# The Influence of Spent Portable Battery Waste on the Aquatic Environment
## 3 Results
### Concentration of Heavy Metals  
In the case of manganese and cadmium ions, their concentrations were below the detection limit of the spectrometer. The exception was in the case of manganese in type A batteries immersed in the solution with pH 5.63 (Mn: 0.31 mg/L) and at pH 8.00 (Mn: 0.69 mg/L). Therefore, in the case of the solution with pH 5.63 in which the A batteries were immersed, there was an exceeding of the maximum allowed value for the quality class III of surface water (0.3 mg/L) (Order no. 161/2006) [43]. An exceedance was observed for this class and for the solution with pH 8.00 in which batteries A were introduced. The copper ion concentration values obtained for the three solutions revealed that only for the C batteries, immersed in a solution with pH 8.00, a slight exceeding of the maximum concentration allowed for quality class I (20.00 \(\upmu\)g L\({}^{-1}\)) (Order no. 161/2006) [43] was observed being far below the maximum allowed limit for the other quality classes (Figure 4). Analyzing the concentration of copper depending on the type of battery and the pH of the solution, it can be observed that the higher the pH of the solution, the lower the concentration of copper, so that at pH = 8.00, the concentration of copper was 6.33 \(\upmu\)g L\({}^{-1}\), and in the case of battery C, the concentration of Cu decreased with increasing pH. As seen in Figure 5, battery A recorded high Pb concentrations regardless of the pH value of the solution. The highest concentration was observed in the case of sample A2 (4.09 \(\upmu\)g L\({}^{-1}\)). The concentration of Pb in the solutions in which the type C batteries were immersed decreased with the increase in pH. For batteries A and B, it was not possible to establish whether the pH influences the amount of Pb that was transferred into the solution because there were variations depending on the pH of the immersion solution. Figure 4: Copper ions concentration in different pH solutions. The results of laboratory tests indicated a high concentration of zinc in the case of type C batteries, highlighting a double concentration in the case of solutions with pH = 5.63 compared to solutions with pH = 8 (Figure 6). However, even the highest concentration of 12.05 \(\upmu\)g L\({}^{-1}\) (sample C2) was significantly lower than the maximum limit provided for class I surface water quality (Order no. 161/2006) [43]. At pH = 4.00, the concentration of zinc in the solution was insignificant (Figure 6), regardless of the type of battery used in the experiment, but it increased with the pH value, highlighting that battery C has the highest concentrations at pH = 5.63 and pH = 8.00, respectively. A higher concentration is also noticeable in the case of battery A at pH = 8.00 (sample A3 = 2.48 \(\upmu\)g L\({}^{-1}\)) compared to the values obtained at low pH (4.00 and 5.63, respectively). It can be concluded that a higher pH value influences the Zn concentration transferred into the immersion solution. In the case of nickel ions for the three types of solutions, there were exceedances of the maximum allowed value for the first quality class of surface water (10.00 \(\upmu\)g L\({}^{-1}\)) (Order no. 161/2006) [43]. Thus, slight exceedances were recorded for the solution with pH 8.00 in which batteries A were immersed and the solution with pH 5.63 containing batteries C. There was a higher exceedance in the case of the solution with pH 5.63 in which batteries B were immersed (Figure 7). Figure 5: Lead ion concentration in different pH solutions. Figure 6: Zinc ions concentration in different pH solutions. The highest concentrations of nickel (B2: 22.93 \(\upmu\)g L\({}^{-1}\) and C2: 12.83 \(\upmu\)g L\({}^{-1}\)) were recorded in the solution with pH = 5.63 (batteries B and C), the exception being battery A (Figure 7), which has higher concentrations elevated at pH = 8.00 (A3: 10.73 \(\upmu\)g L\({}^{-1}\)). Following these results, it can be concluded that at pH = 5.63, the transfer of nickel from the battery to the solution takes place.