PEC_sw_exposit_drainage: Calculate PEC surface water due to drainage as in Exposit 3

In jranke/pfm: Utilities for Pesticide Fate Modelling

Calculate PEC surface water due to drainage as in Exposit 3

Description

This is a reimplementation of the calculation described in the Exposit 3.02 spreadsheet file, in the worksheet "Konzept Drainage". Although there are four groups of compounds ("Gefährdungsgruppen"), only one distinction is made in the calculations, between compounds with low mobility (group 1) and compounds with modest to high mobility (groups 2, 3 and 4). In this implementation, the group is derived only from the Koc, if not given explicitly. For details, see the discussion of the function arguments below. It is recommened to specify the arguments rate, Koc, DT50, t_drainage, V_ditch and V_drainage using units::units from the units package.

Usage

PEC_sw_exposit_drainage(
  rate,
  interception = 0,
  Koc = NA,
  mobility = c(NA, "low", "high"),
  DT50 = set_units(Inf, "d"),
  t_drainage = set_units(3, "days"),
  V_ditch = set_units(30, "m3"),
  V_drainage = set_units(c(spring = 10, autumn = 100), "m3"),
  dilution = 2
)

Arguments

rate	The application rate in g/ha
interception	The fraction intercepted by the crop
Koc	The sorption coefficient to soil organic carbon used to determine the mobility. A trigger value of 550 L/kg is used in order to decide if Koc >> 500.
mobility	Overrides what is determined from the Koc.
DT50	The soil half-life in days
t_drainage	The time between application and the drainage event, where degradation occurs, in days
V_ditch	The volume of the ditch is assumed to be 1 m * 100 m * 30 cm = 30 m3
V_drainage	The drainage volume, equivalent to 1 mm precipitation on 1 ha for spring/summer or 10 mm for autumn/winter/early spring.
dilution	The dilution factor

Value

A list containing the following components

perc_drainage_total

Gesamtaustrag (total fraction of the residue drained)

perc_peak

Stoßbelastung (fraction drained at event)

PEC_sw_drainage

A matrix containing PEC values for the spring and autumn scenarios. If the rate was given in g/ha, the PECsw are in microg/L.

Source

Excel 3.02 spreadsheet available from https://www.bvl.bund.de/SharedDocs/Downloads/04_Pflanzenschutzmittel/zul_umwelt_exposit.html

See Also

perc_runoff_exposit for runoff loss percentages and perc_runoff_reduction_exposit for runoff reduction percentages used

Examples

  PEC_sw_exposit_drainage(500, Koc = 150)

jranke/pfm documentation built on Nov. 17, 2024, 6:42 a.m.