## 3 Results and Discussion
\begin{table}
\begin{tabular}{l l l} \hline
**Comparison** & **Difference** & \(p\) **Value** \\ \hline control 0 \(\times\) control 7 & 0.167 & ns \(p>0.05\) \\ control 0 \(\times\) control 14 & 0.733 & ns \(p>0.05\) \\ control 0 \(\times\) control 21 & 1.233 & ns \(p>0.05\) \\ control 0 \(\times\) control 28 & 1.467 & ns \(p>0.05\) \\ control 0 \(\times\) eluate 0 & 2.400 & * \(p<0.05\) \\ control 0 \(\times\) eluate 7 & 1.000 & ns \(p>0.05\) \\ control 0 \(\times\) eluate 14 & 1.567 & ns \(p>0.05\) \\ control 0 \(\times\) eluate 21 & 1.900 & ns \(p>0.05\) \\ control 0 \(\times\) eluate 28 & 2.167 & * \(p<0.05\) \\ control 0 \(\times\) suspense 0 & 0.667 & ns \(p>0.05\) \\ control 0 \(\times\) suspense 7 & 0.867 & ns \(p>0.05\) \\ control 0 \(\times\) Suspense 14 & 1.367 & ns \(p>0.05\) \\ control 0 \(\times\) suspense 21 & 1.467 & ns \(p>0.05\) \\ control 0 \(\times\) suspense 28 & 1.533 & ns \(p>0.05\) \\ control 7 \(\times\) control 14 & 0.567 & ns \(p>0.05\) \\ control 7 \(\times\) control 21 & 1.067 & ns \(p>0.05\) \\ control 7 \(\times\) control 28 & 1.300 & ns \(p>0.05\) \\ control 7 \(\times\) eluate 0 & 2.233 & * \(p<0.05\) \\ \hline \end{tabular} Notes: 0 = time 0, 7 = 7 days of exposure, 14 = 14 days of exposure, 21 = 21 days of exposure, 28 = 28 days of exposure. Control = control samples without pollutants, eluate = the eluate of waste tire particles in distilled water, suspension = a mix of waste tire particles with distilled water. \(p\) value = rate of significance, ns = not significant, * = significant.  
\end{table} 
Table 2: Results of the statistical analysis. One-way analysis of variance (ANOVA) with the GraphPad InStat software was used (InStat version 3, San Diego, CA, USA). The multiple-comparison Tukey–Kramer test was performed at a 0.05 significance level. Figure 4: Rate of toxicity (%) during 7, 14, 21 and 28 days of exposure (the data were calculated according to Formula (3)). The other question is the usability of own tire particles or elements involving them as a source of nutrients for microorganisms. Generally, in order for microorganisms to live, they require mainly basic nutrients such as carbon, oxygen, sulfur, phosphorus, nitrogen and many microelements. The tire samples tested in the present study contained all of the basic elements. The particles contained about 50% carbon, followed by sulfur (10%), oxygen (26%), zinc (3%), and silicon (2%) [51]. Special attention should be focused on zinc, which is one of the essential elements. Adversely, it is used today in nanoform as an antimicrobial agent in many applications [17; 56]. A question worth considering is how much zinc influences the microbial biomass fluctuation during the time period. For this reason, we can assume that its toxicity could be caused mainly by the presence of a relatively high concentration of zinc. No similar studies have been reported yet and for this reason we cannot compare our data to other literature sources. Some studies only describe the ability of individual bacterial strains to resist PAH toxicity or the ability to gradually biodegradation individual PAHs [17; 56; 57]. The conclusions of these studies are different, but they are very difficult to put into practice, because in nature there are different microbial communities, not individual species or strains of bacteria. The species diversity of such communities varies over time and within a single locality due to changes in climatic conditions [17; 56; 57]. The main unique aspect of this study consists of the methodology of the tests. The particles from the tires were analyzed using two types of tests that were not applied simultaneously in the same study to date. The comparison of their results in terms of convenience, applicability and relevance of the obtained data thus led to quite new findings. A partial unique aspect of the present study is the research and confirmation effect of the design of the experiment on the observed results.