The evolution of copper concentrations in Lake Orta, ItalyFunded under: JRC-ENVPROT 5C
Experimental results from a triennial sampling campaign in Lake Orta were analysed to define the state of lake pollution with respect to total Cu concentration, as determined by the residual Cu load before water acidity neutralisation (liming) experiments. The model's framework consists of a system of two linear differential equations with constant coefficients, complemented by a computer program to solve the equations numerically in the case when the time dependence of the coefficients must be taken into account. It is applied to both the lake-sediment and to the epilimnion-hypolimnion system. On the basis of an assessed Cu mean residence time in the lake of approximately 5 years, the total Cu concentration in equilibrium with the residual Cu load is around 33 mg Cu/m3 (pre-liming Cu concentration, approximately 38 mg/m3). The effect of possible internal Cu loading is shown to be negligible, while the annual evolution of the metal distribution coefficient, suspended matter concentration and mixing coefficient is shown to make the epilimnetic Cu concentration oscillate between a summer and a winter value. Finally, the short-term effect of epilimnetic water acidity neutralisation is briefly discussed.
Bibliographic Reference: Article: Ecological Modelling (1992) No. 64, pp. 23-45
Record Number: 199211563 / Last updated on: 1994-11-29
Original language: en
Available languages: en