diff options
Diffstat (limited to 'R')
| -rw-r--r-- | R/PEC_sw_drainage_UK.R | 25 |
1 files changed, 14 insertions, 11 deletions
diff --git a/R/PEC_sw_drainage_UK.R b/R/PEC_sw_drainage_UK.R index d773f40..b935dea 100644 --- a/R/PEC_sw_drainage_UK.R +++ b/R/PEC_sw_drainage_UK.R @@ -1,7 +1,8 @@ #' Calculate initial predicted environmental concentrations in surface water due to drainage using the UK method #' #' This implements the method specified in the UK data requirements handbook and was checked against the spreadsheet -#' published on the CRC website +#' published on the CRC website. Degradation before the start of the drainage period is taken into account if +#' `latest_application` is specified and the degradation parameters are given either as a `soil_DT50` or a `model`. #' #' @param rate Application rate in g/ha #' @param interception The fraction of the application rate that does not reach the soil @@ -37,17 +38,19 @@ PEC_sw_drainage_UK <- function(rate, interception = 0, Koc, latest <- as.Date(paste(latest_application, "1999"), "%d %b %Y") tmp <- Sys.setlocale("LC_TIME", lct) degradation_time <- as.numeric(difftime(as.Date("1999-10-01"), units = "days", latest)) - if (!missing(soil_DT50)) { - k = log(2)/soil_DT50 - as.Date(paste(latest_application, "1999"), "%d %B %Y") + if (degradation_time > 0) { + if (!missing(soil_DT50)) { + k = log(2)/soil_DT50 + as.Date(paste(latest_application, "1999"), "%d %B %Y") - amount_available <- amount_available * exp(-k * degradation_time) - if (!missing(model)) stop("You already supplied a soil_DT50 value, implying SFO kinetics") - } - if (!missing(model)) { - fraction_left <- pfm_degradation(model, parms = model_parms, - times = degradation_time)[1, "parent"] - amount_available <- fraction_left * amount_available + amount_available <- amount_available * exp(-k * degradation_time) + if (!missing(model)) stop("You already supplied a soil_DT50 value, implying SFO kinetics") + } + if (!missing(model)) { + fraction_left <- pfm_degradation(model, parms = model_parms, + times = degradation_time)[1, "parent"] + amount_available <- fraction_left * amount_available + } } } |