100
Marine Sediments
agreed well with the values reported by the US National Bureau of Standards or the
National Research Council of Canada. For antimony, only the potassium hydroxide
fusion procedure yielded accurate results. Two dissolution procedures provided consistent results for selenium - sodium hydroxide fusion and acid digestion in sealed
Teflon vessels.
Photon Activation Analysis. This technique has been used [280] to determine 12 trace
elements and 8 minor elements in a certified marine sediment standard reference
material (BCSS-I). Photon activation analysis was carried out at the National Research Council of Canada electron linear accelerator using the Bremsstrahlung produced by the impact of a focussed electron beam on a tungsten converter. An example of
a gamma ray spectrum of the marine sediment following photo initiation at 25 MeV
beam energy is shown in Fig 4.5. Table 4.7 compares the analyses obtained by photon
activation analysis and certified values for the BCSS-I sediments. Detection limits are
also quoted. In general, very good agreement was obtained with reference values.
Neutron Activation Analysis. This technique has been applied to the determination of
cobalt, chromium, caesium, iron, rubidium, antimony, scandium, and strontium in
suspended matter isolated from seawater [281].
Miscellaneous. Bryan et al. [691] evaluated three burrowing species, the polychaete
Nereis diversicolor and the deposit-feeding bivalves Scrobicularia plana and Macoma
balthica as indicators of the biological availability of metals in estuarine sediments.
Their ability to accumulate a range of 13 trace metals was determined from observations of the concentration of these elements in the tissues of these animals and in the
surrounding sediments from 30 different estuaries in southwest England and South
Wales. Results demonstrated that availability differed by several orders of magnitude
between contaminated and uncontaminated sites. Scrobicularia was studied in most
detail, and was the best accumulator of metals, with a slow exchange rate making it a
good indicator of long-term changes in chronic pollution. The polychaete Nereis
diversicolor also proved to be a useful indicator for silver, cadmium, copper, and
mercury, but not for zinc, which it regulates. The results permitted a preliminary
classification of the estuaries according to their severity of pollution for each metal.
4.3
Non-Metals
4.3.1
Boron
Kiss [283] examined various techniques for the efficient separation and preconcentration of boron from marine sediments. Alkaline fusion with potassium carbonate was
used to render boron reactive, even in the most resistant silicate minerals. Fusion
cakes were extracted with water and borate was isolai:ed by Amberlite XE-243 boronselective resin. Borate was determined spectrophotometrically, following elution with
2 mol I-I hydrochloric acid. Either the carminic acid complex (620 nm), formed in
Marine Sediments
agreed well with the values reported by the US National Bureau of Standards or the
National Research Council of Canada. For antimony, only the potassium hydroxide
fusion procedure yielded accurate results. Two dissolution procedures provided consistent results for selenium - sodium hydroxide fusion and acid digestion in sealed
Teflon vessels.
Photon Activation Analysis. This technique has been used [280] to determine 12 trace
elements and 8 minor elements in a certified marine sediment standard reference
material (BCSS-I). Photon activation analysis was carried out at the National Research Council of Canada electron linear accelerator using the Bremsstrahlung produced by the impact of a focussed electron beam on a tungsten converter. An example of
a gamma ray spectrum of the marine sediment following photo initiation at 25 MeV
beam energy is shown in Fig 4.5. Table 4.7 compares the analyses obtained by photon
activation analysis and certified values for the BCSS-I sediments. Detection limits are
also quoted. In general, very good agreement was obtained with reference values.
Neutron Activation Analysis. This technique has been applied to the determination of
cobalt, chromium, caesium, iron, rubidium, antimony, scandium, and strontium in
suspended matter isolated from seawater [281].
Miscellaneous. Bryan et al. [691] evaluated three burrowing species, the polychaete
Nereis diversicolor and the deposit-feeding bivalves Scrobicularia plana and Macoma
balthica as indicators of the biological availability of metals in estuarine sediments.
Their ability to accumulate a range of 13 trace metals was determined from observations of the concentration of these elements in the tissues of these animals and in the
surrounding sediments from 30 different estuaries in southwest England and South
Wales. Results demonstrated that availability differed by several orders of magnitude
between contaminated and uncontaminated sites. Scrobicularia was studied in most
detail, and was the best accumulator of metals, with a slow exchange rate making it a
good indicator of long-term changes in chronic pollution. The polychaete Nereis
diversicolor also proved to be a useful indicator for silver, cadmium, copper, and
mercury, but not for zinc, which it regulates. The results permitted a preliminary
classification of the estuaries according to their severity of pollution for each metal.
4.3
Non-Metals
4.3.1
Boron
Kiss [283] examined various techniques for the efficient separation and preconcentration of boron from marine sediments. Alkaline fusion with potassium carbonate was
used to render boron reactive, even in the most resistant silicate minerals. Fusion
cakes were extracted with water and borate was isolai:ed by Amberlite XE-243 boronselective resin. Borate was determined spectrophotometrically, following elution with
2 mol I-I hydrochloric acid. Either the carminic acid complex (620 nm), formed in