156 Organic compounds in soils, sediments & sludges
Sackmauerevá et al [171, 172] have described the method, given below, for
the determination of chlorinated insecticides (BHC isomers, DDE, DDT and hexachlorobenzene) in sediments, also water and fish.
The sediment sample is allowed to dry in open air and then sieved. To 20 g of the
sample 20% distilled water is added for deactivation purposes and the excess water
is then bound to active silica (Siloxide), so that a powdery consistency is obtained.
The insecticides studied are extracted with petroleum ether (b.p. 30–60
◦ C in a Soxhlet
apparatus. The extract is concentrated using the vacuum rotary evaporator and the
coextractants are separated on a Celite oleum column. The petroleum ether eluate is
then concentrated to a volume of 1ml and used for gas chromatography under the
following conditions [173–174].
Recoveries of the BHC isomers mentioned above from sediment were in the range
90–106%.
The average concentration of the BHC and γ isomer and α + isomer, and of DDE
and DDT in sediment was found to be 0.010, 0.010, 0.016, 2.11 and 0.70 mg kg
−1 ,
respectively. These results suggest that chlorinated insecticides, due to their physical
and chemical properties, can accumulate and adsorb on to solid particles.
This layer chromatography on silica gel plates was used to confirm the identity of
chlorinated insecticides previously identified by gas chromatography. The compounds
can be separated by single or repeated one-dimensional development in n-heptane or
in n-heptane containing 0.3% ethanol. The plate is dried at 65
◦ C for 10 minutes and
detected by spraying with a solution of silver nitrate plus 2 phenoxy-ethanol. Thereafter, the plate was dried at 65
◦ C for 10 minutes and illuminated with an ultraviolet
light (λ + 254 nm) until spots representing the smallest amounts of standards were visible (10–15 minutes). The pesticide residues may be evaluated semi-quantitively by
simple visual evaluation of the size and of the intensity of spot colouration and by
comparing extracts with standard solutions.
Other methods for the determination of organochlorine insecticides in non-saline
sediments includes the determination of TDE, Aldrin and Dieldrin [180–182], chlorinated insecticide contaminated with polychlorobiphenyls [34, 183] and DDT, Kepone
and permethrin [84] and α, β and γ BHC, heptachlor, heptachlor oxide [184], Aldrin,
Dieldrin, Endrin, ppDDE, pp’TDE and pp’DD.
Dragan et al [185] have carried out a detailed study of the occurrence of polychlorinated biphenyls and organochlorine pesticides, such as DDT and analogues,
hexachlorcyclohexane (HCH) isomers and hexachlorobenzene (HCB) in surface soils
and sediments from Eastern Romania. Thirty nine soil samples from the forested zone,
eight soil samples from a municipal waste disposal site and 10 sediment samples from
the Bahlui River along the Iassy city were analysed using accelerated solvent extraction and gas chromatography coupled to electron detection or mass spectrometry. The
low mean concentrations of organochlorine pesticides (11–31 and 22–84 ng g
−1 for
HCHs and DDTs, respectively) and polychlorobiphenyls (8–43 ng g
−1 ), in soil samples
from the forested zone suggest that contamination at most of these sites occurred
predominantly through atmosphere transport from zones where these compounds
were used and subsequently through atmosphere deposition. Contrarily, soil samples collected in the vicinity of a waste disposal site near Iassy contained higher mean
levels of polychlorobiphenyls (278 ng g
−1 , range 34–1132 ng g
−1 ) than organochlorine
(6 and 101 ng g
−1 of soil for HCHs and DDTs, respectively). The sediment samples
Sackmauerevá et al [171, 172] have described the method, given below, for
the determination of chlorinated insecticides (BHC isomers, DDE, DDT and hexachlorobenzene) in sediments, also water and fish.
The sediment sample is allowed to dry in open air and then sieved. To 20 g of the
sample 20% distilled water is added for deactivation purposes and the excess water
is then bound to active silica (Siloxide), so that a powdery consistency is obtained.
The insecticides studied are extracted with petroleum ether (b.p. 30–60
◦ C in a Soxhlet
apparatus. The extract is concentrated using the vacuum rotary evaporator and the
coextractants are separated on a Celite oleum column. The petroleum ether eluate is
then concentrated to a volume of 1ml and used for gas chromatography under the
following conditions [173–174].
Recoveries of the BHC isomers mentioned above from sediment were in the range
90–106%.
The average concentration of the BHC and γ isomer and α + isomer, and of DDE
and DDT in sediment was found to be 0.010, 0.010, 0.016, 2.11 and 0.70 mg kg
−1 ,
respectively. These results suggest that chlorinated insecticides, due to their physical
and chemical properties, can accumulate and adsorb on to solid particles.
This layer chromatography on silica gel plates was used to confirm the identity of
chlorinated insecticides previously identified by gas chromatography. The compounds
can be separated by single or repeated one-dimensional development in n-heptane or
in n-heptane containing 0.3% ethanol. The plate is dried at 65
◦ C for 10 minutes and
detected by spraying with a solution of silver nitrate plus 2 phenoxy-ethanol. Thereafter, the plate was dried at 65
◦ C for 10 minutes and illuminated with an ultraviolet
light (λ + 254 nm) until spots representing the smallest amounts of standards were visible (10–15 minutes). The pesticide residues may be evaluated semi-quantitively by
simple visual evaluation of the size and of the intensity of spot colouration and by
comparing extracts with standard solutions.
Other methods for the determination of organochlorine insecticides in non-saline
sediments includes the determination of TDE, Aldrin and Dieldrin [180–182], chlorinated insecticide contaminated with polychlorobiphenyls [34, 183] and DDT, Kepone
and permethrin [84] and α, β and γ BHC, heptachlor, heptachlor oxide [184], Aldrin,
Dieldrin, Endrin, ppDDE, pp’TDE and pp’DD.
Dragan et al [185] have carried out a detailed study of the occurrence of polychlorinated biphenyls and organochlorine pesticides, such as DDT and analogues,
hexachlorcyclohexane (HCH) isomers and hexachlorobenzene (HCB) in surface soils
and sediments from Eastern Romania. Thirty nine soil samples from the forested zone,
eight soil samples from a municipal waste disposal site and 10 sediment samples from
the Bahlui River along the Iassy city were analysed using accelerated solvent extraction and gas chromatography coupled to electron detection or mass spectrometry. The
low mean concentrations of organochlorine pesticides (11–31 and 22–84 ng g
−1 for
HCHs and DDTs, respectively) and polychlorobiphenyls (8–43 ng g
−1 ), in soil samples
from the forested zone suggest that contamination at most of these sites occurred
predominantly through atmosphere transport from zones where these compounds
were used and subsequently through atmosphere deposition. Contrarily, soil samples collected in the vicinity of a waste disposal site near Iassy contained higher mean
levels of polychlorobiphenyls (278 ng g
−1 , range 34–1132 ng g
−1 ) than organochlorine
(6 and 101 ng g
−1 of soil for HCHs and DDTs, respectively). The sediment samples