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Abstract

Sediments are of primary importance because they are the memory of a catchment basin. The two areas investigated for evaluating spatial-temporal distribution of concentrations of four micropollutants are Pallanza Bay (8.4 km{2}) and the south of the Lake Maggiore (4.2 km{2}). The first area has suffered, and still does, from industrial contamination of Cu, Cr and Hg; the second area investigated represents the terminal peace of the south end Lake, the sediments describe the results of the total catchment basins. The work represents 21 sediment cores 16 cm deep, and divided into 4 centimetre sections. The age of samples has been investigated by analysing 137 Cs, and the period of time shown is approximately 30 years, while the concentration of Ba, Sb, Se and Co has been determined by neutron activation analyses.
The barium element represents a constant distribution of concentration in the two areas. The mean values range from 556 to 630 mg/kg (Pallanza Bay), and from 460 to 642 mg/kg (south area).
A similar situation is represented for Co, its mean values range from 19.9 to 25.6 mg/kg (Bay), from 15.4 to 19.5 mg/kg (south Lake). The spatial-temporal distribution of the concentration of Sb is different to Ba and Co, because it shows a major heterogeneity. The values range from 0.3 to 1.8 mg/kg (Pallanza Bay), from 0.5 to 6.5 mg/kg (south area). The last element, Se, represents a similar decrease of concentration in the two areas. The means values range from 1.7 to 10.1 mg/kg (Pallanza Bay), and from 0.7 to 11.1 mg/kg (south Lake).
The concentrations of Ba, Co and Sb (only Bay) are similar to the concentration of European lake sediments, and they are similar to the geochemical values of the investigated area.
The concentration obtained of Se and Sb (only south Lake area), show two different sources: a geochemical contribution and a non-identified anthropogenic source. Because every sample has showed the first 8 centrimetres of sediment in this part the concent ent

Additional information

Authors: CENCI R M, JRC Ispra (IT);MANTAU H, JRC Ispra (IT)
Bibliographic Reference: Paper presented: Società Italiana di Ecologia VII Congresso Nazionale, Napoli (IT), 11-14 September, 1996
Availability: Available from (1) as Paper IT 39846 ORA
Record Number: 199610739 / Last updated on: 1996-09-30
Category: PUBLICATION
Original language: it
Available languages: it