**3.2 Statistical analysis**

In **Table 5**, the ANOVA analysis of variance is shown, all the results are within the normal distribution (*p* < 0.05).

For Cu (*p* = 0.5136, *p* > 0.05) it shows that there are no statistically significant differences by site, however, for the climatic season, the statistical results show that there is a highly significant difference (*p* = 0.000, *p* < 0.05). The climatic season has a great influence on Cu abundance, as shown by a recent study [11, 27]. The maximum levels


*Quantification of Heavy Metal Levels in Sediments of the "Palizada" River in a Protected… DOI: http://dx.doi.org/10.5772/intechopen.104657*

#### **Table 5.**

*Results of analysis of variance (ANOVA) for Cu, Cd, Fe, Mg, and Mn.*

of Cu were recorded during the rainy season, which can be related to the very particular circulation mechanisms of the coastal zone at this time [2]. In previous studies [19, 28] similar levels of Cu were reported. Cu is associated with fine particles and OM [29] its high levels come from wastewater discharges and the hydrocarbon industry [30, 31]. In this study, no significant relationships between Cu, texture, and OM are shown (**Table 6**).

For Cd (**Table 5**) there is no significant difference for the site (*p* = 0.0531, *p* > 0.05). But there is a statistically significant difference in the climatic season (*p* = 0.000, *p* < 0.05), the greatest influence on the presence and distribution of heavy metals is due to the climatic season. **Table 7** shows the correlation results; none of the values show a significant relationship.

For Fe, only the climatic season influences the variation of the data (**Table 5**); **Table 8** shows the correlation analyses; there is no evidence of relationships between heavy metals and sediment texture. There is a significant relationship between organic matter and Fe, which can be found forming oxides.


#### **Table 6.**

*Correlation values of texture and organic OM with Cu.*


#### **Table 7.**

*Correlation values of texture and OM with Cd.*


#### **Table 8.**

*Correlation values of texture and OM with Fe.*


#### **Table 9.**

*Values of the correlations of texture and organic matter with Mg.*


**Table 10.**

*Correlation values of texture and OM with Mn.*

Mg is a natural element of the sediments and forms part of the hardness of the waters, it is abundant in calcareous sediments and is a source of available minerals. The statistical results are shown in **Table 5** and confirm that only the climatic season influences the presence and availability.

The results of the relationships between sediment texture and OM with Mg are presented in **Table 9**. (No significant relationships are shown).

For Mn, the results show that only the climatic season influences the presence and distribution of the metal (**Table 5**), The relationships between sediment texture and organic matter are shown in **Table 10** (No significant relationships shown).

*Quantification of Heavy Metal Levels in Sediments of the "Palizada" River in a Protected… DOI: http://dx.doi.org/10.5772/intechopen.104657*


#### **Table 11.**

*Values of metal-metal correlations.*

A correlation analysis (**Table 11**) between metal-metal was performed to determine the degree of relationship and if they have sources of generation in common.
