Human Exposure Pathways - Dealing with Contaminated Sites: From Theory Towards Practical Application - page 463

BCF pl-soil relation = BCF based on plant-soil relation [(mg/kg dw-plant )/

(mg/kg dw-soil )]
w j = vegetable-consumption-rate-weighing factor, for vegetables for which a

geometric mean BCF is used [-]
BCF geo mean =

BCF based on geometric mean [(mg/kg dw-plant )/(mg/kg dw-soil )]

STcf BCF = soil specific correction factor [-]

The following nine vegetable groups have been distinguished in the Netherlands:
Potatoes, Roots and tubers, Bulbous vegetables, Fruiting vegetables, Cabbages,
Leafy vegetables, Legumes, Beans, Stem and stalk vegetables. The number of
vegetables for which plant-soil relations are available varies widely between the dif-
ferent vegetable groups. Therefore, if plant-soil relations were to be used for each
individual vegetable, some vegetable groups with a large number of different types
of vegetable would be over-represented in the overall vegetable-consumption-rate-
weighed BCF. In order to prevent too much weight being given to such groups, the
overall consumption-rate-weighed BCF is based on the plant-soil relations, or geo-
metric means, for the vegetable groups instead of for the individual vegetables. To
this purpose, the BCFs for each vegetable group ( BCF vegetable group ) are calculated
from the BCFs for each separate vegetable within that group and the contribution of
that vegetable to total consumption of all vegetables in that group, calculated accord-
ingtoEq.( 11.2 ). These BCFs for each vegetable can either result from a plant-soil
relation or from a geometric mean of measured BCFs with soil type correction.
Subsequently, the vegetable-group-consumption-rate-weighed , BCF veg-gr-cr-weighed ,
is calculated as follows:

BCF veg-gr-cr-weighed = ( u i × BCF vegetable group ) (11.3)

in which

u i = vegetable-group-consumption-rate-weighing factor [-]

BCF vegetable group vegetable-consumption-rate-weighed average BCF for a

specific vegetable group [(mg/kg dw-plant )/(mg/kg dw-soil )]

=

11.2.4 Input Parameters

11.2.4.1 Consumption of Vegetables

Obviously, the type of vegetables that are home-grown strongly depends on the cli-
mate and local soil conditions. But even in areas with the same climatic conditions,
even within relatively small countries, the home-grown vegetable pattern can vary
widely, mainly because of differences in soil properties and region-specific condi-
tions. As a consequence, for every Risk Assessment the national, regional, or local
vegetable consumption pattern, i.e., consumption rate of all relevant vegetables, has
to be determined.