemi:a I Abstracts narre: (R *,R* )-(±)-fJ-[(4 -chlorophenyl)lrr!thylj-o.-(l,J -dilrr!thy lethyl)-l H-l ,2,4-'iazole-l -e thanol

:AS: 76738-62-0 UP AC nam:: (2RS, 3 M)-I-(4-chlorophenyl)-4 ,4 -dilrr!thyl-2 -(1 H-l ,2,4 -triazol-l-yl)pentan-3-o1

:hemi:a I structure:

~ K-'Ck1 C 7' I P. .... C(CH

3h

'>-.. CH2-CH I

~) (2S,35)­

,1oecuar formua:C' 5H2o ClN"30 !loar rmss : 293.8 g rro rl l apourpressure:9.999178 x 10·7 Pa at20'C Vater soubility: 26 mg rl at 20'C

( , w 14561 ~ o

ogK" = 3.2

Ck1

CVp H_/-.... C(CH3h

+ ~CHrfH

() (2R,3R)-

The fonowing assumptDns were rmde to run the FTM-p rmdel: for the estirmtion of BCF vaue,

n nital pacbbutrazol concentratDn of 1.0 mg kg' I of soi~ a flVe-years-otl rmngo orchard was

( )1--------536 l

...

consiiered wth a total pant dry rmss of 6,250.00 kg ha" , correspondng to 250 pants per hectare, wih

25 kg dry rmss per pant; transpratDn stream was estimated in 20 ,548.00 I da/ ha· 1 (750 mm year'1 ha· I);

pant growth rate was estimted n2.7~0·5 da" (0.01 per year) and a pacbbutrazol rretabolEm rate n

rmngo pants of 0.0462 dayl (the rretabolEm rate was based on half-life average vaues of organi:

corrpounds in pants estirmted by Cousins and Mackay, 2001); the estirmted water fbw vaue necessary

to )Ioduce 1. 0 kg of fresh fruit was 5 I kg.l, based on the rmngo pant water dermnd ncrease durilg fru i

devebprrent period; the estirmted pacbbutrazol degradatDn rate n soil was 0.0073 da/, corresponding

to a half-life of 9S days, experirrentally determined n soil;; from tradiional Brazilan rmngo producng

areas (Silva et al 2003); the pacbbutrazol rretabolEm rate n rmngo pants and half-life tm n soil

resuied the dEs pat ion rate n soil-pant system of 0.0389 da/ (k " , ), what corresponded to the

dEs pat ion half-life tirre of 18 day.; in the soil-pant sy.;te m

The soil data used n the sirnuation were obtaned from a Brazilan rmngo produc ing semi-arid

regiln , located at the SubrredD Sao FrancEco River, cbse to Petrolna muni:pal dEtri:t , State of

P ermmbuco, Brazil In genera ~ the rmngo orchards are establEhed in soil;; wit h 1he folbw iog attrbutes,

experirrentally determined in soilsampes from the (}'0.20 m depth ayer (Pessrn, 2003): orgaoi: carbon =

0.007 g g.1 ; vo u rretri: water content at fe Id capaciy = 0.15 g gl; aT volurretr i: content = 0. 08 g g.1 ; soil

densty n a dry bas E = 1. 51 kg r'; soil dens ity i1 a humid bas E = 1.76 kg rl .

Nu merical Results and Discussion

The organi: carbon-water partiDn coeffi:imt vaue of 492,00 I kg" , estirmted through Eq. (9) ,

indi:ated that pac bbutra 201 has rroderate affmity wth the soil crg;lni: rmtter, what might tum diffi:uk is

transbcation fro m soil soJut ion to fruts (Chiou et aI, 200 I). The va ue of 4.56x lO ' 0 obtained for the aT­

water partiDO coeffi:ent, estilmted wih the data from Tabe 1, ndi:ated that pacbbutrazol E not

voatie at room temperature (Trapp and Harand, 1995). The TSCF va ue of 0.625, estirmted through Eq.

(3), ndi:ated that pacbbutrazolhas good rrobility n the xycm, what E ao important )Icperty for pant

growth reguhtors (Lever et aI , 1981). The stem-water partition coeffl::ent vaue of 57,0 I kg"

( 537 )1--------------l

esults and Discussion

'u merical simu lation

The pesti.;ile paclobutrazol and a hYJXltheti::al rmngo crop were seected to ilbstrate the pesti::ide

,CF vabe estimate n fruis using the FTM-p rmdel In rmngo orchards, the pesti::ile pacbbutrazol s

so used as growth reguator to control pant growth, rmximi2e rmngo produ:tnn, reduce the Ill.IIT.ber of

uts and turn easi:r the crchard ceanng procedures. Soil appli.;atnn of paclorutrazol has been found to

~ rmre responsive n reg)ud to suppressng the vegetative growth and enhanc ng the reprcxiuctive growth

I rmngo than folar appli::ati:m (S ngh, 2000). Sharrm and Awasthi (2005) stated that there s an

nvi"onrrenta I contamnation rsk in areas where pacloootrazol s reguarly appli:d, because thE pesti.; ile

