Essential characteristics of natural dissolved organic matter affecting the sorption of hydrophobic organic contaminants

Abstract

Association of benzo[a]pyrene (BaP), pyrene, 3,3¢,4,4¢-tetrachlorobiphenyl (TCB) and 2,2¢,4,4¢-tetrabromo diphenyl ether (TBDE) with natural dissolved organic matter (DOM) was studied. The DOM samples were previously collected from natural waters at five Nordic sites during fall 1999 and spring 2000, isolated by the reverse osmosis method, and thoroughly characterized. The purpose was to determine the essential characteristics that predict the sorption capacity of DOM for hydrophobic contaminants. DOM isolates were dissolved in artificial freshwater to give a dissolved organic carbon concentration of 15 mg L -1 . Partition coefficients (K DOC ) of the model compounds between water and DOM were measured by the equilibrium dialysis method. Further, the bioavailability of BaP and pyrene to Daphnia magna Aquatic Sciences was tested in the presence of DOM with various qualities. A strong negative correlation was found for the K DOC values of BaP (R = -0.922) and pyrene (R = -0.929) with spectral absorbency ratio (A 254 /A 400 ), while the correlation (R = -0.760) was weaker for the K DOC values of TCB. The K DOC values for TCB correlated (R = 0.849) strongly with specific visible absorbency (A 600 /TOC), while the K DOC values for TBDE correlated (R = -0.739) with relative fluorescence emission. Generally, bioavailability of BaP and pyrene to D. magna reflected the measured association of the compounds with DOM. The data emphasize the importance of aromaticity of DOM, estimated by simple spectroscopic methods, in predicting sorption capacity for polycyclic aromatic hydrocarbons. The situation with halogenated compounds still remains unclear.

Partitioning of tetra‐ and pentabromo diphenyl ether and benzo[a]pyrene among water and dissolved and particulate organic carbon along a salinity gradient in coastal waters

“…The properties of DOM, such as molecular size, weight [24,25], and aromaticity of DOC, affect the sorption of anthropogenic hydrophobic organic chemicals [14], as observed in the current study. Our results showed that all three model compounds sorbed more to HAs than to FAs.…”

“…In the aquatic environment, hydrophobic compounds tend to associate with dissolved organic matter (DOM) and particulate organic matter. The partition coefficient of BDE-47 in artificial fresh water dissolved organic carbon (DOC) systems (DOC concentration of 15 mg/L) was from 4.57 to 4.90 (log K DOC ) [14].The source of DOM greatly affects the sorption of BaP [14,15]. In addition, increasing water hardness has been shown to slightly decrease sorption of organic compounds to DOM [14].…”

“…The source of DOM greatly affects the sorption of BaP [14,15]. In addition, increasing water hardness has been shown to slightly decrease sorption of organic compounds to DOM [14].…”

“…The partition coefficient of BDE-47 in artificial fresh water dissolved organic carbon (DOC) systems (DOC concentration of 15 mg/L) was from 4.57 to 4.90 (log K DOC ) [14].…”

Predicting the export and concentrations of organic carbon, nitrogen and phosphorus in boreal lakes by catchment characteristics and land use: A practical approach

“…When present in lakes, TOC affects transparency and thereby the temperature and thermal stratification of lake (Keskitalo and Eloranta 1999;Findlay and Sinsabaugh 2003) and the structure of aquatic food webs (Jansson et al 2000;Kankaala et al 2010). It also has impacts on the acid-base chemistry of surface waters (Buffam et al 2008), C budgets of catchments (Kindler et al 2011;Schelker et al 2012), greenhouse gas fluxes , and the mobility, toxicity and bioavailability of organic pollutants and trace metals such as mercury (Porvari et al 2003;Akkanen et al 2004;Ravichandran 2004;Bergknut et al 2011).…”