From fef0bb7fe916f91dcff089c17aa3290c0ea1ab1f Mon Sep 17 00:00:00 2001 From: Johannes Ranke Date: Fri, 12 Jun 2015 02:19:38 +0200 Subject: Add sediment PEC calculations using the percentage method --- pkg/R/PEC_sw_sed.R | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 50 insertions(+) create mode 100644 pkg/R/PEC_sw_sed.R (limited to 'pkg/R/PEC_sw_sed.R') diff --git a/pkg/R/PEC_sw_sed.R b/pkg/R/PEC_sw_sed.R new file mode 100644 index 0000000..56396e8 --- /dev/null +++ b/pkg/R/PEC_sw_sed.R @@ -0,0 +1,50 @@ +# Copyright (C) 2015 Johannes Ranke +# Contact: jranke@uni-bremen.de +# This file is part of the R package pfm + +# This program is free software: you can redistribute it and/or modify it under +# the terms of the GNU General Public License as published by the Free Software +# Foundation, either version 3 of the License, or (at your option) any later +# version. + +# This program is distributed in the hope that it will be useful, but WITHOUT +# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS +# FOR A PARTICULAR PURPOSE. See the GNU General Public License for more +# details. + +# You should have received a copy of the GNU General Public License along with +# this program. If not, see + +#' Calculate initial predicted environmental concentrations in sediment from +#' surface water concentrations +#' +#' The method 'percentage' is equivalent to what is used in the CRD spreadsheet +#' PEC calculator +#' +#' @param PEC_sw Numeric vector or matrix of surface water concentrations in µg/L for +#' which the corresponding sediment concentration is to be estimated +#' @param percentage The percentage in sediment, used for the percentage method +#' @param method The method used for the calculation +#' @param sediment_depth Depth of the sediment layer +#' @param water_depth Depth of the water body in cm +#' @param sediment_density The density of the sediment in L/kg (equivalent to +#' g/cm3) +#' @param PEC_sed_units The units of the estimated sediment PEC value +#' @return The predicted concentration in sediment +#' @export +#' @author Johannes Ranke +#' @examples +#' PEC_sw_sed(PEC_sw_drift_ini(100, distances = 1), percentage = 50) +PEC_sw_sed <- function(PEC_sw, percentage = 100, method = "percentage", + sediment_depth = 5, water_depth = 30, + sediment_density = 1.3, + PEC_sed_units = c("\u00B5g/kg", "mg/kg")) +{ + method = match.arg(method) + PEC_sed_units = match.arg(PEC_sed_units) + if (method == "percentage") { + PEC_sed = PEC_sw * (percentage/100) * (water_depth / sediment_depth) * (1 / sediment_density) + if (PEC_sed_units == "mg/kg") PEC_sed <- PEC_sed / 1000 + } + return(PEC_sed) +} -- cgit v1.2.1