!silue ml?;ht persst n the soil for a bng pernd oftiIre. The appocation of paclobutrazol n tbe Brazilan

ortheastem serm.arid regnn has becorre a common practi.;e in comrrercn I rmngo orchards. The

hys i::akhemi::al charactersti::s (ntrinsi:: properti:s) of pacbbutrazol were obtaned from Syracuse

~esearch Ccrporatnn (SRC, 2006) (http i/www.syrres.com.esc/phy;;derm.htm) and are presented n Tabe

'abe I - Physi::akhemi::al characterSti::s of pacbbutrazol growth reguhtor used n the FTM-p to imuate the pacbbutrazolBCF va be in fruts, :ommon narre: paclohutrazol :hemi.;a I Abstracts mrre: (R *,R* ) -(±)-fJ-[(4 -chlolVphenyl)rrethylJ-{l.-(I,J -dirrethylethyl)-l H-l ,2,4--iazole-l-ethanol

:AS: 76738-62-0 UP AC nam:: (2RS, 3 RS)-1-(4-chlorophenyl)-4,4 -dirrethyl-2 -(1 H-l ,2,4 -triawl-l-yl)pentan-3-o1

:hemi::a I structure: 0'1

C -7 I F .... C(CH3h ~ H-'

~ CH2-CH I

~) (2S,3S)­

lIoecuar formua:C'5H2oClN]O tfoar rmss:293.8 g rmr' 1apour pressure: 9.999178 x 10.7 Pa at 20'C Vater sobbility : 26 mg r' at 20'C (,w 114 .56 .~ o

ogK" = 3.2

0'1

C~ H--/-.... C(CH3h

+ ~CHz-fH

~ (2R,3R)-

The fonowing assumptims were rmde to run the FTM-p rmdel: for the estimation of BCF vabe,

n nitnl pacbbutrazol concentrati:m of 1.0 mg kg" of soi~ a fIve-years-oll rmngo orchard was

--------t( 536 )J---------

-...! ;

..

consilered wth a total pant dry rmss of 6,250.00 kg ha" , corresp::mdng to 250 pants per hectare, wih

25 kg dry rmss per pant; transpi-atim stream was estimated in 20 ,548.00 I day"' ha" (750 mm year" ha");

pant growth rate was estimted n 2.74110.5 d a " (0.01 per year) and a pacbbutrazol rretabolsm rate n

rmngo pants of 0,0462 day' (the rretabolsm rate was based on half-life average vabes of organi.;

corrpounds in pants estimated by Cousins and Mackay, 2001); the estimated water fbw vabe necessary

to IYoduce 1.0 kg of fresh fruit was 5 I kg" , based on the rmngo pant water dermnd ncrease durilg frui

devebprrent period; the estimated pac bbutrazol degradatnn rate n soil was 0. 0073 day', corresponding

to a half-life of 95 days, experirrentally determined n soil> from tradiional Brazilan rmngo producng

areas (Silva et al 2003); the pac bbutrazo I rretabolsm rate n rmngo pants and half-life tirre n soil

resuied the cti;s jJat ion rate n soil-pant system of 0.0389 dai' (k ", ), what corresponded to the

cti;s pat ion half-life tirre of 18 days in the soil-pant system

The soil data used n the simuation were obtaned from a Brazilnn rrnngo produc ing serm.arid

regnn, located at the Subrridn Sao Francsco River, cbse to Petrolna muni:: pa I dstri::t , State of

Permmbuco, Brazil In genera~ the rmngo orchards are establEhed in sois with lhe folbw ing attrbutes,

experimentally determined in soil sampes from the ()'0.20 m depth oyer (Pessrn, 2003): organ i:: carbon =

o.om g g" ; vob rretri:: water content at fe Id capacty = O. 15 g g" ; ai- volurretr i:: content = 0.08 g g' ; soil

densiy n a dry bass = 1.51 kg r'; soil oonsity i1 a humid baSE = 1.76 kg r'.

Nu meTical Results and Discussion

The organi:: carbon-water partinn coeffi::i:nt vabe of 492,00 I kg", estirmted through Eg. (9),

indi::ated that pacbbutra2D1 has rmderate affmity wth the soil crlflni:: rmtter, what might turn diffi::ui is

transbcation from soil solut ion to fruis (Chiou et a 1,200 I). The va be of 4.56x 10' 0 obtained for the ai-­

water partiDn coeffi::i:nt, estimated wih the data from Tabe I, indi::ated that pacbbutrazol E not

voatie at room temperature (Trapp and Harand, 1995). The TSCF va ue of 0.625 , estimated through Eq.

(3), ndi::ated that pacbbutrazolhas goal rmbility n the xyem, what E an important IYcperty for pant

growth reguhtors (Lever et al , 1981). The stem-water partiion coeffx::i:nt vabe of 57,0 I kg'i

----------i( 537 )1----------

KWood

•1V

. 7,0) ildi:ated that pacbbutrazol ha s a sgnifi:ant affmty with the woody plant rmtern I

Trapp et aL, 200 1).

