RESULTS OF INVESTIGATIONS
a. Environmental
The geophysical investigations and the chemical analyses of soil and water samples, with determination of concentration of different parameters, confirm the previous indications of extensive infiltration of acid and basic effluents, extending in some cases down to the groundwater. Figure 1 shows the results of typical contamination concentrations evidence in plan and profile, at the old anodization site. In general, large variations of contamination were observed both in plan and with
depth. These variations can be due to:
- the contamination can be originated from a point source (localized teak) or in greater extension (pipes, ditches, tanks);
- leakage rates can vary with time, function of process alterations, repairs, etc.
-detected and corrected leaks lead to a reduction in contamination levels in open areas; in fact, in some parts of the anodization and extrusion areas, more superficial layers show less contamination than deeper ones, suggesting a natural cleaning process;
- the contamination flow occurs essentially vertically in the direction of the groundwater table; a simplified estimate of rate of infiltration gives a value of the order of up to 7,0 m/year;
- alternation of acid and basic infiltrations in the same area, with possible neutralizations.