An official website of the United States government.

TIM Version 3.0 beta Technical Description and User Guide - Appendix C -Parameters used in TIM v3.0

View TIM models and other TIM information.

Appendix C. Parameters used in TIM v3.0

Symbol

Definition

Variable Type*

Units

A

Area of home range

Random

m2

AEk

Assimilation efficiency for food item k

Random

none

Arate

Application rate of pesticide

Constant

lb a.i./A

B

Length of in-field spray drift buffer

Constant

m

Bvol

Volume-based biotransfer factor; function of Henry’s law constant and Log Kow

Constant

µg/L fresh weight leaf/ μg/L air

BW

Body weight

Random

g/bird

Cair(t)(drops)

Pesticide concentration in a volume of air for the time step immediately following the pesticide application

Constant

μg/mL

Cair(t)(vol)

Concentration of the pesticide in air at time t (resulting from volatilization)

Random

μg/mL

CH

Height of crop

Constant

m

Ck(t)

Pesticide concentration on food item k at time t

Random

μg pesticide/g food

Ck(t=0)

Starting residue concentration on the day of application

Random

μg pesticide/g food

Cplant(t)

Concentration of the pesticide in crop foliage at time t

Random

mg/kg

Cw(dew)(t)

Concentration of dissolved pesticide in dew at time t

Random

μg/mL

Cw(puddle)(t)

Concentration of the pesticide in puddle at time t

Random

μg/mL

D

Fraction of hour where pesticide is applied

Constant

none

d

length of home range

Random

m

d1

portion of d that overlaps with the treated field

Random

m

d2

portion of d that is off of the treated field

Random

m

d3

distance between edge of treated field and edge of home range (that does not overlap with treated field)

Random

m

DAF

Dermal absorption fraction

Constant

none

Dcontact(t)

Incidental Dermal Contact Dose

Random

μg pesticide/g-bw

Ddermal(t)

Dose through dermal exposure for a pesticide at time t

Random

μg pesticide/g-bw

Ddew(t)

Dose through drinking dew for a pesticide at time t

Random

μg pesticide/g-bw

Ddiet(t)

Dose through diet for a pesticide at time t

Random

μg pesticide/g-bw

Ddrinking(t)

Dose through drinking water for a pesticide at time t

Random

μg pesticide/g-bw

DFk

Fraction of diet attributed to food item k

Constant

none

Dinhalation(t)

Dose through inhalation for a pesticide at time t

Random

μg pesticide/g-bw

Dintercept(t)

Intercepted Dermal Dose

Random

μg pesticide/g-bw

dnon-feeding

location of bird during non-feeding hours relative to edge of treated field

Random

m

DPR

Dislodgeable pesticide residues

Constant

mg/m2

dsoil

Depth of soil at equilibrium with water (in puddle)

Constant

cm

Dspray(t)

Droplet Inhalation Dose

Random

μg pesticide/g-bw

dt

distance from edge of field at time t

Random

m

Dtotal(t)

Dose from all exposure routes

Random

μg pesticide/g-bw

Dvapor(t)

Volatilization inhalation dose; function of pesticide concentration in air, volume of inhaled air, and body weight of the bird

Random

μg pesticide/g-bw

dw

Depth of puddle water

Random

cm

DWIR

Drinking water intake rate

Random

mL/day

e

Base of natural logarithm (2.7182)

Constant

none

EECdiet(t)

Estimated exposure concentration through diet for a pesticide at time t

Random

μg pesticide/g-bw

FAM

Ratio of avian to mammalian pulmonary membrane diffusion rates from USEPA 2004

Constant

none

FCk

Fraction of food that is contaminated

Constant

none

Fdfr

Dislodgeable foliar residue adjustment factor

Constant

kg/m2

Ffield

Fraction of on field exposure

Random

none

FLUXwater

Total daily water ingestion rate

Random

mL/day

FMA

Food matrix adjustment factor

Constant

none

FMR

Free-living metabolic rate

Random

kcal/bird-day

foc(soil)

Fraction of organic carbon in soil

Constant

none

FOF

Frequency on field

Random

none

Fre

Avian route equivalency factor

Constant

none

Fred

dermal route equivalency factor

Constant

none

Frespired

Volumetric fraction of droplet spectrum not exceeding the upper size limit of respired particles for birds

Constant

none

Fretained

Fraction of pesticide that is retained in the bird from one time step to the next

Constant

none

FWk

Fraction of water in fresh food item k

Constant

None

G

Gorging factor

Constant

None

GEk

Gross energy for food item k

Random

kcal/g food

H

Henry’s law constant

Constant

atm/m3/mol

HF(t)

Hourly fraction of total daily intake rate of food consumed at time t

Random

none

k

Food item

Constant

none

Koc

Organic carbon-water partition coefficient

Constant

mL/g OC

Kow

Octanol-water partition coefficient

Constant

none

LD50

Lethal dose sufficient to kill 50% of exposed individuals

Constant

mg/kg

mwax

Amount of wax per surface area of leaf cuticle

Constant

Ug/cm2

MEk

Metabolizable energy for food item k

Random

kcal/g food

MEtotal

Total metabolizable energy

Random

kcal/g food

Mpesticide

Pesticide concentration on the treated field at time t (accounting for dissipation); function of application rate

Random

mg

mplant

Mass of plant per hectare

Constant

kg

mwax

mass of wax per surface area of leaf cuticle

Constant

μg/cm2

n

Flock size

Constant

none

P00

Probability that a bird, now off the field, will remain off the field in the next hour

Random

none

P01

Probability that a bird, now off the field, will be on the field in the next hour

Random

none

P10

Probability that a bird, now on the field, will be off the field in the next hour

Random

none

P11

Probability that a bird, now on the field, will be on the field in the next hour

Random

none

P(x)

Probability of mortality to x birds

Constant

none

p

Fraction of total birds that died during simulation

Constant

none

Q

Fidelity factor

Constant

none

R

Universal gas constant (8.205 e-5)

Constant

atm/m3/mol-K

r

degredation rate constant

Constant

hour-1

Rfoliar contact

Rate of foliar contact

Constant

cm2foliage/cm2body surface (per hour)

RH

height of spray release

Constant

m

rk

Pesticide specific dissipation rate constant (for food item k)

Constant

hour-1

Rrate

Respiration rate

Random

L/h

s

Mineau scaling factor

Constant

none

SAtotal

Total surface area of bird

Random

cm2

SF

Food ingestion scale factor

Random

none

SI

Inhalation scale factor

Random

none

SW

Water adjustment scale factor

Random

none

T

Air temperature

Constant

K

t

Time of simulation

Sequential value

hour

t1/2k

Dissipation half-life for food item k

Constant

days

TDIR

Total daily intake rate

Random

g food/bird-day

Tmortality

Individual threshold for mortality

Random

μg pesticide/g-bw

TPR

Total pesticide residues

Constant

mg/kg

Vair

Volume of air in 1 ha to a height equal to the height of the crop canopy

Constant

L

Vinhalation

Volume of air respired

Random

L

waterfood

Daily volume of water consumed by a bird through food

Random

mL/day

x

Number of dead birds (out of predetermined flock); used to determine probability

Constant

none

εt

Presence on-field, off-field parameter

Random

none

θsoil

Porosity of soil

Constant

none

ρb

Bulk density of soil

Random

kg/L

ρp

density of soil particles

Constant

kg/L

ρwater

density of water (1)

Constant

kg/L

ρplant

Density of the crop tissue assumed as fresh leaf

Constant

kg/L

* "Constant" indicates that the parameter is set to one value. "Random" indicates that the parameter’s value varies based on a distribution of possible values.

Top of Page