The paclobutra2D1 concentration il rm ngo fruits (CFr>,;') sinu ated by FTM-p rmdel E ilUstrated

1 Fig. I. I nt ally, fru it concentration E null, ilcreases continuously unt il a rmximum va lie a nd after that

lecreases with tine. This pattern E due to the de gradati:m fr st order kilet i: rrode I suppose d for the

lacbbutrazol concentratDn in the soil solution (CSoil), to is dissipa tion rate from the pant (B) a nd to its

Iptake rate ilto the pilnt (A). At the 27"' day (I,':" . 7) after lllcbbutrazo l appli:ation to the soil, is

:oncentratDn il fruit reaches the simu ated rmx imum va lue of 0.11 mg kg·1 .

The pacbbutrazol bioconcentration in the fruit E prese nted il Fig. 2, and E defined as the quotent "

x:tween the coneentratDn in fruit and the concentratDn il soil solution, BCF(t) " ,,,,,(t) /C,(t). This

'igure also shows that thE quotent equilibrium state E reached for a mit valle of 1.87 I kg", a nd thE E

he paclobutrazol BCF value for the rmngo fruit. This va lie can aso be obta ile d drectly from E q. (6).

a20 Jr---~--~---'--~~--~--~---'----r---~--~

~ Q" 1l-······ft ~ ~ "0 ............ ~ ............... ! .............. l .............. , ............. .

U 005 ........... ~ .. ... . n-L; :

i i . l : :

0001 I I I I I I I I

20 40 60 80 100 120 140 160 180 200

lime (d..,.)

°igu re I - P acbbutrazol growth reguata- concentration il rm ngo frui ts smu ated by mea ns of FTM-p.

200

" ~ 13

11

~

b co

QOO~ , , I , , , , , , 20 '0 60 80 'DO 120 "0 160 180 200

11 rre (day)

- - - ---- ----ir 538 11----------

Figure 2 - Pac bbutrazol growth reguator b ioe oncentra tion factor in rmngo fruits simu ated by mea ns of FTM-p. BCF(t) " Frn,,(t) / Cw(t).

Fig. 2 shows that, intally, the pacbbutrazol bDconcentratnn kineti:s in rna ngo fruits E zero,

ilcreases continuous Iy following an assocative exponenta I pattern and E limted on the upper part by an

asymptote at the evel 0 f 1.87 I kg" para l.k: I to the time a xis. Suc h pattern re aching a patea u at the eve I of

BCF value is a c onse que nee of the fact that the FTM -p mod e I negects the pesti:i:le tra nsforrmtion

processes il the fruit. If the model would incorporate the terms of such processes, the BCF va lle could be

estirmted by the quotent between the fruit upta ke rate and elimilatnn rate experimentally determ ined.

Sa ne ho et aL (2003) ana Iyz ing sampes of pea rs obla ned from the fruit rmrket il Spa in, did not

find any paclobutrazol residues il fruits, bu t did find paclobutrazol re sidues at the concentratDn e ve l of

5.0 fLg g.1 in pear sampes colected from Spanish commercal orchards n which paclobutrazo l had been

appled to pear trees. P acbbutrazol re sidues we re a so found il a ppe pulp a nd dry concentrated jui:e at

12-fold higher eves than il the non-processed fre sh jui:e (J UPAC, 1994). Osu na -Ga ree et aL (2001)

found pacbbutrazol traces il Mexican mango fruits (commercal 'tommy atkils") treated with

pacbbutrazol rates during two consecutive ye a IS. but did not find any re sidue whe n pants were treated il

akernated years . In China , Chua et aL (2005) aso found paclobutra zo l re sidues in commerca l appe

jui:es.

FTM-p model sensitivity analys is

Tra pp et aL (2003) eva lIated the FT M mode I senst iv t y as cone erned to the entry parameters and

cone lude d that the rrode IE" robust" with respect to pant tra nspi-atnn a nd growth rates and stem dry

biom ass vo lume. Tra pp et aL (2003 ) aso agree d that uncertailtes il these parameter va lues do not

sgnifi:antiy affect the BCF valle n fruts for organi: co mpounds in the range 0.8 a,gK" • . 0 . The

- - -------I( 539 )t--- ------

KWood

•W .7,0) ildi::ated that pacbbutrazol ha s a sgnifi::ant affrniy with the woody plant rmtern I

Tl1Ipp et al, 2001).

The paclobutrarol concentrat ion il lIB ngo fruits (CFru il) sinu ated by FTM-p rnxIel is illIstrated

1 Fig. I. I ni i:llly, ITu it concentration is null, ilcreases continuously unt il a lIBX imum va ue a nd after that

lecreases with tire. This pattern is due to the degradafun frst order kileti:: nndel supposed for the

lacbbutrazol concentratvn in the soil solution (CSoil ), to is dissipa tion rate from the pant (B) a nd to its

Iptake rate ilto the pant (A). At the 27th day (t ,',:" .7) after plcbbutrazol appli::ation to the soil, is

:oncentrafun il fruit reaches the simu ated lIBX imum va lue of 0.11 mg kg-' .

The pacbbutrazol bioconcentration in the fruit f; prese nted il Fig. 2, and f; de fine d as the quotent ~ .

lCtween the coneentratvn in fruit and the concentratnn il soil so lution , BCF(I) . , .. ,, (t) / C . (I). This

'igure also shows that this quotent equilibrium stare is reached for a linit vaue of 1.87 I kg- I, and this f;

he paclobutrazol BCF value for the rmngo fruit. This va ue can aso be obta ile d di"ectly from Eq. (6) .

