Organometallic compounds in saline sediments 205
Various factors influence the concentration of organotin compounds found in
bottom sediments. These include such as sediment particle size, surface properties,
percentage clay, organic matter content and pH, salinity and temperature of the water
column. Various gas chromatographic techniques have been employed embodying
flame photometric detection (LD0 05–10 ng Sn g
−1 ) pulsed flame photometric (LD
0.07–038 pg Sn g
−1 ), atomic emission spectrometry (LD 0.2–10 pg Sn g
−1 ) mass spectrometry (LD1 pg Sn g
−1 ), flame ionisation detection (LD pg Sn g
−1 ) and electron
capture detection (LD pgSn g
−1 ). Liquid chromatography has also been employed
to identify and determine organotin compounds in sediments with detection limits in
the pgSn g
−1 region, see Table 9.1.
Al Sheikh et al [37] studied the seasonal behaviour of organotin compounds in
protected subtropical ecosystems in Okinawa, Japan. Studies were conducted from
February to October 2006. Butyltin compounds were frequently detected in all seasons, while phenyltin compounds were found in winter and early spring. In Manko
estuary, the total mean concentrations of butyltin and phenyltin compounds were
22.78 ± 30.85, (mean ± SD, n = 53) and 0.08 ± 0.27 ng (Sn) L
−1 , respectively. In
Okukubi estuary, BTCs and PhTs were 12.58 ± 23.96 and 0.47 ± 1.67 (n = 55) ng
(Sn) L
−1 , respectively. The Manko sediments can be classified as lightly contaminated,
while the Okukubi sediments were uncontaminated with tributyltin. The mean levels
of tributyltin shown in Manko estuary exceeded the threshold level and represent an
ecotoxicological risk to sensitive aquatic life. Generally, this study reports the occurrence and continuous input of organotin compounds in the protected estuaries, even
16 years after legal restriction of tributyltin usage in coastal waters was implemented
by the Japanese Environmental Authorities.
Seasonal variations of organotin compounds are depicted in Figure 9.1.
Bustamante et al [38] monitored levels of polycyclic aromatic hydrocarbons,
polychlorinated biphenyls, methylmercury (MeHg
+ ) and butyltins (mono-, di- and
tri-butyltin) sediments collected in different sampling points of the UNESCO reserve
of the biosphere of Urdaibai (Bay of Biscay) from March 2006 to June 2007. Sediment
concentrations ranged as follows: total polyaromatic compounds (856–3495 µg kg
−1 )
and total polychlorobiphenyls (58–220 µg kg
−1 ). Organometallic species were always
below the limits of detection (0.24 µg kg
−1 for MeHg
+ , 0.6 µg kg
−1 for MBT, 0.
48 µg kg
−1 for DBT and 1.1 ng kg
−1 for TBT). In both sediment and oyster PAH sources
were mostly combustion. In the case of polychlorobiphenyls, 4–6 chlorine-atom congeners were the most abundant ones. Slight differences in the profile of polyaromatic
compounds as well as polychlorobiphenyls can be detected when the matrices were
compared with each other. Finally, the case of polyaromatic compounds, sediment and
water column played the main role in the accumulation pathway into the organism in
all the sampling stations.
Gas chromatography
Gilmour et al [11] have developed an extremely sensitive purge and trap method for
the determination of methyltin compounds as methylstannanes in marine sediments.
Hydride derivatives were prepared with sodium borohydrides in a closed, flow through
system consisting of a purge vessel, chromatograph and mass spectrometer. Borate
buffer added to samples generated hydrogen from sodium borohydride, resulting in
Various factors influence the concentration of organotin compounds found in
bottom sediments. These include such as sediment particle size, surface properties,
percentage clay, organic matter content and pH, salinity and temperature of the water
column. Various gas chromatographic techniques have been employed embodying
flame photometric detection (LD0 05–10 ng Sn g
−1 ) pulsed flame photometric (LD
0.07–038 pg Sn g
−1 ), atomic emission spectrometry (LD 0.2–10 pg Sn g
−1 ) mass spectrometry (LD1 pg Sn g
−1 ), flame ionisation detection (LD pg Sn g
−1 ) and electron
capture detection (LD pgSn g
−1 ). Liquid chromatography has also been employed
to identify and determine organotin compounds in sediments with detection limits in
the pgSn g
−1 region, see Table 9.1.
Al Sheikh et al [37] studied the seasonal behaviour of organotin compounds in
protected subtropical ecosystems in Okinawa, Japan. Studies were conducted from
February to October 2006. Butyltin compounds were frequently detected in all seasons, while phenyltin compounds were found in winter and early spring. In Manko
estuary, the total mean concentrations of butyltin and phenyltin compounds were
22.78 ± 30.85, (mean ± SD, n = 53) and 0.08 ± 0.27 ng (Sn) L
−1 , respectively. In
Okukubi estuary, BTCs and PhTs were 12.58 ± 23.96 and 0.47 ± 1.67 (n = 55) ng
(Sn) L
−1 , respectively. The Manko sediments can be classified as lightly contaminated,
while the Okukubi sediments were uncontaminated with tributyltin. The mean levels
of tributyltin shown in Manko estuary exceeded the threshold level and represent an
ecotoxicological risk to sensitive aquatic life. Generally, this study reports the occurrence and continuous input of organotin compounds in the protected estuaries, even
16 years after legal restriction of tributyltin usage in coastal waters was implemented
by the Japanese Environmental Authorities.
Seasonal variations of organotin compounds are depicted in Figure 9.1.
Bustamante et al [38] monitored levels of polycyclic aromatic hydrocarbons,
polychlorinated biphenyls, methylmercury (MeHg
+ ) and butyltins (mono-, di- and
tri-butyltin) sediments collected in different sampling points of the UNESCO reserve
of the biosphere of Urdaibai (Bay of Biscay) from March 2006 to June 2007. Sediment
concentrations ranged as follows: total polyaromatic compounds (856–3495 µg kg
−1 )
and total polychlorobiphenyls (58–220 µg kg
−1 ). Organometallic species were always
below the limits of detection (0.24 µg kg
−1 for MeHg
+ , 0.6 µg kg
−1 for MBT, 0.
48 µg kg
−1 for DBT and 1.1 ng kg
−1 for TBT). In both sediment and oyster PAH sources
were mostly combustion. In the case of polychlorobiphenyls, 4–6 chlorine-atom congeners were the most abundant ones. Slight differences in the profile of polyaromatic
compounds as well as polychlorobiphenyls can be detected when the matrices were
compared with each other. Finally, the case of polyaromatic compounds, sediment and
water column played the main role in the accumulation pathway into the organism in
all the sampling stations.
Gas chromatography
Gilmour et al [11] have developed an extremely sensitive purge and trap method for
the determination of methyltin compounds as methylstannanes in marine sediments.
Hydride derivatives were prepared with sodium borohydrides in a closed, flow through
system consisting of a purge vessel, chromatograph and mass spectrometer. Borate
buffer added to samples generated hydrogen from sodium borohydride, resulting in