Organic Carbon Parameters
llS
on a magnetic stirrer, and the contents were stirred for approximately 10 min. The
resulting solution was transferred to an acid-washed 125-mllinear polyethylene bottle.
The precision of this method was evaluated by performing replicate analysis of NBS
SRM 1646 estuarine sediment (Table 5.2). The test result indicated that aluminium,
titanium, chromium, and copper have significantly different variances, at the 5 %
level, from the nominal concentrations in the sediment (i. e. Fe> S).
Neutron Activation Analysis. Ellis and Chattopadhya [338] investigated the determination of 28 elements in estuarine suspended solids by neutron activation analysis
and found detection limits for most of the elements ranged between 0.3 7 and 1.0 ng.
Average precision ranged between 10 and 16 % and accuracy within 10 %.
X-ray Secondary Emission Spectrometry. Baker and Piper [339] applied this method
to the determination of aluminium, phosphorus, silicon, potassium, calcium, titanium, iron, chromium, manganese, nickel, copper, and zinc in estuarine sediments.
S.2
Organic Carbon Parameters
5.2.7
Carbon Content
Electron beam X-ray excitation [340], wet oxidation [278,341], and micro combustion
techniques [341] have all been employed for the determination of organic carbon in
estuarine sediments.
The persulphate oxidation technique [287], referred to in Sect. 4.3.3, has also been
applied to estuarine sediments. Organic carbon was determined at 10 g kg- 1 in bay and
estuarine sediments with a coefficient of variation of about 10 %.
Dankers and Laane [341] compared two methods, based on wet oxidation with
potassium peroxydisulphate and loss on ignition at 560°C, for the determination of
particulate organic carbon in estuarine suspended matter. They found that in estuarine sediments with a high clay content, loss on ignition overestimated organic matter
content approximately four times. Discrepancies were attributed to incomplete oxidation in the wet digestion method and loss of carbonates and water in the dry ignition
method.
5.2.2
Oxygen Uptake
Nothlich and Reuter [342] have devised an apparatus for the measurement of oxygen
uptake by sediments from coastal waters and estuaries. The specific oxygen uptake
per unit surface area of undisturbed sediment was very much smaller (by a factor of
about 30) than that of the suspended sediments, which is of considerable significance
for an assessment of the oxygen balance in waters transporting dredged solids. In
addition, the content of organic degradable matter increases with an increase in the
proportion of fines in the suspended sediment, which further enhances the oxygen
llS
on a magnetic stirrer, and the contents were stirred for approximately 10 min. The
resulting solution was transferred to an acid-washed 125-mllinear polyethylene bottle.
The precision of this method was evaluated by performing replicate analysis of NBS
SRM 1646 estuarine sediment (Table 5.2). The test result indicated that aluminium,
titanium, chromium, and copper have significantly different variances, at the 5 %
level, from the nominal concentrations in the sediment (i. e. Fe> S).
Neutron Activation Analysis. Ellis and Chattopadhya [338] investigated the determination of 28 elements in estuarine suspended solids by neutron activation analysis
and found detection limits for most of the elements ranged between 0.3 7 and 1.0 ng.
Average precision ranged between 10 and 16 % and accuracy within 10 %.
X-ray Secondary Emission Spectrometry. Baker and Piper [339] applied this method
to the determination of aluminium, phosphorus, silicon, potassium, calcium, titanium, iron, chromium, manganese, nickel, copper, and zinc in estuarine sediments.
S.2
Organic Carbon Parameters
5.2.7
Carbon Content
Electron beam X-ray excitation [340], wet oxidation [278,341], and micro combustion
techniques [341] have all been employed for the determination of organic carbon in
estuarine sediments.
The persulphate oxidation technique [287], referred to in Sect. 4.3.3, has also been
applied to estuarine sediments. Organic carbon was determined at 10 g kg- 1 in bay and
estuarine sediments with a coefficient of variation of about 10 %.
Dankers and Laane [341] compared two methods, based on wet oxidation with
potassium peroxydisulphate and loss on ignition at 560°C, for the determination of
particulate organic carbon in estuarine suspended matter. They found that in estuarine sediments with a high clay content, loss on ignition overestimated organic matter
content approximately four times. Discrepancies were attributed to incomplete oxidation in the wet digestion method and loss of carbonates and water in the dry ignition
method.
5.2.2
Oxygen Uptake
Nothlich and Reuter [342] have devised an apparatus for the measurement of oxygen
uptake by sediments from coastal waters and estuaries. The specific oxygen uptake
per unit surface area of undisturbed sediment was very much smaller (by a factor of
about 30) than that of the suspended sediments, which is of considerable significance
for an assessment of the oxygen balance in waters transporting dredged solids. In
addition, the content of organic degradable matter increases with an increase in the
proportion of fines in the suspended sediment, which further enhances the oxygen