Tin - Toxicology of Metals - page 824

concentration ranged up to 2.5 µ g/L in seawater in 1994 (Sudaryanto et al ., 2004). Contamination of 14.7 g/L

has been recorded in harbor water in Bahrain (Hasan
and Juma, 1992). Triphenyltin levels in ambient water
and sediments in the Tokyo Bay area were estimated at
1.8 ng/L and 0.19 ng/g in 1993, respectively. The concen-
trations of butyl- or phenyltins in water depend on both
fresh input and degradation and absorption kinetics.
However, their fresh input is predominant to overwhelm
elimination by degradation and absorption. Concentra-
tions of up to 0.2

µ

and 0.3 g/L in seawater and 17.5 mg/g in sediments

in 1998 (Ritsema et al ., 1998). Considerable variability
in butyltin concentrations has been detected on the
French coast. Maximum concentrations exceed 100 ng/L
(Michel and Averty, 1999). The levels of tributyltin in the
harbor of Osaka City, Japan, is in the range of 2-33 ng/L
in water and 0.002-0.966 mg/kg dry wt in sediments,
whereas in costal areas of Otsuchi Bay, the level is in the
range 8-74 ng/L and 0.01-0.64 mg/kg in seawater and
sediments, respectively (Harino et al ., 1998). It was sug-
gested that high concentrations of organotins in water
could be a result of their release from sediments. The
sediments in the marinas act as a long-term source of
dissolved-phase contamination, because the water
phase is in equilibrium with the sediments (Ritsema
et al ., 1998). The retention of butyltins in seawater is highly
variable, depending on temperature, pH, and light. The
calculated half-lives range from 6 days in summer time
for turbid water to 127 days in winter for nonturbid
water (Alzieu, 2000). The retention of the total miner-
alization of tributyltins is in the range of 50-75 days
(Rudel, 2003). Degradation in anaerobic sediments can
range from 2 years up to decades. Half-lives of 10.2 and
5.1 days are calculated for tributyltin and dibutyltin,
respectively, in an activated sludge system (Stasinakis
et al ., 2005), whereas the half-life of tributyltin added to
estuarine samples ranged from 3 to 13 days (Lee et al .,
1989). Organotins are hydrophobic substances and,
hence, only slightly soluble in water. Therefore, orga-
notins may remain in marine sediments for many years
because of their relative stability under the anoxic condi-
tions in sediments (Fent, 1996a). It has been shown that
the retention time for tributyltin is approximately 2.1
years and those for dibutyl- and monobutyltin are 1.9
and 1.1 years, respectively, in sediments (Sarradin et al .,
1995). In salt water, the toxicity of organotins is less than
in freshwater because of reduced interactions between
organotins and microorganisms (White et al ., 1999).
The existing sediment certifi ed reference material
(CRM) is estimated as 1.27 mg/kg for controlling the
quality of highly polluted sediments; however, it can-
not be used for the quality control of analysis of coastal
sediment with low butyltin content (USEPA, 1997). The
average contamination of butyltins in harbor sediments
of the U.S. costal area is approximately 54

µ

g/L of triphenyltin were detected in
boat harbors, and a concentration of 1.5

µ

g/L was deter-
mined in areas where triphenyltin fungicides had been
sprayed (Fent and Hunn, 1991). Triphenyltin concentra-
tions in foliage and soils were determined as 8.5-37

µ

µ g/g

dry weight and 1.2-12 g/g dry weight, respectively

(Kannan and Lee et al ., 1996b). The largest contamination
of organotin compounds in fresh water river systems has
been documented in South Carolina in 2000 and was
>10 mg/kg in surface-water bed sediments.In bed sedi-
ments of a beaver pond located approximately 1.6 km
downstream of the release, the organotin concentra-
tions reached 40 mg/kg (Landmeyer et al ., 2004).
The concentration of organotins detected in raw
municipal wastewater ranged between a few nano-
grams and a few micrograms per liter (Chau et al .,
1992). Organotins accumulate on the suspended solids
reaching concentrations up to 1.5 mg/kg in digested
sludge (Fent, 1996b). Various organotin compounds are
detected in surface and pore waters. For example, in
Ganga Plain in Kanpur-Unnao industrial region, their
concentrations in surface water range from 2.1-70.1 ng
Sn/L for monobutyltin, 1.7-101.1 for dibutyltin, and
2.9-19.8 for tributyltin (Ansari et al ., 1998).

µ

4.2 Working Environment
The limit value (time-weighed average) for tin in
air was set 0.1 mg/m 3 in 1979 specifi ed as a maximum
worksite concentration. The Occupational Safety and
Health Administration (OSHA) and the National Insti-
tute for Occupational Safety and Health (NIOSH) have
established a workplace exposure limit for organic
tin compounds, which is 0.1 mg/m 3 as Sn, regarding
tin and inorganic tin compounds, it is 2 mg/m 3 as Sn
except tin oxide.

g/kg dry
wt., whereas levels 10 times lower are recorded in sedi-
ments collected 25 km from Vancouver harbor (Canada)
(Stewart and Thompson, 1994). The concentrations of
organotin compounds are high in costal areas of the
Asian countries, where no regulations on the use of tris-
ubstituted organotin compounds have been adopted.
Butyltin contamination is widely distributed along the
costal water of Malaysia, with concentration in the range
of 2.8-1100 ng/g dry weight for tributyltin in sediments

µ

5 METABOLISM

5.1 Inorganic Tin

5.1.1 Absorption

5.1.1.1 Inhalation
Various case reports on effects of occupational
exposure to tin dust have been published. Long-term