34 Organic compounds in soils, sediments & sludges
was observed for several nitroaromatic compounds. The extent of the intensity was
affected by calcium hydroxide concentration, suggesting the existence of desorption
processes in the soil. The extent of the increase also depends on the soil investigated,
the highest being observed with 1,3,5-trinitrobenzene (239 mg kg
−1 compared to the
baseline concentration of 24 mg kg
−1 ) in the another soil. This indicates incomplete
nitoraromatic compounds extraction and, hence, to o low nitro-aromatic compounds
concentration measured in soils when conventional extraction procedures are used.
Tricyclazole and tetracycline have been determined by gas chromatography – mass
spectrometry [193]. Persistent tetracycline residues have been determined in soil by
high-performance liquid chromatography with electrospray ionisation tandem mass
spectrometry [194].
Nitrogen-containing explosives [195] and trinitro-toluene [196] have been determined in soil by gas chromatography with thermionic NP detection and reverse
phase high-performance liquid chromatography. Warmhoudt et al [197] used tunable
infrared laser detection to study the pyrloysis products of explosives in soil.
2.4.3 N-Oxides
Kido et al [198] determined basic organic compounds such as quinoline, acridine,
asa-fluorene and their N-oxides in marine sediments found in an industrial area. The
sediments were extracted with benzene using a continuous extractor for 12 hours.
Hydrochloric acid solution (1N) was added to the benzene extracts and the mixture
was shaken for five minutes; the acid layer separated from the benzene layer was made
alkaline by the addition of sodium hydroxide, and the alkaline aqueous solution was
extracted with diethyl ether; the ether extracts were then dehydrated with anhydrous
sodium sulphate and concentrated with a Kuderna-Danish evaporator. The concentrations were separated and analysed by gas chromatography-mass spectrometry and gas
chromatography-high-resolution mass spectrometry.
2.4.4 Nitrosamines
Many N-nitrosamines are toxic and carcinogenic, and furthermore the carcinogenic
action exhibits a high degree of organ specificity. Nitrosamines are formed by interaction between nitrite and an amine with varying ease, depending on the nature of the
amine and the prevailing conditions. The reaction is not restricted to secondary amines,
but also occurs with primary and tertiary amines and even quaternary ammonium salts.
Thus, the precursors are widespread, both as naturally occurring compounds and in
many commercial and industrial processes nitrosamines are generated and it is therefore conceivable that trace amounts may be present in air and water in the vicinity of
industrial sites. Nitrosamines in minute amounts have been found in deionised water,
generated from the resins.
Mills and Alexander et al [199] have discussed the factors affecting the formation
of dimethylnitrosamine in samples of soil. Dimethylnitrosamine was formed as readily
in sterilized samples as in non-sterile samples, indicating that, although micro organisms can carry out an enzymatic nitrosation in some soils, dimethylnitrosamine can
be formed by a non-enzymic reaction, even at near neutral conditions. The presence
of organic matter appears to be important in promoting nitrosation in the presence of
the requisite precursors.
was observed for several nitroaromatic compounds. The extent of the intensity was
affected by calcium hydroxide concentration, suggesting the existence of desorption
processes in the soil. The extent of the increase also depends on the soil investigated,
the highest being observed with 1,3,5-trinitrobenzene (239 mg kg
−1 compared to the
baseline concentration of 24 mg kg
−1 ) in the another soil. This indicates incomplete
nitoraromatic compounds extraction and, hence, to o low nitro-aromatic compounds
concentration measured in soils when conventional extraction procedures are used.
Tricyclazole and tetracycline have been determined by gas chromatography – mass
spectrometry [193]. Persistent tetracycline residues have been determined in soil by
high-performance liquid chromatography with electrospray ionisation tandem mass
spectrometry [194].
Nitrogen-containing explosives [195] and trinitro-toluene [196] have been determined in soil by gas chromatography with thermionic NP detection and reverse
phase high-performance liquid chromatography. Warmhoudt et al [197] used tunable
infrared laser detection to study the pyrloysis products of explosives in soil.
2.4.3 N-Oxides
Kido et al [198] determined basic organic compounds such as quinoline, acridine,
asa-fluorene and their N-oxides in marine sediments found in an industrial area. The
sediments were extracted with benzene using a continuous extractor for 12 hours.
Hydrochloric acid solution (1N) was added to the benzene extracts and the mixture
was shaken for five minutes; the acid layer separated from the benzene layer was made
alkaline by the addition of sodium hydroxide, and the alkaline aqueous solution was
extracted with diethyl ether; the ether extracts were then dehydrated with anhydrous
sodium sulphate and concentrated with a Kuderna-Danish evaporator. The concentrations were separated and analysed by gas chromatography-mass spectrometry and gas
chromatography-high-resolution mass spectrometry.
2.4.4 Nitrosamines
Many N-nitrosamines are toxic and carcinogenic, and furthermore the carcinogenic
action exhibits a high degree of organ specificity. Nitrosamines are formed by interaction between nitrite and an amine with varying ease, depending on the nature of the
amine and the prevailing conditions. The reaction is not restricted to secondary amines,
but also occurs with primary and tertiary amines and even quaternary ammonium salts.
Thus, the precursors are widespread, both as naturally occurring compounds and in
many commercial and industrial processes nitrosamines are generated and it is therefore conceivable that trace amounts may be present in air and water in the vicinity of
industrial sites. Nitrosamines in minute amounts have been found in deionised water,
generated from the resins.
Mills and Alexander et al [199] have discussed the factors affecting the formation
of dimethylnitrosamine in samples of soil. Dimethylnitrosamine was formed as readily
in sterilized samples as in non-sterile samples, indicating that, although micro organisms can carry out an enzymatic nitrosation in some soils, dimethylnitrosamine can
be formed by a non-enzymic reaction, even at near neutral conditions. The presence
of organic matter appears to be important in promoting nitrosation in the presence of
the requisite precursors.