Q20jr---~--~--~--~'---~--~--~----r---.---,

~ •

,51/: ......... i Oi 1

~ l E 0. 10 ... ········l·· .. ······y············l .... -.. ~

j ! ! (J 0.05 ..... ~ !

Gao J I I I I I I I I I

20 40 60 80 100 120 1040 160 180 200

lime (day)

°igure I - P acbbutrazo l growth reguatcr concentration il lIB ngo fruits sinu ated by mea ns of FT M-p .

200"r--~----r---~--~~-,~--~--~--~----~--,

v ~ lsa l··········· ~ 1. 00 ..... ······ ~············· + ··············l·········· .. -l····· ·····i·············+·· .. ·········;··············;······ ........ + ........ -... ~ " ~ b • sa ........... ; ............. ; ........... ! ·······-+· .. _·······;·······:·····_·····i ······i·····:+··········· j

OJ

o.ooJ I I I I I I I :

20 40 60 80 l Oa 120 ,AO 160 180 200

li rre (day)

----------lr 538 11---------

Figure 2 - Pacbbutrazol growth reguator bioconcentration factor in lIBngo fruits simuated by rreans of FTM-p. BCF(t) . Frni,(t) / C ,,(t).

Fig . 2 shows that, inti:llly, the pacbbutrazol bnconcentratvn kineti::s in mango fruits is zero,

ilcreases continuous Iy followi ng an associ:ltive expone nti:l I pattern and is limied on the upper part by an

asymptote at the eve I of 1.87 Ikg-I parall::lto the time axis . Such pattern reaching a pateau at the l::velof

BCF value is a c onse que nee of the fact that the FTM -p mode I negects the pesti::rle tra nsfonmtion

processes n the fruit. If the model would incorporate the terms of such processes, the BCF va ue could be

estimated by the quotent between the fruit uptake rare and elimilatvn rate experimentally d::termined .

Sa oc ho et al (2003) am lyz ing sampes of txa rs obta iled from the fruit rmrket il Spa in, did not

find any paclobutrazol residues il fruits, but did find pac lobutra zo l re sidues at the concentrafun evel of

5.0 ~g g-I in pear sampes colected from Spanish comrrerci:ll orc ha rds il wh ich paclobutrazol had been

appled to pear trees_ Pacbbutrazolresidues were ako found il appe pulp and dry concentratedjui::e at

12-fold higher eves tha n il the non-proce ss ed fresh jui::e a UPA C, 1994). Os una-Ga rca et al (200 1)

found pacbbutrazol traces il Mexican mango fruits (comrrerci:ll "tommy atkils") treared with

pacbbutrazol rates during two consecutive ye a rs, but did not find any re sidue whe n pants were treated il

akernated years . In China, Chua et al (2005) aso found pac lobutra zol residue s in comrrerci:l l appe

jui::es.

FTM-p /TWdel sensitivity analysis

Trapp et al (2003) evallated the FrM model sensiiviy as concerned to the entry parameters and

c ooc lude d that the nnde I is "robust" with respect to pant tl1l nspratvn a nd growth rates and stem dry

biom ass vo lume . TI1I pp et al (2003) aso agree d that uncertailtes il these pararreter va lues do not

signifi::antly affect the BCF vaue il fruis fo r organi:: compounds in the range 0.8 . gK" • . 0. The

----------J( 539 )1---------

a ulllO rs spccllh lCd lhat lIIKCTt:1ill e s U1 BCF va llie might be assoc tllcd to the xc nob iotic n-x:taboli::

pro ce s,;;: s in the pbnt 0 nd vobt i1i Z:lIion.

The sc nsrtiv ity ana Iys i; of FT M -p mode I can be run dn'ectt' throug h Eq. (6). because the pes ti::ide

BCF va lue i1 I'ruit s i; depe nde nt on the wa ter vol ume U1 the phloem per I kg offr~sh fruit (Ql'h""",), on the

tra ns pira t on rate (Q) a nd on the tra nspn'at on stream concentra ton factor (T SC F). A Is o. the pesti:: de

BCF va lie was ob serve d to be nwerse Iy de pc ndc nt to rt s diss ipa tion rate from the soi~ p hnt syste III (k EGS) .

to rt s phnt-wa ter pa rt ition coe fti: ent (K" .. "u,) and to the phnt dry biomass (1I'n. Some of the

sc nsit iv rty ana Iys i; rc suits reh te d to the e ntr), data va rnbility are il~l s trated in Figs. 3 and 4. This

analys i; was run

wi th the pac bblltrazolond mango ph nt data.

