(18)Equation 18 (non-radionuclides), equation 19 (radionuclides), and Table 13 present the exposure variables for the surface water/groundwater produce ingestion pathway. The produce ingestion pathway is conducted for the agricultural pathway only.
(18)
(19)
Table 13. Surface Water/Groundwater Produce Ingestion Parameters
|
Parameter |
Units |
Agricultural |
|
Non-radionuclide chemical concentration in water = Cwn |
mg/L |
Chemical-specific |
|
Radionuclide chemical concentration in water = Cwr |
pCi/L |
Chemical-specific |
|
Irrigation rate = rirr |
L/m2 day |
2.08 (Kennedy and Strenge 1992) |
|
Irrigation period = firr |
unitless |
0.25 (3 months) |
|
Soil to plant uptake factor (wet) = BVwet |
kg/kg |
Chemical-specific |
|
Mass loading factor = MLF |
unitless |
0.26 (Pinder and McLeod 1989) |
|
Effective removal rate = ër |
1/day |
ël+ëhl |
|
Soil leaching rate = ël |
1/day |
2.7E-5 (NCRP 1989) |
|
Radionuclide half-life = ëhl |
1/day |
Chemical-specific |
|
Long-term deposition and buildup = tb |
day |
10950 (NCRP 1985) |
|
Areal density for root zone = P |
kg/m2 |
240 (Hoffman et al. 1982) |
|
Interception fraction = If |
unitless |
0.42 (Miller 1980) |
|
Translocation factor = T |
unitless |
1 (McKone 1994) |
|
Decay for removal on produce = ëE |
1/day |
ël+0.693/tw (NCRP 1989) |
|
Weathering half-life = tw |
1/day |
14 (NCRP 1985) |
|
Above ground exposure time = tv |
days |
60 (NCRP 1985) |
|
Plant yield (wet) = Yv |
kg/m2 |
2 (NCRP 1985) |
|
Diet fraction = FIv |
unitless |
0.4 (EPA 1989b) |
|
Ingestion rate = IRv |
kg/d |
0.2 (EPA 1989b) |
|
Exposure frequency = EF |
d/year |
350 (EPA 1989a) |
|
Exposure duration = ED |
years |
30 (EPA 1989a) |
|
Body weight (adult) = BW |
kg |
70 (EPA 1989a) |
|
Conversion Factor = CF2 |
days/yr |
365 |
|
Lifetime = LT |
years |
70 (EPA 1989a) |
|
Averaging time = AT |
years |
LT (carcinogen) ED (noncarcinogen) |