## 3 Results
### Environmental Behavior of Sediments, Vase and a Composite Sample
#### 3.4.2 Weathering Cells Results  
The results of the geochemical behavior of the studied samples are presented in Figures 6 and 7. The pH of the leachates from the sediment was circumventral and varied between 7 and 8.3 (Figure 6A). These circumventral pH values can be attributed to the low amounts of acid-producing minerals, such as pyrite and chalcopyrite, compared to the acid-consuming minerals contents, such as of carbonates. The electrical conductivities of the leachates from the sediment are relatively low, but tend to decrease slowly (3690 \(\upmu\)S/cm at the beginning of the tests and 90.6 \(\upmu\)S/cm at 70 days (Figure 6B)). The high values of electrical conductivity analyzed at the beginning of the process of weathering the cells can be attributed to the pre-oxidized and exchangeable elements.  
The pH of the vase leachate has gradually decreased; it initially remained close to the pH of the deionized water, then gradually decreased until a minimum of 3.48 was reached (Figure 6A). This decrease in pH suggests a release of metals and/or sulfide oxidation reactions. Similarly, the electrical conductivity fluctuated significantly; it started at 6500 \(\upmu\)S/cm at 3 days, then reached 703 \(\upmu\)S/cm after 30 days, then rose to 4040 \(\upmu\)S/cm at 55 days when the pH decreased to attain acidic values (pH = 4) (Figure 6B). These electrical conductivity fluctuations are linked to pH variations; when the pH decreases, it causes a greater release of ions, thus increasing the conductivity of the leachate. Concerning the composite sample, the pH was around 6.5 for about 30 days and then decreased to attain acidic values ranging between 3.89 and 4.5 (Figure 6A). The electrical conductivity showed a similar trend in the sediment and vase samples (Figure 6B). The Eh values for the three studied samples ranged between 350 and 600 mV (Figure 6C).  
The visible peaks in acidity (Figure 6D) can be related to variations in pH; the pH of the composite decreased at 30 days to reach a minimum of 3.89 at 42 days, and the acidity measured reached its maximum of 1697 mgCaCO\({}_{3}\)/eq at the same time. In the same way, for the vase, the pH gradually decreased to reach a minimum at 62 days, while its acidity reached its highest value. These fluctuations are also supported by the concentrations of Fe, Mg and Al obtained in the leachate (Figure 7).  
The chemical quality of the leachates from the three studied samples is presented in Figures 7 and 8. The concentrations are presented as cumulated mass normalized. Ca and Mg were chosen to represent acid-consuming minerals dissolution (carbonate dissolution), Fe and S indicate acid-producing minerals oxidation (sulfide oxidation), Al indicates aluminosilicate minerals dissolution and Zn and Cu were chosen as examples of metal-contamination. The composite sample was the most reactive one compared to the vase and sediments. Almost all the analyzed elements were released at greater quantities by the composite sample, except for Zn. The Ca normalized mass was about 1295, 2740 and 3808 mg/kg for the sediment, vase and composite samples, respectively. The Mg release rates were higher than 1200 mg/kg for the composite sample and lower than 400 mg/kg for the other samples. Zn was released at negligible concentrations by the sediments, while it was released at concentrations higher than 4000 mg/kg by the vase and composite samples. Similarly, the Fe release was about 14.5, 63.7 and 190.3 mg/kg for sediment, vase and composite samples, respectively. Additionally, Al, S and Cu were released at high concentrations by the composite sample. The rates of Al, S and Cu release by composite samples were around 68, 11,000 and 721 mg/kg, respectively.