The dngra III color bo rs in Fig. 3 shows the BCF va ~Ie va rnbility in III a ngo fru it s de rive d from the

jo in t sens rt iv ity ana Iys i; of Q a nd M. Th i; dngra m allows in ferring that there i; no sign if eant va rn bilit y

n1 pac b butra zo l B CF va ~Ie ill Illa ngo fruits i1 C onse qucnce of the pi1t va rn bilit y of the transpn'ation rate

and dry bi omass phnt val ucs. There i; no s ignifeant n1fuence of Q va rnb ility on the cal:: ulus of

pacbbutra zol BCF va luc in 1m ng o fru it for the tra nspn'aton rate inte rva l usua Ill' occ urrin g in adult ma ngo

a rc In rd s. a rou nd 22.000.00 I da / ha·' . Also. there is no s ignifl:ant n1f ~lc nce of mango phnt dry bi om a ss

va ric1bilit y on the catu~ls of paclobutrazol BCF va luc fo r the M va lues ll5Ua Ill' occ ulT ing in adult mango

ore ha rd s. arou nd 6.000.00 kg ha-'. Once known that the vo lume of wate r n1 the ph loem stream necessary

to produce I kg of fresh fruit (QPh'n,,,,) is dependent on Q, it might be a!;o inferred that the varnbility on

QI'M""n va lue s do not signi fea nt Iy a ffect the pac lobut!a zo l 1113ngo fru it BCF va lue s.

The dn gra m color bars n1 Fig. 4 shows the pesteide BCF va lue varnbility in nl<111 go fruits

resukant fr om the p 01t ana Iys i; of peste de k ' Ii and

bgK oll" This dn gra m shows that no s ignifeant va rnbility is observed on the 1113n go fr uit pc.de BCF

va lucs for pes teides with log K . , 1.0 and

b g K ", • . 5 (Fig. 4). Howeve r, the sa lre c1agram and co lor tars are n1d eat n1g the re is sign ifea nt

varnb ilit y on 1113 ngo fruit peste ide BCF va lues in function of the varabil ity on peste de dissipation rate

i1 s oi~phnt system for peste des in the range 1.0.gK" • . 5 (F ig. 4). Th is is a co nsequence ofa

non-linea I' rehtion of T SCF an d K W"ntl.Jv with log Kow parameters. The optimum pestede transport from

so il to frui ts occ urs for pestei:le with log Kow around 2.2.

( 540 '\

10000

9000

6000

700:J

.. 6000 ~ ~5000

4000

2000

BCF (I/kg)

25 Q(l/day/ha)

J( 10~

Fi gure 3 - 0 ia gra III rep re se nt in g the pint re ht ion of Illa ngo ph llt dry biolll ass ( lI n 3 nd tra nspn'a t iOIl rat e (Q) wi th the pacbblltr3 zo 1 boconcentration fac tor (BCF ) in mongo fruits sllllllhteci by In; 3 115 ot'FT M-p .

BCF tllkg)

0.6

05

~O. 4 2. ~O.3

0.2

D.'

., LogKow

Figure 4 - Dia gill m reple se ntin g thejointrehtion ofpesteide oc tano~wa te r partition coeffecnl (logK() /i') a nd the pesteide diss ipa tio n rate in thc soi~phnt system (kEGS ) with the pes teicle boconcentrat ion fa ctor (BC F) 01 III a ngo fruit s snnu hted by mea ns of FT M-p.

r 541 1---

a ulh ors spccuh lcd thai uncel"ta ill e s Ul BCF va luc might be assoc [1!cd to Ihe xc nobiot ic n-x:taboli::

prl1ce s,;;: s in the pbnl 0 nd vobl ili zllIion.

The sc nsniv ity ana Iys ii of FT M-p mode I can be run dU'ect~' through Eq. (6). because the pes ti::ide

BCF va lue Ul I'ru it s Ii dependenl on the wa ter volume ulthe phl oem per I kg offresh fruit (Ql'hlo",, ), on the

Imnsp iratl)n rate (Q)and on the transpu'aton stTeamconcentrat on fa ctor (T SCF). Also . the pesti:: de

BCF va llC was observe d to be ulVerse Iy de pc nde nl to ns diss ipa tion rate from the soi~ p hnt system (k Ees) ,

to ns phnt -wa ter pa rtition coefti: ent (K" ",, 1)1 ) a nd to the phnt dry biom as s (11h Some of the

se nsn ivny ana Iys Ii re suits rehte d to the e nlry da ta va rnbility are i l~l s trate d in F igs. 3 and 4. Th is

analys i; was run

wilh the pac bbutrazo l a nd ma ngo phnt data.

The dngram color bors in Fig. 3 shows the BCF va ~le va rnb ility in mango fruits d:! ri ved from the

jo in t sensit ivit y ana lys ii of Qa nd M. Thli dngra m allows inferring tha t there i; no sign if e ant va rnbi lit y

Ul pac bbulro zo I B CF va ~Ie in ma ngo fr u its Ul C onse que nce of tl-e .PUlt va rn bilit y 0 f the transpu'ation rate

a nd dry bi omass phnt va lues. There Ii no s ignifeant ulfuence of Q va rnbilty on the cal:: ulus of

pa cbbutra zol BCF va lue in 1m ngo fru it fo r the tta nspu'aton rate interva l usua lI y occurrin g in adult ma ngo

orc In rds. a ro und 22.000.00 I da / ha·l . Also. there Ii no s ignifeant ulf ~le nce of man go phnt dry bio m a ss

va ri:lbil ity on the ca k:ubs of paclobutrazol BCF va luc for tl-e M Vlllues ll5Ua lI y occ ulT ing in adult mango

orc ha rd s. aroun d 6.000. 00 kg ha·l . Once known that tl-e vo lu me of wate r U) the phl oem strea m necessa ry

to produ ce I kg of fresh fr uit (QPh l",,,,) is dependent on Q, it might be a so inferred that the varnbility on

QpM"o" va lue s do not signife ant ly affect the pac lobutra zo l ma ngo fru it BCF va lues.

