Calculation from sediment organic carbon

APEO concentrations in suspended matter samples were similar to the sediment concentrations. From these values, in situ organic carbon corrected suspended matter/water distribution coefficients (log Koc) were calculated. For the separate ethoxymers NP, A9PE0i, A9PE02,... 

Fluxes (mg m d-i) of organic carbon and biochemical classes at 9°N, 5°N, and the equator. Compound class fluxes are in mg of compound, not mg C. The amino acids are present as peptides. Fluxes for net plankton are derived from primary production rates and measurements of biochemical content of net plankton. Fluxes into surface sediments were calculated using the sediment Corg content and accumulation rates and biochemical content measurements. Source From Wakeham, S. G., et al. (1997). Geochimica et Cosmochimica Acta 61, 5363-5369. 

Nonionizable chemicals (e.g., hydrocarbons, ethers, alcohol) that sorb onto organic materials in an aquifer (i.e., organic carbon) are retarded in their movement in groundwater. The sorbing solute travels at linear velocity that is lower than the groundwater flow velocity by a factor of Ra, the retardation factor. If the Koc of a compound is known, the retardation factor may be calculated using the following equation from Freeze and Cherry (1974) for unconsolidated sediments ... 

The partition coefficient (K ) was used for the conversion of TBT concentrations in sediment and SPM to TBT concentrations in water. This Kp for TBT was calculated by multiplying the organic carbon partition coefficient (K ) with the measured fraction organic carbon (f ). Consequently, the K value has a strong impact on the final results of the risk prognosis. Generally, in risk predictions the lowest K value is applied to calculate concentrations in water (EC, 2003). This results in a worst-case water concentration, in accordance with the precautionary principle. However, with literature values for the K of TBT ranging from 3.0 - 6.2 (Lepper, 2002), it is more appropriate to base an assessment on local measured values. In this study the... 

Levels of total organic carbon (TOC) followed a gradient pattern, and ranged from 4.9% at the near-field to 0.7% in the far-far field (mean 3.1%), primarily due to historical fibre deposits. Oil contamination was present in the near-field and far-field sediments. Triplicate samples were collected using a standard Ponar grab and pooled. Invertebrates were preserved until they were counted and identified. Statistically significant differences between reference and exposure areas were observed for three of the five invertebrate community indices calculated (Tab. 8). 

The hydrophobic nature of CDDs, combined with their great affinity for organic carbon, suggests that a major proportion of CDDs in the aquatic environment is sorbed to organic matter and sediment. Because only a minute fraction of CDDs are dissolved in the natural environment, bioconcentration is not the primary route of exposure for most aquatic organisms. Whereas the term bioconcentration is defined as the uptake of a chemical from water only, the term bioaccumulation refers to the combined uptake of a chemical from both dietary sources (e.g., food) and water. A bioaccumulation factor (BAF) that includes the ingestion route of uptake can be calculated based on fish uptake from water, food, and sediment (Sherman et al. 1992). 

The current version of GEM-AQ has five size-resolved aerosols types, viz. sea salt, sulphate, black carbon, organic carbon, and dust. The microphysical processes which describe formation and transformation of aerosols are calculated by a sectional aerosol module (Gong et al. 2003). The particle mass is distributed into 12 logarithmically spaced bins from 0.005 to 10.24 pm radius. This size distribution leads to an additional 60 advected tracers. The following aerosol processes are accounted for in the aerosol module nucleation, condensation, coagulation, sedimentation and dry deposition, in-cloud oxidation of SO2, in-cloud scavenging, and below-cloud scavenging by rain and snow. 

---