228 Organic compounds in soils, sediments & sludges
Gas chromatography
Workers at the US Environmental Protection Agency [93] evaluated protocols for
chlorinated insecticides and PCBs in raw waste water and sewage effluents. They
concluded that the gas chromatographic method performed satisfactorily at the parts
per billion level.
Skinner et al [94] showed for the first time the application of mass fragmentography to residue analysis, namely the determination of PCBs along with DDE in
extracts of a sewage effluent.
Polychlorobiphenyl congeners 77, 126 and 169 have been determined in sewage
sludge at detection limits as low as 100 µg kg
−1 by gas chromatography negative ion
mass spectrometry [95]
The electron capture negative ion chemical ionisation mass spectrometric method
[96] has been applied to determination of polychlorobiphenyls in sludges.
10.3.6 Polychloro-p-benzodioxins and polychlorodibenzofurans
Polychlorinated dibenzo-p-Dioxin, polychlorinated dibenzofurans and orthounsubstituted polychlorinated biphenyls (non-ortho polychlorobiphenyls) are three
structurally and toxicologically related families of anthropogenic chemical compounds
that have in recent years been shown to have the potential to cause serious environmental contamination due to their extreme toxicity [97–102]. These substances
are trace-level components or by-products in several large-volumes and widely used
synthetic chemicals, principally polychlorobiphenyls and chlorinated phenols [103,
104] and can also be produced during combustion processes [105–107] and by photolysis [108, 109]. In general polychlorodibenzo-p-dioxins and dibenzofurans and
non-ortho polychlorobiphenyls are classified as highly toxic substances [110], although
the toxicities are dramatically dependent on the number and positions of the chlorine
substituents [111]. About ten individual members of a total of 216 polychlorodibenzop-dioxins and dibenzofurans, and non-ortho polychlorobiphenyls are among the most
toxic man-made or natural substances to a variety of animal species [97–100]. The
toxic hazards posed by these chemicals are exacerbated by their propensity to persist
in the environment [112–114] and to readily bio-accumulate [115–117], and although
the rate of metabolism and elimination is strongly species dependent [117], certain
high toxic isomers have been observed to persist in the human body for more than
ten years [118].
The majority of scientific and government concerns for the hazards of these compounds have been directed toward analytical methodologies, toxicology, epidemiology
and determination of the disposition in the environment of the single most toxic isomer,
2,3,7,8-tetrachlorodibenzo-p-dioxin [97–102].
More recently, however, investigations into the formation and occurrence of polychlorodibenzofurans suggest that this family of toxic compounds may commonly occur
at comparable or greater levels than the dibenzodioxins and could generally pose a
greater hazard than polychlorodibenzo-p-dioxins. Polychlorodibenzofurans are often
found as cocontaminants in and are readily produced from pyrolysis of polychlorobiphenyls [115, 119, 120, 131–134]. Most important, the polychlorodibenzofurans
produced from pyrolysis of polychlorobiphenyls are predominantly the most toxic
isomers, those having a 2,3,7,8-chlorine substitution pattern [101]. A number of recent
Gas chromatography
Workers at the US Environmental Protection Agency [93] evaluated protocols for
chlorinated insecticides and PCBs in raw waste water and sewage effluents. They
concluded that the gas chromatographic method performed satisfactorily at the parts
per billion level.
Skinner et al [94] showed for the first time the application of mass fragmentography to residue analysis, namely the determination of PCBs along with DDE in
extracts of a sewage effluent.
Polychlorobiphenyl congeners 77, 126 and 169 have been determined in sewage
sludge at detection limits as low as 100 µg kg
−1 by gas chromatography negative ion
mass spectrometry [95]
The electron capture negative ion chemical ionisation mass spectrometric method
[96] has been applied to determination of polychlorobiphenyls in sludges.
10.3.6 Polychloro-p-benzodioxins and polychlorodibenzofurans
Polychlorinated dibenzo-p-Dioxin, polychlorinated dibenzofurans and orthounsubstituted polychlorinated biphenyls (non-ortho polychlorobiphenyls) are three
structurally and toxicologically related families of anthropogenic chemical compounds
that have in recent years been shown to have the potential to cause serious environmental contamination due to their extreme toxicity [97–102]. These substances
are trace-level components or by-products in several large-volumes and widely used
synthetic chemicals, principally polychlorobiphenyls and chlorinated phenols [103,
104] and can also be produced during combustion processes [105–107] and by photolysis [108, 109]. In general polychlorodibenzo-p-dioxins and dibenzofurans and
non-ortho polychlorobiphenyls are classified as highly toxic substances [110], although
the toxicities are dramatically dependent on the number and positions of the chlorine
substituents [111]. About ten individual members of a total of 216 polychlorodibenzop-dioxins and dibenzofurans, and non-ortho polychlorobiphenyls are among the most
toxic man-made or natural substances to a variety of animal species [97–100]. The
toxic hazards posed by these chemicals are exacerbated by their propensity to persist
in the environment [112–114] and to readily bio-accumulate [115–117], and although
the rate of metabolism and elimination is strongly species dependent [117], certain
high toxic isomers have been observed to persist in the human body for more than
ten years [118].
The majority of scientific and government concerns for the hazards of these compounds have been directed toward analytical methodologies, toxicology, epidemiology
and determination of the disposition in the environment of the single most toxic isomer,
2,3,7,8-tetrachlorodibenzo-p-dioxin [97–102].
More recently, however, investigations into the formation and occurrence of polychlorodibenzofurans suggest that this family of toxic compounds may commonly occur
at comparable or greater levels than the dibenzodioxins and could generally pose a
greater hazard than polychlorodibenzo-p-dioxins. Polychlorodibenzofurans are often
found as cocontaminants in and are readily produced from pyrolysis of polychlorobiphenyls [115, 119, 120, 131–134]. Most important, the polychlorodibenzofurans
produced from pyrolysis of polychlorobiphenyls are predominantly the most toxic
isomers, those having a 2,3,7,8-chlorine substitution pattern [101]. A number of recent