The dn gram color bars Ul Fig. 4 shows the pes teide BCF va lue va rnb ility in 1l1<1 ngo frui ts

resukant fr om the jo Ult ana Iys ii of peste de k 10 and

bgK oll" Thi s dngram shows that no s ignifeant va rnbility Ii observed on the Imn go fru it pe.de BCF

va lues for pes teides with log K . , 1.0 and

b g K " • . 5 (F ig. 4). However, tl-e sa n"e dngram and co lor ba rs are indeat ulg the re Ii signifeant

va rnbi lit y on tm ngo fruit pcsteide BCF va lues in fu nc tion of the varnbility on peste de di ss ipat ion rate

Ul s oi~phnt system for peste des in the I11nge 1.0 . g K" • . 5 (Fi g. 4). Th is Ii a conse que nce ofa

non -linea r rehtion of TSCF and K W"od .JV with log Ko". paran-eters. The optim um pestede transport from

so il to fruit s occ urs for pes te de with log Kow around 2.2.

( 540 "I

l00J0

9000

8000

7000

" 6000 ~ ~5000

2000

25 O(l/day/ha) " , 10

BC F (likg)

Fig ure 3 - DiagIllm represent in g the jo int re ht ion of mango phnt dry biomas s (Jlf) :1nd tra nspu'a t ion rale (Q) wi lh the pac bbutra zo l boconcentration t:1ctor (BC F) in mango fruits s Ul1lIhted by n); :1I1S of'FTM- p.

BCF (lIkg) 0.7

0.6

05

~O. 4 2. !O.3

0.2

0.1

·1 LogKow

Figure 4 - 0 ia glll m re pn:: se ntin g the joint re ht ion of pest e ide oc tano~wa te l' partit ion coc ffeent (logKoll') and the peste ide dissipation rate in the soi~phnt system (kEGS ) with tl-e pes te ide boconcentration factor (BC F) D) ma ngo frui ts sunu hted by mea ns of FT M-p.

r 541 1---

Summar izing. tl);: FTM-p mode l sens iiv ~ y ana lys t; shows that the nud e l t; " ro bu st" agailst

JnCt'rla fil t es in the phys 0 log e n I para meters va lucs of trees (Q, QI''''o,.", a nd /II) a nd to the soil -phnt sys tem

.1iss pat ion r;lte of peste i±s in log K , • an d logK , • . 5 (Fig. 4). Unce rtailt e s Ul the ea \: ulus of

lIa ngo fruit pest eide BCF va lue might be assocHted with uncertaintcs ;1 the pes tede di ss ipa tion and

ransforma t~ln rates ulli'UIIS and that lI'ere not mode led in this stud y.

Con elu sions

The FTM-p mod el presented in this wo rk allows es tin-nting the pesteide BCF value Ul fru its of

woody and perenn[ll plants. Pes te ides are organK: compou nds sub.¢ct to degrading reaet o ns in soi ls and

are ta ken up by phnts from the soi l solution through the wa ter transpu'ation strea III The mode s FT M a nd

FTM -p are conse rvative because both hypothe ses nege ct the peste ide tra ns forma tion processes in the,

fruit. Probab ly, if both modes would incorpo ra te the equatio n terms reh ted to such processes, the BC F

va ~le might be ca cuated as tl-e quotent betwee n the pes terle upt a ke rate an d e limulaton rate by the

fr uit. The te rm added to thc FTM model corre sponde nt to the peste de ocgradatio n m the so i!. durin g

deve lop me nt of FTM-p model, allowed concl uding that pesti::ide BCF value m n-nngo fruit s do not

de re nd on the soil pes ti:: de conce ntraton a nd on the fresh fruit mass, but is reated to the pesti::de

phys i::a k hc mi::a I character Eti::s (Kolt' , kEGS) and to the pant phys io b gi::a l pa rameters (M a nd Q). The

se ns iriv ~y analysis 0)' FTM -p model uldi::ates that pesti::rles with 1.0 a gK ,,, • . 5 present opt in-nl

c onditions to boconcentrate 11 fruit s of woody and perennal plants . And a lso, that the FTM- p mode l is

"ro bu st" with respect to the phnt dry biomass values (M) and water transpraton rate (Q). Thi s ana lYS E

abo indi::ates that the mod e I might be sensitive to the p::sti::rle dissipa tion rate m the so il-pant sys tem

(k EGS ) for pes ti::des with J. O. ogK" • . 5 (Fig. 4). The results of the sensit ivity analySE can be app le d

to preve nt fruit contammation with pes ti::ides with 10gK " arou nd 2.2 . Feld a nd abora tory experiments

must be can'ed ou t in orde r to validate the use of E q. (6) pl1: se nte d Ul thE work.

