Black carbon-inclusive modeling approaches for estimating the aquatic fate of dibenzo-p-dioxins and dibenzofurans.
A novel black carbon (BC) inclusive modeling tool is applied to estimate the distribution and long-term fate of dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in the Norwegian Grenland Fjords. Three versions of the model were developed in which sediment-water partitioning was described using (i) an amorphous organic carbon (AOC) partitioning sorption model without BC sorption, (ii) a combined AOC and BC sorption model based on the Freundlich isotherm, and (iii) a combined BC-AOC model based on the Langmuir isotherm. The predictive ability of the three different models was evaluated for 17 PCDD/Fs by comparison of model predictions with observed organic carbon normalized sediment-water partition coefficients (K(TOC)) and with measured concentrations. All three versions of the model were able to predict concentrations that were in reasonable agreement with measured particulate concentrations (i.e., within a factor of 4 of median values). Estimated particulate concentrations were less sensitive to the model choice because the majority of the mass of these hydrophobic chemicals is associated with particulates regardless. However, for estimation of K(TOC) or dissolved water concentrations, both versions of the combined AOC and BC sorption models provided greatly improved estimates compared to the AOC-only model.
Armitage
James M
JM
Department of Applied Environmental Science (ITM), Stockholm University, SE-10691 Stockholm, Sweden.
Cousins
Ian T
IT
Persson
N Johan
NJ
Gustafsson
Orjan
O
Cornelissen
Gerard
G
Saloranta
Tuomo
T
Broman
Dag
D
Naes
Kristoffer
K
D001572:Benzofurans / Q000032:analysis*; D002244:Carbon / Q000737:chemistry*; D004147:Dioxins / Q000032:analysis*; D004784:Environmental Monitoring; D008962:Models, Theoretical; D014874:Water Pollutants, Chemical / Q000032:analysis*
D001572:Benzofurans; D004147:Dioxins; D014874:Water Pollutants, Chemical; D002244:Carbon; C023614:dibenzofuran; C020887:dibenzo(1,4)dioxin