68
R. Ferrara
4.5
Mercury in the River Water and Thermal Springs
During mining activity in the years 1960-1970, the mercury concentration in the
wastewaters discharged into the rivers was estimated to be approximately 180 ngll
(Bacci et al. 1978). Some data are available from 1967 (Dall' Aglio 1967) on
mercury levels in freshwater, but one should keep in mind that reliable
techniques for mercury determination in water have been available only in the
past 10 years. Since 1980 mercury levels in the courses of the Albegna, Fiora and
Paglia rivers, from the source to the estuary have been determined (Ferrara et al.
1983). At the sources of the rivers the mercury concentration are quite low
(~1O ngll) and comparable to those obtained for other water courses of the
Italian peninsula. At the estuaries, the waters instead are rich in particulate
matter in suspension and can reach concentrations of the order of 10-250 ng/l.
The contribution of mercury from thermal springs localized at Bagno Vignoni
and Bagno San Filippo to the environmental contamination proved to be
negligible (Barghigiani et al. 1989).
4.6
Mercury in the Sediments
The concentration of mercury in surface sediment from the upper course of the
Paglia river (the most polluted) displayed a value of 10 pg/g (Ferrara et al. 1991).
The mercury content in the Fiora and Albegna sediment, taken upstream from
the mixing zone with the Tyrrhenian Sea, ranges from 5 to 7 ~lg/g. Similar
concentrations were measured by Baldi and Bargagli (1982) in the sediments of
the coastal areas near the mouths of the two rivers.
4.7
Mercury in the Biota
Foliose lichens belonging to the genus Parmelia have been used as biomonitors
of air mercury concentration in the Amiata district (Bargagli 1990). Results show
that mercury distribution in lichen corresponds closely to that in surface soil,
indicating that the ore deposits and mining and smelting of mercury constitute
the major source of pollution.
The lowest concentration in Parmelia sulcata (0.31 pg/g d.w.) is two times
higher than that usually found in samples collected in background areas.
Maximum mercury content (7.80 ~lg/g) was found in the zone most affected by
air vented from mine shafts. Of particular interest are the data available on
mushrooms that show high concentration with a methylmercury percentage that
can be as high as 15% (Bargagli and Baldi 1984). Mercury levels in agricultural
products and their relations with soils and air concentrations are reported by
Barghigiani and Ristori (1994).
R. Ferrara
4.5
Mercury in the River Water and Thermal Springs
During mining activity in the years 1960-1970, the mercury concentration in the
wastewaters discharged into the rivers was estimated to be approximately 180 ngll
(Bacci et al. 1978). Some data are available from 1967 (Dall' Aglio 1967) on
mercury levels in freshwater, but one should keep in mind that reliable
techniques for mercury determination in water have been available only in the
past 10 years. Since 1980 mercury levels in the courses of the Albegna, Fiora and
Paglia rivers, from the source to the estuary have been determined (Ferrara et al.
1983). At the sources of the rivers the mercury concentration are quite low
(~1O ngll) and comparable to those obtained for other water courses of the
Italian peninsula. At the estuaries, the waters instead are rich in particulate
matter in suspension and can reach concentrations of the order of 10-250 ng/l.
The contribution of mercury from thermal springs localized at Bagno Vignoni
and Bagno San Filippo to the environmental contamination proved to be
negligible (Barghigiani et al. 1989).
4.6
Mercury in the Sediments
The concentration of mercury in surface sediment from the upper course of the
Paglia river (the most polluted) displayed a value of 10 pg/g (Ferrara et al. 1991).
The mercury content in the Fiora and Albegna sediment, taken upstream from
the mixing zone with the Tyrrhenian Sea, ranges from 5 to 7 ~lg/g. Similar
concentrations were measured by Baldi and Bargagli (1982) in the sediments of
the coastal areas near the mouths of the two rivers.
4.7
Mercury in the Biota
Foliose lichens belonging to the genus Parmelia have been used as biomonitors
of air mercury concentration in the Amiata district (Bargagli 1990). Results show
that mercury distribution in lichen corresponds closely to that in surface soil,
indicating that the ore deposits and mining and smelting of mercury constitute
the major source of pollution.
The lowest concentration in Parmelia sulcata (0.31 pg/g d.w.) is two times
higher than that usually found in samples collected in background areas.
Maximum mercury content (7.80 ~lg/g) was found in the zone most affected by
air vented from mine shafts. Of particular interest are the data available on
mushrooms that show high concentration with a methylmercury percentage that
can be as high as 15% (Bargagli and Baldi 1984). Mercury levels in agricultural
products and their relations with soils and air concentrations are reported by
Barghigiani and Ristori (1994).