Refe rences

Arma s, E. D., Monteiro, R.T.R., Amane i::>, A.V., Co rrea, R.M.L., Guercio, M.A. 2005. Uso de agrotoxicos

em cana-de-ayucar na baCH do ri o Co ruillbata ie 0 rE eo oc poJuiya o hiiri::a. Quim. Nova, 28(6), 975 -982.

Bacci, E. 1994. Ecotoxi::ology of organic contaminants . Lew is Publishers, Boca Raton.

Chiou. C T., Peters, L..J ., Freed, V. H. 1979 . A phys e a I concept of soil-water equ il ibrH for nonionic

orga nie co mp ou nd s. Scence , 206, 83 1-8 32.

Bu rk e n, .I.G ., Sc hnoo r, .I .L. 199 8. Predictive re ati::>ns hips fo r up ta ke of orga nic contamulants by hybrid

pop la r trees. Environ. Sc i Tec hno!. , 32(2 1), 3379-3385.

( , 542 J

Chua . X.G .. Hu. XI, Yao. H.Y. 2005. Detcrlllulat ion of 206 pes teidc res idues ill app\:; "~ Ii:: C by lnltr ix

sol icl -pha;;c dis pe l's ion a nd gas c hro n-ntogra I'hy- ma ss sc \:;ct ~' c de tect DIl . .1 Chrom a togr Sn. A. 100-' .

:01-210.

Cousins . I. T .. Mackay . D. 2001 . Strategc s lill" ull'luciing \'cgcwt ion cOllll'arlnl: llI s il muirimcd n nl1Ckls

CI);:lnlsp herc. 44. 64}-0 ~4.

E USE S: Europea n Un ion Sys tem for the Eva kJaton of Subsla nces (Na tDlla I Inst itute of Public Hea hh and

the Environme nt (RI VM) . The Netherlands). 1996. Isp ra :The Eu ropean Che meals Bureau: EC European

Co mmis sion . (E ClOG X I).

Fujisaw:J. T .. Ich ise. K .. Fukushi ma , M., Katagi T .. Takunoto . Y. 2002. Improved upnkc mode ls of

non ioni zed peste des to fo lHge a nd see d of crops . .I . Agr ic. Food Chcm. :i0. 5 3 ~ -5)7.

Hung. H .. Mackay, D. 199 7. A nove l and sunpe lllode l ofthe uptake of organic chellli:: al; by vegetation

from a o' a nd so il. Chemos pherc . 35 , 959-9 77.

IUPA C INTE RN rHIO NAL UN ION OF PUR E AND APP LIE D CHEM ISTRY. 1994. Applied

Che mistry Divi si on. COlllm iss io n on Agroe hellleaS. Effec ts of slOrage and processlllg on pcsti:: de

re sidues in phnt prod ucts. Techni::a l Report. Pure Appl. Chem 66(2), 33:i -356.

Lever, B.G., Shearing, S.l. , Batch, J.J. 1982. A Il;W broad slx: et rum growt h retardant. Proc . 19R2 . Brit.

Crop Prot. Conf. Weeds. 1,3 -10.

Mar-the s, M., Be hn~ndt , H 19 95 . Dyna llli::s of c achin g. uptake, a nd transloc aton: the sunubtion model

ne twork a tm os phe re -plant -so il (SNAPS). In: Tmpp, S., McFa rbne, .I. C (Eel.). Phnt contamulaton:

mode lIulg a nd simuat on of orga n ic c hemi::a I pro c esses. CRC Press, Boca Ra ton .

OEC D. 1981. Organization for Econo mi:: Cooperation and Deve lopment. Gu id e lin es for tes tulg of

chemi::a s: boaccumu ht on sequent H I stat isti:: fish test. OE CD, Pa ri s.

Osu na-Ga rca ,J.A., Baez-Safiudo, R., Medina -U mltia , V.M. , Chavez -Cont reras , X. 2001. Res dualidad de

pae bbutrazo l en fr utos de mango (Ma ngifera uldi::a L.) cllhiva r tommy at kin s. Rev . D>l pingo. Sc r.

Hortic. 7(2),273-282.

Pa terson , S, Mac ka y, D. 1995. Interpre tin g chemea I pa rt ~ oning Ul so ibpant-a r sys telTlS with a fugac it y

mode !. In : Tra pp , S.; McFarane, 1. C. (Ed .). Pla nt conta mination: mode llm g a nd simuation of orga nic

chemi::a l proc esses. CRC Press, Boca Raton .

Pessoa, M.C.Y .P., Chaim, A. , Gorres, M.A. F., S ilva, A.S ., Soare s, .I.M. 2003 . S imuayao de a k"learb e

tebuth iuro n lllov im en to em so los sob cllitivos de banana e cana-de-ayuca r no sem~arido bras ieit"o. Re v.

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Rederer, M. 1995. Parthllling a nd transport of orga ni:: chemi::ab between tl-e a tlm spheric envi ro nme nt

eaves . In : Tra pp, S. , McFarla ne , J. C. (E d. ). Pant contamulation: modelling an d s imuht on of

orga nic chemi::a l processes. CRC Pre ss, Boca Raton.

