diff options
Diffstat (limited to 'R/PEC_sw_drainage_UK.R')
| -rw-r--r-- | R/PEC_sw_drainage_UK.R | 36 |
1 files changed, 23 insertions, 13 deletions
diff --git a/R/PEC_sw_drainage_UK.R b/R/PEC_sw_drainage_UK.R index d773f40..4b3111e 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 @@ -24,6 +25,9 @@ #' @author Johannes Ranke #' @examples #' PEC_sw_drainage_UK(150, Koc = 100) +#' PEC_sw_drainage_UK(60, interception = 0.5, Koc = 550, +#' latest_application = "01 July", soil_DT50 = 200) + PEC_sw_drainage_UK <- function(rate, interception = 0, Koc, latest_application = NULL, soil_DT50 = NULL, model = NULL, model_parms = NULL) @@ -34,20 +38,26 @@ PEC_sw_drainage_UK <- function(rate, interception = 0, Koc, if (!missing(latest_application)) { lct <- Sys.getlocale("LC_TIME") tmp <- Sys.setlocale("LC_TIME", "C") - latest <- as.Date(paste(latest_application, "1999"), "%d %b %Y") + if (latest_application == "29 February") { + ref_year <- 2000 + } else { ref_year <- 1999} + latest <- as.Date(paste(latest_application, ref_year), "%d %b %Y") + if (is.na(latest)) stop("Please specify the latest application in the format '%d %b', e.g. '01 July'") 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") + degradation_time <- as.numeric(difftime(as.Date(paste0(ref_year,"-10-01")), units = "days", latest)) + 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 + } } } |