Environmental Organic Chemistry Instructor: Jaeweon Cho

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Environmental Organic ChemistryInstructor
Jaeweon Cho
7th Week Class
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Week 6
9. Sorption I Organic Matters (Particulate and
Dissolved)
This textbook supposes organic matter as
hydrophobic, i.e., humic substances thats OK
and sometimes true for NOM present in US,
however, there are others as well, especially in
Korea and some of European country.Please
remember humic is not an only NOM! I am not
sure yet on NOM of other Asian and African
countries.Measurements of POM as POC, and DOC
what is ratio of DOC/POC?Once again, sorption
to organic matters is very important as once
sorbed it can represent very different trends in
transportation, transformation (including bio-),
toxicity, oxidation (degree of expose to light)
possibility, and many others (e.g., virus with
NOM can travel almost gt 2km/year in groundwater,
as opposed to virus adsorbed on soils with travel
of a few cms
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• Mid-term ExaminationProblem 1.
• Predict the Koc value for triflusulfuron methyl
  based on its Kow. Compare this Koc estimate to
  the value, for the soil, measured by the
  researchers.
• The researchers cite a pKa of 4.3 for
  triflusulfuron. Which functional group is
  ionized?
• Explain the effect of dissolved organic matter on
  the phytotoxicity of triflusulfuron methyl on
  oilseed rape.

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10. Sorption II Partitioning to living media
Bioaccumulation and Baseline Toxicity
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Mid-term Examination Problem 2. Hargrave et al.
(2000) reported that slopes for regressions of
log octanol-water partition coefficients for nine
organochlorine compounds and log BAF decreased
from gt 0.9 during ice cover to lt0.6 in the open
water period. One of the reasons noted for this
decrease was the presence of more suspended
particulate organic matter during the open water
period. Make an estimate of the amount of
dieldrin you would expect in the biota (mol g-1
wet weight) during (a) the ice cover period and
(b) the open water period in the shallow water
(0-50 m depth). Assume that dieldrin is
partitioning between the biota (the zooplankton,
biota mass concentration of Mbio/Vw1mg/L), the
suspended particles, and the water. Use average
values of the lipid contents for the ranges of
lipid contents reported in the paper. The
suspended particle concentrations are given in
units of g/m2 these values must be
differentiated over the upper 50m of water depth
to give units of g/m3, and ultimately converted
to kg/L. The suspended particles are measured as
particulate organic carbon, so foc 1.0 for
these particles.
Due for Mid-term Examination Nov. 9 (Thurs.)