Sa l'Ch o, .l. V., Pozo, 1.0. , Zamora, T. , Grima t S. , He mindez, F. 2003. Dn"cc t determulaton of

( ) 543 l J

Summarizing. tl~ FTM -p model se nsiiv it y analys !; shows that the nud e l !; " ro bu st" agailst

JnCt'nault e s in the physolog i:: a l para mcters values of trees (Q, Ql' hlo .. ",and /II) and to the soil -phnt system

.1iss l'a tion rate of pesti:: i±s in 10gK , • and 10gK , •. 5 (Fig. 4). Uncertail te s Ul the ea \:: ulus of

11a ng o fruit pesti::ide BCF va lue might be assoc i!ted with uneertaintes ;1 the pesti::de di ss ipa tion a nd

ransformatDn rates ulli'UIIS and that lI'ere not modeled in this stud y.

Con elu sions

The FTM -p mode l presented in this work allows es tin'flting the pesti::ide BCF value al fru its of

wood y a nd perenn[ll plants. Pes ti:: ides are organi:: compo und s sub);ct to degradi ng reaetons in soils and

are ta ken up by phnts from the soi l solution through the wa ter transpa'at ion strea III The mode s FT M a nd

FTM -p are conse rva tive because both hypothe ses negect the pes ti:: ide tra ns fo rma tion processes in the,

fruit. Proba bly, if both modes would incorpo ra te the equation term; reh tedto such processes, the BC F

va ~le might be ca cuhted as tl-e quotent betwee n the pes ti::rle upta ke rate and e limalaton rate by the

fruit. The te rm added to the FTM model corre spondent to the pes ti::dc degradatio n al the soi l. dur ing

deve lopme nt of FTM-p model, allowed conclud ing that pesti::ide BCF value in n'flngo fruit s do not

de pc nd on the soil pesti:: de concentraton a nd on the fres h fruit mass, but is rehted to the pes ti::de

ph ys i::a k hcmi::a I character i;ti::s (KoH' , kEGS ) and to the phnt phys iobgi::a l pa ran"l':ters (M and Q). The

sc ns rtiv~y analys E of FTM-p model uldi::ates that pesti::rles with 1.0 a gK ,,, • . 5 present optimcll

conditions to boconccntrate al fr uits of woody and perennni plants. And also , that the FTM-p mode l is

"ro bu st" with respect to the phnt dry biomass Vlllues (M) and watcr transpraton rate (Q ). Thi s analysis

aso indi::ates that the mod e I might be sensitive to the pestcrle dissipa tion rate in the soil-phnt system

(k Ecsl for pes ti::rles with 1. 0 . ogK" • . 5 (Fi g. 4). The results of the sensitivity analys i; can be app li: d

to preve nt fruit contamination with pesti::ides with 10gK " arou nd 2.2. Feld and hbora tory experin"l':nts

must be carred ou t in order to validate the use ofEq. (6) pl1ese nte d Ul thi; work.

Refe rences

Arma s, E. D., Monteiro , R.T.R. , Amaneo, A.V., Correa, R.M.L., Guerc io, M.A. 2005. Uso de agrotoxicos

em cana-dc-ayucar m baci! do rio Co rum ba ta ie 0 ris co de poiuiya o hrlri::a. Qui1ll. Nova , 28(6), 975-9 82 .

Bacci, E. 1994 . Ecoto xi::ology of organ ic contaminants. Lew is Publi shers, Boca Raton.

Chiou . C T. , Peters, L..J ., Freed , V. H. 1979. A ph ys i:: a I concept of soil- water equilibrn for non ionic

orga nic co mpound s. Scencc , 206, 83 1- 832.

Bu rken, LG ., Sc hnoo r, .I. L. 1998. Predictive rehtons hips fo r up ta ke of orga nic contamulants by hybrid

popla r trecs. Environ. Sci Technol., 32( 21 ),3379-3385.

( , 542 J

Chull . X.G .. Hu. X.Z, Yao . H.Y. 2005. Detcrillalat ioll of 206 pest i::idc res iducs ill appc "~ Ii:: e by n'fltr ix

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CI'<:IHlsphe rc . 44.643-654.

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Fuj isawa . T .. khise. K .. Fuku shima , M., Katagi T .. TakunoiO. Y. ] 00 2. Impro ved uplakc models of

noni onized pest i::rle s tCl foli! ge a nd seed of crops . .I . Agric. Food Chc lll. 50. 53]-5:17

Hung . H .. Mackay, D. 1997. A novel and sunpe Illodel ofthe uptake oforgonic chellli::ali by vcgctatiClll

fro m an' a nd so il. Che illos phere . 35 , 959 -977.

IUPAC. INTERN rHIO NAL UN IO N OF PURE AND APP LIE D CHEM ISTRY . 1994. Applied

Che mistr y Divi sio n. Comm iss io n on Agroc hellli::as. Effec ts of storage a nd process lllg on pesti:: de

res idue s ill phnt prod ucts. Techni::al Report. Pure Appl. Chem 66(2), 335 -356.

Lever, B.G., Shearing. S.l. , Batch, J.J. 1982. A lew broad slx:ctrum growth retardant. Proc. 1982 . Brrt.

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